Faculty Opinions recommendation of Muscle-specific expression of PPARgamma coactivator-1alpha improves exercise performance and increases peak oxygen uptake.

The induction of peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α), a key regulator of mitochondriogenesis, is well-established under multiple physical exercise regimens, including, endurance, resistance, and sprint training. We wanted to determine if increased expression of PGC-1α in muscle is sufficient to improve performance during exercise in vivo. We demonstrate that muscle-specific expression of PGC-1α improves the performance during voluntary as well as forced exercise challenges. Additionally, PGC-1α transgenic mice exhibit an enhanced performance during a peak oxygen uptake exercise test, demonstrating an increased peak oxidative capacity, or whole body oxygen uptake. This increased ability to perform in multiple exercise paradigms is supported by enhanced mitochondrial function as suggested by increased mitochondrial gene expression, mitochondrial DNA, and mitochondrial enzyme activity. Thus this study demonstrates that upregulation of PGC-1α in muscle in vivo is sufficient to greatly improve exercise performance under various exercise paradigms as well as increase peak oxygen uptake.

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Voluntary fluid intake, hydration status, and aerobic performance of adolescent athletes in the heat

Applied Physiology Nutrition and Metabolism ◽

10.1139/h10-084 ◽

2010 ◽

Vol 35 (6) ◽

pp. 834-841 ◽

Cited By ~ 12

Author(s):

Boguslaw Wilk ◽

Brian W. Timmons ◽

Oded Bar-Or

Keyword(s):

Body Weight ◽

Oxygen Uptake ◽

Exercise Performance ◽

Fluid Intake ◽

Tap Water ◽

Peak Oxygen Uptake ◽

Adolescent Male ◽

Aerobic Performance ◽

Hydration Status ◽

Time To Exhaustion

We determined whether beverage flavoring and composition would stimulate voluntary drink intake, prevent dehydration, and maintain exercise performance in heat-acclimated adolescent males running in the heat. Eight adolescent (age, 13.7 ± 1.1 years) runners (peak oxygen uptake, 59.5 ± 4.0 mL·kg–1·min–1) underwent at least four 80-min exercise heat-acclimation sessions before completing 3 experimental sessions. All sessions were performed at 30 °C and 60%–65% relative humidity. Each experimental session consisted of five 15-min treadmill runs at a speed eliciting 65% peak oxygen uptake, with a 5 min rest prior to each run. Ten minutes after the final run, a time to exhaustion test was performed at a speed eliciting 90% peak oxygen uptake. Counterbalanced experimental sessions were identical, except for fluid intake, which consisted of tap water (W), flavored water (FW), and FW with 6% carbohydrate and 18 mmol·L–1 NaCl (CNa) consumed ad libitum. Fluid intake and body weight were monitored to calculate dehydration. Voluntary fluid intake was similar to fluid losses in W (1032 ± 130 vs. 1340 ± 246 g), FW (1086 ± 86 vs. 1451 ± 253 g), and CNa (1259 ± 119 vs. 1358 ± 234 g). As a result, significant dehydration was avoided in all trials (–0.45% ± 0.68% body weight in W, –0.66% ± 0.50% body weight in FW, and –0.13% ± 0.71% body weight in CNa). Core temperature increased by ~1 °C during exercise, but was not different between trials. Time to exhaustion was not different between trials and averaged 8.8 ± 1.7 min. Under exercise conditions more closely reflecting real-life situations, heat-acclimatized adolescent male runners can appropriately gauge fluid intake regardless of the type of beverage made available, resulting in consistency in exercise performance.

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Skeletal Muscle-Specific Expression of PGC-1α-b, an Exercise-Responsive Isoform, Increases Exercise Capacity and Peak Oxygen Uptake

PLoS ONE ◽

10.1371/journal.pone.0028290 ◽

2011 ◽

Vol 6 (12) ◽

pp. e28290 ◽

Cited By ~ 86

Author(s):

Miki Tadaishi ◽

Shinji Miura ◽

Yuko Kai ◽

Yutaka Kano ◽

Yuichi Oishi ◽

...

Keyword(s):

Skeletal Muscle ◽

Oxygen Uptake ◽

Exercise Capacity ◽

Peak Oxygen Uptake ◽

Specific Expression

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Exercise performance after salbutamol inhalation in non-asthmatic, non-athlete individuals: a randomised, controlled, cross-over trial

BMJ Open Sport & Exercise Medicine ◽

10.1136/bmjsem-2018-000397 ◽

2018 ◽

Vol 4 (1) ◽

pp. e000397 ◽

Cited By ~ 3

Author(s):

Filip Eckerström ◽

Christian Emil Rex ◽

Marie Maagaard ◽

Sune Rubak ◽

Vibeke Elisabeth Hjortdal ◽

...

Keyword(s):

Heart Rate ◽

Oxygen Uptake ◽

Exercise Performance ◽

Minute Ventilation ◽

Cardiopulmonary Exercise Testing ◽

Peak Oxygen Uptake ◽

Forced Expiratory Volume ◽

Peak Exercise ◽

Breath Rate ◽

Randomised Controlled

BackgroundAsthma is a frequent diagnosis in competitive sports, and inhaled β2-agonists are commonly used by athletes. Although inhaled β2-agonists do not seem to improve performance in athletes, it has remained uncertain whether they can increase exercise performance in non-athletes.ObjectiveTo investigate the effect of inhaled β2-agonists on exercise performance in healthy non-athlete individuals.MethodsIn a double-blinded, placebo-controlled, cross-over trial, healthy, non-asthmatic, non-athlete individuals were randomised to inhalation of either 900 µg of salbutamol or placebo. Cardiopulmonary exercise testing, dynamic spirometry and impulse oscillometry were performed. The primary outcome was the effect from salbutamol on peak oxygen uptake, whereas secondary outcomes were breathing reserve and ventilation efficiency, and workload, heart rate, breath rate and minute ventilation at peak exercise under influence of salbutamol.ResultsA total of 36 healthy subjects with a mean age of 26±5 years were included. Salbutamol had no effect on peak oxygen uptake compared with placebo, 46.8±1.3 mL/kg/min versus 46.6±1.2 mL/kg/min, p=0.64. Salbutamol had no effect on workload, p=0.20, heart rate, p=0.23, breath rate, p=0.10, or minute ventilation, p=0.26, at peak exercise compared with placebo. Salbutamol lowered oxygen uptake, p=0.04, and workload, p=0.04, at anaerobic threshold compared with placebo. Forced expiratory volume in 1 s, 116%±13% of predicted, and peak expiratory flow, 122%±16% of predicted, increased after inhalation of salbutamol compared with placebo; 109%±13% and 117%±17%, respectively, p<0.01. Breathing reserve was found to be higher, 22%±2%, after salbutamol inhalation than after placebo, 16%±2%, p<0.01.ConclusionInhaled salbutamol did not improve peak oxygen uptake in healthy, non-asthmatic, non-athlete individuals compared with placebo.Trial registration numberNCT02914652.

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Is peak oxygen uptake a determinant of moderate-duration self-paced exercise performance in the heat?

Applied Physiology Nutrition and Metabolism ◽

10.1139/h11-111 ◽

2011 ◽

Vol 36 (6) ◽

pp. 863-872 ◽

Cited By ~ 13

Author(s):

Zachary J. Schlader ◽

Stephen R. Stannard ◽

Toby Mündel

Keyword(s):

Cardiac Output ◽

Oxygen Uptake ◽

Skin Temperature ◽

Exercise Performance ◽

Perceived Exertion ◽

Peak Oxygen Uptake ◽

Performance Outcomes ◽

Peak Exercise ◽

Thermal Discomfort ◽

Male Subjects

This study aimed to identify whether reductions in peak oxygen uptake (VO2peak) dictate performance outcomes during 30 min of self-paced exercise in the heat, which is expected to induce minimal hyperthermia. On 4 occasions, 11 male subjects completed peak and self-paced exercise in both hot (HOT, 40.2 ± 0.3 °C) and moderate (MOD; 20.4 ± 0.7 °C) conditions. During peak exercise, submaximal oxygen uptake (VO2) was ∼8% higher in HOT, but VO2peak (MOD, 4.64 ± 0.83 L·min–1; HOT, 4.54 ± 0.77 L·min–1) and peak cardiac output (Qpeak) were similar. Self-paced exercise performance was reduced by ∼21% in HOT. VO2 was similar through 15 min, but lower in HOT thereafter. Relative to MOD, this represented a higher and lower %VO2peak during the initial and latter stages. Cardiac output was similar in both trials (MOD, 31.6 ± 6.6 L·min–1; HOT, 30.1 ± 6.0 L·min–1), representing a similar percentage of Qpeak throughout. Rectal temperature was similar in both conditions until 30 min (MOD, 38.5 ± 0.3 °C; HOT, 38.7 ± 0.3 °C), while skin temperature was higher throughout in HOT (mean: MOD, 32.4 ± 1.1 °C; HOT, 37.3 ± 0.4 °C). Perceived exertion rose similarly in both conditions, while thermal discomfort was higher in HOT. These data indicate that when only skin temperature is elevated, reductions in exercise performance during moderate-duration self-paced exercise are not associated with changes in VO2peak. Rather, increases in VO2 at a given submaximal external workload and (or) thermal discomfort appear to play a larger role.

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Nutritional ketone salts increase fat oxidation but impair high-intensity exercise performance in healthy adult males

Applied Physiology Nutrition and Metabolism ◽

10.1139/apnm-2016-0641 ◽

2017 ◽

Vol 42 (10) ◽

pp. 1031-1035 ◽

Cited By ~ 44

Author(s):

Trevor O’Malley ◽

Etienne Myette-Cote ◽

Cody Durrer ◽

Jonathan P. Little

Keyword(s):

Steady State ◽

Oxygen Uptake ◽

Exercise Performance ◽

Healthy Adult ◽

Time Trial ◽

Fat Oxidation ◽

Substrate Oxidation ◽

Peak Oxygen Uptake ◽

Adult Males ◽

Cycling Exercise

This study investigated the impact of raising plasma beta-hydroxybutyrate (β-OHB) through ingestion of ketone salts on substrate oxidation and performance during cycling exercise. Ten healthy adult males (age, 23 ± 3 years; body mass index, 25 ± 3 kg/m2, peak oxygen uptake, 45 ± 10 mL/(kg·min)−1) were recruited to complete 2 experimental trials. Before enrollment in the experimental conditions, baseline anthropometrics and cardiorespiratory fitness (peak oxygen uptake) were assessed and familiarization to the study protocol was provided. On experimental days, participants reported to the laboratory in the fasted state and consumed either 0.3 g/kg β-OHB ketone salts or a flavour-matched placebo at 30 min prior to engaging in cycling exercise. Subjects completed steady-state exercise at 30%, 60%, and 90% ventilatory threshold (VT) followed by a 150-kJ cycling time-trial. Respiratory exchange ratio (RER) and total substrate oxidation were derived from indirect calorimetry. Plasma glucose, lactate, and ketones were measured at baseline, 30 min post-supplement, post–steady-state exercise, and immediately following the time-trial. Plasma β-OHB was elevated from baseline and throughout the entire protocol in the ketone condition (p < 0.05). RER was lower at 30% and 60% VT in the ketone compared with control condition. Total fat oxidation was greater in the ketone versus control (p = 0.05). Average time-trial power output was ∼7% lower (–16 W, p = 0.029) in the ketone condition. Ingestion of ketone salts prior to exercise increases fat oxidation during steady-state exercise but impairs high-intensity exercise performance.

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Can normalization for peak oxygen uptake of ventilatory response increase prognostic power of cardiopulmonary exercise test in patients with chronic heart failure?

European Journal of Heart Failure Supplements ◽

10.1016/s1567-4215(08)60201-5 ◽

2008 ◽

Vol 7 ◽

pp. 73-74

Author(s):

A TOSTE ◽

R SOARES ◽

J FELICIANO ◽

R RAMOS ◽

S SILVA ◽

...

Keyword(s):

Heart Failure ◽

Chronic Heart Failure ◽

Oxygen Uptake ◽

Exercise Test ◽

Ventilatory Response ◽

Peak Oxygen Uptake ◽

Cardiopulmonary Exercise Test ◽

Cardiopulmonary Exercise ◽

Response Increase ◽

Prognostic Power

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Physiological responses and cycle characteristics during double-poling versus diagonal-stride roller-skiing in junior cross-country skiers

European Journal of Applied Physiology ◽

10.1007/s00421-021-04689-2 ◽

2021 ◽

Author(s):

Erik P. Andersson ◽

Irina Hämberg ◽

Paulo Cesar Do Nascimento Salvador ◽

Kerry McGawley

Keyword(s):

Oxygen Uptake ◽

Perceived Exertion ◽

Lactate Concentration ◽

Blood Lactate Concentration ◽

Peak Oxygen Uptake ◽

Submaximal Exercise ◽

Rating Of Perceived Exertion ◽

Time To Exhaustion ◽

Double Poling ◽

Cross Country

Abstract Purpose This study aimed to compare physiological factors and cycle characteristics during cross-country (XC) roller-skiing at matched inclines and speeds using the double-poling (DP) and diagonal-stride (DS) sub-techniques in junior female and male XC skiers. Methods Twenty-three well-trained junior XC skiers (11 women, 12 men; age 18.2 ± 1.2 yr.) completed two treadmill roller-skiing tests in a randomized order using either DP or DS. The exercise protocols were identical and included a 5 min warm-up, 4 × 5 min submaximal stages, and an incremental test to exhaustion, all performed at a 5° incline. Results No significant three-way interactions were observed between sex, submaximal exercise intensity, and sub-technique. For the pooled sample, higher values were observed for DP versus DS during submaximal exercise for the mean oxygen uptake kinetics response time (33%), energy cost (18%), heart rate (HR) (9%), blood lactate concentration (5.1 versus 2.1 mmol·L−1), rating of perceived exertion (12%), and cycle rate (25%), while cycle length was lower (19%) (all P < 0.001). During the time-to-exhaustion (TTE) test, peak oxygen uptake ($$\dot{V}$$ V ˙ O2peak), peak HR, and peak oxygen pulse were 8%, 2%, and 6% lower, respectively, for DP than DS, with a 29% shorter TTE during DP (pooled data, all P < 0.001). Conclusion In well-trained junior XC skiers, DP was found to exert a greater physiological load than DS during uphill XC roller-skiing at submaximal intensities. During the TTE test, both female and male athletes were able to ski for longer and reached markedly higher $$\dot{V}$$ V ˙ O2peak values when using DS compared to DP.

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