Mathieu Gayda

Acute Responses to High-Intensity Intermittent Exercise in CHD Patients

PURPOSE although the acute physiological responses to continuous exercise have been well documented in CHD patients, no previous study has examined the responses to high-intensity intermittent exercise in these patients. The purpose of this study was to compare the physiological responses to a high-intensity interval exercise (HIIE) protocol versus a moderate-intensity continuous exercise (MICE) protocol of similar energy expenditure in CHD patients. METHODS twenty patients with stable CHD (19 males and 1 female, 62 ± 11 yr) were assigned in random order to a single session of HIIE corresponding to 15-s intervals at 100% of peak power output (PPO) and 15-s passive recovery intervals and, 2 wk later, to an isocaloric MICE corresponding to 70% of PPO. RESULTS both protocols were equivalent in terms of energy expenditure. The HIIE protocol resulted in lower mean ventilation (P < 0.001) for a small difference in metabolic demand. All participants preferred the HIIE mainly because the perceived exertion measured by the Borg scale was lower (P < 0.05). No elevation of serum concentration of troponin T was found in all participants at baseline and at 20 min and 24 h after the exercise sessions, thus excluding the presence of any exercise-induced myocardial injury in our patients. CONCLUSIONS when considering physiological responses, safety, and perceived exertion, the HIIE protocol seemed to be well tolerated and more efficient in this group of stable CHD patients.

Long-term Lifestyle Intervention with Optimized High-Intensity Interval Training Improves Body Composition, Cardiometabolic Risk, and Exercise Parameters in Patients with Abdominal Obesity

ObjectiveThe aim of this study was to study the impact of a combined long-term lifestyle and high-intensity interval training intervention on body composition, cardiometabolic risk, and exercise tolerance in overweight and obese subjects. DesignSixty-two overweight and obese subjects (53.3 ± 9.7 yrs; mean body mass index, 35.8 ± 5 kg/m2) were retrospectively identified at their entry into a 9-mo program consisting of individualized nutritional counselling, optimized high-intensity interval exercise, and resistance training two to three times a week. Anthropometric measurements, cardiometabolic risk factors, and exercise tolerance were measured at baseline and program completion. ResultsAdherence rate was 97%, and no adverse events occurred with high-intensity interval exercise training. Exercise training was associated with a weekly energy expenditure of 1582 ± 284 kcal. Clinically and statistically significant improvements were observed for body mass (−5.3 ± 5.2 kg), body mass index (−1.9 ± 1.9 kg/m2), waist circumference (−5.8 ± 5.4 cm), and maximal exercise capacity (+1.26 ± 0.84 metabolic equivalents) (P < 0.0001 for all parameters). Total fat mass and trunk fat mass, lipid profile, and triglyceride/high-density lipoprotein ratio were also significantly improved (P < 0.0001). At program completion, the prevalence of metabolic syndrome was reduced by 32.5% (P < 0.05). Independent predictors of being a responder to body mass and waist circumference loss were baseline body mass index and resting metabolic rate; those for body mass index decrease were baseline waist circumference and triglyceride/high-density lipoprotein cholesterol ratio. ConclusionsA long-term lifestyle intervention with optimized high-intensity interval exercise improves body composition, cardiometabolic risk, and exercise tolerance in obese subjects. This intervention seems safe, efficient, and well tolerated and could improve adherence to exercise training in this population.

Usefulness of self-reported leisure-time physical activity to predict long-term survival in patients with coronary heart disease.

Self-reported leisure-time physical activity level correlates well with both cardiovascular (CV) and non-CV mortality in subjects without coronary heart disease (CHD). The impact of leisure-time physical activity on long-term outcomes has not been well studied in patients with preexisting CHD, who are often physically limited because of symptoms, medications, and co-morbid conditions. The aim was to determine the long-term prognostic value of self-reported leisure-time physical activity in a large CHD cohort. Leisure-time physical activity was evaluated using a self-administered questionnaire and categorized using a 4-level scale (sedentary, mild, moderate, and strenuous) in 14,021 of 24,958 subjects from the Coronary Artery Surgery Study Registry with suspected or proven CHD who underwent cardiac catheterization from 1974 to 1979. Median long-term follow-up was 14.7 years (interquartile range 9.8 to 16.2). Clinical outcomes were evaluated according to physical activity level and adjusted for potential confounders. Long-term all-cause and CV mortality progressively increased from most to least active subjects, with sedentary patients showing a 1.6-fold increase in mortality for both these outcomes (hazard ratio [HR] 1.63, 95% confidence interval [CI] 1.34 to 1.97, p <0.0001 for all-cause mortality). Similar trends were noted for men and women and in adjusted models, although HRs were attenuated after adjusting for age, gender, smoking, hypertension, diabetes mellitus, total cholesterol, body mass index, and ejection fraction (adjusted HR 1.23, 95% CI 1.01 to 1.49, p = 0.03 for all-cause mortality; adjusted HR 1.25, 95% CI 0.99 to 1.57, p = 0.05 for CV mortality). In conclusion, leisure-time physical activity independently predicted long-term survival in men and women with chronic stable CHD.

High-Intensity Aerobic Interval Exercise in Chronic Heart Failure

Aerobic exercise training is strongly recommended in patients with heart failure (HF) and reduced left ventricular ejection fraction (LVEF) to improve symptoms and quality of life. Moderate-intensity aerobic continuous exercise (MICE) is the best established training modality in HF patients. For about a decade, however, another training modality, high-intensity aerobic interval exercise (HIIE), has aroused considerable interest in cardiac rehabilitation. Originally used by athletes, HIIE consists of repeated bouts of high-intensity exercise interspersed with recovery periods. The rationale for its use is to increase exercise time spent in high-intensity zones, thereby increasing the training stimulus. Several studies have demonstrated that HIIE is more effective than MICE, notably for improving exercise capacity in patients with HF. The aim of the present review is to describe the general principles of HIIE prescription, the acute physiological effects, the longer-term training effects, and finally the future perspectives of HIIE in patients with HF.

Angiopoietin-Like 2 Promotes Atherogenesis in Mice

Background Angiopoietin like‐2 (angptl2), a proinflammatory protein, is overexpressed in endothelial cells (ECs) from patients with coronary artery disease (CAD). Whether angptl2 contributes to atherogenesis is unknown. We tested the hypothesis that angptl2 promotes inflammation and leukocyte adhesion onto ECs, thereby accelerating atherogenesis in preatherosclerotic dyslipidemic mice. Methods and Results In ECs freshly isolated from the aorta, basal expression of TNF‐α and IL‐6 mRNA was higher in 3‐month‐old severely dyslipidemic mice (LDLr−/−; hApoB100+/+ [ATX]) than in control healthy wild‐type (WT) mice (P<0.05) and was increased in both groups by exogenous angptl2 (100 nmol/L). Angptl2 stimulated the adhesion of leukocytes ex vivo on the native aortic endothelium of ATX, but not WT mice, in association with higher expression of ICAM‐1 and P‐selectin in ECs (P<0.05). Antibodies against these endothelial adhesion molecules prevented leukocyte adhesion. Intravenous administration of angptl2 for 1 month in preatherosclerotic 3‐month‐old ATX mice increased (P<0.05) total cholesterol and LDL‐cholesterol levels, strongly induced (P<0.05) the expression of endothelial proinflammatory cytokines and adhesion molecules while accelerating atherosclerotic lesion formation by 10‐fold (P<0.05). Plasma and aortic tissue levels of angptl2 increased (P<0.05) with age and were higher in 6‐ and 12‐month‐old ATX mice than in age‐matched WT mice. Angptl2 accumulated to high levels in the atherosclerotic lesions (P<0.05). Finally, angptl2 was greatly expressed (P<0.05) in ECs cultured from CAD patients, and circulating angptl2 levels were 6‐fold higher in CAD patients compared with age‐matched healthy volunteers. Conclusions Angptl2 contributes to the pathogenesis of atherosclerosis.

Central hemodynamic responses during acute high-intensity interval exercise and moderate continuous exercise in patients with heart failure

The aim of this study was to compare the acute hemodynamic responses during high-intensity intermittent exercise (HIIE) session compared with moderate-intensity continuous exercise (MICE) session in patients with heart failure and reduced ejection fraction (HFREF). Thirteen patients with HFREF (age, 59 ± 6 years; left ventricular ejection fraction, 27% ± 6%; New York Heart Association class I to III) were randomly assigned to a single session of HIIE (2 × 8 min) corresponding to 30 s at 100% of peak power output (PPO) and 30 s passive recovery intervals or to a MICE (22 min) at 60% of PPO. Gas exchange and central hemodynamic parameters (cardiac bioimpedance) were measured continuously during exercise. Oxygen uptake, stroke volume (SV), cardiac output (CO), and arterio-venous difference (C(a-v)O(2)) were compared. Mean oxygen uptake and ventilation were lower during HIIE vs. MICE. CO, SV, and C(a-v)O(2)) were not different between MICE and HIIE. Optimized HIIE was well tolerated (similar perceived exertion) and no significant ventricular arrhythmias and (or) abnormal blood pressure responses occurred during HIEE session. Compared with MICE, optimized HIIE elicited similar central hemodynamic and C(a-v)O(2) responses in HFREF patients with lower oxygen uptake and ventilation. HIIE may be an efficient exercise training modality in patients with HFREF.

High-intensity aerobic interval training in a patient with stable angina pectoris.

Recently, high-intensity aerobic interval training was shown to be more effective than continuous moderate-intensity exercise for improving maximal aerobic capacity and endurance in patients with coronary heart disease. However, patients with exercise-induced ischemia were not included in those studies. We present the acute cardiopulmonary responses of a 67-yr-old man with stable angina pectoris during a 34-min session of high-intensity aerobic interval training. Exercise was well tolerated with neither significant arrhythmia nor elevation of cardiac troponin-T. We observed a complete disappearance of symptoms and signs of myocardial ischemia after 24 mins of exercise. This observation is similar to the warm-up angina phenomenon, an adaptation to myocardial ischemia that remains poorly understood. We conclude that high-intensity aerobic interval training is a promising mode of training for patients with stable coronary heart disease that should also be investigated further in patients with exercise-induced ischemia.

Acute responses to intermittent and continuous exercise in heart failure patients.

BACKGROUND The purpose of this study was to compare cardiopulmonary responses, exercise adherence, tolerance, and safety of optimized high-intensity interval exercise (HIIE) compared with moderate-intensity continuous exercise (MICE) in patients with heart failure and reduced ejection fraction (HFREF). METHODS Twenty patients with HFREF (aged 61 ± 9.9 years) were randomly assigned to HIIE corresponding to 2 × 8 minutes of 30-second intervals at 100% of peak power output and 30-second passive recovery intervals and to a 22-minute MICE corresponding to 60% of peak power output. Gas exchange, electrocardiogram, and blood pressure were measured continuously. Cardiac troponin T (cTnT), C-reactive protein (CRP), and brain natriuretic peptide (BNP) were measured before, 20 minutes after, and 24 hours after HIIE and MICE. RESULTS Cardiopulmonary responses did not differ between MICE and HIIE. Higher exercise adherence and efficiency were observed on HIIE with a similar perceived exertion and time spent above 90% of peak oxygen consumption compared with MICE. Neither HIIE nor MICE caused any significant arrhythmias or increased CRP, BNP, or cTnT. CONCLUSIONS Compared with MICE, HIIE demonstrated a higher exercise adherence and was well tolerated in patients with HFREF, while still providing a high-level physiological stimulus and leaving indices of inflammation (CRP), myocardial dysfunction (BNP), and myocardial necrosis (cTnT) unaffected.

EFFECT OF INTERVAl TRAININg ON COgNITIVE FUNCTIONINg AND CEREBRAl OxygENATION IN OBESE PATIENTS: A PIlOT STUDy

OBJECTIVE To assess the effect of a 4-month high-intensity interval training programme on cognitive functioning, cerebral oxygenation, central haemodynamic and cardiometabolic parameters and aerobic capacity in obese patients. METHODS Cognitive functioning, cerebral oxygenation, central haemodynamic, cardiometabolic and exercise para-meters were measured before and after a 4-month high-intensity interval training programme in 6 obese patients (mean age 49 years (standard deviation 8), fat mass percentage 31 ± 7%). RESULTS Body composition (body mass, total and trunk fat mass, waist circumference) and fasting insulin were improved after the programme (p < 0.05). V. O2 and power output at ventilatory threshold and peak power output were improved after the programme (p < 0.05). Cognitive functioning, including short-term and verbal memory, attention and processing speed, was significantly improved after training (p < 0.05). Cerebral oxygen extraction was also improved after training (p < 0.05). CONCLUSION These preliminary results indicate that a 4-month high-intensity interval training programme in obese patients improved both cognitive functioning and cere-bral oxygen extraction, in association with improved exercise capacity and body composition.

A Single Bout of High-Intensity Interval Exercise Does Not Increase Endothelial or Platelet Microparticles in Stable, Physically Fit Men With Coronary Heart Disease

BACKGROUND High-intensity interval exercise (HIIE) is gaining in popularity in fitness centres, even among coronary heart disease (CHD) patients. However, whether HIIE can have deleterious acute effects on the vasculature in CHD has not been studied. We hypothesized that when compared with moderate-intensity continuous exercise (MICE), a single bout of HIIE could lead to vascular damage and increasing numbers of circulating endothelial and platelet microparticles (EMPs, PMPs) in stable, physically fit CHD patients. METHODS Nineteen male CHD patients (aged 62 ± 11 years) underwent, in random order, a single session of HIIE corresponding to 15-second intervals at 100% of peak power output and 15-second passive recovery intervals, and an isocaloric MICE session. EMPs (CD31+ and/or CD62E+ and CD42b-); PMPs (CD42b+); nitrates and nitrites; prostacycline; and troponin T, cardiac form (cTnT), were measured 10 minutes before exercise and 20 minutes, 24 hours, and 72 hours after both exercise sessions. RESULTS EMPs, PMPs, nitrates and nitrites, prostacycline, and cTnT remained unchanged after both HIIE and MICE exercise sessions. Initial EMP concentration correlated inversely with EMP concentration 20 minutes post exercise, irrespective of exercise modality (r = 0.78, P < 0.0001). CONCLUSIONS A single HIIE session with very short exercise and passive recovery periods appears safe and does not induce changes to markers of endothelial function. Future studies are required to determine the safety of a long-term HIIE training program.