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Individual cardiovascular responsiveness to work-matched exercise within the moderate- and severe-intensity domains.
Maturana, FM, Schellhorn, P, Erz, G, Burgstahler, C, Widmann, M, Munz, B, Soares, RN, Murias, JM, Thiel, A, Nieß, AM
European journal of applied physiology. 2021;(7):2039-2059
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Abstract
PURPOSE We investigated the cardiovascular individual response to 6 weeks (3×/week) of work-matched within the severe-intensity domain (high-intensity interval training, HIIT) or moderate-intensity domain (moderate-intensity continuous training, MICT). In addition, we analyzed the cardiovascular factors at baseline underlying the response variability. METHODS 42 healthy sedentary participants were randomly assigned to HIIT or MICT. We applied the region of practical equivalence-method for identifying the levels of responders to the maximal oxygen uptake (V̇O2max) response. For investigating the influence of cardiovascular markers, we trained a Bayesian machine learning model on cardiovascular markers. RESULTS Despite that HIIT and MICT induced significant increases in V̇O2max, HIIT had greater improvements than MICT (p < 0.001). Greater variability was observed in MICT, with approximately 50% classified as "non-responder" and "undecided". 20 "responders", one "undecided" and no "non-responders" were observed in HIIT. The variability in the ∆V̇O2max was associated with initial cardiorespiratory fitness, arterial stiffness, and left-ventricular (LV) mass and LV end-diastolic diameter in HIIT; whereas, microvascular responsiveness and right-ventricular (RV) excursion velocity showed a significant association in MICT. CONCLUSION Our findings highlight the critical influence of exercise-intensity domains and biological variability on the individual V̇O2max response. The incidence of "non-responders" in MICT was one third of the group; whereas, no "non-responders" were observed in HIIT. The incidence of "responders" was 11 out of 21 participants in MICT, and 20 out of 21 participants in HIIT. The response in HIIT showed associations with baseline fitness, arterial stiffness, and LV-morphology; whereas, it was associated with RV systolic function in MICT.
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Cocoa-flavanols enhance moderate-intensity pulmonary [Formula: see text] kinetics but not exercise tolerance in sedentary middle-aged adults.
Sadler, DG, Draijer, R, Stewart, CE, Jones, H, Marwood, S, Thijssen, DHJ
European journal of applied physiology. 2021;(8):2285-2294
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Abstract
INTRODUCTION Cocoa flavanols (CF) may exert health benefits through their potent vasodilatory effects, which are perpetuated by elevations in nitric oxide (NO) bioavailability. These vasodilatory effects may contribute to improved delivery of blood and oxygen (O2) to exercising muscle. PURPOSE Therefore, the objective of this study was to examine how CF supplementation impacts pulmonary O2 uptake ([Formula: see text]) kinetics and exercise tolerance in sedentary middle-aged adults. METHODS We employed a double-blind cross-over, placebo-controlled design whereby 17 participants (11 male, 6 female; mean ± SD, 45 ± 6 years) randomly received either 7 days of daily CF (400 mg) or placebo (PL) supplementation. On day 7, participants completed a series of 'step' moderate- and severe-intensity exercise tests for the determination of [Formula: see text] kinetics. RESULTS During moderate-intensity exercise, the time constant of the phase II [Formula: see text] kinetics ([Formula: see text]) was decreased by 15% in CF as compared to PL (mean ± SD; PL 40 ± 12 s vs. CF 34 ± 9 s, P = 0.019), with no differences in the amplitude of [Formula: see text] (A[Formula: see text]; PL 0.77 ± 0.32 l min-1 vs. CF 0.79 ± 0.34 l min-1, P = 0.263). However, during severe-intensity exercise, [Formula: see text], the amplitude of the slow component ([Formula: see text]) and exercise tolerance (PL 435 ± 58 s vs. CF 424 ± 47 s, P = 0.480) were unchanged between conditions. CONCLUSION Our data show that acute CF supplementation enhanced [Formula: see text] kinetics during moderate-, but not severe-intensity exercise in middle-aged participants. These novel effects of CFs, in this demographic, may contribute to improved tolerance of moderate-activity physical activities, which appear commonly present in daily life. TRIAL REGISTRATION Registered under ClinicalTrials.gov Identifier no. NCT04370353, 30/04/20 retrospectively registered.
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VO2peak and 24-hour sleep, sedentary behavior, and physical activity in Australian truck drivers.
Gilson, ND, Mielke, GI, Coombes, JS, Feter, N, Smith, E, Duncan, MJ, Wallis, G, Brown, WJ
Scandinavian journal of medicine & science in sports. 2021;(7):1574-1578
Abstract
This study assessed cardiorespiratory fitness (CRF) and 24-h sleep, sedentary behavior (SB), and physical activity (PA) in Australian truck drivers. Participants (n = 37 men) attended clinic sessions for an exercise test to exhaustion to establish CRF and wore an accelerometer (Actigraph GT3X+) to estimate sleep, SB, and PA. Relative to normative values, CRF was "below percentile 25" in 51% of drivers (mean [SD] VO2peak=30 .1 [7.6] mL.kg-1.min-1). Accelerometer data indicated that total vigorous-intensity (3.5-4.5 min/day) and sustained moderate- to vigorous-intensity PA (>5 min; 0.5-1.6 bouts/day) were limited. The findings show there is a need to design and test PA interventions that can improve poor levels of CRF in truck drivers.
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The effect of L-arginine supplementation on maximal oxygen uptake: A systematic review and meta-analysis.
Rezaei, S, Gholamalizadeh, M, Tabrizi, R, Nowrouzi-Sohrabi, P, Rastgoo, S, Doaei, S
Physiological reports. 2021;(3):e14739
Abstract
BACKGROUND The efficacy and safety of L-arginine supplements and their effect on maximal oxygen uptake (VO2 max) remained unclear. This systematic review aimed to investigate the effect of L-arginine supplementation (LAS) on VO2 max in healthy people. METHODS We searched PubMed, Scopus, Web of Science, Cochrane, Embase, ProQuest, and Ovid to identify all relevant literature investigating the effect of LAS on VO2 max. This meta-analysis was conducted via a random-effects model for the best estimation of desired outcomes and studies that meet the inclusion criteria were considered for the final analysis. RESULTS The results of 11 randomized clinical trials indicated that LAS increased VO2 max compared to the control group. There was no significant heterogeneity in this meta-analysis. Subgroup analysis detected that arginine in the form of LAS significantly increased VO2 max compared to the other forms (weighted mean difference = 0.11 L min-1 , I2 = 0.0%, p for heterogeneity = 0.485). CONCLUSIONS This meta-analysis indicated that supplementation with L-arginine could increase VO2 max in healthy people. Further studies are warranted to confirm this finding and to identify the underlying mechanisms.
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Cardiorespiratory optimal point during exercise testing is related to cardiovascular and all-cause mortality.
Laukkanen, JA, Kunutsor, SK, Araújo, CG, Savonen, K
Scandinavian journal of medicine & science in sports. 2021;(10):1949-1961
Abstract
Cardiorespiratory optimal point (COP) during exercise may be a potentially clinically useful cardiopulmonary exercise testing (CPET) variable, but its prognostic relevance for adverse cardiovascular disease (CVD) outcomes is unknown. We aimed to assess the association of COP during exercise with fatal mortality outcomes and the extent to which COP could improve the prediction of CVD mortality. Cardiorespiratory optimal point, the minimum value of the ventilatory equivalent for oxygen (VE/VO2) in a given minute of a CPET, was defined in 2,205 men who underwent CPET. Hazard ratios (HRs) (95% confidence intervals [CIs]) for outcomes and measures of risk discrimination for CVD mortality were calculated. During a median follow-up of 28.8 years, 402 fatal CHDs, 607 fatal CVDs, and 1,348 all-cause mortality events occurred. COP was continually associated with each outcome in a dose-response manner. On adjustment for established and emerging risk factors, the HRs (95% CIs) for fatal CHD, fatal CVD, and all-cause mortality were 3.05 (1.94-4.81), 2.82 (1.91-4.18) and 2.46 (1.85-3.27), respectively, per standard deviation increase in COP. After further adjustment for high sensitivity C-reactive protein, the HRs were 2.82 (1.78-4.46), 2.57 (1.73-3.81), and 2.27 (1.70-3.02), respectively. Addition of COP to a CVD mortality risk prediction model containing established risk factors was associated with a C-index change of 0.0139 (0.0040 to 0.0238; p = 0.006) at 25 years. COP during exercise is directly associated with fatal cardiovascular and all-cause mortality events in dose-response fashions. COP during exercise may improve the prediction of the long-term risk for CVD mortality.
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Effects of indulgent food snacking, with and without exercise training, on body weight, fat mass, and cardiometabolic risk markers in overweight and obese men.
Tucker, WJ, Jarrett, CL, D'Lugos, AC, Angadi, SS, Gaesser, GA
Physiological reports. 2021;(22):e15118
Abstract
We hypothesized that exercise training would prevent gains in body weight and body fat, and worsening of cardiometabolic risk markers, during a 4-week period of indulgent food snacking in overweight/obese men. Twenty-eight physically inactive men (ages 19-47 yr) with body mass index (BMI) ≥25 kg/m2 consumed 48 donuts (2/day, 6 days/week; ~14,500 kcal total) for 4 weeks while maintaining habitual diet. Men were randomly assigned to control (n = 9), moderate-intensity continuous training (MICT; n = 9), or high-intensity interval training (HIIT; n = 10). Exercise training occurred 4 days/week, ~250 kcal/session. Controls did not increase body weight, body fat, or visceral abdominal fat. This was partially explained by a decrease in self-reported habitual energy (-239 kcal/day, p = 0.05) and carbohydrate (-47 g/day; p = 0.02) intake. Large inter-individual variability in changes in body weight, fat, and fat-free mass was evident in all groups. Fasting blood pressure, and blood concentrations of glucose, insulin, and lipids were unchanged in all groups. Glucose incremental area under the curve during an oral glucose tolerance test was reduced by 25.6% in control (p = 0.001) and 32.8% in MICT (p = 0.01) groups. Flow-mediated dilation (FMD) was not changed in any group. VO2max increased (p ≤ 0.001) in MICT (9.2%) and HIIT (12.1%) groups. We conclude that in physically inactive men with BMI ≥25 kg/m2 , consuming ~14,500 kcal as donuts over 4 weeks did not adversely affect body weight and body fat, or several markers of cardiometabolic risk. Consumption of the donuts may have prevented the expected improvement in FMD with HIIT.
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Nicotinamide mononucleotide supplementation enhances aerobic capacity in amateur runners: a randomized, double-blind study.
Liao, B, Zhao, Y, Wang, D, Zhang, X, Hao, X, Hu, M
Journal of the International Society of Sports Nutrition. 2021;(1):54
Abstract
BACKGROUND Recent studies in rodents indicate that a combination of exercise training and supplementation with nicotinamide adenine dinucleotide (NAD+) precursors has synergistic effects. However, there are currently no human clinical trials analyzing this. OBJECTIVE This study investigates the effects of a combination of exercise training and supplementation with nicotinamide mononucleotide (NMN), the immediate precursor of NAD+, on cardiovascular fitness in healthy amateur runners. METHODS A six-week randomized, double-blind, placebo-controlled, four-arm clinical trial including 48 young and middle-aged recreationally trained runners of the Guangzhou Pearl River running team was conducted. The participants were randomized into four groups: the low dosage group (300 mg/day NMN), the medium dosage group (600 mg/day NMN), the high dosage group (1200 mg/day NMN), and the control group (placebo). Each group consisted of ten male participants and two female participants. Each training session was 40-60 min, and the runners trained 5-6 times each week. Cardiopulmonary exercise testing was performed at baseline and after the intervention, at 6 weeks, to assess the aerobic capacity of the runners. RESULTS Analysis of covariance of the change from baseline over the 6 week treatment showed that the oxygen uptake (VO2), percentages of maximum oxygen uptake (VO2max), power at first ventilatory threshold, and power at second ventilatory threshold increased to a higher degree in the medium and high dosage groups compared with the control group. However, there was no difference in VO2max, O2-pulse, VO2 related to work rate, and peak power after the 6 week treatment from baseline in any of these groups. CONCLUSION NMN increases the aerobic capacity of humans during exercise training, and the improvement is likely the result of enhanced O2 utilization of the skeletal muscle. TRIAL REGISTRATION NUMBER ChiCTR2000035138 .
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Effects of chronic decaffeinated green tea extract supplementation on lipolysis and substrate utilization during upper body exercise.
Blicher, S, Bartholomae, E, Kressler, J
Journal of sport and health science. 2021;(2):237-242
Abstract
BACKGROUND Decaffeinated green tea extract (dGTE) can increase fat oxidation during leg exercise, but dGTE is unsuitable for many people (e.g., those with injuries/disabilities), and its effects on arm exercise and women are unknown. METHODS Eight adults (23-37 years old, 4 women) performed an incremental arm cycle test to measure peak oxygen uptake (VO2peak), followed by four 1-h trials at 50% VO2peak. Subjects were randomly assigned to 650 mg of dGTE or placebo (PLA) for 4 weeks followed by a 4-week washout and crossover trial. Blood samples were obtained pre-exercise and post-exercise for glycerol and free fatty acid analysis. Respiratory gases were collected continuously. RESULTS VO2 showed no differences across trials ((0.83-0.89) ± (0.19-0.25) L/min, p = 0.460), neither did energy expenditure ((264-266) ± (59-77) kcal, p = 0.420) nor fat oxidation (dGTE = 0.11 to 0.12 g/min vs. PLA = 0.10 to 0.09 g/min, p = 0.220). Fat oxidation as percentage of energy expenditure was not different for dGTE vs. PLA (23% ± 12% to 25% ± 11% vs. 23% ± 10% to 21% ± 9%, p = 0.532). Glycerol concentration increased post-exercise in all trials, independent of treatments (pre = (3.4-5.1) ± (0.6-2.6) mg/dL vs. post = (7.9-9.8) ± (2.6-3.7) mg/dL, p = 0.867, η2 = 0.005 for interaction), as did free fatty acid ((3.5-4.8) ± (1.4-2.2) mg/dL vs. (7.2-9.1) ± (2.6-4.5) mg/dL, p = 0.981, η2 = 0.000). CONCLUSION Chronic dGTE supplementation had no effect on lipolysis and fat oxidation during arm cycle exercise in men and women.
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Cardiorespiratory fitness in children with overweight/obesity: Insights into the molecular mechanisms.
Plaza-Florido, A, Altmäe, S, Esteban, FJ, Löf, M, Radom-Aizik, S, Ortega, FB
Scandinavian journal of medicine & science in sports. 2021;(11):2083-2091
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Abstract
OBJECTIVES High cardiorespiratory fitness (CRF) levels reduce the risk of developing cardiovascular disease (CVD) during adulthood. However, little is known about the molecular mechanisms underlying the health benefits of high CRF levels at the early stage of life. This study aimed to analyze the whole-blood transcriptome profile of fit children with overweight/obesity (OW/OB) compared to unfit children with OW/OB. DESIGN 27 children with OW/OB (10.14 ± 1.3 years, 59% boys) from the ActiveBrains project were evaluated. VO2 peak was assessed using a gas analyzer, and participants were categorized into fit or unfit according to the CVD risk-related cut-points. Whole-blood transcriptome profile (RNA sequencing) was analyzed. Differential gene expression analysis was performed using the limma R/Bioconductor software package (analyses adjusted by sex and maturational status), and pathways' enrichment analysis was performed with DAVID. In addition, in silico validation data mining was performed using the PHENOPEDIA database. RESULTS 256 genes were differentially expressed in fit children with OW/OB compared to unfit children with OW/OB after adjusting by sex and maturational status (FDR < 0.05). Enriched pathway analysis identified gene pathways related to inflammation (eg, dopaminergic and GABAergic synapse pathways). Interestingly, in silico validation data mining detected a set of the differentially expressed genes to be related to CVD, metabolic syndrome, hypertension, inflammation, and asthma. CONCLUSION The distinct pattern of whole-blood gene expression in fit children with OW/OB reveals genes and gene pathways that might play a role in reducing CVD risk factors later in life.
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Multiple-day high-dose beetroot juice supplementation does not improve pulmonary or muscle deoxygenation kinetics of well-trained cyclists in normoxia and hypoxia.
Rokkedal-Lausch, T, Franch, J, Poulsen, MK, Thomsen, LP, Weitzberg, E, Kamavuako, EN, Karbing, DS, Larsen, RG
Nitric oxide : biology and chemistry. 2021;:37-44
Abstract
Dietary nitrate (NO3-) supplementation via beetroot juice (BR) has been reported to lower oxygen cost (i.e., increased exercise efficiency) and speed up oxygen uptake (VO2) kinetics in untrained and moderately trained individuals, particularly during conditions of low oxygen availability (i.e., hypoxia). However, the effects of multiple-day, high dose (12.4 mmol NO3- per day) BR supplementation on exercise efficiency and VO2 kinetics during normoxia and hypoxia in well-trained individuals are not resolved. In a double-blinded, randomized crossover study, 12 well-trained cyclists (66.4 ± 5.3 ml min-1∙kg-1) completed three transitions from rest to moderate-intensity (~70% of gas exchange threshold) cycling in hypoxia and normoxia with supplementation of BR or nitrate-depleted BR as placebo. Continuous measures of VO2 and muscle (vastus lateralis) deoxygenation (ΔHHb, using near-infrared spectroscopy) were acquired during all transitions. Kinetics of VO2 and deoxygenation (ΔHHb) were modeled using mono-exponential functions. Our results showed that BR supplementation did not alter the primary time constant for VO2 or ΔHHb during the transition from rest to moderate-intensity cycling. While BR supplementation lowered the amplitude of the VO2 response (2.1%, p = 0.038), BR did not alter steady state VO2 derived from the fit (p = 0.258), raw VO2 data (p = 0.231), moderate intensity exercise efficiency (p = 0.333) nor steady state ΔHHb (p = 0.224). Altogether, these results demonstrate that multiple-day, high-dose BR supplementation does not alter exercise efficiency or oxygen uptake kinetics during normoxia and hypoxia in well-trained athletes.