Does Heat Stress Improve the Acute Metabolic and Cardiovascular Adaptations to Exercise
Northern Arizona University
Summary
Life in space is completely void of physical and environmental stress. It is well known that living things need regular physical stress (e.g. exercise) to remain strong, functional and healthy. More and more research is showing that regular environmental stress, for example heat and hypoxia, can further improve physical health. Astronauts aboard the international space station (ISS) exercise for 1-2 hours every day to avoid physical deconditioning that would otherwise cause them to age rapidly in space. Although physical exercise is very effective in remedying this deconditioning, today's astronauts still have physiological changes that indicate accelerated aging. This is a cause for concern given NASA's priority to travel to mars within the next decade; a mission that will require at least double the duration in space for our astronauts. The investigators think that the complete absence of environmental stress, i.e., heat, may be contributing to the accelerated aging that occurs during spaceflight. Our study will assess the health effects of adding heat stress to exercise that could be performed in space by astronauts. The goal is to inform best practice for astronauts to avoid physical deconditioning during long-duration spaceflight. This information will also be relevant to life on earth as spaceflight is a model of inactivity here on earth. Therefore, the potential benefits of adding heat stress will likely translate to life in space and on earth.
Description
Experimental procedures: Participants will visit the lab on seven occasions. Participants will be required to practice regular exercise and dietary habits that can be easily replicated in the 24 hours prior to every laboratory visit. Exercise and dietary patterns will be documented during the first visit and thereafter the participants will be reminded of these practices and instructed to match them as closely as possible in the 24 hours leading up to all subsequent visits. Participants will only be instructed to avoid heavy exercise in the 12 hours prior to testing sessions. On the first vis…
Eligibility
- Age range
- 18–50 years
- Sex
- All
- Healthy volunteers
- Yes
Inclusion Criteria: -regularly physically active as determined via ParQ+ Exclusion Criteria: * smokers * bronchial asthma * chronic obstructive pulmonary disease * obese * alcoholism * requiring daily medications that may effect responses to exercise, * anti-arrhythmogenics * inhalers * history of cardiovascular, respiratory, neurological, skeletal muscle disease * irregular/absent menstrual cycle (females) * unexpected responses to pre-experimental exercise tests * previous diagnosis of heat stroke
Interventions
- BehavioralExercise
Exercise for 90 minutes (cycling) while minimizing thermal strain
- BehavioralHeat strain
Exercise for 90 minutes (cycling) while maximizing thermal strain
Location
- Northern Arizona UniversityFlagstaff, Arizona