Is estimated cardiorespiratory fitness an effective predictor for cardiovascular and all-cause mortality? A meta-analysis

Association between estimated cardiorespiratory fitness trajectory and stroke and its subtypes: A prospective cohort study

BACKGROUND AND AIMS

The association between estimated cardiorespiratory fitness (eCRF) and stroke is ethnically heterogeneous, and conclusions are inconsistent among different stroke subtypes. The aim was to examine the relationship between eCRF trajectory and stroke and its subtypes in the Chinese population.

METHODS AND RESULTS

37,881 participants from the Kailuan Study (2006-2021) who underwent three waves survey and were free of cancer and stroke before or during 2010 were included in this study. The main outcome was stroke, involving ischemic stroke (IS) and intracerebral hemorrhage (ICH). The relationships were assessed using the Cox proportional hazard model. Three distinct eCRF trajectories were identified during 2006-2010: low, moderate, and high. A total of 2150 stroke events, including 1944 cases of IS and 231 cases of ICH, were reported during a median follow-up of 11.04 (interquartile range: 10.65-11.33) years. Compared to the low eCRF trajectory group, participants in the high eCRF trajectory group were associated with a 31 % lower risk of stroke (hazard ratio [HR] [95 % CI], 0.69 [0.60-0.81]), a 30 % lower risk of IS (0.70 [0.59-0.82]), and a 43 % lower risk of ICH (0.57 [0.36-0.91]). Notably, the association between the high eCRF trajectory and IS (Pinteraction = 0.0270) was stronger among women than men.

CONCLUSION

A long-term high eCRF level is associated with a decreased risk of stroke, especially ICH. Therefore, achieving or sustaining a high eCRF level over time could be a beneficial strategy for decreasing the risk of stroke.

The Effects of Exercise Training on Body Composition and Cardiometabolic Risk Factors in Type 1 Diabetes Mellitus: A Systematic Review and Meta-Analysis

INTRODUCTION AND AIM

We performed a systematic review and meta-analysis to investigate the effects of exercise training on body composition and cardiometabolic health in patients with Type 1 diabetes (T1D).

METHOD

A search in three main databases including PubMed, Web of Science, and Scopus was conducted from the inception of this review until June 2024 to identify randomized control trials investigating the effects of exercise training compared to a control on body composition and cardiometabolic risk factors in patients with T1D. The data were pooled using random effects models to calculate weighted mean differences (WMDs), standardized mean differences (SMDs), and 95% confidence intervals (CIs).

RESULTS

Overall, 25 studies involving 1120 patients with T1D were included in the meta-analysis. Exercise training decreased body mass index (BMI) [WMD: -0.18 kg.m2, p = 0.02], fasting glucose [WMD: -14.97 mg/dl, p = 0.01], and HbA1c [WMD: -0.49%, p = 0.003], and increased VO2max/peak [WMD: 2.76 mL/kg/min, p = 0.001] as compared with controls. Exercise training had no effect on body fat percentage or lean body mass, lipid profiles, or blood pressure. Subgroup analysis indicated that age, exercise mode, and intervention duration were the main moderators for the beneficial effects of exercise training.

CONCLUSIONS

In patients with T1D, exercise training is effective for decreasing body weight and cardiometabolic risk factors.

Validation of Aerobic Capacity (VO2max) and Pulse Oximetry in Wearable Technology

INTRODUCTION

As wearable technology becomes increasingly popular and sophisticated, independent validation is needed to determine its accuracy and potential applications. Therefore, the purpose of this study was to evaluate the accuracy (validity) of VO2max estimates and blood oxygen saturation measured via pulse oximetry using the Garmin fēnix 6 with a general population participant pool.

METHODS

We recruited apparently healthy individuals (both active and sedentary) for VO2max (n = 19) and pulse oximetry testing (n = 22). VO2max was assessed through a graded exercise test and an outdoor run, comparing results from the Garmin fēnix 6 to a criterion measurement obtained from a metabolic system. Pulse oximetry involved comparing fēnix 6 readings under normoxic and hypoxic conditions against a medical-grade pulse oximeter. Data analysis included descriptive statistics, error analysis, correlation analysis, equivalence testing, and bias assessment, with the validation criteria set at a concordance correlation coefficient (CCC) > 0.7 and a mean absolute percentage error (MAPE) < 10%.

RESULTS

The Garmin fēnix 6 provided accurate VO2max estimates, closely aligning with the 15 s and 30 s averaged laboratory data (MAPE for 30 s avg = 7.05%; Lin's concordance correlation coefficient for 30 s avg = 0.73). However, it failed to accurately measure blood oxygen saturation (BOS) under any condition or combined analysis (MAPE for combined conditions BOS = 4.29%; Lin's concordance correlation coefficient for combined conditions BOS = 0.10).

CONCLUSION

While the Garmin fēnix 6 shows promise for estimating the VO2max, reflecting its utility for both individuals and researchers, it falls short in accurately measuring BOS, limiting its application for monitoring acclimatization and managing pulmonary diseases. This research underscores the importance of validating wearable technology to leverage its full potential in enhancing personal health and advancing public health research.

Non-exercise Estimated Cardiorespiratory Fitness and Mortality Among Adults With Hypertension

BACKGROUND

The non-exercise estimated cardiorespiratory fitness (eCRF) has been recognized as an important predictor of mortality among the general population. This study sought to evaluate the relationship between eCRF and mortality from all causes, cardiovascular disease (CVD), and cancer in hypertensive adults.

METHODS

We included 27,437 adults with hypertension from the National Health and Nutrition Examination Survey (NHANES) III and 10 NHANES cycles from 1999 to 2018. Multivariate Cox proportional hazard models were used to assess the hazard ratios and 95% confidence intervals (CIs) of eCRF for mortality.

RESULTS

A total of 8,023 deaths were recorded throughout a median 8.6-year follow-up, including 2,338 from CVD, and 1,761 from cancer. The eCRF with per 1 metabolic equivalent increase was linked to decreased risk of all-cause (adjusted HR 0.78, 95% CI: 0.75-0.81) and CVD mortality (adjusted HR 0.79, 95% CI: 0.74-0.84), rather than cancer mortality (adjusted HR 0.94, 95% CI: 0.86-1.03). Moreover, a stronger protective effect of eCRF was observed for females (HR 0.66 (95% CI: 0.62-0.72) versus HR 0.78 (95% CI: 0.73-0.83), Pinteraction < 0.001 for all-cause mortality; HR 0.70 (95% CI: 0.61-0.80;) versus HR 0.82 (95% CI: 0.73-0.92), Pinteraction = 0.026 for CVD mortality) compared with males. Findings did not significantly differ in subgroup analyses and sensitivity analyses.

CONCLUSIONS

Among adults with hypertension, eCRF was inversely related to all-cause and CVD mortality, but not cancer mortality. A significant interaction effect existed between sex and eCRF. Further studies are needed to verify this association in different populations.

Effect of aerobic training versus resistance training for improving cardiorespiratory fitness and body composition in middle-aged to older adults: A systematic review and meta-analysis of randomized controlled trials

This systematic review and meta-analysis aimed to examine the influence of aerobic training (AT) versus resistance training (RT) on cardiorespiratory fitness and body composition in middle-aged to older adults. Four electronic databases including PubMed, Scopus, Cochrane CENTRAL, and web of science, as well as reference lists of included randomized controlled trials (RCTs) were searched from inception to April 2024. Data were pooled by the inverse-variance method and reported as mean differences (MDs) with 95 % confidence intervals (CIs). Thirty-eight RCTs, with a pooled sample of 1682 participants, met our inclusion criteria. Meta-analysis revealed that AT significantly improved VO2max/peak (MD = 1.80, 95 % CI: 0.96 to 2.64, p < 0.0001) and 6-MWT (MD = 18.58, 95 % CI: 10.38 to 26.78, p < 0.00001), and significantly decreased body mass (MD = -1.23, 95 % CI: -1.98 to -0.47, p = 0.001) versus RT. However, changes in lean body mass favored RT over AT. Moreover, changes in VO2max/peak and 6-MWT following AT were significant among both healthy and unhealthy participants, or men and women, after medium-term (< 24 weeks) and long-term (≥ 24 weeks) interventions, and among participants aged ≤65 and >65. Our results propose that AT should be considered an efficient approach to improving cardiorespiratory fitness and overall body composition with aging, particularly in terms of VO2max and 6-MWT performance. However, for improvements in lean body mass, RT may be more beneficial. Therefore, a combination of AT and RT might be optimal for comprehensive fitness and body composition improvements with aging.

Association of estimated cardiorespiratory fitness in middle-aged and elderly people with cardiovascular disease: Evidence from the China health and retirement longitudinal study

BACKGROUND AND AIM

Cardiovascular diseases (CVD) is a major threat to public health, while cardiorespiratory fitness (CRF) is a key predictor of chronic disease. Given this, the purpose of this study was to investigate the relationship between estimated CRF (eCRF) and CVD in middle-aged and elderly Chinese people.

METHODS AND RESULTS

The China Health and Retirement Longitudinal Study (CHARLS) with 4761 individuals were included in analysis. Participants were divided into three groups according to eCRF quantile in sex subgroups. Cox proportional hazards regression models were used to explore the correlation of eCRF with CVD (stroke or cardiac events). In total, 4761 participants were included in this cohort study (2500 [52.51%] women). During a 7-year follow-up from 2011 to 2018, 796 CVDs (268 Strokes and 588 cardiac events) were recorded. In multivariable-adjusted analyses, for per 1 SD increase of eCRF, the age-adjusted risk of CVD was reduced by about 18% (HR = 0.82; 95% CI, 0.72-0.93) in men, and was reduced by about 29% (HR = 0.71; 95% CI, 0.62-0.81) in women. Similar associations were also found between eCRF and stroke and cardiac events. Both subgroup and interaction analyses showed that the interaction of age had a statistically significant effect on CVD risk.

CONCLUSION

ECRF was inversely associated with CVD risk (stroke or cardiac events) in both men and women. Remarkable sex and age differences exist in the effectiveness of increasing eCRF to reduce the risk of CVD. As a potential, efficient and cost-effective risk prediction tool, eCRF deserves further attention and wide application.

Comparison of objectively measured and estimated cardiorespiratory fitness to predict all-cause and cardiovascular disease mortality in adults: A systematic review and meta-analysis of 42 studies representing 35 cohorts and 3.8 million observations

BACKGROUND

Cardiorespiratory fitness (CRF) is a powerful health marker recommended by the American Heart Association as a clinical vital sign. Comparing the predictive validity of objectively measured CRF (the "gold standard") and estimated CRF is clinically relevant because estimated CRF is more feasible. Our objective was to meta-analyze cohort studies to compare the associations of objectively measured, exercise-estimated, and non-exercise-estimated CRF with all-cause and cardiovascular disease (CVD) mortality in adults.

METHODS

Systematic searches were conducted in 9 databases (MEDLINE, SPORTDiscus, Embase, Scopus, PsycINFO, Web of Science, PubMed, CINAHL, and the Cochrane Library) up to April 11, 2024. We included full-text refereed cohort studies published in English that quantified the association (using risk estimates with 95% confidence intervals (95%CIs)) of objectively measured, exercise-estimated, and non-exercise-estimated CRF with all-cause and CVD mortality in adults. CRF was expressed as metabolic equivalents (METs) of task. Pooled relative risks (RR) for all-cause and CVD mortality per 1-MET (3.5 mL/kg/min) higher level of CRF were quantified using random-effects models.

RESULTS

Forty-two studies representing 35 cohorts and 3,813,484 observations (81% male) (362,771 all-cause and 56,471 CVD deaths) were included. The pooled RRs for all-cause and CVD mortality per higher MET were 0.86 (95%CI: 0.83-0.88) and 0.84 (95%CI: 0.80-0.87), respectively. For both all-cause and CVD mortality, there were no statistically significant differences in RR per higher MET between objectively measured (RR range: 0.86-0.90) and maximal exercise-estimated (RR range: 0.85-0.86), submaximal exercise-estimated (RR range: 0.91-0.94), and non-exercise-estimated CRF (RR range: 0.81-0.85).

CONCLUSION

Objectively measured and estimated CRF showed similar dose-response associations for all-cause and CVD mortality in adults. Estimated CRF could provide a practical and robust alternative to objectively measured CRF for assessing mortality risk across diverse populations. Our findings underscore the health-related benefits of higher CRF and advocate for its integration into clinical practice to enhance risk stratification.

Cardiorespiratory fitness is a strong and consistent predictor of morbidity and mortality among adults: an overview of meta-analyses representing over 20.9 million observations from 199 unique cohort studies

OBJECTIVE

To examine and summarise evidence from meta-analyses of cohort studies that evaluated the predictive associations between baseline cardiorespiratory fitness (CRF) and health outcomes among adults.

DESIGN

Overview of systematic reviews.

DATA SOURCE

Five bibliographic databases were searched from January 2002 to March 2024.

RESULTS

From the 9062 papers identified, we included 26 systematic reviews. We found eight meta-analyses that described five unique mortality outcomes among general populations. CRF had the largest risk reduction for all-cause mortality when comparing high versus low CRF (HR=0.47; 95% CI 0.39 to 0.56). A dose-response relationship for every 1-metabolic equivalent of task (MET) higher level of CRF was associated with a 11%-17% reduction in all-cause mortality (HR=0.89; 95% CI 0.86 to 0.92, and HR=0.83; 95% CI 0.78 to 0.88). For incident outcomes, nine meta-analyses described 12 unique outcomes. CRF was associated with the largest risk reduction in incident heart failure when comparing high versus low CRF (HR=0.31; 95% CI 0.19 to 0.49). A dose-response relationship for every 1-MET higher level of CRF was associated with a 18% reduction in heart failure (HR=0.82; 95% CI 0.79 to 0.84). Among those living with chronic conditions, nine meta-analyses described four unique outcomes in nine patient groups. CRF was associated with the largest risk reduction for cardiovascular mortality among those living with cardiovascular disease when comparing high versus low CRF (HR=0.27; 95% CI 0.16 to 0.48). The certainty of the evidence across all studies ranged from very low-to-moderate according to Grading of Recommendations, Assessment, Development and Evaluations.

CONCLUSION

We found consistent evidence that high CRF is strongly associated with lower risk for a variety of mortality and incident chronic conditions in general and clinical populations.

Characteristics and Outcomes of Cardiac Rehabilitation Patients With and Without Cancer: Insights From Western Sydney

AIM

Increased cardiovascular events are common in cancer survivors and contribute to an emerging cardio-oncology patient group requiring secondary prevention strategies including cardiac rehabilitation (CR). This study aimed to compare characteristics and outcomes for patients participating in CR with and without an existing cancer diagnosis.

METHOD

Observational cohort study including consecutive patients enrolled in a single-centre outpatient CR program in Western Sydney between 2018-2022. Clinical history, demographics and CR outcome data were collected as part of standard care at program enrolment and completion. Patients with and without a cancer diagnosis were compared at enrolment and outcomes were analysed in both groups.

RESULTS

A total of 1,792 patients enrolled in CR, 191 (11%) had a documented history of cancer; prostate (18%), skin (12%), colon (9%) and breast (8%) malignancies were most prevalent. The most common treatments were surgical resection (80%) and chemotherapy or radiotherapy (37%). Cardio-oncology patients were older (68.8±10.6 vs 59.8±13.7yrs, p<0.001), more likely female (33% vs 21%, p<0.001), born in Australia (46% vs 35%, p=0.004), non-partnered (34% vs 25%, p=0.002) and had a prior history of hypertension (65% vs 56%, p=0.010) or stroke (8% vs 5%, p=0.045). After adjusting for age and sex, the overall cohort improved their mean peak exercise capacity and waist circumference after CR, however there were no differences between groups. There were also no between-group differences for adherence and completion of CR program or any other cardiovascular risk factors. Sub-analyses revealed a clinically meaningful improvement in waist circumference for cancer patients with a history of radiation therapy and a blunted peak exercise capacity adaptation for those with a history of chemotherapy treatment.

CONCLUSIONS

Despite differences in demographic and clinical characteristics of CR patients with and without cancer, all patients showed significant and clinically relevant improvements in peak exercise capacity and waist circumference after CR. Results also highlighted potential associations between specific cancer treatments and changes in fitness outcomes, which warrants further evaluation.

Physical fitness in male adolescents and atherosclerosis in middle age: a population-based cohort study

OBJECTIVES

To examine the associations between physical fitness in male adolescents and coronary and carotid atherosclerosis in middle age.

METHODS

This population-based cohort study linked physical fitness data from the Swedish Military Conscription Register during adolescence to atherosclerosis data from the Swedish CArdioPulmonary bioImage Study in middle age. Cardiorespiratory fitness was assessed using a maximal cycle-ergometer test, and knee extension muscular strength was evaluated through an isometric dynamometer. Coronary atherosclerosis was evaluated via Coronary Computed Tomography Angiography (CCTA) stenosis and Coronary Artery Calcium (CAC) scores, while carotid plaques were evaluated by ultrasound. The associations were analysed using multinomial logistic regression, adjusted (marginal) prevalences and restricted cubic splines.

RESULTS

The analysis included 8986 male adolescents (mean age 18.3 years) with a mean follow-up of 38.2 years. Physical fitness showed a reversed J-shaped association with CCTA stenosis and CAC, but no consistent association was observed for carotid plaques. After adjustments, compared with adolescents in the lowest tertile of cardiorespiratory fitness and muscular strength, those in the highest tertile had 22% (OR 0.78; 95% CI 0.61 to 0.99) and 26% (OR 0.74; 95% CI 0.58 to 0.93) lower ORs for severe (≥50%) coronary stenosis, respectively. The highest physical fitness group (high cardiorespiratory fitness and muscular strength) had 33% (OR 0.67; 95% CI 0.52 to 0.87) lower OR for severe coronary stenosis compared with those with the lowest physical fitness.

CONCLUSION

This study supports that a combination of high cardiorespiratory fitness and high muscular strength in adolescence is associated with lower coronary atherosclerosis, particularly severe coronary stenosis, almost 40 years later.

Resistance training and inter-interindividual response differences on cardiorespiratory fitness in older adults: An ancillary meta-analysis of randomized controlled trials

Examine true inter-individual response differences (IIRD) as a result of resistance training on cardiorespiratory fitness in older adults. Data from a recent meta-analysis of 22 randomized controlled trials representing 552 men and women (292 resistance training, 260 control) ≥ 60 years of age were included. The primary outcome was cardiorespiratory fitness (VO2max) in ml.kg-1.min-1. Using the inverse variance heterogeneity (IVhet) model, statistically significant treatment effect (resistance training minus control) increases in VO2max in ml.kg-1.min-1 were found (mean, 1.8, 95% CI, 0.4 to 3.3 ml.kg-1.min-1, p = 0.01; Q = 82.8, p < 0.001; I2 = 74.6%, 95% CI, 61.6 to 83.3%; τ 2 =1.1). The 95% prediction interval (PI) was -0.8 to 4.5 ml.kg-1.min-1. However, no statistically significant IIRD was observed (mean, 0.6, 95% CI, -1.1 to 1.4 ml.kg-1.min-1; τ 2 =1.5). The 95% PI was -1.8 to 2.0 ml.kg-1.min-1. In conclusion, while progressive resistance training may increase VO2max in ml.kg-1.min-1, a lack of true resistance-training-associated IIRD exist.

Association between Estimated Cardiorespiratory Fitness and Abnormal Glucose Risk: A Cohort Study

BACKGROUND

Cardiorespiratory fitness (CRF) is a predictor of chronic disease that is impractical to routinely measure in primary care settings. We used a new estimated cardiorespiratory fitness (eCRF) algorithm that uses information routinely documented in electronic health care records to predict abnormal blood glucose incidence.

METHODS

Participants were adults (17.8% female) 20-81 years old at baseline from the Aerobics Center Longitudinal Study between 1979 and 2006. eCRF was based on sex, age, body mass index, resting heart rate, resting blood pressure, and smoking status. CRF was measured by maximal treadmill testing. Cox proportional hazards regression models were established using eCRF and CRF as independent variables predicting the abnormal blood glucose incidence while adjusting for covariates (age, sex, exam year, waist girth, heavy drinking, smoking, and family history of diabetes mellitus and lipids).

RESULTS

Of 8602 participants at risk at baseline, 3580 (41.6%) developed abnormal blood glucose during an average of 4.9 years follow-up. The average eCRF of 12.03 ± 1.75 METs was equivalent to the CRF of 12.15 ± 2.40 METs within the 10% equivalence limit. In fully adjusted models, the estimated risks were the same (HRs = 0.96), eCRF (95% CIs = 0.93-0.99), and CRF (95% CI of 0.94-0.98). Each 1-MET increase was associated with a 4% reduced risk.

CONCLUSIONS

Higher eCRF is associated with a lower risk of abnormal glucose. eCRF can be a vital sign used for research and prevention.

Cumulative Muscle Strength and Risk of Cardiovascular Disease and All-cause mortality: A Prospective Cohort Study

BACKGROUND

The existing literature regarding the association between muscle strength and cardiovascular disease (CVD) and all-cause mortality relies mostly on a single measurement of muscle strength but has seldomly focused on the accumulated exposure.

OBJECTIVE

This study explored the association between cumulative muscle strength and risks of CVD and all-cause mortality in middle-aged and older adults.

METHODS

A total of 6,972 patients from the China Health and Retirement Longitudinal Study, who underwent 3 repeated measurements of muscle strength over 4 years and were followed-up for another 3 years for CVD and all-cause mortality outcomes participated in this study. Muscle strength was evaluated by grip strength and chair-rising time. Cumulative muscle strength was calculated as the area under the curve. Odds ratio (OR) and 95% confidence intervals (CIs) were analyzed.

RESULTS

The odds of CVD and all-cause mortality decreased as cumulative grip strength increased or cumulative chair-rising time decreased. For each 1 standard deviation (SD) increment in cumulative grip strength, the multivariable-adjusted OR for CVD and all-cause mortality were 0.81 (95% CI 0.73-0.91) and 0.85 (95% CI 0.73-0.99), respectively. For each 1 SD decrease in cumulative chair-rising time, the corresponding OR were 0.81 (95% CI 0.75-0.88) and 0.87 (95% CI 0.77-0.98), respectively. However, neither the change-slope of grip strength nor that of chair-rising time was related to decreased OR of CVD or of all-cause mortality.

CONCLUSIONS

Cumulative muscle strength was associated with a reduced risk of CVD and all-cause mortality in middle-aged and older Chinese adults.

Epidemiological, mechanistic, and practical bases for assessment of cardiorespiratory fitness and muscle status in adults in healthcare settings

Given their importance in predicting clinical outcomes, cardiorespiratory fitness (CRF) and muscle status can be considered new vital signs. However, they are not routinely evaluated in healthcare settings. Here, we present a comprehensive review of the epidemiological, mechanistic, and practical bases of the evaluation of CRF and muscle status in adults in primary healthcare settings. We highlight the importance of CRF and muscle status as predictors of morbidity and mortality, focusing on their association with cardiovascular and metabolic outcomes. Notably, adults in the best quartile of CRF and muscle status have as low as one-fourth the risk of developing some of the most common chronic metabolic and cardiovascular diseases than those in the poorest quartile. The physiological mechanisms that underlie these epidemiological associations are addressed. These mechanisms include the fact that both CRF and muscle status reflect an integrative response to the body function. Indeed, muscle plays an active role in the development of many diseases by regulating the body's metabolic rate and releasing myokines, which modulate metabolic and cardiovascular functions. We also go over the most relevant techniques for assessing peak oxygen uptake as a surrogate of CRF and muscle strength, mass, and quality as surrogates of muscle status in adults. Finally, a clinical case of a middle-aged adult is discussed to integrate and summarize the practical aspects of the information presented throughout. Their clinical importance, the ease with which we can assess CRF and muscle status using affordable techniques, and the availability of reference values, justify their routine evaluation in adults across primary healthcare settings.

Longitudinal cardio-respiratory fitness prediction through wearables in free-living environments

Cardiorespiratory fitness is an established predictor of metabolic disease and mortality. Fitness is directly measured as maximal oxygen consumption (VO2max), or indirectly assessed using heart rate responses to standard exercise tests. However, such testing is costly and burdensome because it requires specialized equipment such as treadmills and oxygen masks, limiting its utility. Modern wearables capture dynamic real-world data which could improve fitness prediction. In this work, we design algorithms and models that convert raw wearable sensor data into cardiorespiratory fitness estimates. We validate these estimates' ability to capture fitness profiles in free-living conditions using the Fenland Study (N=11,059), along with its longitudinal cohort (N = 2675), and a third external cohort using the UK Biobank Validation Study (N = 181) who underwent maximal VO2max testing, the gold standard measurement of fitness. Our results show that the combination of wearables and other biomarkers as inputs to neural networks yields a strong correlation to ground truth in a holdout sample (r = 0.82, 95CI 0.80-0.83), outperforming other approaches and models and detects fitness change over time (e.g., after 7 years). We also show how the model's latent space can be used for fitness-aware patient subtyping paving the way to scalable interventions and personalized trial recruitment. These results demonstrate the value of wearables for fitness estimation that today can be measured only with laboratory tests.

Validity and reproducibility of a method to estimate cardiorespiratory fitness in college adults

Introduction: Cardiorespiratory fitness is a predictor of cardiovascular and all-cause mortality. Its assessment in different groups has clinical and public health usefulness. Objective: To evaluate the validity and reproducibility of a no-exercise method [National Aeronautics and Space Administration (NASA) method] to estimate the maximum oxygen consumption (VO2máx) in college adults. Materials and methods: This study included 94 healthy individuals of both sexes (18-55 years). The gold standard was ergospirometry. The validity and reproducibility were evaluated with the intraclass correlation coefficient (ICC) and the Bland-Altman method. Results: Among the participants, we found a mean age of 30.54 ± 9.33 years and a VO2máx of 41.29 ± 9.54 ml O2.kg-1.min-1; 48.9 % were women. A mean difference of VO2máx between ergospirometry and that estimated by the NASA method of 3.41 ± 5.64 ml O2.kg-1.min-1 was found. The concordance between the two methods was good, with an ICC of 0.858 (CI95% 0.672-0.926). The percentage of error was 29.70 %. The reproducibility of the two estimates by the NASA method was excellent, with an ICC of 0.986 (CI95% 0.927-0.995). Conclusions: The NASA method is valid and reproducible to estimate VO2máx in college adults. In addition, it is safe and easy to apply. Estimating cardiorespiratory fitness is recommended to improve screening in cardiometabolic risk programs and to implement timely interventions.

Updating Framingham CVD risk score using waist circumference and estimated cardiopulmonary function: a cohort study based on a southern Xinjiang population

Purpose

To explore the association between waist circumference (WC), estimated cardiopulmonary function (eCRF), and cardiovascular disease (CVD) risk in southern Xinjiang. Update the Framingham model to make it more suitable for the southern Xinjiang population.

Methods

Data were collected from 7705 subjects aged 30–74 years old in Tumushuke City, the 51st Regiment of Xinjiang Production and Construction Corps. CVD was defined as an individual's first diagnosis of non-fatal acute myocardial infarction, death from coronary heart disease, and fatal or non-fatal stroke. The Cox proportional hazards regression analysis was used to analyze the association between WC, eCRF and CVD risk. Restricted cubic spline plots were drawn to describe the association of the two indicators with CVD risk. We update the model by incorporating the new variables into the Framingham model and re-estimating the coefficients. The discrimination of the model is evaluated using AUC, NRI, and IDI metrics. Model calibration is evaluated using pseudo R² values.

Results

WC was an independent risk factor for CVD (multivariate HR: 1.603 (1.323, 1.942)), eCRF was an independent protective factor for CVD (multivariate HR: 0.499 (0.369, 0.674)). There was a nonlinear relationship between WC and CVD risk (nonlinear χ2 = 12.43, P = 0.002). There was a linear association between eCRF and CVD risk (non-linear χ2 = 0.27, P = 0.6027). In the male, the best risk prediction effect was obtained when WC and eCRF were added to the model (AUC = 0.763((0.734,0.792)); pseudo R² = 0.069). In the female, the best risk prediction effect was obtained by adding eCRF to the model (AUC = 0.757 (0.734,0.779); pseudo R² = 0.107).

Conclusion

In southern Xinjiang, WC is an independent risk factor for CVD. eCRF is an independent protective factor for CVD. We recommended adding WC and eCRF in the male model and only eCRF in the female model for better risk prediction.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-022-14110-y.

Impact of concurrent training versus aerobic or resistance training on cardiorespiratory fitness and muscular strength in middle-aged to older adults: A systematic review and meta-analysis

The effects of aerobic training (AT) on cardiorespiratory fitness (CRF), and resistance training (RT) on muscular strength, are well known in older adults. However, less is known about the potential additive benefits of concurrent training (CT) versus AT or RT alone in this population. We conducted a systematic review and meta-analysis to investigate the effects of CT, versus AT or RT, on CRF and muscular strength in middle-aged to older adults. PubMed and Web of Science were searched through October 2021 to identify randomized trials evaluating CT versus AT and/or RT in middle-aged and older adults (>50 yrs). Studies were included that measured CRF, using maximal or peak oxygen uptake (VO_2max/peak); and/or lower- and upper-body muscular strength measured using 1-repetition maximum (1RM) to 10RM tests during isoinertial contractions, or peak torque during isometric dynamometry or isokinetic dynamometry at 30 to 60°/s. Standardized mean differences (SMD) and 95% confidence intervals (95% CIs) were determined using random or fixed effects models. Forty-nine studies involving 2,587 middle-aged to older participants with mean ages ranging from 55 to 88 years, were included in the meta-analysis. Results indicated that CT effectively increased VO_2max/peak (SMD: 0.77, p = 0.005, 12 intervention arms) when compared to RT. In addition, CT effectively increased lower- (SMD: 0.60, p = 0.001, 43 intervention arms) and upper-body (SMD: 0.57, p = 0.001, 28 intervention arms) muscular strength when compared to AT. However, there were no differences in VO_2max/peak (SMD: 0.09, p = 0.09, 33 intervention arms) between CT and AT, or in lower-body (SMD: 0.07, p = 0.48, 21 intervention arms) and upper-body (SMD: -0.07, p = 0.38, 17 intervention arms) muscular strength between CT and RT. Overall, CT was shown to be effective for increasing CRF and muscular strength in middle-aged to older adults and there was no negative effect on the magnitude of changes in these outcomes compared to either AT or RT alone. These results suggested that CT should be considered a viable strategy to improvement of CRF and muscular strength with aging.

Estimating VO2peak in 18–90 Year-Old Adults: Development and Validation of the FitMáx©-Questionnaire

Purpose

Cardiorespiratory fitness (CRF) plays an essential role in health outcomes and quality of life. However, it is often not assessed nor estimated. Objective CRF assessment is costly, labour intensive and not widely available. Patient-reported outcome measures estimate CRF more cost-efficiently, but current questionnaires lack accuracy. The aim of this study is to develop a new self-reported questionnaire to estimate CRF.

Materials and Methods

The FitMáx©-questionnaire, consisting of only three questions assessing walking, stair climbing, and cycling capacity, was compared with the commonly used Duke Activity Status Index (DASI) and Veterans Specific Activity Questionnaire (VSAQ). These questionnaires were compared to peak oxygen uptake (VO_2peak) as measured with cardiopulmonary exercise testing. This study included 759 cardiac, pulmonary and oncologic patients and healthy persons aged 18‒90.

Results

FitMáx© strongly correlated (r = 0.94 (0.92‒0.95) SEE = 4.14 mL∙kg⁻¹∙min⁻¹) with measured VO_2peak. Bias between predicted and measured VO_2peak was −0.24 (−9.23‒8.75; 95% limits of agreement) mL·kg⁻¹·min⁻¹. The FitMáx© scored superiorly on correlation and SEE compared with the DASI and VSAQ, r = 0.75 (0.68‒0.80) SEE = 4.62 mL∙kg⁻¹∙min⁻¹ and r = 0.87 (0.83‒0.90) SEE = 6.75 mL∙kg⁻¹∙min⁻¹, respectively.

Conclusion

FitMáx© is a valid and accessible questionnaire to estimate CRF expressed as VO_2peak in clinical practice and shows substantial improvement compared to currently used questionnaires.

Birth Weight was Favorably Associated With Physical Fitness in Childhood After Adjustment for Several Perinatal Factors

BACKGROUND

The purpose was to examine the potential associations of birth weight and infant growth with physical fitness (PF) components in childhood.

METHOD

A random sample of 5125 dyads of children aged 8-9 years and their mothers were evaluated. Telephone interviews were carried out with the use of a standardized questionnaire for the collection of maternal lifestyle factors. Mothers were asked to provide information contained in their medical booklets and pregnancy ultrasound records. Data from 5 PF tests were used to assess cardiorespiratory fitness, speed, and body strength. Linear regression analysis was applied to assess the associations between birth weight and infant growth with PF test performances and logistic regression analysis to evaluate the associations of normal weight versus low birth weight and normal versus accelerated infant growth with PF tests performance categories (low vs high/average).

RESULTS

Birth weight was favorably associated with cardiorespiratory fitness (b = 0.12 stage increase per SD increase in birth weight, P = .047), lower body strength (b = 1.07, P = .037), upper body strength (b = 0.10, P = .038), and speed (b = -0.04, P = .001), and infant growth was associated with upper body strength (b = 0.21 cm increase per SD increase in infant weight gain, P < .001) after adjusting for children's body mass index and several perinatal factors. Low birth weight children had 35% increased odds for low performances in PF tests compared with their normal birth weight counterparts.

CONCLUSION

Low birth weight negatively affects childhood PF, and hence, it could play an unfavorable role in the future health of the offspring.