International journal of sport nutrition and exercise metabolism最新文献

Capsaicinoids and capsinoids are bioactive compounds mostly found in peppers. Although preclinical studies have reported that these compounds can improve exercise performance due to transient receptor potential vanilloid subtype 1 (TRPV1)-mediated thermogenesis, sympathetic modulation, and releasing calcium, it is still unclear how they affect exercise performance in humans as ergogenic supplements. Conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses reporting guide 2020, this systematic review examined the ergogenic effect of capsaicinoids and capsinoids on exercise performance in healthy adults. A total of 19 randomized placebo-controlled trials were included in the study. Studies were accessed by searching five databases (PubMed, Scopus, SPORTDiscus, Web of Science, and Cochrane Library). The quality of the studies was evaluated using the Cochrane risk-of-bias assessment tool. According to the study results, 10 studies examining the effect of capsaicinoid and capsinoid supplements on exercise performance reported positive effects. Also, the effect of capsaicinoids and capsinoids on exercise performance is more pronounced in resistance training. This difference, which varies according to the type of exercise, may be due to the correlation between capsaicin transient receptor potential vanilloid subtype 1 and insulin-like growth factor-1.

Previous observations demonstrate New Zealand blackcurrant (NZBC) extract to alter cardiovascular responses at rest without prior exercise. However, the prolonged effects of NZBC on blood pressure and heart rate variability following exercise are not known. Participants (n15 [five women], age: 31 ± 9 years, maximal oxygen uptake: 44 ± 9 ml·kg-1·min-1) undertook a control condition of 2 hr of lying supine rest. Subsequently, in a double-blind, placebo (PLA)-controlled, randomized crossover design participants completed 1 hr of treadmill exercise at 50% maximal oxygen uptake followed by 2-hr supine rest with blood pressure and heart rate variability measurement following a 7-day intake of NZBC and PLA. With NZBC, there was an increase in average fat oxidation (NZBC: 0.24 ± 0.11 vs. PLA: 0.17 ± 0.11 g/min, p = .005), and larger high-frequency relative power during the exercise (p = .037). In the 2-hr rest period, delta change for systolic pressure was larger with NZBC than PLA (Control vs. NZBC: -5.6 ± 6.4, Control vs. PLA: -3.5 ± 6.0 mmHg, p = .033) but was not different for diastolic or mean arterial pressure. There were no alterations in heart rate variabilities during the 2 hr following the exercise with NZBC. A 7-day intake of NZBC causes a larger postexercise hypotension response in young, physically active men and women following 1 hr of treadmill exercise at 50% maximal oxygen uptake.

This study investigated the effects of an acute dose (900 mg) of New Zealand Blackcurrant (NZBC) extract on 5-km running performance, alongside associated physiological and metabolic responses. Sixteen trained male runners (age 26 ± 5 years, stature 173.4 ± 7.3 cm, body mass 73.7 ± 6.9 kg, maximal oxygen consumption [V˙O2max] 55.4 ± 6.1 ml·kg-1·min-1) ingested either capsules containing NZBC extract (3 × 300 mg CurraNZ, 315 mg anthocyanins) or a matched placebo (3 × 300 mg gluten-free flour) 2 hr before exercise in a double-blind, randomized, crossover design. Performance time, physiological, and metabolic responses were assessed in a 5-km time trial, preceded by 10-min exercise at the lactate threshold on a treadmill. NZBC extract did not alter the physiological or metabolic responses to exercise at the lactate threshold (oxygen uptake, respiratory exchange ratio, minute ventilation, carbohydrate oxidation, fat oxidation, heart rate, blood lactate, or rating of perceived exertion, p > .05). The 5-km time trial was completed in a faster time in the NZBC extract condition compared with placebo (NZBC: 1,308.96 ± 122.36 s, placebo: 1,346.33 ± 124.44, p = .001, d = -0.23, confidence interval range = [-0.46, 0.00 s]). No differences in physiological or metabolic responses were apparent between conditions for the 5-km time trial (p > .05). Ingesting 900 mg of NZBC extract as an acute dose improves performance in trained male runners without altering physiological or metabolic responses to exercise. Further research is needed to assess a wider range of possible mechanisms (e.g., cardiovascular function, metabolite profiles) to advance insight into improved performance following supplementation.

The purpose of this study was to investigate the influence of mouth rinsing and ingesting unpleasant salty or bitter solutions on cycling sprint performance and knee extensor force characteristics. Eleven male and one female trained cyclists (age: 34 ± 9 years, maximal oxygen uptake 56.9 ± 3.9 ml·kg-1·min-1) completed a ramp test and familiarization followed by four experimental trials. In each trial, participants completed an all-out 30-s cycling sprint with knee extensor maximal voluntary contractions before and immediately after the sprint. In a randomized, counterbalanced, cross-over order, the four main trials were: a no solution control condition, water, salty (5.8%), or bitter (2 mM quinine) solutions that were mouth rinsed (10 s) and ingested immediately before the cycling sprint. There were no significant differences between conditions in mean power (mean ± SD, no solution: 822 ± 115 W, water: 818 ± 108 W, salt: 832 ± 111 W, bitter: 818 ± 105 W); peak power (no solution: 1,184 ± 205 W, water: 1,177 ± 207 W, salt: 1,195 ± 210 W, bitter: 1,184 ± 209 W); or fatigue index (no solution: 51.5% ± 5.7%, water: 50.8% ± 7.0%, salt: 51.1% ± 5.9%, bitter: 51.2% ± 7.1%) during the sprint. Maximal force and impulse declined postexercise; however, there were no significant differences between conditions in knee extensor force characteristics. The present data do not support the use of unpleasant salty or bitter solutions as an ergogenic aid to improve sprint exercise performance.

Endurance exercise can disturb intestinal epithelial integrity, leading to increased systemic indicators of cell injury, hyperpermeability, and pathogenic translocation. However, the interaction between exercise, diet, and gastrointestinal disturbance still warrants exploration. This study examined whether a 6-day dietary intervention influenced perturbations to intestinal epithelial disruption in response to a 25-km race walk. Twenty-eight male race walkers adhered to a high carbohydrate (CHO)/energy diet (65% CHO, energy availability = 40 kcal·kg FFM-1·day-1) for 6 days prior to a Baseline 25-km race walk. Athletes were then split into three subgroups: high CHO/energy diet (n = 10); low-CHO, high-fat diet (LCHF: n = 8; <50 g/day CHO, energy availability = 40 kcal·kg FFM-1·day-1); and low energy availability (n = 10; 65% CHO, energy availability = 15 kcal·kg FFM-1·day-1) for a further 6-day dietary intervention period prior to a second 25-km race walk (Adaptation). During both trials, venous blood was collected pre-, post-, and 1 hr postexercise and analyzed for markers of intestinal epithelial disruption. Intestinal fatty acid-binding protein concentration was significantly higher (twofold increase) in response to exercise during Adaptation compared to Baseline in the LCHF group (p = .001). Similar findings were observed for soluble CD14 (p < .001) and lipopolysaccharide-binding protein (p = .003), where postexercise concentrations were higher (53% and 36%, respectively) during Adaptation than Baseline in LCHF. No differences in high CHO/energy diet or low energy availability were apparent for any blood markers assessed (p > .05). A short-term LCHF diet increased intestinal epithelial cell injury in response to a 25-km race walk. No effect of low energy availability on gastrointestinal injury or symptoms was observed.

The study aimed to determine the effects of two differing amino acid beverage interventions on biomarkers of intestinal epithelial integrity and systemic inflammation in response to an exertional-heat stress challenge. One week after the initial assessment, participants (n = 20) were randomly allocated to complete two exertional-heat stress trials, with at least 1 week washout. Trials included a water control trial (CON), and one of two possible amino acid beverage intervention trials (VS001 or VS006). On VS001 (4.5 g/L) and VS006 (6.4 g/L), participants were asked to consume two 237-ml prefabricated doses daily for 7 days before the exertional-heat stress, and one 237-ml dose immediately before, and every 20 min during 2-hr running at 60% maximal oxygen uptake in 35 °C ambient conditions. A water volume equivalent was provided on CON. Whole blood samples were collected pre-, immediately post-, 1 and 2 hr postexercise, and analyzed for plasma concentrations of cortisol, intestinal fatty acid protein, soluble CD14, and immunoglobulin M (IgM) by ELISA, and systemic inflammatory cytokines by multiplex. Preexercise resting biomarker concentrations for all variables did not significantly differ between trials (p > .05). A lower response magnitude for intestinal fatty acid protein (mean [95% CI]: 249 [60, 437] pg/ml, 900 [464, 1,336] pg/ml), soluble CD14 (-93 [-458, 272] ng/ml, 12 [-174, 197] ng/ml), and IgM (-6.5 [-23.0, 9.9] MMU/ml, -10.4 [-16.2, 4.7] MMU/ml) were observed on VS001 and V006 compared with CON (p < .05), respectively. Systemic inflammatory response profile was lower on VS001, but not VS006, versus CON (p < .05). Total gastrointestinal symptoms did not significantly differ between trials. Amino acid beverages' consumption (i.e., 4.5-6.4 g/L), twice daily for 7 days, immediately before, and during exertional-heat stress ameliorated intestinal epithelial integrity and systemic inflammatory perturbations associated with exercising in the heat, but without exacerbating gastrointestinal symptoms.

An increase in visceral fat is associated with an increase in insulin resistance, so reducing body fat mass through exercise may help alleviate type 2 diabetes mellitus (T2DM). The current meta-analysis evaluated the effect of changes in body fat via an intervention of regular exercise on hemoglobin A1c (HbA1c) in patients with T2DM. The inclusion criteria were randomized controlled trials involving adults with T2DM, intervention involving exercise alone, an overall duration of intervention ≥12 weeks, and reporting HbA1c and body fat mass. The mean differences (MDs) were defined as the MD between the exercise group and the control group, and the MDs in HbA1c (in percentage) and body fat mass (in kilograms) were calculated. All MDs in HbA1c were pooled as overall effects. A meta-regression analysis was performed to evaluate the relationship between the MD in the body fat mass (in kilograms) and the MD in HbA1c. Twenty studies (1,134 subjects) were analyzed. The pooled MD in HbA1c (in percentage) decreased significantly (-0.4; 95% confidence interval [-0.5, -0.3]) but contained significant heterogeneity (Q = 52.7, p < .01; I2 = 41.6%). A meta-regression analysis showed that a decrease in the MD in body fat mass was significantly associated with a decrease in the MD in HbA1c (R2 = 80.0%) and heterogeneity decreased (Q = 27.3, p = .61; I2 = 11.9%), and a reduction in body fat mass of 1 kg was estimated to decrease the HbA1c (%) by approximately 0.2. The current study suggested that a decrease in HbA1c due to regular exercise depends on a reduction in body fat mass in patients with T2DM.