Effect of creatine supplementation on cycle ergometer exercise in a hyperthermic environment
J David Branch1, William D Schwarz, Bonnie Van Lunen
1Department of Exercise Science, Sport, Physical Education and Recreation, Old Dominion University, Norfolk, Virginia 23529, USA. dbranch@odu.edu
Journal of Strength and Conditioning Research
|February 23, 2007
Summary
Creatine supplementation reduced plasma volume loss during intense exercise in heat. This study found creatine (CR) supplementation did not otherwise alter thermoregulatory responses in athletes.
Area of Science:
- Exercise Physiology
- Sports Nutrition
- Thermoregulation
Background:
- Athletes often exercise in hot environments, posing risks of dehydration and heat illness.
- Creatine supplementation is popular among athletes for performance enhancement.
- The impact of creatine on thermoregulation during exercise in heat is not fully understood.
Purpose of the Study:
- To investigate the effects of creatine supplementation on the body's thermoregulatory response.
- To determine if creatine influences physiological markers during prolonged exercise in a hyperthermic environment.
Main Methods:
- Seven male cyclists/triathletes performed three 1-hour exercise sessions in a hot environment (38.7°C).
- Participants underwent a baseline session, followed by sessions after 5 days of creatine (CR) or placebo (PL) supplementation.
- Measurements included body mass, tympanic temperature, heart rate, blood pressure, perceived exertion, and blood markers (lactate, cortisol, aldosterone).
Main Results:
- Body mass changes and core temperature responses were similar across all conditions.
- Heart rate, blood pressure, perceived exertion, and stress hormone levels did not differ significantly between CR and PL groups.
- A significantly smaller decrease in plasma volume was observed following creatine supplementation compared to placebo.
Conclusions:
- Creatine supplementation appears to mitigate plasma volume reduction during prolonged exercise in heat.
- Beyond reducing plasma volume loss, creatine does not significantly alter other thermoregulatory responses in this context.
- Further research is needed to elucidate the mechanisms behind creatine's effect on plasma volume during hyperthermic exercise.
Related Concept Videos
01:24Muscle Recovery and Fatigue
Muscle fatigue refers to the decline in a muscle's ability to maintain the force of contraction after prolonged activity. It primarily stems from changes within muscle fibers. Even before experiencing muscle fatigue, one may feel tired and have the urge to stop the activity. This response, known as central fatigue, occurs due to changes in the central nervous system, namely the brain and spinal cord. While there is no single mechanism that induces fatigue, it may serve as a protective response...
01:20Exercise and Cardiovascular Response
Exercise significantly impacts cardiovascular response, which is crucial for understanding patient health and designing effective treatment plans.
Light to moderate physical activity initiates a series of interconnected responses in the body. The heart rate modestly increases in anticipation of the workout, followed by widespread vasodilation as oxygen consumption by skeletal muscles increases. This results in decreased peripheral resistance, increased capillary blood flow, and accelerated...
Light to moderate physical activity initiates a series of interconnected responses in the body. The heart rate modestly increases in anticipation of the workout, followed by widespread vasodilation as oxygen consumption by skeletal muscles increases. This results in decreased peripheral resistance, increased capillary blood flow, and accelerated...
01:27Exercise and Muscle Performance
Exercise induces a range of adaptations in muscle tissue, depending on the type and duration of activity. Such physical training can be broadly categorized into two types: endurance exercises and resistance exercises.
Endurance exercises
Endurance exercises involve running, swimming, or cycling, which require repetitive movements with low force output. When a person engages in endurance exercise, a few noticeable changes occur in their skeletal muscles. For instance, the number of capillaries...
Endurance exercises
Endurance exercises involve running, swimming, or cycling, which require repetitive movements with low force output. When a person engages in endurance exercise, a few noticeable changes occur in their skeletal muscles. For instance, the number of capillaries...
01:25Energy Supply for Muscle Contraction
Skeletal muscle fibers have the unique ability to switch between rest and contraction states, using different sources of ATP for energy. The contraction cycle and Ca2+ transport back into the sarcoplasmic reticulum for relaxation require significant ATP. However, the ATP reserves in muscle fibers are limited and can only sustain contractions for a few seconds. Additional ATP production becomes necessary for prolonged contractions. As a result, muscle fibers generate ATP through various sources,...
01:17Exercise and Cardiac Output
Regular physical activity is essential for maintaining cardiovascular health, with aerobic exercises being particularly effective. According to the American Heart Association, 150 minutes of moderate to intense aerobic exercise per week is recommended for a healthy heart. Aerobic activities may include brisk walking, running, bicycling, cross-country skiing, and swimming, ideally performed three to five times per week.
Sustained exercise increases the muscles' oxygen demand, which can be met...
Sustained exercise increases the muscles' oxygen demand, which can be met...