BackgroundRecent studies have begun to identify the molecular determinants of inter-individual variability of cardiorespiratory fitness (CRF) in response to exercise training programs. However, we still have an incomplete picture of the molecular mechanisms underlying trainability in response to exercise training.ObjectiveWe investigated baseline serum and skeletal muscle metabolomics profile and its associations with maximal power output (MPO) gains in response to 8-week of continuous endurance training (ET) and high-intensity interval training (HIIT) programs matched for total units of exercise performed (the TIMES study).MethodsEighty healthy sedentary young adult males were randomized to one of three groups and 70 were defined as completers (> 90% of sessions): ET (n = 30), HIIT (n = 30) and control (CO, n = 10). For the CO, participants were asked to not exercise for 8 weeks. Serum and skeletal muscle samples were analyzed by 1H-NMR spectroscopy. The targeted screens yielded 43 serum and 70 muscle reproducible metabolites (intraclass > 0.75; coefficient of variation < 25%). Associations of baseline metabolites with MPO trainability were explored within each training program via three analytical strategies: (1) correlations with gains in MPO; (2) differences between high and low responders to ET and HIIT; and (3) metabolites contributions to the most significant pathways related to gains in MPO. The significance level was set at P < 0.01 or false discovery rate of 0.1.ResultsThe exercise programs generated similar gains in MPO (ET = 21.4 ± 8.0%; HIIT = 24.3 ± 8.5%). MPO associated baseline metabolites supported by all three levels of evidence were: serum glycerol, muscle alanine, proline, threonine, creatinine, AMP and pyruvate for ET, and serum lysine, phenylalanine, creatine, and muscle glycolate for HIIT. The most common pathways suggested by the metabolite profiles were aminoacyl-tRNA biosynthesis, and carbohydrate and amino acid metabolism.ConclusionWe suggest that MPO gains in both programs are potentially associated with metabolites indicative of baseline amino acid and translation processes with additional evidence for carbohydrate metabolism in ET.

Increase in muscle mass and strength through resistance exercise (RE) has been highly recommended for healthy aging. On the other hand, RE could lead to acute cardiovascular risks prompted mainly by intense blood pressure elevations and cardiac autonomic imbalance. We compared the cardiovascular responses to three different RE protocols performed by 21 healthy elderly on a leg press machine. The protocols tested were high load (80% 1RM) until muscular failure (HL); low load (30% 1RM) until muscular failure (LL); low load, 30 repetitions followed by 3 sets of 15 repetitions, with 50% blood flow restriction (LL-BFR); and a control session (CON). Based on heart rate variability analysis, only LL kept parasympathetic indexes lower than CON at 30 min recovery. By finger photoplethysmography, LL-BFR prompted higher systolic and mainly diastolic blood pressure increments in many sets. The heart rate and cardiac output increase, and total peripheral resistance reduction following exercise were not different among RE protocols. There was no significant post-exercise hypotension and carotid arterial compliance changes. HL seems to be the safer protocol to be recommended for the healthy elderly, because it induces lower blood pressure increments and faster parasympathetic recovery compared to LL and LL-BFR.

This study investigated the autonomic and haemodynamic responses to different aerobic exercise loads, with and without blood flow restriction (BFR). In a crossover study, 21 older adults (8 males and 13 females) completed different aerobic exercise sessions: low load without BFR (LL) (40% VO), low load with BFR (LL-BFR) (40% VO + 50% BFR) and high load without BFR (HL) (70% VO). Heart rate variability and haemodynamic responses were recorded during rest and throughout 30 min of recovery. HL reduced R-R interval, the root mean square of successive difference of R-R intervals and high frequency during 30 min of recovery at a greater magnitude compared with LL and LL-BFR. Sympathetic-vagal balance increased the values for HL during 30 min of recovery at a greater magnitude when compared with LL and LL-BFR. Post-exercise haemodynamic showed reduced values of double product at 30 min of recovery compared to rest in LL-BFR, while HL showed higher values compared to rest, LL-BFR and LL. Reduced systolic blood pressure was observed for LL-BFR (30 min) compared to rest. Autonomic and haemodynamic responses indicate lower cardiovascular stress after LL-BFR compared to HL, being this method, besides the functional adaptations, a potential choice to attenuate the cardiovascular stress after exercise in older adults.

This article is a methodological description of a randomized clinical trial (ClinicalTrials.gov U1111-1181-4455) aiming to evaluate the time-course (monthly) and associations between blood pressure changes and other health-related adaptations in response to exercise training in hypertensive elderly. Methods: The patients will be randomized to a control or combined training group interventions (aerobic and resistance exercise), with monthly assessments in four months. Although, the changes in baseline blood pressure is the primary clinical outcome, the secondary outcomes include: body composition, cardiorespiratory fitness, muscle strength, arterial stiffness, baroreceptor sensitivity, cardiovascular autonomic modulation, inflammatory markers, oxidative stress, growth factors, tissue remodeling markers, metabolic profile, renal function, cognitive function and quality of life. Results: To support the understanding of the blood pressure changes in hypertensive elderly, a time-course of exercise-induced adaptations including cardiovascular and immunological adaptations are fundamental for research in this field. Conclusion: To investigate the time-course of combined training-induced adaptations including all the diverse aspects of health in hypertensive elderly a well-controlled protocol design is necessary, mainly to clarify the relationship between cardiovascular and immunological exercise-induced adaptations.

Intrinsic cardiorespiratory fitness (iCRF) indicates the CRF level in the sedentary state. However, even among sedentary individuals, a wide interindividual variability is observed in the iCRF levels, whose associated molecular characteristics are little understood. This study aimed to investigate whether serum and skeletal muscle metabolomics profiles are associated with iCRF, measured by maximal power output (MPO). Seventy sedentary young adults were submitted to venous blood sampling, a biopsy of the vastus lateralis muscle and iCRF assessment. Blood serum and muscle tissue samples were analyzed by proton nuclear magnetic resonance ( 1 H NMR) spectroscopy. Metabolites related to iCRF were those supported by three levels of evidence: (1) correlation with iCRF, (2) significant difference between individuals with low and high iCRF, and (3) metabolite contribution to significant pathways associated with iCRF. From 43 serum and 70 skeletal muscle analyzed metabolites, iCRF was positively associated with levels of betaine, threonine, proline, ornithine, and glutamine in serum and lactate, fumarate, NADP+, and formate in skeletal muscle. Serum betaine and ornithine and skeletal muscle lactate metabolites explained 31.2 and 16.8%, respectively, of the iCRF variability in addition to body mass. The results suggest that iCRF in young adults is positively associated with serum and skeletal muscle metabolic levels, indicative of the amino acid and carbohydrate metabolism.

Introduction: Resistance exercise (RE) training is widely recommended for increasing muscle strength and mass in older adults. RE is also a potential stimulus to improve cognitive functions (CF), but the best protocol for this purpose is unknown. Objective: To compare the effects of different RE protocols on CF in the same group of individuals. Methods: Twenty-four older adults were randomized (cross over) to control (CON) and lower limb RE protocols with high load (HL - 80% of 1RM), low load (LL - 30% of 1RM) and LL with blood flow restriction (LL-BFR - 30% of 1RM and 50% BFR). For CF assessment, participants underwent the Stroop test before and after each RE protocol. Results: Reduction in response time for Stroop neutral stimuli was greater after LL (effect size (ES) = -0.92) compared to CON (ES = -0.18) and HL (ES = -0.03), but was not different from LL-BFR (ES = -0.24). The reduced response time was associated with reduced parasympathetic modulation and increased cardiac output across protocols. Conclusion: LL was the most effective RE protocol to improve CF of older adults and a potential beneficial effect of LL-BFR on CF (non-significant) was identified. Therefore, LL resistance exercise appears to stimulate acute cognitive improvements in healthy older adults, probably through exercise-induced optimal autonomic modulation changes. Level of Evidence I; Therapeutic studies-Investigating the results of treatment.

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