Cardiorespiratory fitness and cardiovascular disease - The past, present, and future

The Value of Cardiopulmonary Exercise Testing in Predicting the Severity of Coronary Artery Disease

Background: There have been a limited number of quantitative studies on the relationship between coronary artery disease (CAD) and cardiorespiratory fitness (CRF), as measured by cardiopulmonary exercise testing (CPET). Thus, we aimed to investigate the association between CRF and the severity of coronary artery disease from the most comprehensive perspective possible, and to affirm the predictive value of CPET in the severity assessment of CAD. Methods: Our study included 280 patients with coronary angiography, who had undergone CPET in Tongji Hospital. The patients’ CRF was measured through their peak oxygen uptake (VO2@peak), their oxygen uptake at the anaerobic threshold (VO2@AT) and through other parameters of CPET on a bicycle ergometer. The severity of the coronary artery disease was assessed in the following three layers: functionally significant lesions (quantitative flow ratio [QFR] ≤ 0.8), the number of stenotic coronary arteries (SCA, stenosis ≥ 50%) and the Gensini score. The correlation analyses were carried out between the CRF and the severity of the coronary artery disease. A ROC curve was plotted, and the AUC was calculated to distinguish the severe CAD and the non-severe CAD patients, as measured by the QFR, the number of SCA, and the Gensini score. Results: The VO2@AT and VO2@peak were inversely associated with the QFR. The VO2@AT, VO2@peak and VO2/kg@peak were associated with the number of SCA. Meanwhile, the VO2@AT, VO2/kg@AT, VO2@peak and VO2/kg@peak were associated with the Gensini score. An ROC analysis proved that a combination of traditional clinical risk factors and the VO2@peak/VO2prediction is valuable in predicting CAD severity. Conclusions: Our study demonstrated a strong and inverse association between CRF and the severity of CAD. A combination of traditional clinical risk factors and CRF is valuable in predicting CAD severity.

Association between cardiorespiratory fitness and risk of all-cause and cause-specific mortality

OBJECTIVE

The association of cardiorespiratory fitness (CRF) with all-cause and cause-specific mortality remains unclear in Chinese population. This study aimed to evaluate the risk of all-cause, cardiovascular disease (CVD), cancer and other-cause mortality in Chinese adults using estimated CRF (eCRF).

PATIENTS AND METHODS

We analysed data for 15,566 participants aged ≥20 years recruited in The Rural Chinese Cohort Study during 2007 to 2008 and followed for mortality during 2013 to 2014. eCRF was calculated with sex-specific longitudinal non-exercise algorithms. Cox proportional-hazards models were used to calculate hazard ratios (HRs) and 95% confidence intervals (CIs) for all-cause and cause-specific mortality risk according to baseline eCRF.

RESULTS

During a median of 6.01 years of follow-up, 859 deaths occurred, including 359 from CVD, 221 from cancer, and 279 from other causes. Each 1 metabolic equivalent increment in eCRF was associated with decreased risk of all-cause mortality (men: HR 0.70, 95% CI [0.66-0.74]; women: 0.59, [0.54-0.64]); CVD mortality (men: 0.70 [0.64-0.77]; women: 0.55, [0.48-0.62]); and other-cause mortality (men: 0.68 [0.62-0.75]; women: 0.57, [0.49-0.66]). The area under receiver operating characteristic curve was significantly higher for eCRF than its modifiable components (waist circumference, body mass index and resting heart rate) in predicting all-cause and cause-specific mortality incidence (all p < .001).

CONCLUSION

eCRF was inversely associated with all-cause, CVD and other-cause mortality.

Association of Smartphone Use Duration with Physical Fitness among University Students: Focus on Strength and Flexibility

High-frequency smartphone use leads to physical inactivity and may consequently cause the loss of physical fitness. Although the relationship between smartphone usage and physical fitness has been investigated, most of these studies focused on partial physical fitness, and the evaluation of the duration of smartphone use was insufficient. Therefore, this study aimed to investigate the relationship between the time period of using smart phones and physical fitness in Chinese university students. In this cross-sectional study, 8977 college students (5189 men and 3788 women) were enrolled. The assessment of smartphone usage was performed using a self-reported questionnaire. Physical fitness was measured in a sports facility, consisting of grip strength, standing long jump, and sit-and-reach test. The post adjustment relationship between smartphone use duration and physical fitness was examined by using the ANCOVA test. In the final adjusted model, an inverse association was observed between the smartphone use duration and grip strength in male and female participants (p = 0.003 and <0.001, respectively). The smartphone use duration was also negatively associated with standing long jump in both sexes (p = 0.003 for male and = 0.026 for female). In male participants, the longer the period of using smartphones, the lower their flexibility (p = 0.026). In conclusion, this study investigated the association between the duration of smartphone use and physical fitness. The results showed that longer durations of smartphone use were associated with weaker grip strength, a shorter standing long jump, and lower flexibility. Controlling smartphone-use duration might be beneficial for physical fitness among university students.

Efficacy and Safety of a Combined Aerobic, Strength and Flexibility Exercise Training Program in Patients with Implantable Cardiac Devices

Purpose: The “FIDE Project” (Fitness Implantable DEvice) was organized by the Institute of Sports Medicine and Science and the World Society of Arrhythmias with the aim of demonstrating the usefulness of exercise training in improving functional capacity in patients with implantable cardiac devices. Materials and Methods: Thirty sedentary patients were selected for the project (25 males and 5 females), with a mean age of 73 ± 5 years (range 44–94 years). Twenty-five were implanted with a Pacemaker (PM) and five with an Implantable Cardioverter Defibrillator (ICD). Atrial fibrillation/atrial flutter was present in ten (34%) patients, post-ischemic dilated cardiomyopathy in five (17.2%), sick sinus syndrome in six (20,7%), complete atrium-ventricular block in six (20.7%), hypertrophic cardiomyopathy in one (3.4%) and recurrent syncope in one (3.4%). The baseline assessment comprised cardiovascular examination, resting and stress ECG, cardiopulmonary exercise testing (V ̇O2peak), strength assessment of different muscle groups, and a flexibility test. The same measurements were repeated after 15–20 consecutive training sessions, over a 2-month period. The exercise prescription was set to 70–80% of HRR (Heart rate reserve) and to 50–70% of 1RM (1-repetition maximum, muscular force). The training protocol consisted of two training sessions per week performed in our institute, 90 min for each (warm-up, aerobic phase, strength phase and stretching) and one or more at home autonomously. Results: The cardiopulmonary testing after the training period documents a significant improvement in V ̇O2peak (15 ± 4 mL/kg/min vs. 17 ± 4; p = 0.001) and in work load (87 ± 30 watts vs. 108 ± 37; p = 0.001). Additionally, strength capacity significantly increased after the cardiac rehabilitation program, (quadriceps: 21 ± 18 kg vs. 29 ± 16 kg, p = 0.00003). Flexibility tests show a positive trend, but without statistical significance (sit-and-reach test: −19 ± 11 cm vs. −15 ± 11.7 cm; back-scratch test: −19 ± 11.6 cm vs. −15 ± 10 cm; lateral flexibility right −44 ± 1.4 cm vs. −43 ± 9.5 cm; left −43 ± 5 vs. −45 ± 8.7 cm). Conclusion: A brief period of combined aerobic, strength and flexibility exercise training (FIDE project) proved to be effective and safe in improving functional capacity in patients with cardiac implantable devices.

Joint Associations of Obesity and Cardiorespiratory Fitness With Coronary Artery Calcium Composition: IS THERE EVIDENCE FOR FAT-BUT-FIT?

INTRODUCTION

The purpose of this study was to examine the individual and joint associations of obesity and cardiorespiratory fitness (CRF) with indices of coronary artery calcification (CAC) in 2090 middle-aged men.

METHODS

Obesity was defined as a body mass index (BMI) ≥25 kg/m2 and a waist circumference (WC) ≥90 cm. Cardiorespiratory fitness was operationally defined as peak oxygen uptake (V˙o2peak) directly measured using gas analysis. Participants were then divided into unfit and fit categories based on age-specific V˙o2peak percentiles. Agatston scores >100 and volume and density scores >75th percentile were defined as indices of CAC, signifying advanced subclinical atherosclerosis.

RESULTS

Obese men had increased CAC Agatston, volume, and density scores, while higher CRF was associated with lower Agatston and volume scores after adjusting for potential confounders. In the joint analysis, unfit-obese men had higher CAC Agatston and CAC volume. The fit-obesity category was not associated with CAC Agatston (OR = 0.91: 95% CI, 0.66-1.25, for BMI and OR = 1.21: 95% CI, 0.86-1.70, for WC) and CAC volume (OR = 1.14: 95% CI, 0.85-1.53, for BMI and OR = 1.23: 95% CI, 0.90-1.69, for WC), which were similar to estimates for the fit-normal weight category.

CONCLUSIONS

These findings demonstrate that while obesity is positively associated with the prevalence of moderate to severe CAC scores, CRF is inversely associated with the prevalence of moderate to severe CAC scores. Additionally, the combination of being fit and obese was not associated with CAC scores, which could potentially reinforce the fat-but-fit paradigm.

Age-Related Differences for Cardiorespiratory Fitness Improvement in Patients Undergoing Cardiac Rehabilitation

Objective

We investigated age-related differences for peak oxygen uptake (peak VO₂) improvement with exercise training during cardiac rehabilitation (CR).

Patients and Methods

This was a retrospective cohort study of the Mayo Clinic Rochester CR program including adult patients who attended CR (≥1 session) for any eligible indication between 1999 and 2017 and who had a cardiopulmonary exercise test pre and post CR with VO₂ data (peak respiratory exchange ratio ≥1.0). Younger (20–49 yrs), midlife (50–64 yrs), and older adults (≥65 yrs) were compared using ANOVA for delta and percent change in peak VO₂; and percentage of peak VO₂ responders (>0% change).

Results

708 patients (age: 60.8 ± 12.1 years; 24% female) met inclusion criteria. Delta and percent change in peak VO₂ was lower for older adults (1.6 ± 3.2 mL.kg.min⁻¹; 12 ± 27%) compared with younger (3.7 ± 4.0 mL.kg.min⁻¹, p < 0.001; 23 ± 28%, p = 0.002) and midlife adults (2.8 ± 3.8 mL.kg.min⁻¹, p < 0.001; 17 ± 28%, p = 0.04). For midlife, delta change, but not percent change in peak VO₂ was significantly lower (p = 0.02) compared with younger. Percentage of responders was only different between older and younger (72 vs. 86%; p = 0.008). Sensitivity analyses in non-surgical patients showed similar differences for delta change, and differences in percent change remained significant between older and younger adults (10 ± 20% vs. 16 ± 18%; p = 0.04).

Conclusions

In CR patients, older adults had lower improvement in cardiorespiratory fitness than younger and midlife adults. While excluding surgical patients reduced age-related differences, older adults still had lower cardiorespiratory fitness improvement during CR. These findings may have implications for individualizing CR programming in aging populations to reduce future cardiovascular risk.

High-sensitivity C-reactive protein and all-cause mortality in four diverse populations: The CRONICAS Cohort Study

PURPOSE

To assess the association between all-cause mortality and hs-CRP, based mainly on the cumulative burden approach.

METHODS

Cohort study with adults ≥35 years from general population, using hs-CRP at two timepoints: at baseline and 30 months later to establish different exposures: change over time, cumulative, and weighted cumulative hs-CRP. The outcome was all-cause mortality assessed 7 years later. Cox models were generated to quantify the association.

RESULTS

Data from 3,119 participants (mean age 55.6 years, and 51.2% females), were analyzed. During follow-up, 164 (5.6%) deaths occurred over 20,314.5 person-years, indicating an overall mortality rate of 8.1 per 1,000 person-years. In multivariable model, hs-CRP at baseline was associated with high risk of mortality (HR = 1.77; 95%CI: 1.28-2.46). Similarly, hs-CRP change over time (HR = 2.50; 95%CI: 1.46-4.29), as well as cumulative and weighted cumulative hs-CRP (HR = 2.05; 95%CI: 1.31-3.20) were associated with greater risk of all-cause mortality. The weighted cumulative hs-CRP had the best goodness-of-fit for mortality prediction.

CONCLUSIONS

In this cohort across diverse geographical low-resource settings, high levels of hs-CRP were strongly associated with all-cause mortality. Two measurements of hs-CRP are better than one to predict mortality, and the weighted cumulative approach had the best prognostic fit.

Low cardiopulmonary fitness is associated with higher liver fat content and higher gamma-glutamyltransferase concentrations in the general population - "The Sedentary's Liver"

BACKGROUND

We investigated the association between low cardiorespiratory fitness and liver fat content (LFC) in the general population.

MATERIALS AND METHODS

We evaluated data from 2151 adults (51.1% women) from two population-based cohorts of the Study of Health in Pomerania (SHIP-2 and SHIP-TREND-0). We analysed the cross-sectional associations of peak oxygen uptake (VO_2peak ) with LFC, assessed by magnetic resonance imaging proton density fat fraction, as well as serum gamma-glutamyltransferase (GGT) and aminotransferase concentrations by multivariable regression models.

RESULTS

We observed significant inverse associations of VO_2peak with LFC and serum GGT, but not with serum aminotransferase levels. Specifically, a 1 L/min lower VO_2peak was associated with a 1.09% (95% confidence interval [CI]: 0.45-1.73; P = .002) higher LFC and a 0.18 μkatal/L (95% CI: 0.09-0.26; P < .001) higher GGT levels. The adjusted odds ratio (OR) for the risk of prevalent hepatic steatosis (HS) by a 1 L/min decrease in VO_2peak was 1.61 (95% CI: 1.22-2.13; P = .001). Compared to subjects with high VO_2peak , obese and overweight individuals with low VO_2peak had 1.78% (95% CI: 0.32-3.25; P = .017) and 0.94% (95% CI: 0.15-1.74; P = .021) higher mean LFC, respectively. Compared to those with high VO_2peak , low VO_2peak was independently associated with a higher risk of prevalent HS in the obese (adjusted-OR 2.29, 95% CI=1.48-3.56; P < .001) and overweight (adjusted OR 1.57, 95% CI=1.16-2.14; P = .04) groups.

CONCLUSIONS

Lower VO_2peak was significantly associated with greater LFC and higher serum GGT levels in a population-based cohort of adult individuals. Our results suggest that low VO_2peak might be a risk factor for HS.

Updated Reference Standards for Cardiorespiratory Fitness Measured with Cardiopulmonary Exercise Testing: Data from the Fitness Registry and the Importance of Exercise National Database (FRIEND)

OBJECTIVE

To provide updated reference standards for cardiorespiratory fitness (CRF) for the United States derived from cardiopulmonary exercise (CPX) testing when using a treadmill or cycle ergometer.

PATIENTS AND METHODS

Thirty-four laboratories in the United States contributed data to the Fitness Registry and the Importance of Exercise National Database. Analysis included 22,379 tests (16,278 treadmill and 6101 cycle ergometer) conducted between January 1, 1968, through March 31, 2021, from apparently healthy adults (aged 20 to 89 years). Percentiles of peak oxygen consumption for men and women were determined for each decade from 20 through 89 years of age for treadmill and cycle exercise modes, as well as when defining maximal effort as respiratory exchange ratio (RER) greater than or equal to 1.0 or RER greater than or equal to 1.1.

RESULTS

For both men and women, the 50^th percentile scores for each exercise mode decreased with age and were higher in men across all age groups and higher for treadmill compared with cycle CPX. The average rate of decline per decade over a 6-decade period was 13.5%, 4.0 mLO₂·kg^-1·min^-1 for treadmill CPX and 16.4%, 4.3 mLO₂·kg^-1·min^-1 for cycle CPX. Observationally, the mean peak oxygen consumption was similar whether using an RER criterion of greater than or equal to 1.0 or greater than or equal to 1.1 across the different test modes, ages, and for both sexes. The updated reference standards for treadmill CPX were 1.5 - 4.6 mLO₂·kg^-1·min^-1 lower compared with the previous 2015 standards whereas the updated cycling standards were generally comparable to the original 2017 standards.

CONCLUSION

These updated cardiorespiratory fitness reference standards improve the representativeness of the US population compared with the original standards.

The Importance of Physical Activity to Augment Mood during COVID-19 Lockdown

The purpose of this study was to assess the effect of COVID-19 lockdown on mood and objective physical activity. A sample of 78 college students in Spain completed an assessment of mood using the valid Profile of Mood State (POMS) questionnaire and had their physical activity tracked objectively using a validated wrist-worn accelerometer (Xiaomi Mi Band 2) for one week before being under COVID-19 lockdown (T1) and for one week during COVID-19 lockdown (T2). Paired samples t-tests revealed significantly greater (p = 0.027) POMS Total Mood Disturbance (TMD) Score T2 (mean ± SD) (22.6 ± 28.0) compared to T1 (17.7 ± 22.6) (lower score represents better mood) and significantly lower (p ≤ 0.001) POMS Vigor Score T2 (14.1 ± 5.0) compared to T1 (18.2 ± 4.5) (lower vigor score represents lower mental and physical energy levels). Additionally, Total Objective Steps was significantly less (p ≤ 0.001) lT2 (15,841.9 ± 17,253.2 steps) compared to T1 (64,607.0 ± 50,525.2 steps). Regression analyses demonstrated significant negative relationships of Total Objective Steps and POMS Depression (p = 0.014, Beta = −0.277, t = −2.511), POMS Anger (p = 0.040, Beta = −0.233, t = −2.091), and POMS TMD (p = 0.007, Beta = −0.302, t = −2.754) T2. The regressions also revealed a significant positive relationship (p = 0.012, Beta = 0.283, t = 2.57) of Total Objective Steps and POMS Vigor T2. These data suggest that being in a lockdown due to a pandemic may have negative physical and mental health-related consequences and that engaging in physical activity may reduce these deleterious mental health-related consequences during lockdowns and quarantines.

Effect of Weight Self-Stigma and Self-Esteem on Aerobic Exercise Capacity in Adult Women with Different Body Compositions

Background: Overweight individuals face weight-related stigmatization, driving self-exclusion from exercise and physical activity. The extent to which weight self-stigma and self-esteem are associated with aerobic capacity remains unclear. Therefore, this study aimed to characterize the cardiopulmonary fitness, weight self-stigma, and self-esteem of overweight women and examine whether weight self-stigma and self-esteem predict cardiopulmonary aerobic capacity. Methods: A cross-sectional study was conducted with 66 women stratified into two groups: a normal weight (NW) group and an overweight (OW) group. The mean body mass indexes and ages of the NW and OW groups were 20.4 ± 0.36 kg/m² and 29.5 ± 0.8 kg/m², and 24 ± 7 years and 21 ± 3 years, respectively. Submaximal exercise testing using the modified Bruce treadmill protocol was conducted to measure the predicted oxygen uptake (VO_{2 peak}) and energy expenditure. The Weight Self-Stigma Questionnaire and the Rosenberg Self-Esteem Scale were used. Results: Significantly lower mean of predicted VO_{2 peak} and higher mean of energy expenditure were reported in the OW group compared with the NW group (25.8 ± 5.3 mL/kg/min vs. 28.7 ± 4.8 mL/kg/min, p = 0.001 and 9.7 ± 1.9 kcal/min vs. 7.5 ± 1.8 kcal, p = 0.03, respectively). There was a significant difference in weight self-stigma and self-esteem between the groups. Regression model analysis indicated that weight self-stigma and self-esteem explained 45% of the variance in the predicted VO_{2 peak}. Conclusion: Strategies enhancing self-esteem and avoiding stigmatization should be embraced to promote fitness and engagement in physical activity among OW women.

Cardiovascular health behavior and cardiorespiratory fitness in adolescents: a longitudinal study

Cardiorespiratory fitness has been substantially associated with health status. However, longitudinal studies on cardiorespiratory fitness and ideal cardiovascular health behavior (ICHB) in adolescents are scarce. The aim of this study was to evaluate the longitudinal association between ICHB (at baseline) and cardiorespiratory fitness (at follow-up). This is a 2-year prospective analysis of 445 adolescents (232 girls) aged 12-18 years. The ICHB was developed by the American Heart Association as meeting the ideal health behaviors for a healthy diet, physical activity, smoking status, and body mass index. ANCOVAS adjusted by age, sex, pubertal stage, socioeconomic status, and cardiorespiratory fitness showed that the higher the number of ICHB metrics accumulated at baseline (from 1 to 4), the higher the cardiorespiratory fitness levels over a 2-year period (p = 0.038). In logistic regressions, after adjusting for potential confounders, the odds ratios for having high cardiorespiratory fitness at follow-up was 4.9 (95% CI, 1.2-20.1, p = 0.02) for those who accumulated all four metrics of ICHB, when compared to those with 1 or less metrics of ICHB. In addition, the higher the number of ICHB metrics accumulated, the higher the likelihood of having a high cardiorespiratory fitness level over a 2-year period (p for trend = 0.01).

CONCLUSION

 We identified a significant association between ICBH and cardiorespiratory fitness in adolescents. Therefore, improving ICBH in adolescence is likely to benefit the cardiorespiratory fitness.

WHAT IS KNOWN

• Smoking status, body mass index, physical activity, and diet are associated to cardiorespiratory fitness in adulthood. • Lifestyle behaviors such as physical activity, smoking, body weight, and healthy diet are individually linked with cardiorespiratory fitness and, however, have not been examined jointly, as combined health behaviors.

WHAT IS NEW

• Accumulation of cardiovascular health behavior metrics was positively associated with cardiorespiratory fitness at a 2-year follow-up, in adolescents. • Meeting all the four metrics of ideal cardiovascular health behavior seems important for healthy cardiorespiratory fitness during adolescence.

OSA and cardiorespiratory fitness: a review

The effects of untreated obstructive sleep apnea (OSA) on cardiopulmonary function remain unclear. Cardiorespiratory fitness (CRF), commonly reflected by VO₂ max measured during cardiopulmonary exercise testing, has gained popularity in evaluating numerous cardiopulmonary conditions and may provide a novel means of identifying OSA patients with the most clinically significant disease. This emerging testing modality provides simultaneous assessment of respiratory and cardiovascular function with results helping uncover evidence of evolving pathology in either organ system. In this review, we highlight the current state of the literature in regard to OSA and CRF with a specific focus on changes in cardiovascular function that have been previously noted. While OSA does not appear to limit respiratory function during exercise, studies seem to suggest an abnormal cardiovascular exercise response in this population including decreased cardiac output, a blunted heart rate response (ie, chronotropic incompetence), and exaggerated blood pressure response. Surprisingly, despite these observed changes in the cardiovascular response to exercise, results involving VO₂ max in OSA remain inconclusive. This is reflected by VO₂ max studies involving middle-aged OSA patients showing both normal and reduced CRF. As prior studies have not extensively characterized oxygen desaturation burden, we propose that reductions in VO₂ max may exist in OSA patients with only the most significant disease (as reflected by nocturnal hypoxia). Further characterizing this relationship remains important as some research suggests that positive airway pressure therapy or aerobic exercise may improve CRF in patients with OSA. In conclusion, while it likely that severe OSA, via an abnormal cardiovascular response to exercise, is associated with decreased CRF, further study is clearly warranted to include determining if OSA with decreased CRF is associated with increased morbidity or mortality.

CITATION

Powell TA, Mysliwiec V, Brock MS, Morris MJ. OSA and cardiorespiratory fitness: a review. J Clin Sleep Med. 2022;18(1):279-288.

Cardiorespiratory fitness measured with cardiopulmonary exercise testing and mortality in patients with cardiovascular disease: A systematic review and meta-analysis

BACKGROUND

Cardiorespiratory fitness (CRF) is inversely associated with mortality in apparently healthy subjects and in some clinical populations, but evidence for the association between CRF and all-cause and/or cardiovascular disease (CVD) mortality in patients with established CVD is lacking. This study aimed to quantify this association.

METHODS

We searched for prospective cohort studies that measured CRF with cardiopulmonary exercise testing in patients with CVD and that examined all-cause and CVD mortality with at least 6 months of follow-up. Pooled hazard ratios (HRs) were calculated using random-effect inverse-variance analyses.

RESULTS

Data were obtained from 21 studies and included 159,352 patients diagnosed with CVD (38.1% female). Pooled HRs for all-cause and CVD mortality comparing the highest vs. lowest category of CRF were 0.42 (95% confidence interval (95%CI): 0.28-0.61) and 0.27 (95%CI: 0.16-0.48), respectively. Pooled HRs per 1 metabolic equivalent (1-MET) increment were significant for all-cause mortality (HR = 0.81; 95%CI: 0.74-0.88) but not for CVD mortality (HR = 0.75; 95%CI: 0.48-1.18). Coronary artery disease patients with high CRF had a lower risk of all-cause mortality (HR = 0.32; 95%CI: 0.26-0.41) than did their unfit counterparts. Each 1-MET increase was associated with lower all-cause mortality risk among coronary artery disease patients (HR = 0.83; 95%CI: 0.76-0.91) but not lower among those with heart failure (HR = 0.69; 95%CI: 0.36-1.32).

CONCLUSION

A better CRF was associated with lower risk of all-cause mortality and CVD. This study supports the use of CRF as a powerful predictor of mortality in this population.

The relationships between step count and all-cause mortality and cardiovascular events: A dose-response meta-analysis

BACKGROUND

A goal of 10,000 steps per day is widely advocated, but there is little evidence to support that goal. Our purpose was to examine the dose-response relationships between step count and all-cause mortality and cardiovascular disease risk.

METHODS

Cochrane Central Register of Controlled Trials, EMBASE, OVID, PubMed, Scopus, and Web of Science databases were systematically searched for studies published before July 9, 2021, that evaluated the association between daily steps and at least 1 outcome.

RESULTS

Sixteen publications (12 related to all-cause mortality, 5 related to cardiovascular disease; and 1 article contained 2 outcomes: both all-cause death and cardiovascular events) were eligible for inclusion in the meta-analysis. There was evidence of a nonlinear dose-response relationship between step count and risk of all-cause mortality or cardiovascular disease (p = 0.002 and p = 0.014 for nonlinearity, respectively). When we restricted the analyses to accelerometer-based studies, the third quartile had a 40.36% lower risk of all-cause mortality and a 35.05% lower risk of cardiovascular event than the first quartile (all-cause mortality: Q1 = 4183 steps/day, Q3 = 8959 steps/day; cardiovascular event: Q1 = 3500 steps/day, Q3 = 9500 steps/day; respectively).

CONCLUSION

Our meta-analysis suggests inverse associations between higher step count and risk of premature death and cardiovascular events in middle-aged and older adults, with nonlinear dose-response patterns.

Heart Rate Variability and Cardiovascular Fitness: What We Know so Far

Fluctuation analysis in intervals between heartbeats provides important indices related to autonomic modulation of heart rate variability (HRV). These indices are considered predictors of morbidity and mortality as they are frequently altered in patients with chronic degenerative diseases, especially in those with cardiovascular and metabolic diseases. Similarly, a reduction in HRV is common with aging. In all cases, cardiovascular fitness is often reduced to below the predicted values. In turn, increases in cardiovascular fitness through regular physical exercise, especially aerobic exercise, represent an important therapeutic tool capable of promoting positive adjustments in cardiac autonomic modulation. These adjustments are characterized by reduced sympathetic modulatory influence and/or increased vagal modulatory influence on the heart, increasing the HRV. Therefore, several methodological tools have been used to assess the degree of impairment of autonomic modulation and the therapeutic effects of physical exercise. In contrast, establishment of strict protocols in experimental design is a main challenge in establishing HRV analysis as a robust parameter for evaluating cardiovascular homeostasis. Thus, this review aimed to contribute to the understanding of autonomic modulation of HRV and its relationship with cardiovascular fitness, highlighting the advances made thus far, the applicability of analysis tools, and the confounding factors observed frequently.

Reference Standards for Cardiorespiratory Fitness by Cardiovascular Disease Category and Testing Modality: Data From FRIEND

Background

The importance of cardiorespiratory fitness for stratifying risk and guiding clinical decisions in patients with cardiovascular disease is well‐established. To optimize the clinical value of cardiorespiratory fitness, normative reference standards are essential. The purpose of this report is to extend previous cardiorespiratory fitness normative standards by providing updated cardiorespiratory fitness reference standards according to cardiovascular disease category and testing modality.

Methods and Results

The analysis included 15 045 tests (8079 treadmill, 6966 cycle) from FRIEND (Fitness Registry and the Importance of Exercise National Database). Using data from tests conducted January 1, 1974, through March 1, 2021, percentiles of directly measured peak oxygen consumption (VO_2peak) were determined for each decade from 30 through 89 years of age for men and women with a diagnosis of coronary artery bypass surgery, myocardial infarction, percutaneous coronary intervention, or heart failure. There were significant differences between sex and age groups for VO_2peak (P<0.001). The mean VO_2peak was 23% higher for men compared with women and VO_2peak decreased by a mean of 7% per decade for both sexes. Among each decade, the mean VO_2peak from treadmill tests was 21% higher than the VO_2peak from cycle tests. Differences in VO_2peak were observed among the age groups in both sexes according to cardiovascular disease category.

Conclusions

This report provides normative reference standards by cardiovascular disease category for both men and women performing cardiopulmonary exercise testing on a treadmill or cycle ergometer. These updated and enhanced reference standards can assist with patient risk stratification and guide clinical care.

Comparison of the FRIEND and Wasserman-Hansen Equations in Predicting Outcomes in Heart Failure

Background

Percentage of age‐predicted peak oxygen uptake (VO₂) achieved (ppVO₂) has been widely used to stratify risk in patients with heart failure. However, there are limitations to traditional normal standards. We compared the recently derived FRIEND (Fitness Registry and the Importance of Exercise: A National Data Base) equation to the widely used Wasserman‐Hansen (WH) ppVO₂ equation to predict outcomes in patients with heart failure.

Methods and Results

A subgroup of 4055 heart failure patients from the FRIEND registry (mean age 53±15 years) was followed for a mean of 28±16 months. The FRIEND and WH equations along with measured peak VO₂ expressed in mL/kg⁻¹ per min⁻¹ were compared for mortality and composite cardiovascular events. ppVO₂ was higher for the FRIEND versus the WH equation (66±30% versus 58±25%; P<0.001). The areas under the receiver operating characteristic curves were slightly but significantly higher for the FRIEND equation for mortality (0.74 versus 0.72; P=0.03) and cardiac events (0.70 versus 0.68; P=0.008). Area under the receiver operating characteristic curve for measured peak VO₂ was 0.70 (P<0.001) for mortality and 0.73 (P<0.001) for cardiovascular events. For each 1‐SD higher ppVO₂ for the FRIEND equation, mortality was reduced by 18% (hazard ratio, 0.82; 95% CI, 0.69–0.97; P<0.02); for each 1‐SD higher ppVO₂ for the WH equation, the mortality was reduced by 17% (hazard ratio, 0.83; 95% CI, 0.71–0.97; P=0.02). The corresponding reductions in risk per 1 SD for cardiovascular events for the FRIEND and WH equations were 23 and 21%, respectively (both P<0.001).

Conclusions

Peak VO₂ expressed as percentage of an age‐predicted standard strongly predicts mortality and major cardiovascular events in patients with heart failure. The FRIEND registry equation exhibited test characteristics slightly superior to the commonly used WH equation.

Effect of early cardiac rehabilitation on prognosis in patients with heart failure following acute myocardial infarction

Objective

The purpose of this retrospective study is to evaluate the effectiveness of early cardiac rehabilitation on patients with heart failure following acute myocardial infarction.

Methods

Two hundred and thirty-two patients who developed heart failure following acute myocardial infarction were enrolled in this study. Patients were divided into heart failure with reduced ejection fraction group (n = 54) and heart failure with mid-range ejection fraction group (n = 178). Seventy-eight patients who accepted a two-week cardiac rehabilitation were further divided into two subgroups based on major adverse cardiovascular events. Key cardio-pulmonary exercise testing indicators that may affect the prognosis were identified among the cardiac rehabilitation patients.

Results

Early cardiac rehabilitation significantly reduced cardiac death and re-hospitalization in patients. There was more incidence of diabetes, hyperkalemia and low P_ETCO₂ in the cardiac rehabilitation group who developed re-hospitalization. Low P_ETCO₂ at anaerobic threshold (≤ 33.5 mmHg) was an independent risk factor for re-hospitalization.

Conclusions

Early cardiac rehabilitation reduced major cardiac events in patients with heart failure following acute myocardial infarction. The lower P_ETCO₂ at anaerobic threshold is an independent risk factor for re-hospitalization, and could be used as a evaluating hallmark for early cardiac rehabilitation.

Cross-Validation of Predictive Equation for Cardiorespiratory Fitness by Modified Shuttle Walk Test in Adults with Schizophrenia: A Secondary Analysis of the CORTEX-SP Study

Cardiorespiratory fitness (CRF) can be direct or estimated from different field tests. The Modified Shuttle Walk Test (MSWT) is suitable for all levels of function, allowing a peak response to be elicited. Therefore, we aimed (1) to validate the equation presented in the original study by Singh et al. for evaluating the relationship between MSWT with peak oxygen uptake (VO_2peak) in adults with schizophrenia (SZ), (2) to develop a new equation for the MSWT to predict VO_2peak, and (3) to validate the new equation. Participants (N = 144, 41.3 ± 10.2 years old) with SZ performed a direct measurement of VO_2peak through a cardiopulmonary exercise test and the MSWT. A new equation incorporating resting heart rate, body mass index, and distance from MSWT (R² = 0.617; adjusted R² = 0.60; p < 0.001) performs better than the Singh et al. equation (R² = 0.57; adjusted R² = 0.57; p < 0.001) to estimate VO_2peak for the studied population. The posteriori cross-validation method confirmed the model’s stability (R² = 0.617 vs. 0.626). The findings of the current study support the validity of the new regression equation incorporating resting heart rate, body mass index, and distance from MSWT to predict VO_2peak for assessment of CRF in people with SZ.

Cardiorespiratory optimal point during exercise testing and sudden cardiac death: A prospective cohort study

BACKGROUND

Cardiorespiratory optimal point (COP) during exercise, a potentially useful submaximal cardiopulmonary exercise testing (CPET) variable, may be an independent risk factor for cardiovascular disease outcomes. However, the relationship of COP with risk of sudden cardiac death (SCD) has not been previously investigated. We sought to evaluate the association between COP during exercise and SCD risk and determine whether COP improves SCD risk prediction.

METHODS

COP, the minimum value of the ventilatory equivalent for oxygen (VE/VO2) in a given minute of a CPET, was ascertained in 2190 men who underwent clinical exercise testing. Hazard ratios (HRs) (95% confidence intervals [CIs]) and measures of risk discrimination for SCD were calculated.

RESULTS

A total of 240 SCDs death occurred during a median follow-up of 28.8 years. COP was linearly associated with SCD in a dose-response manner. In a multivariable model comprising several established and emerging CVD risk factors, the HR (95% CI) for SCD was 2.51 (1.36-4.62) per standard deviation increase in COP. This was minimally attenuated to 2.36 (1.27-4.37) on further adjustment for high sensitivity C-reactive protein. The association did not vary importantly in several relevant clinical subgroups. Addition of COP to a SCD risk score was associated with a C-index change of 0.0086 (0.0005 to 0.0167; p = .038) and difference in -2 log likelihood (p = .017).

CONCLUSIONS

COP during exercise is strongly, inversely and independently associated with SCD in a graded fashion. COP during exercise may potentially be used for the prediction of the long-term risk for SCD beyond established CVD risk factors.

Lower muscular strength is associated with smaller left and right chambers and lower cardiac mass in the general population - The Sedentary's Heart

BACKGROUND

The cardiac muscle has the ability to adapt to different loading conditions. We analyzed the associations of the age-related decreasing handgrip strength (HGS), a marker of muscular fitness, on cardiac structure and function in a community-based sample.

METHODS

We performed cross-sectional analyses of 4646 subjects (2554 women; 55.0%) aged 20 to 93 years from two independent cohorts of the Study of Health in Pomerania (SHIP-2 and SHIP-TREND-0). We analyzed the associations of HGS with structural and functional left and right ventricular (LV and RV) and left atrial (LA) parameters as determined by echocardiography and magnetic resonance imaging (MRI) as well with log-transformed NT-proBNP values using multivariable-adjusted linear regression models.

RESULTS

MRI data showed that a 1 kg lower HGS was associated with a 0.40 mL (95% confidence interval: 0.26 to 0.54; p < 0.001) lower LV end-diastolic volume, a 0.011 mm (0.005 to 0.018; p = 0.001) lower LV wall-thickness, a 0.59 g (0.43 to 0.75; p < 0.001) lower LV mass, a 0.58 mL/beat (0.43 to 0.74; p < 0.001) lower LV stroke volume, a 0.03 L/min (0.02 to 0.04; p < 0.001) lower LV cardiac output, a 0.48 mL (0.27 to 0.68; p < 0.001) lower LA end-diastolic volume, and a 1.02 mL (0.71 to 1.32) lower RV end-diastolic volume. Similar findings were observed for echocardiographic parameters. Moreover, lower HGS was associated with higher echocardiographic LV diastolic stiffness and NT-proBNP levels.

CONCLUSIONS

In this large population-based sample, lower muscular fitness as assessed by HGS was associated with lower LV wall thickness and mass as well as with smaller chamber size, stroke volume and cardiac output of the LV, LA and RV. Moreover, HGS was inversely related to LV diastolic stiffness and NT-proBNP values. These outcomes might demonstrate the effects of an aging-related decrease in physical activity and lower muscular fitness on the heart - "the sedentary's heart".

Cardiac MRI shows an association of lower cardiorespiratory fitness with decreased myocardial mass and higher cardiac stiffness in the general population - The Sedentary's Heart

BACKGROUND

The heart has the capacity to adapt to different demands. The pathophysiological mechanisms involved with sedentarism are not fundamentally the opposite of those related with physical activity and regular exercise. We investigated the impact of lower cardiorespiratory fitness (CRF) on heart's plasticity and function in a population-based setting.

METHODS

We used data from 1165 participants (539 women; 46.3%) aged 21-81 years from two independent cohorts of the Study of Health in Pomerania (SHIP-2 and SHIP-TREND-0). We analyzed the cross-sectional associations of peak oxygen uptake (VO_2peak), determined by symptom-limited cardiopulmonary exercise testing, with structural and functional left ventricular (LV) and left atrial (LA) parameters determined by magnetic resonance imaging (MRI) using multivariable- adjusted linear regression models.

RESULTS

A 1 L/min lower VO_2peak was associated with a 10.5 g (95% confidence interval: 8.00 to 12.9; p < 0.001) lower LV mass, a 14.8 mL (10.9 to 18.6; p < 0.001) lower LV end-diastolic volume, a 0.29 mm (0.19 to 0.40; p < 0.001) lower LV wall-thickness, a 8.85 mL/beat (6.53 to 11.2; p < 0.001) lower LV stroke volume, a 0.42 L/min (0.25 to 0.60; p < 0.001) lower LV cardiac output and a 7.51 mL (3.88 to 11.1; p < 0.001) lower LA end-diastolic volume. Moreover, there were no associations with a concentric or eccentric remodeling and LV and LA ejection fraction.

CONCLUSIONS

Lower CRF was associated with a smaller heart, LV wall-thickness and mass, LV and LA stroke volume and cardiac output. Conversely, there was no association with LA and LV ejection fraction. Our cross-sectional observations are consistent with cardiac adaptations reflecting reduced volume loading demands of a sedentary lifestyle - "the sedentary's heart".

Exercise heart rate reserve and recovery as risk factors for sudden cardiac death

BACKGROUND

Little is known if heart rate responses during and after exercise test may be associated with the risk of sudden cardiac death (SCD). Our aim was to determine if exercise heart rate reserve and recovery, providing non-invasive indices, may predict SCD risk in general male population.

METHODS

We evaluated the impact of delayed heart rate reserve and slow heart rate recovery and the risk of SCD in the Kuopio Ischemic Heart Disease prospective cohort study of randomly selected 1967 men aged 42-61 years at recruitment. Heart rate reserve was calculated as the difference between the maximal attained heart rate and resting heart rate, whereas heart rate recovery was defined as maximal heart rate minus the heart rate measured at 2 min of recovery, on a symptom-limited cardiopulmonary exercise testing.

RESULTS

During a median follow-up interval of 25 years, 209 events of SCD occurred. The age and examination adjusted relative hazards of SCD were in the lowest third of heart rate reserve 3.86 (95% confidence interval (CI) 2.56-5.80, p < 0.001) and the lowest third of heart rate recovery 2.86 (95% CI 1.95-4.20, p < 0.001) as compared to men in the highest third of heart rate reserve and heart rate recovery, respectively. After adjusting for potential confounders, the respective relative hazards were 1.96 (95% CI 1.24-3.12) and 1.75 (95% CI 1.16-2.64). Each unit increment (1 beat/min) in heart rate reserve and heart rate recovery decreased the incidence of SCD by 1-2%.

CONCLUSIONS

Delayed exercise heart rate reserve and slow heart rate recovery predicted the risk of SCD, suggesting that heart rate responses may be associated with an increased risk for SCD in general population.

The Effects of Exercise on Lipid Biomarkers

The World Health Organization has declared obesity to be a global epidemic that increases cardiovascular disease (CVD) mortality risk factors, such as hypertension, diabetes, dyslipidemia, and atherosclerosis. The increasing ratio of time spent in sedentary activities to that spent performing physically demanding tasks increases the trends to obesity and susceptibility to these risk factors. Dyslipidemia is the foundation of atherosclerotic buildup and lipoproteins serve as cofactors to the inflammatory processes that destabilize plaques. Increasing cardiorespiratory fitness and muscular strength helps attenuate concentrations of low-density lipoproteins (LDLs), such as LDL cholesterol, and increase levels of high-density lipoprotein cholesterol, as well as reduce proprotein convertase subtilisin kexin type 9 expression. Effects of physical activity on the inflammatory pathways of atherosclerosis, specifically C-reactive protein, are more closely related to reducing the levels of adiposity in tandem with increasing fitness, than with exercise training alone. The purpose of this review is to describe the physiology of dyslipidemia and relate it to CVD and exercise therapies.

Combined use of stress echocardiography and cardiopulmonary exercise testing to assess exercise intolerance in patients treated for acute myocardial infarction

Exercise intolerance after acute myocardial infarction (AMI) is a predictor of worse prognosis, but its causes are complex and poorly studied. This study assessed the determinants of exercise intolerance using combined stress echocardiography and cardiopulmonary exercise testing (CPET-SE) in patients treated for AMI. We prospectively enrolled patients with left ventricular ejection fraction (LV EF) ≥40% for more than 4 weeks after the first AMI. Stroke volume, heart rate, and arteriovenous oxygen difference (A-VO2Diff) were assessed during symptom-limited CPET-SE. Patients were divided into four groups according to the percentage of predicted oxygen uptake (VO2) (Group 1, <50%; Group 2, 50-74%; Group 3, 75-99%; and Group 4, ≥100%). Among 81 patients (70% male, mean age 58 ± 11 years, 47% ST-segment elevation AMI) mean peak VO2 was 19.5 ± 5.4 mL/kg/min. A better exercise capacity was related to a higher percent predicted heart rate (Group 2 vs. Group 4, p <0.01), higher peak A-VO2Diff (Group 1 vs. Group 3, p <0.01) but without differences in stroke volume. Peak VO2 and percent predicted VO2 had a significant positive correlation with percent predicted heart rate at peak exercise (r = 0.28, p = 0.01 and r = 0.46, p < 0.001) and peak A-VO2Diff (r = 0.68, p <0.001 and r = 0.36, p = 0.001) but not with peak stroke volume. Exercise capacity in patients treated for AMI with LV EF ≥40% is related to heart rate response during exercise and peak peripheral oxygen extraction. CPET-SE enables non-invasive assessment of the mechanisms of exercise intolerance.

Can functional walk tests add value to the prediction of cardiorespiratory fitness after stroke? A prospective cohort study

BACKGROUND

Cardiorespiratory fitness is often impaired following stroke, and peak oxygen consumption (VO2peak) is an important prognostic value of all-cause mortality. The primary objective was to investigate whether functional walk tests assessed in the subacute phase after stroke added value in predicting VO2peak in chronic stroke, in addition to age, sex and functional dependency. Secondary objectives were to investigate associations between daily physical activity and functional walk tests, and with VO2peak in chronic stroke.

METHODS

This prospective cohort study included eligible participants originally included in the randomized controlled trial Life After Stroke. Functional walk tests, i.e., six-minute walk test (6MWT) and maximal gait speed, were assessed at inclusion and 18 months later. VO2peak [ml/kg/min] was assessed by a cardiopulmonary exercise test on a treadmill 20 months after inclusion. Daily physical activity was measured by a uniaxial accelerometer (activPAL) at 18-month follow-up.

RESULTS

Ninety-two community-dwelling individuals, with a mean (SD) age of 69.2 (10.6) years and 33 (35.9%) women, were included 3 months after stroke onset. Eighty-three (90.2%) participants had a modified Rankin Scale (mRS) score of 1 or 2, indicating functional independence. An overall assessment of four prediction models indicated the combination of age, sex, mRS and 6MWT as predictors to be the best fitted model in predicting VO2peak (adjusted R2 = 0.612). Secondary results showed statistically significant, but not clinically significant, associations between daily physical activity and functional walk tests, and with VO2peak.

CONCLUSIONS

6MWT add significant value to the prediction of mean VO2peak in the chronic phase in mild strokes, in combination with age, sex and functional dependency. This prediction model may facilitate clinical decisions and rehabilitation strategies for mildly affected stroke survivors in risk of low levels of VO2peak. Future studies should validate the model in various stages after stroke and in patients moderately and severely affected.

Association between Cardiorespiratory Fitness and Circulating Proteins in 50-Year-Old Swedish Men and Women: a Cross-Sectional Study

BACKGROUND AND AIMS

A strong cardiorespiratory fitness is suggested to have beneficial effects on cardiovascular risk; the exact mechanisms underlying the cardioprotective effects of fitness remain uncertain. Our aim was to investigate associations between cardiorespiratory fitness and multiple plasma proteins, in order to obtain insights about physiological pathways associated with the effects of exercise on cardiovascular health.

METHODS

In the Prospective investigation of Obesity, Energy and Metabolism (POEM) study (n=444 adults aged 50 years, 50% women), cardiorespiratory fitness was measured by a maximal exercise test on bicycle ergometer with gas exchange (VO₂peak) normalized for body lean mass (dual-energy X-ray absorptiometry (DXA)). We measured 82 cardiovascular proteins associated with cardiovascular pathology and inflammation in plasma samples with a proximity extension assay.

RESULTS

In sex-adjusted linear regression, VO₂peak was associated with 18 proteins after Bonferroni correction for multiple testing (p<0.0006). Following additional adjustment for fat mass (DXA), fasting glucose (mmol/L), low-density lipoprotein (LDL, mmol/L), smoking status, waist/hip ratio, blood pressure (mmHg), education level, and lpnr (lab sequence number), higher VO₂peak was significantly associated with lower levels of 6 proteins: fatty-acid binding protein-4 (FABP4), interleukin-6 (IL-6), leptin, cystatin-B (CSTB), interleukin-1 receptor antagonist (IL-1RA), and growth differentiation factor 15 (GDF-15), and higher levels of 3 proteins: galanin, kallikrein-6 (KLK6), and heparin-binding EGF-like growth factor (HB-EGF), at nominal p-values (p<0.05).

CONCLUSIONS

We identified multiple novel associations between cardiorespiratory fitness and plasma proteins involved in several atherosclerotic processes and key cellular mechanisms such as inflammation, energy homeostasis, and protease activity, which shed new light on how exercise asserts its beneficial effects on cardiovascular health. Our findings encourage additional studies in order to understand the underlying causal mechanisms for these associations.

Differential Age-Related Declines in Cardiorespiratory Fitness Between People With and Without Type 2 Diabetes Mellitus

Objective

To assess the extent to which the established age-related decline in cardiorespiratory fitness (CRF) is augmented in adult men with type 2 diabetes mellitus (T2DM).

Participants and Methods

This study used data from the Aerobics Center Longitudinal Study, conducted between September 18, 1974, and August 3, 2006, in primarily non-Hispanic white, middle-to-upper class adults. The analyses were restricted to adult men with complete data on age, CRF, and T2DM (35,307 participants). Quantile regression models were used to estimate age-related differences in CRF, estimated using a maximal treadmill test, between persons with and without T2DM. Smoking status and birth cohort served as covariates.

Results

Age-related declines in CRF were observed in men with and without T2DM. For men younger than 60 years, at low-mid percentiles of the CRF distribution the magnitude of the age-related decline in CRF was significantly higher (P-values=.00, .02) in men with T2DM than in those without T2DM. At upper percentiles, the decline with age between the 2 groups was virtually identical. Significant declines in CRF in men 45 years or younger were observed only at high levels of CRF for those without T2DM and at low levels of CRF for those with T2DM (P-values .00, .04).

Conclusion

This study reported that men younger than 60 years with T2DM at the low-mid CRF percentiles experience an accelerated age-related decline in CRF. Men younger than 60 years with T2DM exhibiting high levels of CRF experienced a decline in CRF comparable to men without T2DM. This study highlights the importance of incorporating sufficient levels of exercise or activity to maintain high CRF in men with T2DM.

Peak oxygen pulse and mortality risk in healthy women and men: The Ball State Adult Fitness Longitudinal Lifestyle Study (BALL ST)

Peak oxygen pulse (O₂ pulse_peak) may have predictive utility for health outcomes yet, presently, has only been examined in men and only using a single baseline measure.

PURPOSE

The primary aim of this investigation was to evaluate the relationship between O₂ pulse_peak and all-cause mortality in apparently healthy women and men. A secondary aim was to explore the relationship between longitudinal changes to O₂ pulse_peak and mortality.

METHODS

The sample included 3877 participants (43% women) for the primary aim and 759 participants (32% women) who performed two cardiopulmonary exercise tests ≥1 year apart for the secondary aim. Cox proportional hazard models were performed to determine the relationship between O₂ pulse_peak and mortality. Prognostic peak oxygen consumption (VO_2peak) and O₂ pulse_peak models were compared using the concordance index and Akaike information criterion (AIC).

RESULTS

In the assessment from baseline, there were 730 deaths over a 24.7 ± 11.8 year follow-up period. For men, a single measure of O₂ pulse_peak was inversely associated with risk for mortality (P < 0.05). However, the concordance index and AIC indicated lower discrimination compared to VO_2peak models and O₂ pulse_peak did not provide complementary benefit to VO_2peak models. For women, O₂ pulse_peak was not associated with mortality risk. In the longitudinal analysis, there were 168 deaths over a follow-up of 20.1 ± 11.4 years. Changes to O₂ pulse_peak were not significantly related to mortality in either sex.

CONCLUSIONS

Within an apparently healthy cohort, a single assessment of O₂ pulse_peak is related to all-cause mortality in men but not women. Further, longitudinal changes to O₂ pulse_peak are not predictive of mortality in either sex. These findings suggest O₂ pulse_peak may have limited prognostic utility in healthy individuals, particularly within healthy women.

The deleterious effects of acute hypoxia on microvascular and large vessel endothelial function

NEW FINDINGS

What is the central question of this study? The aim was primarily to determine the effect of hypoxia on microvascular function and secondarily whether superior cardiorespiratory fitness is protective against hypoxia-induced impairment in vascular function. What is the main finding and its importance? Hypoxia reduced endothelium-dependent but not endothelium-independent microvascular function. The extent of impairment was twofold higher in the microcirculation compared with the large blood vessels. This study suggests that individuals with superior cardiorespiratory fitness might preserve microvascular function in hypoxia. These findings highlight the sensitivity of the microvascular circulation to hypoxia.

ABSTRACT

Hypoxia is associated with diminished bioavailability of the endothelium-derived vasodilator, nitric oxide (NO). Diminished NO bioavailability can have deleterious effects on endothelial function. The endothelium is a heterogeneous tissue; therefore, a comprehensive assessment of endothelial function is crucial to understand the significance of hypoxia-induced endothelial dysfunction. We hypothesized that acute hypoxia would have a deleterious effect on microvascular and large vessel endothelial function. Twenty-nine healthy adults [24 (SD = 4 ) years of age] completed normoxic and hypoxic [inspired O₂  fraction = 0.209] trials in this double-blinded, counterbalanced crossover study. After 30 min, we assessed the laser Doppler imaging-determined perfusion response to iontophoresis of ACh as a measure of endothelium-dependent microvascular function and iontophoresis of sodium nitroprusside as a measure of endothelium-independent microvascular function. After 60 min, we assessed brachial flow-mediated dilatation as a measure of large vessel endothelial function. Thirty minutes of hypoxia reduced endothelium-dependent microvascular function determined by the perfusion response to ACh (median difference (x̃∆) = -109% {interquartile range: 542.7}, P < 0.05), but not endothelium-independent microvascular function determined by the perfusion response to sodium nitroprusside (x̃∆ = 69% {interquartile range: 453.7}, P = 0.6). In addition, 60 min of hypoxia reduced allometrically scaled flow-mediated dilatation compared with normoxia ( x ¯ Δ = - 1.19 [95% CI = -1.80, -0.58 (Confidence Intervals)]%, P < 0.001). The decrease in microvascular endothelial function was associated with cardiorespiratory fitness (r  = 0.45, P = 0.02). In conclusion, acute exposure to normobaric hypoxia significantly reduced endothelium-dependent vasodilatory capacity in small and large vessels. Collectively, these findings highlight the sensitivity of the microvascular circulation to hypoxic insult, particularly in those with poor cardiorespiratory fitness.

Cardiorespiratory Fitness After Open Repair for Acute Type A Aortic Dissection - A Prospective Study

Cardiorespiratory fitness (as measured by peak oxygen consumption [VO2peak]) is an independent predictor of cardiovascular disease and all-cause mortality. Limited data exist on VO2peak following repair for an acute type A aortic dissection (ATAAD) or proximal thoracic aortic aneurysm (pTAA). This study prospectively evaluated VO2peak, functional capacity, and health-related quality of life (HR-QOL) following open repair. Participants with a history of an ATAAD (n = 21) or pTAA (n = 43) performed cardiopulmonary exercise testing (CPX), 6-minute walk testing, and HR-QOL at 3 (early) and 15 (late) months following open repair. The median age at time of surgery was 55-years-old and 60-years-old in the ATAAD and pTAA groups, respectively. Body mass index significantly increased between early and late timepoints for both ATAAD (p = 0.0245, 56% obese) and pTAA groups (p = 0.0045, 54% obese). VO2peak modestly increased by 0.8 mLO2·kg-1·min-1 within the ATAAD group (p = 0.2312) while VO2peak significantly increased by 2.2 mLO2·kg-1·min-1 within the pTAA group (p = 0.0003). Anxiety significantly decreased in the ATAAD group whereas functional capacity and HR-QOL metrics (social roles and activities, physical function) significantly improved in the pTAA group (p values < 0.05). There were no serious adverse events during CPX. Cardiorespiratory fitness among the ATAAD group remained 36% below predicted normative values >1 year after repair. CPX should be considered post-operatively to evaluate exercise tolerance and blood pressure response to determine whether mild-to-moderate aerobic exercise should be recommended to reduce future risk of morbidity and mortality.

Neck circumference and cardiometabolic risk in children and adolescents: the moderator role of cardiorespiratory fitness

BACKGROUND

The increased incidence of cardiometabolic risk factors has become a public health issue, especially in childhood and adolescence. Thus, early identification is essential to avoid or reduce future complications in adulthood. In this sense, the present study aimed to verify the influence of cardiorespiratory fitness (CRF) as a moderator in the association between neck circumference (NC) and cardiometabolic risk in children and adolescents.

METHODS

Cross-sectional study that included 2418 randomly selected children and adolescents (52.5% girls), aged 6 to 17 years old. Anthropometric measurements, such as NC and body mass index (BMI), and CRF was measured by the six-minute running/walking test, as well as cardiometabolic risk (systolic blood pressure, glucose, HDL-C, and triglycerides), were assessed.

RESULTS

For all age groups, NC showed a negative relationship with CRF. A significant interaction term was found for CRF x NC with cardiometabolic risk for children (6 to 9 years old), early adolescents (10 to 12 years old), and middle adolescents (13 to 17 years old). It was found that children who accomplished more than 1092.49 m in CRF test were protected against cardiometabolic risk when considering NC. In adolescents, protection against cardiometabolic risk was found when the CRF test was completed above 1424.14 m and 1471.87 m (early and middle stage, respectively).

CONCLUSIONS

CRF is inversely associated with NC and acts as a moderator in the relationship between NC and cardiometabolic risk in children and adolescents. Therefore, this detrimental health impact linked to fatness might be attenuated by improving CRF levels.

Interaction between major dietary patterns and cardiorespiratory fitness on metabolic syndrome in Iranian adults: a cross-sectional study

Background

Several researches have been conducted on the associations between diet and cardiorespiratory fitness (CRF) and major cardiovascular risk factors. However, there is no report about the interaction between major dietary patterns and CRF on metabolic syndrome (MetS) and its components. To investigate the combined association of major dietary patterns and CRF on MetS and its components.

Methods

This cross-sectional study was conducted on 270 apparently healthy adults living in Tehran, Iran. Dietary intake was evaluated using a validated food frequency questionnaire (FFQ). CRF was assessed using a graded exercise treadmill test. Socio-economic status, anthropometric measures, biochemical parameters, and blood pressure were evaluated according to standard methods. Major dietary patterns were identified by factor analysis.

Results

Three major identified dietary patterns were (healthy, mixed, and western). Significant positive association was found between mixed dietary pattern and metabolic syndrome (OR = 2.68, 95% CI (1.92,7.78), P = 0.04). There were not relations between tertiles of identified dietary patterns and remained outcomes. Those who had higher adherence to mixed pattern with also higher CRF showed a significant decrease for diastolic blood pressure (P < 0.01). Also we found that there was no significant interaction between any of dietary patterns and CRF on odds of MetS.

Conclusions

Overall, adherence to mixed dietary pattern in this population was associated with increasing odds of MetS. However, nor CRF neither the combination of dietary patterns and CRF was related to the odds of MetS among Iranian adults. More studies are needed to clarify these associations and to consider interpersonal determinants.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12937-021-00695-4.

Potential Association of Circulating MicroRNA-181c and MicroRNA-484 Levels with Cardiorespiratory Fitness after Myocardial Infarction: A Pilot Study

Objectives:

In the field of exercise physiology, there has been great interest in exploring circulating microRNAs (miRs) as potential biomarkers. However, it remains to be determined whether circulating miRs reflect cardiorespiratory fitness. The aim of this study was to investigate the association between circulating levels of specific miRs and cardiorespiratory fitness evaluated by cardiopulmonary exercise testing (CPET) after acute myocardial infarction (MI).

Methods:

Twenty patients who had had an acute MI were included. All patients underwent CPET in the convalescent phase. Quantitative real-time polymerase chain reaction analyses for miR-181 members (a/b/c) and miR-484 were performed to determine the expression levels in the peripheral blood of the included patients and healthy control subjects (n=5).

Results:

Post-MI patients showed impaired exercise tolerance and ventilatory efficiency in CPET analysis. Compared with controls, circulating levels of miR-181a and 181c were gradually and significantly elevated through the 1st to 7th days after acute MI, whereas miR-181b and miR-484 were not. Circulating miR levels did not correlate with clinical or echocardiographic parameters. However, circulating levels of miR-181c and miR-484 on the 7th day showed significant positive correlations with the anaerobic threshold and peak oxygen consumption from CPET analysis. Moreover, miR-181c levels were inversely associated with the ventilatory inefficiency index. Patients with high exercise capacity after MI showed significantly higher expressions of circulating miR-181c and miR-484 than those with low exercise capacity.

Conclusions:

The results of this pilot study suggest that circulating levels of miR-181c and miR-484 after acute MI may be predictive biomarkers of post-MI cardiorespiratory fitness.

Health Consequences of an Elite Sporting Career: Long-Term Detriment or Long-Term Gain? A Meta-Analysis of 165,000 Former Athletes

INTRODUCTION

Exercise is widely accepted to improve health, reducing the risk of premature mortality, cardiovascular disease (CVD) and cancer. However, several epidemiological studies suggest that the exercise-longevity relationship may be 'J' shaped; with elite athlete's likely training above these intensity and volume thresholds. Therefore, the aim of this meta-analysis was to examine this relationship in former elite athletes.

METHODS

38,047 English language articles were retrieved from Web of Science, PubMed and SportDiscus databases published after 1970, of which 44 and 24 were included in the systematic review and meta-analysis, respectively. Athletes were split into three groups depending on primary sport: Endurance (END), Mixed/Team, or power (POW). Standard mortality ratio's (SMR) and standard proportionate mortality ratio (SPMR) were obtained, or calculated, and combined for the meta-analysis.

RESULTS

Athletes lived significantly longer than the general population (male SMR 0.69 [95% CI 0.61-0.78]; female SMR 0.51 [95% CI 0.40-0.65]; both p < 0.01). There was no survival benefit for male POW athletes compared to the general population (SMR 1.04 [95% CI 0.91-1.12]). Although male athlete's CVD (SMR 0.73 [95% CI 0.62-0.85]) and cancer mortality (SMR 0.75 [95% CI 0.63-0.89]), were significantly reduced compared to the general population, there was no risk-reduction for POW athletes CVD mortality (SMR 1.10 [0.86-1.40]) or END athletes cancer mortality (SMR 0.73 [0.50-1.07]). There was insufficient data to calculate female sport-specific SMR's.

DISCUSSION

Overall, athletes live longer and have a reduced incidence of both CVD and cancer mortality compared to the general population, refuting the 'J' shape hypothesis. However, different health risks may be apparent according to sports classification, and between sexes, warranting further investigation. Trial registration PROSPERO (registration number: CRD42019130688).

Relationship between cardiorespiratory fitness and latitude in children and adolescents: Results from a cross-sectional survey in China

Background

This study assessed the correlation between latitude and the cardiorespiratory fitness (CRF) of children and adolescents.

Methods

In 16 provinces and autonomous regions in China, 25,941 children and adolescents aged 10–18 were included. CRF was measured using the 20 m shuttle run test (20 m SRT) and estimated peak oxygen uptake (VO_2peak). One-way ANOVA and multiple regression analysis were used to explore the correlation between CRF and latitude in children and adolescents.

Results

The VO_2peak values of the low (south), middle, and high (north) latitude groups for boys were 43.1, 43.1, and 40.7 mL/kg/min, respectively, and 40.0, 40.0, and 38.5 mL/kg/min for girls, respectively. After adjusting for confounding factors, the regression coefficients (β) between VO_2peak-Z and both latitude-Z and (latitude-Z)² for boys were −0.151 and −0.043, respectively. For girls, they were −0.142 and −0.020, respectively. The Partial correlation coefficient (r) for latitude-Z and (latitude-Z)² were −0.14 and −0.04 for boys, and −0.13 and −0.02 for girls, respectively.

Conclusion

The CRF among children and adolescents in high latitude regions is significantly lower than that in middle and low latitude region, and it generally shows a “parabolic” trend between Latitude-Z and VO_2peak-Z.

The association between cardio-respiratory fitness and incident depression: The Maastricht Study

BACKGROUND

Moderate to vigorous physical activity (MVPA) can help to prevent depression, but identification of the most important psycho-biological pathways involved is unclear. The improvement of cardio-respiratory fitness (CRF) in response to MVPA can vary markedly, we therefore examined the association between CRF and the incidence of depressive symptoms.

METHODS

We used data from The Maastricht Study, a large population-based prospective-cohort study. CRF was estimated at baseline from a graded submaximal exercise protocol and MVPA was measured with accelerometry. Depressive symptoms were assessed using the validated Dutch version of the 9-item Patient Health Questionnaire, both at baseline and during annual follow-up over five years. Cox proportional hazards models were used.

RESULTS

A total of 1,730 individuals without depressive symptoms at baseline were included in the analysis. During the 5-year follow-up, n = 166 (9.6%) of individuals developed depressive symptoms. Compared to individuals with a low CRF, those with a moderate-to-high CRF had a significantly lower risk of developing depressive symptoms, independent of MVPA (medium CRF: HR = 0.49 (95%CI = 0.33-0.72); high CRF: HR = 0.48 (95% CI = 0.30-0.75). These associations were adjusted for age, sex, level of education, diabetes status, smoking status, alcohol use, energy intake, waist circumferences and antidepressant medications.

LIMITATIONS

PHQ-9 is a validated screening instrument, but it is not a diagnostic tool of depression.

CONCLUSIONS

Higher CRF was strongly associated with a lower risk of incident depressive symptoms over 5-year follow-up, independent of the level of MVPA at baseline, suggesting that interventions aimed at improving CRF could reduce the risk of depression.

Clinical, physical, physiological, and cardiovascular risk patterns of adults with schizophrenia: CORTEX-SP study: Characterization of adults with schizophrenia

Schizophrenia (SP) is a severe mental illness with high rates of premature morbidity and mortality, associated with an unhealthy lifestyle and the side effects of drug treatment. The aims of the study were: 1) to determine some key physical, physiological and biochemical markers of health status, including sleep quality, in adults (42±10 yr) with SP (n=126), 2) to estimate cardiovascular risk (CVR), and 3) to compare all studied variables with a healthy control (HC) population (n=30). Assessment was based on body composition, blood pressure, cardiorespiratory condition, sleep quality with triaxial accelerometry for eight days and biochemical analysis. Participants with SP showed a cardiovascular risk profile including "overweight metabolically abnormal", low cardiorespiratory fitness, and impairment of ventilatory efficiency. Although individuals with SP slept more compared to HC, similar sleep efficiency was shown by both groups, but with significantly higher levels of wake after sleep onset by SP. The assessment of CVR revealed significantly higher values in SP (moderate risk) compared to HC (low risk) regardless of the estimation system. The identification of specific clinical, physical, and physiological CVR profiles in SP illness compared to healthy people strongly suggests targeting a comprehensive approach including non-pharmacological interventions. Clinical Trials.gov identifier, NCT03509597. Date of registration: April 26^th, 2018.

Preclinical techniques to investigate exercise training in vascular pathophysiology

Atherosclerosis is a dynamic process starting with endothelial dysfunction and inflammation and eventually leading to life-threatening arterial plaques. Exercise generally improves endothelial function in a dose-dependent manner by altering hemodynamics, specifically by increased arterial pressure, pulsatility, and shear stress. However, athletes who regularly participate in high-intensity training can develop arterial plaques, suggesting alternative mechanisms through which excessive exercise promotes vascular disease. Understanding the mechanisms that drive atherosclerosis in sedentary versus exercise states may lead to novel rehabilitative methods aimed at improving exercise compliance and physical activity. Preclinical tools, including in vitro cell assays, in vivo animal models, and in silico computational methods, broaden our capabilities to study the mechanisms through which exercise impacts atherogenesis, from molecular maladaptation to vascular remodeling. Here, we describe how preclinical research tools have and can be used to study exercise effects on atherosclerosis. We then propose how advanced bioengineering techniques can be used to address gaps in our current understanding of vascular pathophysiology, including integrating in vitro, in vivo, and in silico studies across multiple tissue systems and size scales. Improving our understanding of the antiatherogenic exercise effects will enable engaging, targeted, and individualized exercise recommendations to promote cardiovascular health rather than treating cardiovascular disease that results from a sedentary lifestyle.

Increased dairy product consumption as part of a diet and exercise weight management program improves body composition in adolescent females with overweight and obesity-A randomized controlled trial

BACKGROUND

Exercise can improve body composition in adolescents and adults with overweight/obesity. Consumption of dairy foods, as part of a healthy lifestyle program, can also promote favourable body composition changes in adults with overweight/obesity. However, the few studies examining these combined effects on body composition in adolescents are inconclusive.

OBJECTIVE

To determine whether increased dairy product consumption, as part of a lifestyle modification program featuring exercise training and dietary guidance promotes favourable body composition changes in adolescent females with overweight/obesity.

METHODS

Fifty-four participants (age: 14.8 ± 2.2y; BMI percentile: 95th ± 6) assigned to three groups completed the study. There were two experimental groups: recommended dairy (RDa; n = 24) and low dairy (LDa; n = 22), and a no-intervention control group (Con; n = 8). RDa and LDa participated in a 12-week, eucaloric, lifestyle modification intervention consisting of mixed-mode exercise (3x/week), and nutritional counselling. RDa was provided 4 servings/day of dairy foods, while LDa and Con maintained habitually low intakes (0-2 servings/day). Body weight/composition, waist/hip circumference, cardiovascular fitness and food intake were assessed at weeks 0 and 12.

RESULTS

Weight did not significantly change in any group. RDa significantly decreased fat mass (FM) and increased lean mass (LM) more than LDa and Con (FM: -1.3 ± 2.1 kg, -1.1 ± 2.0 kg, 0.8 ± 1.8 kg; LM: 1.5 ± 1.9 kg, 0.7 ± 1.6 kg, 0.5 ± 1.4 kg, respectively). LDa also significantly decreased FM and increased LM more than Con (P < .005; all interactions).

CONCLUSION

The inclusion of dairy foods in the diet of adolescent females with overweight/obesity, as part of a diet and exercise intervention, favourably improves body composition in the absence of weight loss.

A Review of Obesity, Physical Activity, and Cardiovascular Disease

PURPOSE OF REVIEW

The focus of this review is to discuss obesity, physical activity (and physical inactivity/sedentary behavior), cardiovascular disease (CVD), and their often interrelated health implications. The authors summarize the pathophysiological changes associated with obesity, which lead to the development of CVD, recommendations for interventions such as diet, increased physical activity, and weight loss according to current literature and guidelines, and the critical importance of cardiorespiratory fitness (CRF).

RECENT FINDINGS

Clinical trials continue to demonstrate improved outcomes among overweight or obese individuals who achieve a healthy weight using various methods. Increasing CRF levels appears to demonstrate the largest health improvements, regardless of underlying comorbidities or achieving weight loss. CRF, which is perhaps the single most important predictor of overall health, seems more important than weight loss alone regarding improved CVD outcomes in the obese population. These findings are reproduced in studies involving patients with various forms of CVD and CVD risk factors. The importance of CRF is well established; future endeavors to establish specific CRF targets for various patient cohorts are needed.

The Mediating and Moderating Effects of Physical Fitness of the Relationship between Adherence to the Mediterranean Diet and Health-Related Quality of Life in University Students

The aim of this study was to estimate the relationship between the adherence to the Mediterranean diet (MD) and health-related quality of life (HRQoL) in university students and to assess whether this relationship is mediated or moderated by cardiorespiratory fitness (CRF) and handgrip strength. A cross-sectional study was performed involving 310 first-year Spanish university students. Adherence to the MD was evaluated with the 14-item Mediterranean Diet Adherence Screener (MEDAS), and the HRQoL was evaluated with the Short Form-12 (SF-12) questionnaire. CRF was assessed by the 20 m shuttle run test, and the handgrip strength was determined by dynamometry. ANCOVA models showed that participants with higher CRF and handgrip strength levels had significantly higher scores in the physical component summary (PCS) and mental component summary (MCS) of the SF-12 and in the MEDAS questionnaire than those with medium and low scores (p < 0.050). Additionally, the ANCOVA models showed that students with good adherence to the MD showed higher scores in the MCS of HRQoL than those with low adherence (p = 0.044, ES = 0.013), but these results did not appear for the PCS of HRQoL (p = 0.728, ES = 0.001). In the mediation analysis, it was found that CRF and handgrip strength acted as full mediators of the relationship between adherence to the MD and the MCS of HRQoL. In the moderation analysis, it was evidenced that CRF and handgrip strength did not act as moderators in the relationship between adherence to the MD and the MCS of HRQoL. In conclusion, adherence to the MD does not seem to have a direct effect on the MCS of HRQoL because this association seems to be fully mediated by CRF and handgrip strength.

Physical Exercise and Immune System in the Elderly: Implications and Importance in COVID-19 Pandemic Period

Physical exercise is seen as the main ally for health promotion, preventing and protecting the organism from several diseases. According to WHO, there is a tendency of constant growth in the elderly population in the coming years. The regular practice of exercises by the elderly becomes relevant to minimize the deleterious effects of the aging process and to increase the fitness index. Recently, the world population started a confrontation against Corona Virus Disease (COVID-19), which is the most significant public health challenge globally. Although social isolation is a reasonable measure in an attempt to stop contamination by COVID-19, this measure has limited the ability of individuals to exercise outdoors or in gyms and health clubs, which increased the risk of developing chronic illnesses related to a sedentary lifestyle. The critical point is that the recent recommendations on exercise prescription to combat the potentially harmful effects of COVID-19 failure to adequately address resistance exercise interventions as home-based exercise strategy. Thus, in this paper, we discussed the physical exercise as medicine if the training status is enough to protect the elderly against COVID-19 infection, about the role of physical activity on immunosuppression. Possible risks for COVID-19 infection, and the old training methods, such as no-load resistance training as possible resistance exercise strategies and high-intensity interval training, as new proposals of home-based exercise interventions, could perform during the current COVID-19 pandemic.

An Estimation Model for Cardiorespiratory Fitness in Adults with Rheumatoid Arthritis

PURPOSE

Cardiopulmonary exercise testing of peak oxygen uptake (V˙O2peak) is the gold standard to measure cardiorespiratory fitness (CRF). For resource-intensive evaluation, equations estimating CRF (eCRF) may be used. The purpose was to investigate if an eCRF equation from a healthy population is useful in persons with rheumatoid arthritis (RA), and if necessary, develop new equations for eCRF in this group.

METHODS

V˙O2peak results from 93 persons with RA were compared with eCRF calculated by an established equation for healthy individuals including age, sex, physical activity (PA index), resting HR (RHR), and waist circumference. Because of deviation from the observed V˙O2peak, new equations for eCRF in persons with RA were developed from regression analysis of variables associated with observed V˙O2peak.

RESULTS

The established equation overestimated CRF (R = 0.48, root mean square error [RMSE] = 7.07). The new RA equation more accurately estimated CRF (R = 0.81, RMSE = 4.44) (female = 0, male = 1; never smoked = 0, ever smoked = 1): eCRF = 77.961 + (sex × 28.791) - (age × 0.358) - (age-sex interaction × 0.326) - (body mass index [BMI] × 0.700) - (RHR × 0.125) - (smoking × 1.854) + (PA index × 0.211) - (patient global RA assessment × 0.071). Alternative new RA equation (R = 0.79, RMSE = 4.63): eCRF = 77.851 + (sex × 25.460) - (age × 0.381) - (age-sex interaction × 0.254) - (BMI × 0.743) - (RHR × 0.115) - (smoking × 2.154) + (PA index × 0.209).

CONCLUSIONS

The new RA equations better predicted CRF in individuals with RA, preventing overestimation in low-fit persons. The new equation should be preferred when estimating CRF in individuals with RA. The alternative equation, without patient global assessment, is useful for individuals with RA in population-based studies.