Manipulating Mother Nature to Accelerate Physiological Adaptations to Exercise

University of Technology Sydney. Faculty of Health.Endurance athletes commonly incorporate repeated exposure to either heat or hypoxia into their training program, due to its ability to improve physiological and performance outcomes. However, there is limited understanding of whether the combined effects of both stimuli together can provide even further benefits above either environment alone. Accordingly, this thesis aimed to assess the effectiveness of incorporating heat and hypoxia across a training block to enhance physiological adaptations and performance in endurance athletes. Study one assessed the temperate performance and physiological changes following a three-week overload period of combined heat and ‘Live High, Train Low’ (LHTL) hypoxia. While the combined stimuli induced physiological adaptations, it did not transfer to improved 3-km time-trial running performance with the only performance improvements observed following independent heat training. Study two further investigated the physiological outcomes of combined heat and LHTL, and assessed multiple thermal, cardiovascular, cellular, and perceptual adaptations during submaximal exercise in the heat. Combined heat and LHTL impaired many heat related adaptations relative to the heat only group, indicating that the addition of LHTL provided no greater physiological benefit during exercise in a hot environment. Following from the findings of study one and two, study three and four assessed the performance and physiological outcomes when heat was applied concurrently with IHT. Specifically, study three evaluated changes in 20-km cycling time-trial performance in both temperate and the participant’s assigned environmental condition following three weeks of training in either concurrent heat and IHT, independent heat or a temperate environment. Performance was improved in all groups to a similar extent regardless of the type of environment. In the fourth and final study, the thermal, cardiovascular, and selected cellular responses following three weeks of training in heat and IHT were assessed. When compared to completing the same training in either independent heat or temperate environments, concurrent heat and IHT provided some advantages above temperate training, but no further benefit above heat training alone. Taken collectively, the present findings show the additive stimuli of combining heat and hypoxia does not directly transfer to improved endurance performance. While physiological adaptations were induced when both LHTL and IHT were applied with heat training, it did not provide clear benefits above independent heat training alone

Effect of a Low Carbohydrate-Moderate Protein Supplement on Endurance Performance in Female Athletes

Previous research has shown that consuming a carbohydrate supplement during prolonged endurance exercise improves performance compared to water or placebo. The addition of protein to traditional carbohydrate supplement has been shown to further improve perfomance beyond that of carbohydrate alone. However, few investigations have explored the effect of adding protein to a supplement containing a low carbohydrate concentration. PURPOSE: To investigate if a low carbohydrate and moderate protein supplement, provided during prolonged variable intensity exercise, would improve time to exhaustion in comparison to a traditional carbohydrate supplement. METHODS: Fourteen (n = 14) trained females cyclists and triathletes (30.4 ±1.6 yrs, 2.90 ± 0.15 L⋅min¬-1) cycled on two different occasions for three hours at intensities varying between 45% - 70% VO2max. After three hours, the intensity was increased (average 72.5 % VO2max) and held until exhaustion. Exhaustion was defined as the point at which subjects could no longer hold cadence above 60RPM. Supplements (275ml) were provided every 20 min during exercise and were composed of a 3% carbohydrate/1.2% protein mix (CHO+PRO) or a 6% carbohydrate-only (CHO). The CHO+PRO treatment contained a mixture of glucose (dextrose), maltodextrin and fructose, and whey protein isolate. The CHO treatment was composed of dextrose. CHO+PRO contained half the carbohydrate content and 30% less calories in comparison to CHO. RESULTS: Time to exhaustion (TTE) was significantly greater with CHO+PRO in comparison to CHO (49.94 ± 7.01 vs 42.36 ± 6.21 min, respectively, p = 0.039). CONCLUSIONS: The above result suggests that addition of a moderate protein to a low carbohydrate supplement enhances performance in endurance trained females above that of carbohydrate alone. Improvement in performance occurred despite a lower carbohydrate and caloric content. It is unknown whether the greater performance seen with CHO+PRO was a result of the added protein, the use of a mixture of carbohydrate sources (glucose, maltodextrin and fructose), or their combination

Effects of Chocolate Milk Supplementation on Recovery from Cycling Exercise and Subsequent Time Trial Performance

PURPOSE: Supplementing with carbohydrate plus protein following strenuous endurance exercise has been found to improve both recovery and subsequent aerobic endurance performance beyond that of a carbohydrate supplement alone. The purpose of the present study was to compare the effects of chocolate milk (CM), an isocaloric carbohydrate only supplement (CHO), and placebo (PLA) on markers of endurance exercise recovery and subsequent time trial performance in trained cyclists. METHODS: Ten trained male and female cyclists (5 males, 5 females) performed 3 trials in which they first cycled for 1.5 h at 70% of VO2max, followed by 10 min of intervals that alternated 45% and 90% VO2max. They then recovered in the laboratory for 4 h, and performed a 40 km time trial (TT). The supplements were provided immediately after the first bout and 2 h into the recovery period. Treatments were administered using a double-blind randomized design. RESULTS: TT time was significantly shorter in CM than CHO and PLA (79.43±2.11 vs. 85.74±3.44 and 86.92±3.28 min, respectively, p=\u3c.05). Significant treatment differences were found for plasma insulin, glucose, free fatty acids (FFA) and glycerol. Plasma insulin levels were significantly lower in CM than CHO at recovery time points R45 (47.30±10.54 vs. 58.71±6.01 &#;U/ml, p\u3c.05), R120 (14.32±1.34 vs. 22.53±3.37 &#;U/ml, p\u3c.05) and REnd (15.57±1.53 vs. 34.35±4.55 &#;U/ml, p\u3c.05). Plasma glucose was significantly lower in CM than CHO at recovery time points R45 (76.61±3.08 vs. 101.65±3.47 mg/dL, p\u3c.05) and R120 (74.72±2.22 vs. 81.46±4.87 mg/dL, p\u3c.05). While FFA and glycerol were both higher in PLA than in CM and CHO overall (p\u3c.05 for both), FFA and glycerol were higher in CM than in CHO (p\u3c.05 for both) during recovery and at TTEnd. Blood lactate was significantly higher at R45 and TTEnd in both CM and CHO than in PLA, but no differences were found between CM and CHO. No significant treatment differences were found for myoglobin, CPK, cortisol, and 5 pro- and anti-inflammatory cytokines (TNF-&#;, IL-6, IL-10, IL-8, and IL-1Ra). CONCLUSIONS: Chocolate milk provided during recovery can improve subsequent time trial performance in trained cyclists more effectively than an isocaloric CHO supplement. This may be due to a faster rate of muscle glycogen resynthesis

Aerobic Exercise Training Adaptations Are Increased by Postexercise Carbohydrate-Protein Supplementation

Carbohydrate-protein supplementation has been found to increase the rate of training adaptation when provided postresistance exercise. The present study compared the effects of a carbohydrate and protein supplement in the form of chocolate milk (CM), isocaloric carbohydrate (CHO), and placebo on training adaptations occurring over 4.5 weeks of aerobic exercise training. Thirty-two untrained subjects cycled 60 min/d, 5 d/wk for 4.5 wks at 75–80% of maximal oxygen consumption (VO2 max). Supplements were ingested immediately and 1 h after each exercise session. VO2 max and body composition were assessed before the start and end of training. VO2 max improvements were significantly greater in CM than CHO and placebo. Greater improvements in body composition, represented by a calculated lean and fat mass differential for whole body and trunk, were found in the CM group compared to CHO. We conclude supplementing with CM postexercise improves aerobic power and body composition more effectively than CHO alone

Effect of a low carbohydrate - moderate protein supplement on endurance performance in female athletes

textThe purpose of this study was to investigate if a low mixed carbohydrate plus moderate protein supplement, provided during endurance exercise, would improve time to exhaustion in comparison to a traditional 6% carbohydrate supplement in female athletes exercising at or below their ventilatory threshold. Fourteen (n = 14) trained female cyclists and triathletes cycled on two separate occasions for three hours at intensities varying between 45% - 70% VO₂max, followed by a ride to exhaustion at an intensity approximating the individual's VT (average 75.06% VO₂max). Supplements (275ml) were provided every 20 min during exercise and were composed of a 3% carbohydrate mixture + 1.2% protein (CHO+PRO) or a 6% carbohydrate-only (CHO). The CHO+PRO treatment contained a mixture of dextrose, maltodextrin, fructose, and whey protein isolate. The CHO treatment was composed of dextrose only. Time to exhaustion (TTE) was significantly greater with CHO+PRO in comparison to CHO (49.94 ± 7.01 vs 42.36 ± 6.21 min, respectively, p < 0.05). Blood glucose was signifcantly lower during the CHO+PRO (4.07 ± 0.12 mmol x L⁻¹) trial compared to CHO (4.47 ± 0.12 mmol x L⁻¹), with treatment x time interactions occurring from 118 minutes of exercise until exhaustion (p < 0.05). Heart rate was significantly lowered in the CHO+PRO treatment during exercise as compared to CHO (p < 0.05). There were no significant differences for other blood measures, ratings of perceived exertion or carbohydrate and fat oxidation between trials. Results from the present study suggest that the addition of a moderate amount of protein to a low mixed carbohydrate supplement improves endurance performance in females above that of a traditional 6% carbohydrate supplement. Improvement in performance occurred despite CHO+PRO containing a lower carbohydrate and caloric content. It is likely the greater performance seen with CHO+PRO was a result of the carbohydrate protein combination and the use of a mixture of carbohydrate sources.Kinesiology and Health Educatio

Impaired heat adaptation from combined heat training and "live high, train low" hypoxia

© 2019 Human Kinetics, Inc. Purpose: To determine whether combining training in heat with "Live High, Train Low" hypoxia (LHTL) further improves thermoregulatory and cardiovascular responses to a heat-tolerance test compared with independent heat training. Methods: A total of 25 trained runners (peak oxygen uptake = 64.1 [8.0] mL·min−1·kg−1) completed 3-wk training in 1 of 3 conditions: (1) heat training combined with "LHTL" hypoxia (H+H; FiO2 = 14.4% [3000 m], 13 h·d−1; train at <600 m, 33°C, 55% relative humidity [RH]), (2) heat training (HOT; live and train <600 m, 33°C, 55% RH), and (3) temperate training (CONT; live and train <600 m, 13°C, 55% RH). Heat adaptations were determined from a 45-min heat-response test (33°C, 55% RH, 65% velocity corresponding to the peak oxygen uptake) at baseline and immediately and 1 and 3 wk postexposure (baseline, post, 1 wkP, and 3 wkP, respectively). Core temperature, heart rate, sweat rate, sodium concentration, plasma volume, and perceptual responses were analyzed using magnitude-based inferences. Results: Submaximal heart rate (effect size [ES] = −0.60 [−0.89; −0.32]) and core temperature (ES = −0.55 [−0.99; −0.10]) were reduced in HOT until 1 wkP. Sweat rate (ES = 0.36 [0.12; 0.59]) and sweat sodium concentration (ES = −0.82 [−1.48; −0.16]) were, respectively, increased and decreased until 3 wkP in HOT. Submaximal heart rate (ES = −0.38 [−0.85; 0.08]) was likely reduced in H+H at 3 wkP, whereas CONT had unclear physiological changes. Perceived exertion and thermal sensation were reduced across all groups. Conclusions: Despite greater physiological stress from combined heat training and "LHTL" hypoxia, thermoregulatory adaptations are limited in comparison with independent heat training. The combined stimuli provide no additional physiological benefit during exercise in hot environments

Postexercise carbohydrate-protein supplementation improves subsequent exercise performance and intracellular signaling for protein synthesis.

[[abstract]]Postexercise carbohydrate–protein supplementation improves subsequent exercise performance and intracellular signaling for protein synthesis. J Strength Cond Res 25(5): 1210–1224, 2011—Postexercise carbohydrate–protein (CHO + PRO) supplementation has been proposed to improve recovery and subsequent endurance performance compared to CHO supplementation. This study compared the effects of a CHO + PRO supplement in the form of chocolate milk (CM), isocaloric CHO, and placebo (PLA) on recovery and subsequent exercise performance. Ten cyclists performed 3 trials,cycling 1.5 hours at 70% V_ O2max plus 10 minutes of intervals. They ingested supplements immediately postexercise and 2 hours into a 4-hour recovery. Biopsies were performed at recovery minutes 0, 45, and 240 (R0, R45, REnd). Postrecovery, subjects performed a 40-km time trial (TT). The TT time was faster in CM than in CHO and in PLA (79.43 6 2.11 vs. 85.74 6 3.44 and 86.92 6 3.28 minutes, p # 0.05). Muscle glycogen resynthesis was higher in CM and in CHO than in PLA (23.58 and 30.58 vs. 7.05 mmolg21 wet weight, p # 0.05). The mammalian target of rapamycin phosphorylation was greater at R45 in CM than in CHO or in PLA (174.4 6 36.3 vs. 131.3 6 28.1 and 73.7 6 7.8% standard, p # 0.05) and at REnd in CM than in PLA (94.5 6 9.9 vs. 69.1 6 3.8%, p # 0.05). rpS6 phosphorylation was greater in CM than in PLA at R45 (41.0 6 8.3 vs. 15.3 6 2.9%, p # 0.05) and REnd (16.8 6 2.8 vs. 8.4 6 1.9%, p # 0.05). FOXO3A phosphorylation was greater at R45 in CM and in CHO than in PLA (84.7 6 6.7 and 85.4 6 4.7 vs. 69.2 6 5.5%, p # 0.05). These results indicate that postexercise CM supplementation can improve subsequent exercise performance and provide a greater intracellular signaling stimulus for PRO synthesis compared to CHO and placebo