Differential Evaluating Effect on Exercise Capacity of Cardiopulmonary Exercise Testing and Treadmill Exercise Testing in Post-percutaneous Coronary Intervention Patients

Background: Treadmill exercise testing (TET) is commonly used to measure exercise capacity. Studies have shown that cardiopulmonary exercise testing (CPET) is more accurate than TET and is, therefore, regarded as the “gold standard” for testing maximum exercise capacity and prescribing exercise plans. To date, no studies have reported the differences in exercise capacity after percutaneous coronary intervention (PCI) using the two methods or how to more accurately measure exercise capacity based on the results of TET.Aims: This study aims to measure maximum exercise capacity in post-PCI patients and to recommend exercise intensities that ensure safe levels of exercise.Methods: We enrolled 41 post-PCI patients who were admitted to the Cardiac Rehabilitation Clinic at the First Medical Center, the Chinese PLA General Hospital, from July 2015 to June 2016. They completed CPET and TET. The paired sample t-test was used to compare differences in measured exercise capacity, and multiple linear regression was applied to analyze the factors that affected the difference.Results: The mean maximum exercise capacity measured by TET was 8.89 ± 1.53 metabolic equivalents (METs), and that measured by CPET was 5.19 ± 1.23 METs. The difference between them was statistically significant (p = 0.000) according to the paired sample t-test. The difference averaged 40.15% ± 2.61% of the exercise capacity measured by TET multiple linear regression analysis showed that the difference negatively correlated with waist-hip ratio (WHR).Conclusion: For the purpose of formulating more accurate exercise prescription, the results of TET should be appropriately adjusted when applied to exercise capacity assessment.Clinical Trial Registration:http://www.chictr.org.cn/ number, ChiCTR2000031543.

Body fat predicts exercise capacity in persons with Type 2 Diabetes Mellitus: A machine learning approach

Diabetes mellitus is associated with increased cardiovascular disease (CVD) related morbidity, mortality and death. Exercise capacity in persons with type 2 diabetes has been shown to be predictive of cardiovascular events. In this study, we used the data from the prospective randomized LOOK AHEAD study and used machine learning algorithms to help predict exercise capacity (measured in Mets) from the baseline data that included cardiovascular history, medications, blood pressure, demographic information, anthropometric and Dual-energy X-Ray Absorptiometry (DXA) measured body composition metrics. We excluded variables with high collinearity and included DXA obtained Subtotal (total minus head) fat percentage and Subtotal lean mass (gms). Thereafter, we used different machine learning methods to predict maximum exercise capacity. The different machine learning models showed a strong predictive performance for both females and males. Our study shows that using baseline data from a large prospective cohort, we can predict maximum exercise capacity in persons with diabetes mellitus. We show that subtotal fat percentage is the most important feature for predicting the exercise capacity for males and females after accounting for other important variables. Until now, BMI and waist circumference were commonly used surrogates for adiposity and there was a relative under-appreciation of body composition metrics for understanding the pathophysiology of CVD. The recognition of body fat percentage as an important marker in determining CVD risk has prognostic implications with respect to cardiovascular morbidity and mortality.

Sex differences between pre and post effort ultra marathon athletes

Background: The presence of women in ultramarathon competitions has become increasingly frequent. Physiological adaptations and response to maximum exercise are influenced differently according to gender. Objectives: The aim of this study was to evaluate the differences observed in ultramarathon or ultratrail athletes (mountain races over 42 km), at rest (physiological adaptations) and post-endurance exercise [exercise-induced cardiac fatigue (EICF)], stratified by training parameters. Methods: Twenty-five athletes (6 women) who participated in the Mendoza crossing race (55 km in the mountains) were evaluated before and after the end of the race using Doppler echocardiography and myocardial deformation techniques (post-processing). Training and running parameters were documented with sports watches. Immediate post-endurance exercise blood withdrawal was performed to document variables associated with cardiac fatigue. Results: The race was completed by 24 athletes, 19 men (42±12 years) and 5 women (38±4 years). Women and men presented similar training loads and completed the race with no difference in time. Decreased left myocardial function parameters (EICF) were observed in 50% of men and 5% of women. Conclusions: Despite no differences in training characteristics were found, less baseline physiological adaptation and a lower incidence of EICF was observed in women.

A cardiac rehabilitation program increases the acute respond of endothelial progenitor cells after maximum exercise in patients with chronic heart failure

Background Chronic heart failure (CHF) remains a leading cause of morbidity and mortality and it is characterized by vascular endothelial dysfunction. During the last decades, endothelial progenitor cells (EPCs) are being used as an index of the endothelium restoration potential, therefore reflecting the vascular endothelial function. Exercise training has been shown to stimulate the mobilization of EPCs at rest in CHF patients. However, the effect of exercise training on the acute respond of EPCs after maximum exercise in CHF patients remains unknown. Purpose The purpose of the study was to assess the effect of a cardiac rehabilitation (CR) program on the acute respond of EPCs after maximum exercise in patients with CHF. Methods Forty-four consecutive patients (35 males) with stable CHF [mean±SD, Age (years): 56±10, BMI (kg/m2): 28.7±5.2, EF (%): 33±8, Peak VO2 (ml/kg/min): 18.4±4.4, Peak work rate (watts): 101±39] enrolled a 36-session CR program based on high-intensity interval exercise training. All patients underwent an initial symptom limited maximal cardiopulmonary exercise testing (CPET) on an ergometer before the CR program and a final maximal CPET after the CR program. Venous blood was drawn before and after each CPET. Five circulating endothelial populations were identified and quantified by flow cytometry; CD34+/CD45-/CD133+, CD34+/CD45-/CD133+/VEGFR2, CD34+/CD133+/VEGFR2, CD34+/CD45-/CD133- and CD34+/CD45-/CD133-/VEGFR2. EPCs values are expressed as cells/million enucleated cells in medians (25th-75th percentiles). Results The acute mobilization of EPCs after the final CPET was higher than after the initial CPET in 4 out of 5 circulating endothelial populations. Most specifically, difference of the acute mobilization of CD34+/CD45-/CD133+ cells [initial CPET: 25 (15–46) vs final CPET: 49 (26–71), p=0.002], CD34+/CD45-/CD133+/VEGFR2 cells [initial CPET: 3 (2–5) vs final CPET: 8 (5–12), p<0.001], CD34+/CD45-/CD133- cells [initial CPET: 129 (52–338) vs final CPET: 250 (129–518), p=0.03] and CD34+/CD45-/CD133-/VEGFR2 cells [initial CPET: 2 (1–4) vs final CPET: 6 (3–9), p<0.001] increased after the final CPET. The acute mobilization of CD34+/CD133+/VEGFR2 cells [initial CPET: 3 (−1–7) vs final CPET: 5 (0–15), p=0.441] did not differ between the 2 CPETS. Conclusion A 36-session cardiac rehabilitation program increases the acute respond of endothelial progenitor cells after maximum cardiopulmonary exercise training in patients with chronic heart failure, therefore indicating the beneficial effect of exercise training on the vascular endothelial function. Funding Acknowledgement Type of funding source: Public grant(s) – EU funding. Main funding source(s): Co-financed by Greece and the European Union (European Social Fund- ESF) through the Operational Programme “Human Resources Development, Education and Lifelong Learning” in the context of the project

Cardiorespiratory fitness assessment among firefighters: Is the non-exercise estimate accurate?

BACKGROUND: Minimum cardiorespiratory fitness (CRF) has been recommended for firefighters due to job requirements. Thus, it is important to identify accurate and readily available methods to assess CRF in this population. Non-exercise CRF estimates (NEx-CRF) have been proposed but this approach requires validation in this population. OBJECTIVE: To evaluate the accuracy of a NEx-CRF, as compared to a field maximum exercise test, among career military firefighters of both genders using a comprehensive agreement analysis. METHODS: We evaluated the accuracy of a NEx-CRF estimate compared to the Cooper 12 min running test among 702 males and 106 female firefighters. RESULTS: Cooper and NEx-CRF tests yielded similar CRF in both genders (differences <1.8±4.7 ml/kg–1.min–1; effect size <0.34). However, NEx-CRF underestimated Cooper-derived CRF among the fittest firefighters. NEx-CRF showed moderate to high sensitivity/specificity to detect fit or unfit firefighters (71.9% among men and 100% among women). Among men, the NEx-CRF method correctly identified most firefighters with less than 11 METs or greater than 13 METs, but showed lower precision to discriminate those with CRF between 11–13 METs. CONCLUSIONS: The NEx-CRF method to estimate firefighters’ CRF may be considered as an alternative method when an exercise-based method is not available or may be used to identify those who require more traditional testing (CRF 11–13 METs).

Evaluation of Aerobic Exercise Intensity in Patients with Coronary Artery Disease and Type 2 Diabetes Mellitus

(1) Background: Physical activity is recommended in patients with type 2 diabetes mellitus (T2DM) and coronary artery disease (CAD) to reduce hyperglycemia and cardiovascular risk. Effective aerobic exercise intensity, however, is not well defined. (2) Methods: 60 consecutive patients performed cardiopulmonary exercise testing (CPX) of 30 min duration targeting a respiratory exchange ratio (RER) between 0.85 and 0.95, being strictly aerobic. Plasma glucose (PG) was measured before and after CPX as well as one and two h after exercise. Maximum exercise intensity was evaluated using a standard bicycle exercise test. (3) Results: 50 patients completed the protocol (62 ± 10 years, BMI (body mass index) 30.5 ± 4.9 kg/m2, HbA1c (glycated haemoglobin) 6.9 ± 0.8%, left ventricular ejection fraction 55 ± 8%). Aerobic exercise capacity averaged at 32 ± 21 Watt (range 4–76 Watt) representing 29.8% of the maximum exercise intensity reached. PG before and after CPX was 9.3 ± 2.2 and 7.6 ± 1.7 mmol/L, respectively (p < 0.0001). PG was further decreased significantly at one and two h after exercise to 7.5 ± 1.6 mmol/L and 6.0 ± 1.0 mmol/L, respectively (p < 0.0001 for both as compared to PG before CPX). (4) Conclusions: Aerobic exercise capacity is very low in patients with CAD and T2DM. Exercise at aerobic intensity allowed for significant reduction of plasma glucose. Individual and effective aerobic exercise prescription is possible by CPX.