Generalized equations for predicting functional capacity from treadmill performance

Low cardiorespiratory fitness is associated with elevated intraocular pressure among apparently healthy adults

PURPOSE

To evaluate the association of cardiorespiratory fitness with elevated intraocular pressure (IOP) in healthy adults.

METHODS

In this cross-sectional study, we evaluated 17,990 asymptomatic self-referred adults free of diabetes or cardiovascular disease who were screened in a preventive healthcare setting. All subjects underwent measurement of IOP and completed a maximal exercise stress test according to the Bruce protocol. Fitness was categorized into age and sex-specific quintiles according to the treadmill time and dichotomized to low (lowest quintile) and non-low fitness groups. Elevated IOP was defined as ≥ 21 mmHg.

RESULTS

Median age was 45 (IQR 39-52) years and 12,073 (67%) were men. There were 3,351 (19%) subjects in the low fitness group. Median IOP was 14 mmHg (IQR 12-16) with elevated IOP documented in 188 (1%) subjects. Univariate binary logistic regression model demonstrated that compared with non-low fitness group, subjects in the low fitness group were 2.2 times more likely to have elevated IOP (95% CI 1.598-2.95, p<0.001). Multivariate binary logistic regression with adjustment to known cardiovascular risk factors (age, sex, hypertension, smoking, overweight, regular physical activity, low HDL cholesterol, high triglycerides, and fasting glucose levels) successfully demonstrated that lower fitness was independently and significantly associated with a 90% increased likelihood of elevated IOP (95% CI 1.37-2.61, p<0.001). Subgroup analysis revealed that the association was more pronounced among women compared with men (OR 3.8 vs. 1.6, p for interaction = 0.069).

CONCLUSIONS

Low cardiorespiratory fitness is independently associated with increased IOP among apparently healthy adults.

Improving Reporting of Exercise Capacity Across Age Ranges Using Novel Workload Reference Equations

Exercise capacity (EC) is an important predictor of survival in the general population and in subjects with cardiopulmonary disease. Despite its relevance, considering the percent-predicted workload (%pWL) given by current equations may overestimate EC in older adults. Therefore, to improve the reporting of EC in clinical practice, our main objective was to develop workload reference equations (pWL) that better reflect the relation between workload and age. Using the Fitness Registry and the Importance of Exercise National Database (FRIEND), we analyzed a reference group of 6,966 apparently healthy participants and 1,060 participants with heart failure who underwent graded treadmill cardiopulmonary exercise testing. For the first group, the mean age was 44 years (18 to 79); 56.5% of participants were males and 15.4% had obesity. Peak oxygen consumption was 11.6 ± 3.0 METs in males and 8.5 ± 2.4 METs in females. After partition analysis, we first developed sex-specific pWL equations to allow comparisons to a healthy weight reference. For males, pWL (METs) = 14.1-0.9×10-3×age2 and 11.5-0.87×10-3×age2 for females. We used those equations as denominators of %pWL, and based on their distribution, we determined thresholds for EC classification, with average EC defined by the range corresponding to 85% to 115%pWL. Compared with %pWL using current equations, the new equations yielded better-calibrated %pWL across different age ranges. We also derived body mass index-adjusted pWL equations that better assessed EC in subjects with heart failure. In conclusion, the novel pWL equations have the potential to impact the report of EC in practice.

Long-Term Mortality Risk According to Cardiorespiratory Fitness in Patients Undergoing Coronary Artery Bypass Graft Surgery

The aim of this study was to evaluate the association between cardiorespiratory fitness (CRF) and long-term survival in United States (US) Veterans undergoing CABG. We identified 14,550 US Veterans who underwent CABG at least six months after completing a symptom-limited exercise treadmill test (ETT) with no evidence of cardiovascular disease. During a mean follow-up period of 10.0 ± 5.4 years, 6502 (43.0%) died. To assess the association between CRF and risk of mortality, we formed the following five fitness categories based on peak workload achieved (metabolic equivalents or METs) prior to CABG: Least-Fit (4.3 ± 1.0 METs (n = 4722)), Low-Fit (6.8 ± 0.9 METs (n = 3788)), Moderate-Fit (8.3 ± 1.1 METs (n = 2608)), Fit (10.2 ± 0.8 METs (n = 2613)), and High-Fit (13.0 ± 1.5 METs (n = 819)). Cox proportional hazard models were used to calculate risk across CRF categories. The models were adjusted for age, body mass index, race, cardiovascular disease, percutaneous coronary intervention prior to ETT, cardiovascular medications, and cardiovascular disease risk factors. P-values < 0.05 using two-sided tests were considered statistically significant. The association between cardiorespiratory fitness and mortality was inverse and graded. For every 1-MET increase in exercise capacity, the mortality risk was 11% lower (HR = 0.89; CI: 0.88-0.90; p < 0.001). When compared to the Least-Fit category (referent), mortality risk was 22% lower in Low-Fit individuals (HR = 0.78; CI: 0.73-0.82; p < 0.001), 31% lower in Moderate-Fit individuals (HR = 0.69; CI: 0.64-0.74; p < 0.001), 52% lower in Fit individuals (HR = 0.48; CI: 0.44-0.52; p < 0.001), and 66% lower in High-Fit individuals (HR = 0.34; CI: 0.29-0.40; p < 0.001). Cardiorespiratory fitness is inversely and independently associated with long-term mortality after CABG in Veterans referred for exercise testing.

Associations of objectively measured physical activity, sedentary time and cardiorespiratory fitness with adipose tissue insulin resistance and ectopic fat

BACKGROUND/OBJECTIVES

Inadequate movement, excess adiposity, and insulin resistance augment cardiometabolic risk. This study examined the associations of objectively measured moderate-to-vigorous intensity physical activity (MVPA), sedentary time and cardiorespiratory fitness (CRF), with adipose tissue insulin resistance and ectopic fat.

METHODS

Data were combined from two previous experimental studies with community volunteers (n = 141, male = 60%, median (interquartile range) age = 37 (19) years, body mass index (BMI) = 26.1 (6.3) kg·m-2). Adipose tissue insulin resistance was assessed using the adipose tissue insulin resistance index (Adipo-IR); whilst magnetic resonance imaging (MRI) was used to measure liver, visceral (VAT) and subcutaneous abdominal adipose tissue (ScAT). Sedentary time and MVPA were measured via an ActiGraph GT3X+ accelerometer. Generalized linear models examined the association of CRF, MVPA, and sedentary time with Adipo-IR and fat depots. Interaction terms explored the moderating influence of age, sex, BMI and CRF.

RESULTS

After controlling for BMI and cardiometabolic variables, sedentary time was positively associated with Adipo-IR (β = 0.68 AU [95%CI = 0.27 to 1.10], P < 0.001). The association between sedentary time and Adipo-IR was moderated by age, CRF and BMI; such that it was stronger in individuals who were older, had lower CRF and had a higher BMI. Sedentary time was also positively associated with VAT (β = 0.05 L [95%CI = 0.01 to 0.08], P = 0.005) with the relationship being stronger in females than males. CRF was inversely associated with VAT (β = -0.02 L [95%CI = -0.04 to -0.01], P = 0.003) and ScAT (β = -0.10 L [95%CI = -0.13 to -0.06], P < 0.001); with sex and BMI moderating the strength of associations with VAT and ScAT, respectively.

CONCLUSIONS

Sedentary time is positively associated with adipose tissue insulin resistance which regulates lipogenesis and lipolysis. CRF is independently related to central fat storage which is a key risk factor for cardiometabolic disease.

A High intensity Interval training (running and swimming) and resistance training intervention on heart rate variability and the selected biochemical factors in boys with type 1 diabetes

OBJECTIVE

The purpose of this research is to investigate the effect of High Intensity Interval Training and Resistance training (HIITR) on heart rate variability (HRV), blood glucose, and plasma biomarkers levels in adolescents with type 1 diabetes (T1D).

RESEARCH DESIGN AND METHODS

24 boys with T1D (FBS: 274.66 ± 52.99, age: 15.2 ± 1.78 years, and BMI = 19.61 ± 1.11) and 12 healthy boys (FBS: 92.75 ± 5.22, age: 15.08 ± 1.67 years, and BMI = 20.26 ± 2.66) were divided into three groups: Diabetes Training (DT, n = 12), Diabetes Control (DC, n = 12), and Healthy Control (HC, n = 12). HRV (24 h) was computed in time and frequency domains, anthropometric, biochemical parameters at rest, and aerobic capacity (VO2peak) obtained during a graded exercise testing (GXT). All variables were evaluated at the baseline and following 12 weeks of exercise training, done 3 days weekly. The statistical method used for data analysis was analysis of covariance (ANCOVA) test.

RESULTS

HRV, Hemoglobin A1c (HbA1c) and Fasting blood sugar (FBS), VO2peak, norepinephrine (NEP), and HDL-C indicated significant differences between both T1D groups compared to HC at baseline (p < 0.001). BMI, LDL-C, TC, and TG parameters were similar in all groups. HRV parameters, VO2peak and HDL-C, and NEP were significantly improved by exercise training, and HbA1c and FBS levels were significantly reduced (p < 0.001). There is a negative and significant correlation between LF/HF Ratio Difference (post-test minus pre-test) and VO2Peak Difference variables (post-test minus pre-test) (p < 0.001).

CONCLUSIONS

The present study suggests the importance of early screening for CVD risk factors in adolescent males with T1D. Also, it was revealed HIITR training compared to other training patterns, and cardiovascular health improves via enhancement of autonomic modulation, VO2peak, plasma lipids, and catecholamine levels.

Nonexercise machine learning models for maximal oxygen uptake prediction in national population surveys

OBJECTIVE

Nonexercise algorithms are cost-effective methods to estimate cardiorespiratory fitness (CRF), but the existing models have limitations in generalizability and predictive power. This study aims to improve the nonexercise algorithms using machine learning (ML) methods and data from US national population surveys.

MATERIALS AND METHODS

We used the 1999-2004 data from the National Health and Nutrition Examination Survey (NHANES). Maximal oxygen uptake (VO2 max), measured through a submaximal exercise test, served as the gold standard measure for CRF in this study. We applied multiple ML algorithms to build 2 models: a parsimonious model using commonly available interview and examination data, and an extended model additionally incorporating variables from Dual-Energy X-ray Absorptiometry (DEXA) and standard laboratory tests in clinical practice. Key predictors were identified using Shapley additive explanation (SHAP).

RESULTS

Among the 5668 NHANES participants in the study population, 49.9% were women and the mean (SD) age was 32.5 years (10.0). The light gradient boosting machine (LightGBM) had the best performance across multiple types of supervised ML algorithms. Compared with the best existing nonexercise algorithms that could be applied to the NHANES, the parsimonious LightGBM model (RMSE: 8.51 ml/kg/min [95% CI: 7.73-9.33]) and the extended LightGBM model (RMSE: 8.26 ml/kg/min [95% CI: 7.44-9.09]) significantly reduced the error by 15% and 12% (P < .001 for both), respectively.

DISCUSSION

The integration of ML and national data source presents a novel approach for estimating cardiovascular fitness. This method provides valuable insights for cardiovascular disease risk classification and clinical decision-making, ultimately leading to improved health outcomes.

CONCLUSION

Our nonexercise models provide improved accuracy in estimating VO2 max within NHANES data as compared to existing nonexercise algorithms.

Risk Factors for Cardiometabolic Disease in Professional Firefighters

OBJECTIVE

Firefighters are plagued with cardiometabolic disease (CMD). Obesity, poor cardiorespiratory and muscular fitness, and blood lipids (low-density lipoprotein cholesterol, triglycerides, low high-density lipoprotein cholesterol) are risk factors for CMD. However, markers of oxidative stress, inflammation, and insulin resistance can provide further insight regarding CMD risk.

METHODS

This study investigated the relationships between fitness metrics (cardiorespiratory and muscular fitness, percent body fat, waist circumference), blood lipids, blood pressure, and years of experience as a firefighter to blood markers of insulin resistance: Homeostatic Model Assessment for Insulin Resistance (HOMA-IR), oxidative stress: advanced oxidation protein products (AOPPs), and inflammation: C-reactive protein.

RESULTS

Waist circumference and blood concentrations of triglycerides were significantly related to AOPPs and HOMA-IR. Cardiorespiratory fitness was inversely related to AOPPs, HOMA-IR and C-reactive protein.

CONCLUSION

These findings demonstrate the importance of high cardiorespiratory fitness and low waist circumference to reduce markers of CMD.

High-Intensity Interval Training Versus Moderate-Intensity Continuous Training for Improving Physical Health in Elderly Women

In elderly women, a lack of regular physical exercise may result in faster decreases in general health and functional performance. Although high-intensity interval training (HIIT) and moderate-intensity continuous training (MICT) have been effectively applied in young and clinical groups, there is no evidence to support their use in elderly women to achieve health benefits. Thus, the major goal of this study was to investigate how HIIT affected health-related outcomes in elderly women. Twenty-four inactive elderly women agreed to participate in the 16-week HIIT and MICT intervention. Body composition, insulin resistance, blood lipids, functional capacity, cardiorespiratory fitness, and quality of life were all measured before and after the intervention. The number of differences between groups was determined using Cohen's effect sizes, and the pre-post intra-group changes were compared using paired t-tests. Using 2 × 2 ANOVA, the time × group interaction effects between HIIT and MICT were evaluated. Body fat percentage, sagittal abdominal diameter, waist circumference, and hip circumference all were improved significantly in the 2 groups. HIIT substantially improved fasting plasma glucose and cardiorespiratory fitness as compared to the MICT. HIIT improved the lipid profile and functional ability more significantly compared to the MICT group. These findings show that HIIT is a useful exercise for improving elderly women's physical health.

Normal reference values for aerobic fitness in cystic fibrosis: a scoping review

Objective

The importance of aerobic fitness (VO2peak) in cystic fibrosis (CF) is well established, and regular exercise testing is recommended. To standardise VO2peak, a ‘percentage of predicted’ (%pred) derived from normative reference values (NRV), as promoted by the 2015 European Cystic Fibrosis Society Exercise Working Group (ECFS EWG), can be reported. However, the NRVs used in CF and their relative frequency is unknown.

Method

A scoping review was performed via systematic database searches (PubMed, Embase, Web of Science, SciELO, EBSCO) and forward citation searches for studies that include people with CF and report VO2peakas %pred. Studies were screened using Covidence, and data related to patient demographics, testing modality and reference equations were extracted. Additional analyses were performed on studies published in 2016–2021, following the ECFS EWG statement in 2015.

Results

A total of 170 studies were identified, dating from 1984 to 2022, representing 6831 patients with CF, citing 34 NRV. Most studies (154/170) used cycle ergometry, 15/170 used treadmills, and the remainder used alternative, combination or undeclared modalities. In total, 61/170 failed to declare the NRV used. There were 61 studies published since the ECFS EWG statement, whereby 18/61 used the suggested NRV.

Conclusion

There is a wide discrepancy in NRV used in the CF literature base to describe VO2peakas %pred, with few studies using NRV from the ECFS EWG statement. This high variance compromises the interpretation and comparison of studies while leaving them susceptible to misinterpretation and limiting replication. Standardisation and alignment of reporting of VO2peakvalues are urgently needed.

Firefighters With Higher Cardiorespiratory Fitness Demonstrate Lower Markers of Cardiovascular Disease Risk

OBJECTIVE

High cardiorespiratory fitness (CRF) is associated with reduced markers of oxidative stress and cardiovascular disease (CVD) risk factors; however, this relationship has not been elucidated in firefighters. The purpose of this study was to examine differences in markers of CVD risk between firefighters who have either high or low levels of CRF.

METHODS

Forty-six firefighters participated in a maximal graded exercise test and a dual-energy x-ray absorptiometry scan and provided a fasted blood sample. V˙O 2max values were categorized based on American College of Sports Medicine guidelines to establish high- and low-fitness groups.

RESULTS

High fitness firefighters demonstrated significantly higher high-density lipoprotein cholesterol and lower markers of CVD risk: cholesterol, triglycerides, low-density lipoprotein cholesterol, insulin, homeostatic model assessment for insulin resistance, C-reactive protein, and advanced oxidation protein products concentrations.

CONCLUSION

Firefighters are encouraged to maintain high CRF to reduce risk of CVD.

Leisure-time regular exercise and prevention of the side effects of immune system activity in middle-aged healthy subjects

Regular exercise is recommended to improve immune system function and antioxidant activity, while conversely, it may cause inflammation by increasing neutrophil-derived main enzyme, myeloperoxidase, which produces reactive oxygen species. The present study aimed to investigate changes in myeloperoxidase level, its influence on total oxidant status, and the capacity of the antioxidant defence system to counteract oxidative stress in middle-aged men participating in leisure-time regular exercise compared to untrained peer subjects. Twenty trained (age 53.58±2.94 years, body mass index (BMI) 25.47±1.6) and 17 untrained (age 54.17±2.83 years, BMI 27.83±1.12) healthy middle-aged men participated in this study [Rasht, Gilan, Iran]. Participants performed a modified Bruce treadmill test as a model of progressive exercise training. Blood samples were taken before, immediately after, and one hour after the end of the test. A mixed ANOVA and Bonferroni post hoc test was used for the analysis of variables. A significant difference was observed in myeloperoxidase levels between groups, while the trained group showed a significantly lower concentration than the untrained group (P<0.018). This result was also consistent with the lower total oxidant status in this group (P<0.001). Total antioxidant capacity changed significantly in both groups with higher concentration in the trained group (P<0.001). The leisure-time regular exercise can reduce myeloperoxidase concentration and total oxidant status in healthy middle-aged men while increasing the total antioxidant capacity, which may potentially protect them from the side effects of immune system activity induced by exercise training.

Evaluation of Korean Firefighters’ Fitness Using Candidate Physical Ability Test: Pilot Study

OBJECTIVES The Candidate Physical Ability Capability Test (CPAT) is a complex performance test to assess whether firefighters have sufficient ability to meet the physical demands of firefighting, and is widely used in many countries, especially in North America. In South Korea, however, simple basic physical fitness assessments are still used for firefighters’ fitness evaluation. Here, we report the physical fitness of Korean firefighters using the CPAT for the first time in Korea.METHODS Eighteen male Korean firefighters aged between 20 to 30 years participated in this study. All subjects were measured for maximum oxygen consumption (VO2max) by using gas analyzer and cycle ergometer before CPAT. On a separate day, each subject performed CPAT with the best effort. Each subject’s oxygen consumption (VO₂), heart rate (HR) and completion time were measured during the CPAT. The results of CPAT were analyzed based on VO2max and HRmax and compared to the those of previous study from North American firefighter candidates.RESULTS VO2max was significantly (p< .001) lower and HRmax was significantly (p< .05) higher in Korean firefighters (45.4±4.6 ml/kg/min and 194.2±2.1 beat/min) than American firefighter candidates (53.0±7.4 ml/kg/min and 188.0±8.0 beat/min). During CPAT, Korean firefighters showed 69.4±15.8 %VO2max and 87.6±7.8 %HRmax and American firefighter candidates had 73.1±8.0 %VO2max and 90.1±5.3 %HRmax, but these were not statistically significant. However, the completed time of CPAT was significantly slower in Korean firefighters than American firefighter candidates (726.8±84.6 sec vs. 512.0±51.0 sec, p<.001).CONCLUSIONS Korean firefighters have lower cardiorespiratory endurance capacity and CPAT performance than American firefighter candidates. In addition, Korean firefighters did not complete the CPAT within the pass time limit. It suggests that Korean firefighters need to improve more physical ability for physical demands of firefighting.

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.

High-Intensity Functional Training Guided by Individualized Heart Rate Variability Results in Similar Health and Fitness Improvements as Predetermined Training with Less Effort

Heart rate variability (HRV) may be useful for prescribing high-intensity functional training (HIFT) exercise programs. This study aimed to compare effects of HRV-guided and predetermined HIFT on cardiovascular function, body composition, and performance.

METHODS

Recreationally-active adults (n = 55) were randomly assigned to predetermined HIFT (n = 29, age = 24.1 ± 4.1 years) or HRV-guided HIFT (n = 26, age = 23.7 ± 4.5) groups. Both groups completed 11 weeks of daily HRV recordings, 6 weeks of HIFT (5 d·week-1), and pre- and post-test body composition and fitness assessments. Meaningful changes in resting HRV were used to modulate (i.e., reduce) HRV-guided participants' exercise intensity. Linear mixed models were used with Bonferroni post hoc adjustment for analysis.

RESULTS

All participants significantly improved resting heart rate, lean mass, fat mass, strength, and work capacity. However, no significant between-groups differences were observed for cardiovascular function, body composition, or fitness changes. The HRV-guided group spent significantly fewer training days at high intensity (mean difference = -13.56 ± 0.83 days; p < 0.001).

CONCLUSION

HRV-guided HIFT produced similar improvements in cardiovascular function, body composition, and fitness as predetermined HIFT, despite fewer days at high intensity. HRV shows promise for prescribing individualized exercise intensity during HIFT.

Differential effect of maximal incremental treadmill exercise on tear secretion and tear film stability in athletes and non-athletes

The study investigated the differential response to a single bout of maximal incremental treadmill exercise between athletes and non-athletes without dry eyes regarding tear secretion, tear film stability, visual acuity (VA), and stereoacuity. Additionally, the study examined the effect of gender and the duration of exercise on exercise-induced changes. Study participants included young university students aged 18-25 years who were athletes (male/female: 13/13) or non-athletes (male/female: 17/9). Participants underwent an aerobic exercise session using a treadmill and following the laid down Bruce treadmill test protocol till exhaustion. Measurements were taken in the order of distance VA, stereopsis, non-invasive tear break-up time (TBUT), and phenol red thread test, at baseline and after the exercise regimen. Within- and between-subject analyses using multiple t-tests with correction for multiple comparisons were performed to determine differences before and after exercise in athletes and non-athletes. Subsequently, ANCOVA was used to assess the influence of gender and the duration of exercise. The mean age (SD) of the athletes and the non-athletes was 22.4 ± 2.1 years and 21.8 ± 2.1 years, respectively (p = 0.357). Before exercise, the athletes had higher TBUT than non-athletes (14.6 ± 2.9 s vs. 11.9 ± 3.8 s; p = 0.021), but no difference was observed in any other ocular measurements. After exercise, the athletes showed significant improvement in tear secretion with the basal tear secretion increasing from 22.3 ± 2.5 mm to 25.8 ± 1.7 mm (p < 0.001). The non-athletes on the other hand had a borderline increase in tear secretion from 21.42 ± 2.85 mm to 23.73 ± 2.68 mm (p = 0.08). Also, the TBUT was much improved in the athletes after exercise compared to the non-athletes (17.7 ± 2.7 s vs. 14.8 ± 2.9 s, p = 0.004). Additionally, exercise improved the VA indifferently between the groups, while stereoacuity was unchanged after exercise in either group. Gender had no influence on the differences in the tear function measures between athletes and non-athletes after exercise. The duration of exercise, however, showed a borderline effect on the tear film stability (p = 0.068) after exercise. Our findings support the differential effect of maximal incremental treadmill exercise on tear secretion and tear film stability between athletes and non-athletes. Thus, increased physical fitness and the duration of exercise might be crucial in the improvement of tear function through aerobic exercise.

Cardiac Rehabilitation and Physical Performance in Patients after Myocardial Infarction: Preliminary Research

(1) Background: Cardiovascular diseases, in particular, myocardial infarction (MI), are the main threats to human health in modern times. Cardiac rehabilitation (CR), and especially increased physical activity, significantly prevent the consequences of MI. The aim of this study was to assess physical performance in patients after MI before and after CR. (2) Methods: 126 patients after MI were examined. They were admitted to the cardiac rehabilitation ward twice: in the 3rd month after MI, and then in the 6th month after the last rehabilitation session. CR lasted 20 treatment days (4 weeks with 5 treatment days and 2 days’ break). The exercise stress test on the treadmill and a 6-minute walk test (6MWT) were used to assess physical performance. Patients were assigned to an appropriate rehabilitation model due to their health condition. (3) Results: In the studied group, the exercise stress test time and the metabolic equivalent of task (MET), the maximal oxygen consumption (VO2max), and 6MWT score increased significantly (p = 0.0001) at two time-points of observation. (4) Conclusion: CR significantly improves physical performance in patients after MI.

Exercise blood pressure, cardiorespiratory fitness and mortality risk

OBJECTIVE

To assess the cardiorespiratory fitness (CRF) impact on the association between exercise blood pressure (BP) and mortality risk.

PATIENTS AND METHODS

We assessed CRF in 15,004 US Veterans (mean age 57.5 ± 11.2 years) who completed a standardized treadmill test between January 1, 1988 and July 28, 2017 and had no evidence of ischemia. They were classified as Unfit or Fit according to the age-specific metabolic equivalents (METs) achieved <50% (6.2 ± 1.6 METs; n = 8440) or ≥ 50% (10.5 ± 2.4 METs; n = 6264). To account for the impact of resting systolic BP (SBP) on outcomes, we calculated the difference (Peak SBP-Resting SBP) and termed it SBP-Reserve. We noted a significant increase in mortality associated with SBP-Reserve ≤52 mmHg and stratified the cohort accordingly (SBP-Reserve ≤52 mmHg and > 52 mmHg). We applied multivariable Cox models to estimate hazard ratios (HR) and 95% confidence interval (CIs) for outcomes.

RESULTS

Mortality risk was significantly elevated only in Unfit individuals with SBP-Reserve ≤52 mmHg compared to those with SBP-Reserve >52 mmHg (HR = 1.35; CI: 1.24-1.46; P < 0.001). We then assessed the CRF and SBP-Reserve interaction on mortality risk with Fit individuals with SBP-Reserve >52 mmHg serving as the referent. Mortality risk was 92% higher (HR = 1.92%; 95% CI: 1.77-2.09; P < 0.001) in Unfit individuals with SBP-Reserve ≤52 mmHg and 47% higher (HR = 1.47; 95% CI: 1.33-1.62; P < 0.001) in those with SBP-Reserve >52 mmHg.

CONCLUSION

Low CRF was associated with increased mortality risk regardless of peak exercise SBP. The risk was substantially higher in individuals unable to augment their exercise SBP >52 mmHg beyond resting levels.

Accuracy of Exercise-based Equations for Estimating Cardiorespiratory Fitness

Equations are often used to predict cardiorespiratory fitness (CRF) from submaximal or maximal exercise tests. However, no study has comprehensively compared these exercise-based equations with directly measured CRF using data from a single, large cohort.

PURPOSE

This study aimed to compare the accuracy of exercise-based prediction equations with directly measured CRF and evaluate their ability to classify an individual's CRF.

METHODS

The sample included 4871 tests from apparently healthy adults (38% female, age 44.4 ± 12.3 yr (mean ± SD)). Estimated CRF (eCRF) was determined from 2 nonexercise equations, 3 submaximal exercise equations, and 10 maximal exercise equations; all eCRF calculations were then compared with directly measured CRF, determined from a cardiopulmonary exercise test. Analysis included Pearson product-moment correlations, standard error of estimate values, intraclass correlation coefficients, Cohen κ coefficients, and the Benjamini-Hochberg procedure to compare eCRF with directly measured CRF.

RESULTS

All eCRF values from the prediction equations were associated with directly measured CRF (P < 0.01), with intraclass correlation coefficient estimates ranging from 0.07 to 0.89. Although significant agreement was found when using eCRF to categorize participants into fitness tertiles, submaximal exercise equations correctly classified an average of only 51% (range, 37%-58%) and maximal exercise equations correctly classified an average of only 59% (range, 43%-76%).

CONCLUSIONS

Despite significant associations between exercise-based prediction equations and directly measured CRF, the equations had a low degree of accuracy in categorizing participants into fitness tertiles, a key requirement when stratifying risk within a clinical setting. The present analysis highlights the limited accuracy of exercise-based determinations of eCRF and suggests the need to include cardiopulmonary measures with maximal exercise to accurately assess CRF within a clinical setting.

High fitness might be associated with the development of new-onset atrial fibrillation in obese non-athletic adults

BACKGROUND

Data on the association between AF and fitness are conflicting.

OBJECTIVES

The aim of this analysis was to investigate the association between fitness, obesity and incidence of atrial fibrillation (AF) among apparently healthy non-athlete adults.

METHODS

We investigated 20 410 self-referred subjects who were annually screened in a tertiary medical centre. All subjects were free of AF and completed maximal exercise stress test according to the Bruce protocol at baseline. Fitness was categorised into age- and sex-specific quintiles (Q) according to the treadmill time. Subjects were categorised to low (Q1-Q2) and high fitness (Q3-5) groups. The primary end point was new-onset AF during follow-up.

RESULTS

Mean age was 48 ± 10 years and 72% were men. A total of 463 (2.3%) events occurred during an average follow-up of 8 ± 5 years corresponding to an AF event rate of 0.3% per person year. Univariate and multivariate models showed that AF risk was similar in both fitness groups. However, AF event rate was 0.55% per person year among high fitness obese subjects, compared with 0.31% for low fitness obese subjects (P < .01). Subgroup interaction analysis showed that AF risk is obesity-dependent, such that in the obese group (≥30 kg/m² ) high fitness was independently associated with a significant 79% increased AF risk (95% CI 1.15-2.78; P = .01), whereas among non-obese subjects the rate of events was similar between both fitness groups (P for interaction = (.02)).

CONCLUSIONS

Our findings suggest that high fitness might be associated with increased AF risk among obese subjects.

Cardiorespiratory fitness and survival following cancer diagnosis

Aims

Data on the association of cardiorespiratory fitness with survival of cancer patients are limited. This study aimed to evaluate the association between midlife cardiorespiratory fitness and survival after a subsequent cancer diagnosis.

Methods

We evaluated 19,134 asymptomatic self-referred adults who were screened in preventive healthcare settings. All subjects were free of cardiovascular disease and cancer at baseline and completed a maximal exercise stress test. Fitness was categorised into age-specific and sex-specific quintiles according to the treadmill time and dichotomised to low (quintiles 1–2) and high fitness groups.

Results

The mean age was 50 ± 8 years and 72% were men. During a median follow-up of 13 years (interquartile range 7–16) 517 (3%) died. Overall, 1455 (7.6%) subjects developed cancer with a median time to cancer diagnosis of 6.4 years (interquartile range 3–10). Death from the time of cancer diagnosis was significantly lower among the high fitness group (Plog rank = 0.03). Time-dependent analysis showed that subjects who developed cancer during follow-up were more likely to die (P &lt; 0.001). The association of cancer with survival was fitness dependent such that in the lower fitness group cancer was associated with a higher risk of death, whereas among the high fitness group the risk of death was lower (hazard ratio 20 vs. 15; Pfor interaction = 0.047). The effect modification persisted after applying a 4-year blanking period between fitness assessment and cancer diagnosis (Pfor interaction = 0.003).

Conclusion

Higher midlife cardiorespiratory fitness is associated with better survival among cancer patients. Our findings support fitness assessment in preventive healthcare settings.

Cardiorespiratory Fitness Is an Independent Predictor of Cardiovascular Morbidity and Mortality and Improves Accuracy of Prediction Models

BACKGROUND

Although cardiorespiratory fitness (CRF) is a strong independent predictor of adverse cardiovascular outcomes, it is not considered as a risk enhancer by current guidelines.

METHODS

We evaluated asymptomatic self-referred adults aged 40 to 79 years of age, free of cardiovascular disease at baseline, who were screened annually and completed baseline exercise stress test. Baseline CRF was dichotomized into 2 groups: low (metabolic equivalents < 8) and high. The primary endpoint was the composite of death, nonfatal acute coronary syndrome, and stroke after excluding subjects diagnosed with metastatic cancer during follow-up.

RESULTS

Study population included 15,445 subjects with median age of 49 years (interquartile range: 44-55). During median follow-up of 8 years 1362 (9%) subjects developed the study endpoint. Kaplan-Meier survival analysis showed that both fitness and atherosclerotic cardiovascular disease (ASCVD) were associated with developing of the study endpoint (P < 0.001 for both). Cox regression model with adjustment for ASCVD risk consistently showed that lower fitness was associated with a significant 23% higher risk to develop the study endpoint (P = 0.001). Continuous net reclassification improvement analysis showed an overall improvement of 11.4% (95% confidence interval, 8%-14.6%; P value < 0.001) in the accuracy of classification when fitness was added to the ASCVD model.

CONCLUSIONS

Low CRF is a strong independent predictor of the cardiovascular morbidity and mortality in asymptomatic adults. Addition of fitness to the pooled cohort ASCVD risk significantly improves the accuracy of the model.

Cardiorespiratory fitness as a predictor of short-term and lifetime estimated cardiovascular disease risk

Development of cardiovascular disease (CVD) remains a public health concern for young to middle-aged adults, now exacerbated by the increasing prevalence of obesity and sedentary lifestyles. Cardiorespiratory fitness (CRF) improves the reclassification of short-term (10-year) CVD risk, but has not been uniformly defined across studies. This study evaluated cross-sectional differences in short-term and lifetime CVD risk scores, across both absolute metabolic equivalent (MET) and sex- and age-standardized CRF categories in 805 apparently healthy young to middle-aged adults (68% male; 47.4 ± 7.2 years). CVD risk factors were evaluated, and estimated cardiorespiratory fitness (CRF) measurements (METS and peak VO₂ ) were derived from a submaximal Bruce treadmill test. CRF measures also included post-exercise heart rate recovery (HRR) data. Consistent trends showing more favorable risk factor profiles and lower short-term CVD (QRISK2), and CVD mortality (SCORE) scores, associated with higher levels of CRF were evident in both sexes. Lifetime CVD risk (Q-Lifetime) was highest in the lowest CRF categories. Peak VO₂ and HRR following submaximal exercise testing contributed to the variability in short-term and lifetime CVD risk. Global CVD risk predictions were examined across different contemporary CRF classifications with inconsistent findings. Recommended absolute MET and sex- and age-standardized CRF categories were significantly associated with both short-term and lifetime risk of CVD outcomes. However, compared to internationally derived normative CRF standards, cohort-specific CRF categories resulted in markedly different proportion of individuals classified in the "poor" CRF category at higher CVD risk.

Associations between measures of health-related physical fitness and cardiometabolic risk factors in college students

OBJECTIVE

To determine the influence of health-related fitness on cardiometabolic risk factors in college students.

PARTICIPANTS

75 traditional students (33 men and 42 women, 21.8±1.8 years old) at a university in southeastern U.S.

METHODS

Height, weight, waist circumference, body composition, blood pressure, lipids, glucose, insulin, c-reactive protein, and glucose tolerance were measured. Indices of insulin sensitivity were calculated. Aerobic and muscular fitness were measured. Regression and correlation analyses, and comparisons of cardiometabolic markers in low- vs high-fit participants were performed.

RESULTS

Men and women with low muscular fitness exhibited higher fasting insulin, and poorer insulin sensitivity index scores than those with high muscular fitness. In addition, women with high body fat percentage exhibited higher fasting and 2-hour insulin levels and lower insulin sensitivity index scores than those with low body fat percentages.

CONCLUSIONS

College students possessing low levels of health-related physical fitness exhibited less favorable cardiometabolic risk profiles.

Are Changes in Physical Work Capacity Induced by High-Intensity Functional Training Related to Changes in Associated Physiologic Measures?

High-Intensity Functional Training (HIFT) is a novel exercise intervention that may test body systems in a balanced and integrated fashion by challenging individuals’ abilities to complete mechanical work. However, research has not previously determined if physical work capacity is unique to traditional physiologic measures of fitness. Twenty-five healthy men and women completed a six-week HIFT intervention with physical work capacity and various physiologic measures of fitness assessed pre- and post-intervention. At baseline, these physiologic measures of fitness (e.g., aerobic capacity) were significantly associated with physical work capacity and this relationship was even stronger at post-intervention assessment. Further, there were significant improvements across these physiologic measures in response to the delivered intervention. However, the change in these physiologic measures failed to predict the change in physical work capacity induced via HIFT. These findings point to the potential utility of HIFT as a unique challenge to individuals’ physiology beyond traditional resistance or aerobic training. Elucidating the translational impact of increasing work capacity via HIFT may be of great interest to health and fitness practitioners ranging from strength/conditioning coaches to physical therapists.

Effects of circuit exercise training on vascular health and blood pressure

As the global burden of cardiovascular disease (CVD) rises, public health-related interventions aimed at prevention of heart disease have gained medical attention. Clinical research reports that exercise is a protective risk factor associated with CVD and that clinicians need to provide exercise recommendations to patients. Nevertheless, physical inactivity remains a public health problem. In certain populations, like firefighters (FF), increased risk of CVD is especially concerning. The workload FF face is extreme, 50% of line-of-duty deaths (LODD) in FF are cardiac-related, and research on the volunteer FF population is scarce. Government regulations do not require volunteer FF companies to have fitness testing or programming, so exercise intervention studies are necessary to improve the burden of CVD risk in this population. Therefore, this study examined the effects of a 4-week exercise circuit training (CT) intervention on vascular health and fitness in volunteer FF (N = 27) from the Philadelphia PA area compared to a control group of Non-FF (N = 25). Carotid artery intima-media thickness (IMT), brachial artery flow-mediated dilation (FMD), augmentation index, and pulse pressure (PP), brachial and central blood pressure (BP) and fitness were measured pre- and post- intervention. Overall, volunteer FF had more significant improvements (p < 0.05) in vascular health measures (FMD, IMT, and PP). In both groups, we also found that brachial and central BP decreased with exercise. We show that a 4 week CT program can improve vascular structure and function in the volunteer FF population, suggesting that clinicians may be able to reduce or prevent cardiac LODD by exercise.

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Short term circuit training improves vascular health in volunteer firefighters.

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Core blood pressure and clinic blood pressure are reduced with 4 weeks of training.

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Implementing functional exercise programs in firehouses would improve overall health.

Cardiorespiratory fitness versus physical activity as predictors of all-cause mortality in men

BACKGROUND

Although both cardiorespiratory fitness (CRF) and physical activity (PA) are associated with mortality, whether they are associated with all-cause mortality independent of each other is unclear.

METHODS

CRF was assessed by a maximal exercise test and PA was measured by self-report in 8,171 male veterans. The predictive power of CRF and PA, along with clinical variables, was assessed for all-cause mortality during a mean (±SD) follow-up 8.7 (4.4) years during which there were 1,349 deaths.

RESULTS

CRF was associated with mortality after adjusting for clinical variables and remained a strong predictor of mortality after further adjusting for PA (hazard ratio 0.85, 95% CI 0.83-0.87). PA was a significant predictor of mortality after controlling for clinical variables; however, the association was eliminated after further adjusting for CRF (hazard ratio 0.98, 95% CI 0.88-1.10). In CRF-stratified analysis, being active (≥150 min/wk) was not associated with mortality within the unfit or fit categories (P>.4). However, in PA-stratified analysis, subjects categorized as fit (≥7 metabolic equivalents [METS]) had a lower risk of mortality regardless of PA status (P<.001).

CONCLUSIONS

In adult men, PA was associated with mortality independent of established risk factors, but not CRF. Conversely, CRF remained a strong predictor of mortality independent of PA status and established risk factors.

Evaluation of the convergent validity of an estimated cardiorespiratory fitness algorithm

PURPOSE

Examine the convergent validity of a cardiorespiratory fitness (CRF) algorithm when compared to treadmill-assessed CRF.

METHODS

Data from the 1999-2004 NHANES were used (N = 3259 adults 20-49 years). Cardiorespiratory fitness was estimated from an algorithm. Participants completed a submaximal treadmill-based protocol. We (1) evaluated the pairwise association (and ICC) between estimated and measured cardiorespiratory fitness, (2) employed a paired samples t test to examine potential mean differences between estimated and measured cardiorespiratory fitness, (3) constructed a Bland-Altman plot and 95% limits of agreement (LoA) to explore systematic differences and random error between estimated and measured cardiorespiratory fitness, and (4) examined the association (via linear regression) of estimated and measured cardiorespiratory fitness with chronic disease prevalence and C-reactive protein (CRP).

RESULTS

Mean estimated CRF (10.68 METs) was lower than the mean measured CRF of 11.37 METs (p < 0.0001). The calculated pairwise correlation was of a moderate strength, r = 0.43 (p < 0.0001), with an ICC of 0.40 (p < 0.001). Calculated LoA indicated that estimated CRF may differ from measured CRF by 40% below to 48% above. Regression analyses yielded statistically significant inverse associations of estimated (unstandardized coefficient = - 0.026; p < 0.001) and measured (unstandardized coefficient = - 0.007; p = 0.002) CRF with chronic disease and estimated (unstandardized coefficient = - 0.08; p < 0.001) and measured (unstandardized coefficient = - 0.03; p < 0.001) CRF with CRP.

CONCLUSION

Measured and estimated CRF were moderately correlated. However, estimated and measured CRF were statistically significant different from one another with noteworthy scatter around the average difference. As such, when feasible, objective measurements of CRF should be taken.

Effects of a 12-week cardiovascular rehabilitation programme on systemic inflammation and traditional coronary artery disease risk factors in patients with rheumatoid arthritis (CARDIA trial): a randomised controlled trial

INTRODUCTION

Patients with systemic inflammatory diseases such as rheumatoid arthritis (RA) have an increased risk of cardiovascular disease (CVD) above the baseline risk attributable to traditional CVD risk factors seen in the general population. Exercise in cardiac rehabilitation (CR) is designed specifically for high-risk primary prevention and those with established CVD. Even though the European League Against Rheumatism guidelines state that exercise is safe for individuals with RA and exercise can reduce CVD risk, patients with RA rarely participate in CR. Thus, little is known about CR's impact on inflammatory and CVD risk in the RA population. The purpose of this trial is to determine the feasibility of a 12-week CR programme for patients with RA and whether it decreases CVD risk without exacerbating RA.

METHODS AND ANALYSIS

This is a randomised controlled trial whereby 60 participants with RA will be recruited and randomly assigned to either standard of care (SOC) treatment or SOC plus a 12-week CR programme (60 min of education plus two 60 min aerobic exercise sessions/week). Exercise will be performed at 60%-80% of heart rate reserve. Outcome measures (Framingham Risk Score, resting heart rate, blood pressure, blood lipids, markers of systemic inflammation (ie, interleukin (IL) 6 and tumour necrosis factor-α (TNF-α), Clinical Disease Assessment Index, Disease Activity Score-28, physical activity levels and peak cardiorespiratory fitness) will be assessed preintervention (week-0), postintervention (week-13) and 6 months postintervention.

ETHICS AND DISSEMINATION

Ethical approval was obtained from the Nova Scotia Health Authority Research Ethics Board. Results will be submitted for publication in an appropriate peer-reviewed journal.

TRIAL REGISTRATION NUMBER

NCT01534871; Pre-results.

Impact of Cardiorespiratory Fitness on Mortality in Black Male Veterans With Resistant Systemic Hypertension

Patients with resistant systemic hypertension have poorer outcomes than nonresistant hypertensives. The purpose of this study was to evaluate the association between cardiorespiratory fitness and all-cause mortality in black male Veterans with resistant systemic hypertension. Patients were identified from a cohort undergoing exercise tolerance test at the department of Veterans Affairs Medical Center in Washington, DC. Patients were divided into 4 cardiorespiratory fitness categories based on age-specific peak metabolic equivalents achieved on a standard Bruce protocol. Multivariate Cox models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for all-cause mortality across all fitness categories. A total of 1,276 patients out of 9,068 hypertensives had resistant hypertension defined as systolic and/or diastolic blood pressure >140 and/or >90 mm Hg, respectively, on 3 antihypertensive medications, one of which was a diuretic or use of >4 antihypertensive medications. During a follow-up of 9.5 ± 4.2 years, an inverse association was observed between cardiorespiratory fitness and all-cause mortality in patients with resistant hypertension. Compared with the least-fit group, mortality was reduced by 21% in the low-fit group (HR 0.79, CI 0.60 to 1.05; p value: 0.280), 36% in the moderate-fit group (HR 0.64, CI 0.48 to 0.87; p value 0.001), and 62% in the high-fit group (HR 0.38, CI 0.25 to 0.56; p value <0.001). In conclusion, an inverse association was observed between the level of cardiorespiratory fitness and all-cause mortality in patients with resistant systemic hypertension. Compared with the least-fit referent group, the high-fit group had a significant 62% lower risk of all-cause mortality.

High Intensity Exercise: Can It Protect You from A Fast Food Diet?

The purpose of this study was to assess the ability of high intensity exercise to counteract the deleterious effects of a fast food diet on the cardiometabolic profile of young healthy men. Fifteen men were subjected to an exclusive fast food diet from a popular fast food restaurant chain (three extra value meals/day + optional snack) for 14 consecutive days. Simultaneously, participants were asked to perform each day high intensity interval training (HIIT) (15 × 60 sec sprint intervals (~90% of maximal heart rate)) on a treadmill. Fast food diet and energy expenditure profiles of the participants during the intervention were assessed as well as body composition (DXA), cardiometabolic profile (lipid, hepatic enzymes, glycated hemoglobin, glucose, insulin, hsC-reactive protein (hsCRP) and blood pressure) and estimated maximal oxygen consumption (VO2 max) pre- and post-experiment. We found significant improvements for fat mass, lean body mass, estimated VO₂ max, fasting glucose, serum lipoprotein(a) and hsCRP after the intervention (p < 0.05). HDL-cholesterol significantly decreased (p < 0.002), but the triglycerides/HDL-cholesterol ratio did not change. All other cardiometabolic variables measured remained stable, which includes the primary outcome: the HOMA index (pre: 1.83 ± 1.2 vs. post: 1.54 ± 0.7 values; p = 0.35). In conclusion, in large part, insulin resistance and the cardiometabolic profile of young healthy individuals seems to be protected by HIIT from a fast food diet.

The effect of three different exercise training modalities on cognitive and physical function in a healthy older population

Background

Older adults are encouraged to participate in regular physical activity to counter the age-related declines in physical and cognitive health. Literature on the effect of different exercise training modalities (aerobic vs resistance) on these health-related outcomes is not only sparse, but results are inconsistent. In general, it is believed that exercise has a positive effect on executive cognitive function, possibly because of the physiological adaptations through increases in fitness. Indications are that high-intensity interval training is a potent stimulus to improve cardiovascular fitness, even in older adults; however, its effect on cognitive function has not been studied before.

Therefore, the purpose of this study was to compare the effects of resistance training, high-intensity aerobic interval training and moderate continuous aerobic training on the cognitive and physical functioning of healthy older adults.

Methods

Sixty-seven inactive individuals (55 to 75 years) were randomly assigned to a resistance training (RT) group (n = 22), high-intensity aerobic interval training (HIIT) group (n = 13), moderate continuous aerobic training (MCT) group (n = 13) and a control (CON) group (n = 19) for a period of 16 weeks. Cognitive function was assessed with a Stroop task and physical function with the Timed-Up-and-Go (TUG) and submaximal Bruce treadmill tests.

Results

No significant GROUP x TIME interaction was found for Stroop reaction time (P > .05). The HIIT group showed the greatest practical significant improvement in reaction time on the information processing task, i.e. Stroop Neutral (ES = 1.11). MCT group participants had very large practical significant improvements in reaction time on the executive cognitive tasks, i.e. Stroop Incongruent and Interference (ES = 1.28 and 1.31, respectively). The HIIT group showed the largest practically significant increase in measures of physical function, i.e. walking endurance (ES = 0.91) and functional mobility (ES = 0.36).

Conclusions

MCT and RT proved to be superior to HIIT for the enhancement of older individuals’ executive cognitive function; whereas HIIT were most beneficial for improvement in information processing speed. HIIT also induced the largest gains in physical function.

Acute effect of intermittent and continuous aerobic exercise on release of cardiac troponin T in sedentary men

BACKGROUND

Studies have shown that acute exercise can increase serum concentrations of cardiac biomarkers, including cardiac troponin T (cTnT). We investigated the acute effects of intermittent (IE) and continuous (CE) exercise at the same cardiac workload on myocardial necrosis biomarkers in sedentary men.

METHODS

Eleven sedentary healthy men aged 22.3±1.9years completed the study. The subjects were divided into two groups and performed, in random order, IE (intensity alternating between 50% (2min) and 80% (1min) HRreserve) or CE (60% HRreserve). The study was designed as a single-blinded randomised crossover trial performed on two distinct experimental days separated by a 1-week washout period. Each session consisted of 40min of aerobic exercise, either IE or CE, on a treadmill. Blood samples were taken before (PRE), immediately after (POST) and 1h after (POST-1) each exercise session.

RESULTS

hs-cTnT significantly increased immediately after exercise in both protocols and remained elevated at POST-1 (P<0.05). There was no significant difference between POST and POST-1 values(P>0.05). Neither CE nor IE caused any significant change in CK-MB (P>0.05). The results also showed that HR and RPP increased significantly following both exercise protocols (P=0.001).

CONCLUSIONS

In summary, both CE and IE results in increased serum concentrations of hs-cTnT in sedentary men. However, this increase does not seem to be caused by the irreversible death of cardiomyocytes. CE resulted in a greater hs-cTnT concentration than IE.

Relationship between Academic Performance with Physical, Psychosocial, Lifestyle, and Sociodemographic Factors in Female Undergraduate Students

Background:

The purpose of this study was to investigate the relationship between physical, psychosocial, lifestyle and sociodemographic factors with academic performance in female undergraduate students.

Methods:

One hundred undergraduate female students from the Faculty of Science at the University of Quebec at Montreal participated in this study (mean age = 24.4 ± 4.6 years old). All participants provided their university transcript and had to complete at least 45 course credits from their bachelor degree. Body composition (DXA), handgrip strength, estimated maximal oxygen consumption (VO₂ max) (Bruce Protocol) and blood pressure were measured. Participants also completed a questionnaire on their psychosocial, academic motivation, lifestyle and sociodemographic profile.

Results:

Significant correlations were observed between GPA with estimated VO₂ max (r = 0.32), intrinsic motivation toward knowledge (r = 0.23), intrinsic motivation toward accomplishment (r = 0.27) and external regulation (r = -0.30, P = 0.002). In addition, eating breakfast every morning and being an atheist was positively associated with academic performance (P < 0.05). Finally, a stepwise linear regression analysis showed that external regulation, intrinsic motivation toward accomplishment, VO₂ max levels and eating a daily breakfast explained 28.5 % of the variation in the GPA in our cohort.

Conclusions:

Results of the present study indicate that motivational, physical and lifestyle factors appear to be predictors of academic performance in female undergraduate students.

Cardiorespiratory Fitness and Incidence of Major Adverse Cardiovascular Events in US Veterans: A Cohort Study

OBJECTIVE

To assess the association between exercise capacity and the risk of major adverse cardiovascular events (MACEs).

PATIENTS AND METHODS

A symptom-limited exercise tolerance test was performed to assess exercise capacity in 20,590 US veterans (12,975 blacks and 7615 whites; mean ± SD age, 58.2±11.0 years) from the Veterans Affairs medical centers in Washington, District of Columbia, and Palo Alto, California. None had a history of MACE or evidence of ischemia at the time of or before their exercise tolerance test. We established quintiles of cardiorespiratory fitness (CRF) categories based on age-specific peak metabolic equivalents (METs) achieved. We also defined the age-specific MET level associated with no risk for MACE (hazard ratio [HR], 1.0) and formed 4 additional CRF categories based on METs achieved below (least fit and low fit) and above (moderately fit and highly fit) that level. Multivariate Cox models were used to estimate HR and 95% CIs for mortality across fitness categories.

RESULTS

During follow-up (median, 11.3 years; range, 0.3-33.0 years), 2846 individuals experienced MACEs. The CRF-MACE association was inverse and graded. The risk for MACE declined precipitously for those with a CRF level of 6.0 METs or higher. When considering CFR categories based on the age-specific MET threshold, the risk increased for those in the 2 CFR categories below that threshold (HR, 1.95; 95% CI, 1.73-2.21 and HR, 1.41; 95% CI, 1.27-1.56 for the least-fit and low-fit individuals, respectively) and decreased for those above it (HR, 0.77; 95% CI, 0.68-0.87 and HR, 0.57; 95% CI, 0.48-0.67 for moderately fit and highly fit, respectively).

CONCLUSION

Increased CRF is inversely and independently associated with the risk for MACE. When an age-specific MET threshold was defined, the risk for MACE increased significantly for those below that threshold and decreased for those above it (P<.001).

How Accurate Is the Prediction of Maximal Oxygen Uptake with Treadmill Testing?

BACKGROUND

Cardiorespiratory fitness measured by treadmill testing has prognostic significance in determining mortality with cardiovascular and other chronic disease states. The accuracy of a recently developed method for estimating maximal oxygen uptake (VO2peak), the heart rate index (HRI), is dependent only on heart rate (HR) and was tested against oxygen uptake (VO2), either measured or predicted from conventional treadmill parameters (speed, incline, protocol time).

METHODS

The HRI equation, METs = 6 x HRI- 5, where HRI = maximal HR/resting HR, provides a surrogate measure of VO2peak. Forty large scale treadmill studies were identified through a systematic search using MEDLINE, Google Scholar and Web of Science in which VO2peak was either measured (TM-VO2meas; n = 20) or predicted (TM-VO2pred; n = 20) based on treadmill parameters. All studies were required to have reported group mean data of both resting and maximal HRs for determination of HR index-derived oxygen uptake (HRI-VO2).

RESULTS

The 20 studies with measured VO2 (TM-VO2meas), involved 11,477 participants (median 337) with a total of 105,044 participants (median 3,736) in the 20 studies with predicted VO2 (TM-VO2pred). A difference of only 0.4% was seen between mean (±SD) VO2peak for TM- VO2meas and HRI-VO2 (6.51±2.25 METs and 6.54±2.28, respectively; p = 0.84). In contrast, there was a highly significant 21.1% difference between mean (±SD) TM-VO2pred and HRI-VO2 (8.12±1.85 METs and 6.71±1.92, respectively; p<0.001).

CONCLUSION

Although mean TM-VO2meas and HRI-VO2 were almost identical, mean TM-VO2pred was more than 20% greater than mean HRI-VO2.

Commercially available lifestyle modification program: randomized controlled trial addressing heart and bone health in BRCA1/2+ breast cancer survivors after risk-reducing salpingo-oophorectomy

PURPOSE

The goal of this RCT was to examine the efficacy and safety of a web-based program to improve cardiovascular and bone health outcomes, among 35 BRCA1/2+ breast cancer survivors who underwent prophylactic oophorectomy and thus experienced premature surgical menopause.

METHODS

A 12-month commercially available web-based lifestyle modification program (Precision Nutrition Coaching) was utilized. Cardiovascular fitness, dietary intake, leisure time activity, body composition, bone mineral density, bone structure, and muscle strength were assessed.

RESULTS

Average adherence to all program components was 74.8 %. Women in the intervention group maintained their cardiovascular fitness level over the 12 months (1.1 ± 7.9 %), while the control group significantly decreased fitness capacity (-4.0 ± 7.5 %). There was a significant difference between groups in percent change of whole body bone area (-0.8 ± 2.5 control and 0.5 ± 1.30 intervention). We also observed decreased BMI (-4.7 ± 6.2 %) and fat mass (-8.6 ± 12.7 %) in the intervention group due to significant concomitant decreases in caloric intake and increases in caloric expenditure. The control group demonstrated decreased caloric intake and decreased lean tissue mass.

CONCLUSIONS

In this population at high risk for detrimental cardiovascular and bone outcomes, a commercially available lifestyle intervention program mitigated a decline in cardiovascular health, improved bone health, and decreased weight through fat loss.

IMPLICATIONS FOR CANCER SURVIVORS

Precision Nutrition Coaching has shown benefit in breast cancer survivors for reduced risk of deleterious cardiovascular and bone outcomes.

The effects of aerobic exercise on cognition in schizophrenia: A 3-month follow-up study

Aerobic exercise (AE) has been shown to improve cognition in patients with schizophrenia. However, it remains unclear whether these exercise-induced cognitive benefits persist beyond the training period. Accordingly, the present study sought to examine the immediate and maintenance effects of AE on a wide range of cognitive functions in 75 schizophrenia patients randomized to 12 weeks of either moderate-intensity treadmill exercise or stretching and toning exercise that served as a control. Participants completed assessments of neurocognition and cardiovascular fitness at pretest, posttest, and 3-month follow-up. The results showed that the AE group outperformed the controls on processing speed and attention at the end of intervention. The two groups did not differ significantly in any cognitive outcome measured at follow-up; however, improvement over time was noted in certain cognitive domains in AE group. The average effect sizes at follow-up were 0.53 and 0.35 for AE and control groups, respectively. There were no significant between-group differences in aerobic fitness at posttest and follow-up, and that fitness level was not related to changes in cognitive performance. These findings provide preliminary evidence for a trend towards beneficial effects of physical activity on cognition over a short follow-up period in favor of AE.

Exercise Capacity and Atrial Fibrillation Risk in Veterans: A Cohort Study

OBJECTIVE

To assess the association between exercise capacity and the risk of developing atrial fibrillation (AF).

PATIENTS AND METHODS

A symptom-limited exercise tolerance test was conducted to assess exercise capacity in 5962 veterans (mean age, 56.8±11.0 years) from the Veterans Affairs Medical Center, Washington, DC. None had evidence of AF or ischemia at the time of or before undergoing their exercise tolerance test. We established 4 fitness categories based on age-stratified quartiles of peak metabolic equivalent task (MET) achieved: least fit (4.9±1.10 METs; n=1446); moderately fit (6.7±1.0 METs; n=1490); fit (7.9±1.0 METs; n=1585), and highly fit (9.3±1.2 METs; n=1441). Multivariable Cox proportional hazards regression models were used to compare the AF-exercise capacity association between fitness categories.

RESULTS

During a median follow-up period of 8.3 years, 722 (12.1%) individuals developed AF (14.5 per 1000 person-years; 95% CI, 13.9-15.9 per 1000 person-years). Exercise capacity was inversely related to AF incidence. The risk was 21% lower (hazard ratio, 0.79; 95% CI, 0.76-0.82) for each 1-MET increase in exercise capacity. Compared with the least fit individuals, hazard ratios were 0.80 (95% CI, 0.67-0.97) for moderately fit individuals, 0.55 (95% CI, 0.45-0.68) for fit individuals, and 0.37 (95% CI, 0.29-0.47) for highly fit individuals. Similar trends were observed in those younger than 65 years and those 65 years or older.

CONCLUSION

Increased fitness is inversely and independently associated with the reduced risk of developing AF. The decrease in risk was graded and precipitous with only modest increases in exercise capacity. These findings counter previous suggestions that even moderate increases in physical activity, as recommended by national and international guidelines, increase the risk of AF, with marked protection against AF noted with increasing levels of fitness.

Use of exercise capacity to improve SCORE risk prediction model in asymptomatic adults

AIMS

The SCORE risk estimation system is used for cardiovascular risk stratification in apparently healthy adults and is based on known cardiovascular risk factors. The purpose of the current study was to evaluate whether exercise capacity can improve the accuracy of the SCORE overall survival risk estimation.

METHODS AND RESULTS

We investigated 22 878 asymptomatic men and women who were annually screened in a tertiary medical centre. All subjects were free of known ischaemic heart disease, and had completed maximal exercise stress test according to the Bruce protocol. The SCORE risk estimation system was used to evaluate individual cardiovascular risk for all subjects. The primary endpoint was mortality, after exclusion of patients with metastatic cancer during follow-up. The incremental contribution of exercise capacity in predicting the risk of death was evaluated by net reclassification improvement (NRI) and area under the receiver operating curve (AUROC). Mean age of the study population was 47.4 ± 10.3, and 71.6% were men. There were 505 (2.21%) deaths during a mean follow-up of 9.2 ± 4.1 years. Kaplan-Meier survival analysis showed that both SCORE and low exercise capacity were associated with reduced survival. When added to the SCORE risk prediction, exercise capacity allowed more accurate risk stratification: NRI analysis showed an overall improvement of 56.8% in the accuracy of classification and the AUROC increased (0.782 vs. 0.766).

CONCLUSION

Both SCORE and exercise capacity are strong independent predictors of all-cause mortality. The addition of exercise capacity to the SCORE risk model can improve the accuracy of the model.

A case of fitness to work in a worker with COPD using the exercise stress test

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is a chronic respiratory disease characterized by persistent airflow limitation. Therefore, both work ability and workday length may be affected in individuals with this disease. We studied a worker with suspected COPD and assessed fitness to work using post-bronchodilator spirometry, symptom assessment scales, and the exercise stress test.

CASE REPORT

The patient was a 58-year-old man due to work as a field supervisor in the ship construction sector. He had a 40 pack-year smoking history and experienced occasional dyspnea when climbing stairs. He visited this hospital to receive cardiopulmonary function tests and to determine his ability to work. Post-bronchodilator spirometry revealed severe irreversible airway obstruction corresponding to a modified Medical Research Council grade of 2 on the dyspnea scale. His COPD Assessment Test score was 12, placing him in patient group D (high risk, more symptoms) based on the Global Initiative for Chronic Obstructive Lung Disease classification system. His maximum oxygen uptake (VO2max) was determined to be 19.16 ml/kg/min, as measured by the exercise stress test, and his acceptable workload for 8 h of physical work was calculated to be 6.51 ml/kg/min. His work tasks required an oxygen demand of 6.89 ml/kg/min, which exceeded the acceptable workload calculated. Accordingly, he was advised to adjust the work tasks that were deemed inappropriate for his exercise capacity.

CONCLUSION

As COPD incidence is expected to rise, early COPD diagnosis and determination of fitness to work is becoming increasingly important. Performing the exercise stress test, to evaluate the functional capacity of workers with COPD, is considered an acceptable solution.

Physical and cardiovascular performance in cases with acromegaly after regular short-term exercise

OBJECTIVE

Impaired physical performance is a disturbing complication of acromegaly. We aimed to evaluate the role of regular exercise in amelioration of the impaired physical performance in acromegaly.

METHODS

Patients with acromegaly were divided into two groups according to their participation in a prescheduled programme of exercise. Participants in the study group were exercised 3 days a week for 3 consecutive months. Exercise tolerance was evaluated by maximal oxygen consumption (VO2 max) and time (T) taken to complete the Bruce protocol, muscle flexibility by the sit and reach test (SRT) and muscle strength by the hand grip strength test (HGST). Concomitantly, anthropometric assessment was performed using body mass index (BMI), waist-to-hip ratio (WHR), skinfold measurements from 8 points, percentage body fat (PBF), fat mass (FM) and lean body mass (LBM).

RESULTS

After 3 months of exercise, VO2 max and T were higher in cases that exercised than in cases that did not (P = 0.004 and P = 0.001). Over 3 months, within the exercise group, VO2 max and T of the Bruce protocol increased (P = 0.003 and P = 0.004) and heart rate during warming decreased (P = 0.04). SRT increased within the exercise group after 3 months (P = 0.004). HGSRT did not change significantly (right P = 0.06 and left P = 0.2). The sum of skinfolds, BMI, WHR and LBM remained stable over the study period (P = 0.1, P = 0.08, P = 0.3 and P = 0.09). PBF decreased slightly and FM decreased significantly over 3 months (P = 0.05 and P = 0.03).

CONCLUSION

Even short-term exercise may improve impaired physical performance, muscle activity and disturbed body fat composition in acromegaly.

Exercise capacity and risk of chronic kidney disease in US veterans: a cohort study

OBJECTIVE

To assess the association between exercise capacity and the risk of developing chronic kidney disease (CKD).

PATIENTS AND METHODS

Exercise capacity was assessed in 5812 male veterans (mean age, 58.4±11.5 years) from the Veterans Affairs Medical Center, Washington, DC. Study participants had an estimated glomerular filtration rate of 60 mL/min per 1.73 m(2) or more 6 months before exercise testing and no evidence of CKD. Those who developed CKD during follow-up were initially identified by the International Classification of Diseases, Ninth Revision and further verified by at least 2 consecutive estimated glomerular filtration rate values of less than 60 mL/min per 1.73 m(2) 3 months or more apart. Normal kidney function for CKD-free individuals was confirmed by sequential normal eGFR levels. We established 4 fitness categories on the basis of age-stratified quartiles of peak metabolic equivalents (METs) achieved: least-fit (≤25%; 4.8±0.90 METs; n=1258); low-fit (25.1%-50%; 6.5±0.96 METs; n=1614); moderate-fit (50.1%-75%; 7.7±0.91 METs; n=1958), and high-fit (>75%; 9.5±1.0 METs; n=1436). Multivariable Cox proportional hazard models were used to assess the association between exercise capacity and CKD.

RESULTS

During a median follow-up period of 7.9 years, 1010 developed CKD (20.4/1000 person-years). Exercise capacity was inversely related to CKD incidence. The risk was 22% lower (hazard ratio, 0.78; 95% CI, 0.75-0.82; P<.001) for every 1-MET increase in exercise capacity. Compared with the least-fit individuals, hazard ratios were 0.87 (95% CI, 0.74-1.03) for low-fit, 0.55 (95% CI, 0.47-0.65) for moderate-fit, and 0.42 (95% CI, 0.33-0.52) for high-fit individuals.

CONCLUSION

Higher exercise capacity attenuated the risk of developing CKD. The association was independent and graded.

Is sense of coherence a predictor of lifestyle changes in subjects at risk for type 2 diabetes?

OBJECTIVE

To determine whether the sense of coherence (SOC) could predict the outcome of an 18-month lifestyle intervention program for subjects at risk of type 2 diabetes.

METHODS

Subjects at high risk of type 2 diabetes mellitus were recruited to a low-intensity lifestyle intervention program by their general practitioners. Weight reduction ≥ 5% and improvement in exercise capacity of ≥ 10% from baseline to follow-up indicated a clinically significant lifestyle change. SOC was measured using the 13-item SOC questionnaire.

RESULTS

The study involved 213 subjects with a mean body mass index of 37 (SD ± 6). Complete follow-up data were obtained for 131 (62%). Twenty-six participants had clinically significant lifestyle changes. There was a 21% increase in the odds of a clinically significant lifestyle change for each point increase in the baseline SOC score (odds ratio = 1.21; confidence interval = 1.11-1.32). The success rate was 14 times higher in the highest SOC score tertile group compared with the lowest.

CONCLUSION

High SOC scores were good predictors of successful lifestyle change in subjects at risk of type 2 diabetes. SOC-13 can be used in daily practice to increase clinical awareness on the impact of mastery on the outcome of life-style intervention programs.