Acute impact of conventional and eccentric cycling on platelet and vascular function in patients with chronic heart failure.

Evidence-based guidelines recommend exercise therapy for patients with chronic heart failure (CHF). Such patients have increased atherothrombotic risk. Exercise can transiently increase platelet activation and reactivity and decrease vascular function in healthy participants, although data in CHF is scant. Eccentric (ECC) cycling is a novel exercise modality which may be particularly suited to patients with CHF, but the acute impacts of ECC on platelet and vascular function are currently unknown. Our null hypothesis was that ECC and concentric (CON) cycling, performed at matched external workloads, would not induce changes in platelet or vascular function in patients with CHF. Eleven patients with heart failure with reduced ejection fraction (HFrEF) took part in discrete bouts of ECC and CON cycling. Before and immediately after exercise, vascular function was assessed by measuring diameter and flow mediated dilation (FMD) of the brachial artery. Platelet function was measured by the flow cytometric determination of glycoprotein IIb/IIIa activation and granule exocytosis in the presence and absence of platelet agonists. ECC increased baseline artery diameter (pre: 4.0±0.8mm vs post: 4.2±0.7mm, P=0.04) and decreased FMD%. When changes in baseline artery diameter were accounted for the decrease in FMD post-ECC was no longer significant. No changes were apparent after CON. Neither ECC nor CON resulted in changes to any platelet function measures (all P>0.05). These results suggest both ECC and CON cycling at a moderate intensity and short duration can be performed by patients with HFrEF, without detrimental impacts on vascular or platelet function

Comparing the Impacts of Testosterone and Exercise on Lean Body Mass, Strength and Aerobic Fitness in Aging Men

Abstract Background Based on the largely untested premise that it is a restorative hormone that may reverse the detrimental impacts of aging, prescription of testosterone (T) has increased in recent decades despite no new clinical indications. It is apparent that middle-aged and older men with low-normal serum T levels are considering T supplementation as an anti-aging strategy. At the same time, there is evidence that physical activity (PA) is at historical lows in the Western world. In this review, we compare the impacts of T treatment aimed at achieving physiological T concentrations in middle-aged and older men, alongside the impacts of ecologically relevant forms of exercise training. The independent, and possible combined, effects of T and exercise therapy on physiological outcomes such as aerobic fitness, body composition and muscular strength are addressed. Main Body Our findings suggest that both T treatment and exercise improve lean body mass in healthy older men. If improvement in lean body mass is the primary aim, then T treatment could be considered, and the combination of T and exercise may be more beneficial than either in isolation. In terms of muscle strength in older age, an exercise program is likely to be more beneficial than T treatment (where the dose is aimed at achieving physiological concentrations), and the addition of such T treatment does not provide further benefit beyond that of exercise alone. For aerobic fitness, T at doses aimed at achieving physiological concentrations has relatively modest impacts, particularly in comparison to exercise training, and there is limited evidence as to additive effects. Whilst higher doses of T, particularly by intramuscular injection, may have larger impacts on lean body mass and strength, this must be balanced against potential risks. Conclusion Knowing the impacts of T treatment and exercise on variables such as body composition, strength and aerobic fitness extends our understanding of the relative benefits of physiological and pharmacological interventions in aging men. Our review suggests that T has impacts on strength, body composition and aerobic fitness outcomes that are dependent upon dose, route of administration, and formulation. T treatment aimed at achieving physiological T concentrations in middle-aged and older men can improve lean body mass, whilst exercise training enhances lean body mass, aerobic fitness and strength. Men who are physically able to exercise safely should be encouraged to do so, not only in terms of building lean body mass, strength and aerobic fitness, but for the myriad health benefits that exercise training confers

Higher circulating androgens and higher physical activity levels are associated with less central adiposity and lower risk of cardiovascular death in older men

Objective: Low endogenous sex hormones and low physical activity (PA) levels have been associated with CVD risk. Whether these interact to influence CVD outcomes remains unclear. We assessed whether sex hormone concentrations and PA were additively associated with lower central adiposity and CVD risk. Patients: 3351 community‐dwelling men, mean age 77 years. Measurements: Baseline testosterone (T), dihydrotestosterone (DHT) and oestradiol (E2) were assayed. Levels of PA were ascertained by questionnaire. Men were stratified using median splits into high hormone + high PA (H/H), high hormone + low PA (H/L); low hormone + high PA (L/H) and low hormone + low PA (L/L) groups. Results: A total of 865 CVD events and 499 CVD deaths occurred during 10‐year mean follow‐up. Men with higher T, DHT or SHBG and higher PA had the lowest BMI, waist circumference and risk of metabolic syndrome. Men with higher T had the lowest risk of incident CVD events, irrespective of PA level. Men with higher T or DHT and higher PA had the lowest risk of dying from CVD (eg, hazard ratios for T/PA H/H 0.76 P = 0.031; H/L 0.85 P = 0.222; L/H 0.80 P = 0.075; L/L 1.00). Conclusion: Higher circulating androgens and higher PA were associated with less central adiposity at baseline and fewer CVD deaths during follow‐up. These findings are consistent with a potential additive effect of androgens and PA on cardiometabolic outcomes in older men

Eccentric Cycling: A Promising Modality for Patients with Chronic Heart Failure

Purpose: Chronic heart failure (CHF) is characterized by dyspnea and poor exercise tolerance, which decreases aerobic capacity (V˙ O2peak), a measure strongly correlated with quality of life and mortality. In healthy populations, eccentric (ECC) cycling can be performed at a lower oxygen demand for matched workload, compared with concentric (CON) cycling, but few studies have previously investigated ECC cycling in CHF. We hypothesized that, when matched for external workload (W), an ECC cycling bout would be performed at a lower cardiorespiratory load (V˙ O2) than CON in patients with CHF. Methods: Eleven CHF patients (10 males) with impaired left ventricular systolic function (ejection fraction 31% T 12%) completed a CON V˙ O2peak test, with the subsequent ECC and CON protocols set at 70% of individual maximal CON power (W). Oxygen consumption (V˙ O2), RER, minute ventilation (V˙ E), HR, and rate pressure product were compared between conditions. Results: ECC was performed at a lower V˙ O2 (12.3 T 1.3 vs 14.1 T 0.8 mLIkgj1Iminj1, P = 0.01), RER (0.92 T 0.02 vs 0.96 T 0.01, P = 0.01), and V˙ E (36.5 T 4.4 vs 40.2 T 2.0 LIminj1, P = 0.04) in comparison with CON, despite both conditions being performed at matched workloads. HR (101 T 5 vs 96 T 1 bpm, P = 0.06) and rate pressure product (13,539 T 788 vs 11,911 T 227 bpmImm Hgj1, P = 0.15) were not significantly different between conditions. Conclusion: When matched for external workload, ECC cycling can be performed with a lower oxygen demand than CON in patients with CHF. Eccentric cycling is a promising modality for cardiac rehabilitation in severely deconditioned patients with CHF