NOTE: End date changed to 1/31/2019 per NSSC information and J. McFather/JSC (Ed., 7/8/19)

Current exercise countermeasures are insufficient to prevent muscle atrophy, cardiovascular deconditioning, and bone loss associated with long-duration spaceflight. A known limitation has been the inability of the International Space Station (ISS) exercise hardware to provide sufficient loads to the human body that are required for maintaining physiological function. New flight exercise hardware, including the advanced resistance exercise device (ARED) and 2nd generation treadmill (T2), are designed to provide astronauts with the ability to exercise at higher intensity. This opens an array of new possibilities for exercise programming in long-duration spaceflight. While the ability to do resistance exercises at heavier loads, the ability to run faster and potentially with more body loading are obvious improvements in exercise capabilities, the details of how this new equipment should be used are not so obvious. Towards this end, two workshops were held, the NASA Muscle Workshop in June 2008 and the NASA International Space Station Exercise Prescription Workshop in October 2008. Intramural and extramural experts concluded that using higher intensity resistance exercises and interval aerobic exercise would help to maintain physiological function while simultaneously decreasing total exercise time and volume. The panel then recommended that this evidence-based approach to the development of a novel exercise prescription for use on ISS should immediately be proposed. Therefore the purpose of this research is to evaluate the efficacy of a new integrated resistance and aerobic training (iRAT) program designed to minimize loss of muscle, bone, and cardiovascular function during ISS missions.

Highlights of the iRAT include an increase in the intensity and a reduction in the volume of resistance exercises, inclusion of very short, but high intensity interval-type aerobic exercises, and starting the exercise countermeasures as early as possible in the flight, preferably in the first week. Pre-, in-, and post-flight testing, and data sharing with selected on-going medical assessment tests, will be used to assess the effectiveness of this candidate prescription. Tests include detailed measurements of lower body muscle structure and function (MRI, ultrasound, muscle performance testing, shared muscle medical tests), maximal aerobic capacity, ventilatory threshold, left ventricular mass and cardiac contractility, and bone mineral density. Twenty (20) long duration crew members will be recruited as active subjects in iRAT; and 20 will be asked to serve as controls that perform the standard care exercise prescription and the pre-post flight testing.

This proposal is sponsored by the Exercise Physiology and Countermeasures Project and directly addresses the Human Research Program (HRP) Integrated Research Plan (IRP) Risks of Impaired Performance Due To Reduced Muscle Mass, Strength and Endurance and Risk of Reduced Physical Performance Capabilities Due To Reduced Aerobic Capacity, and Risk of Accelerated Osteoporosis. This proposal addresses Gap M7: Can the current in-flight performance be maintained with reduced exercise volume? The proposal addresses IRP Gap M8 (What is the minimum exercise regimen needed to maintain fitness levels for operationally relevant tasks?) and Gap M9 (What is the minimum set of equipment needed to maintain those (M8) fitness levels?).

A more thorough understanding of how cardiovascular, skeletal muscle, and bone health is affected by exercise.

NOTE: End date changed to 1/31/2019 per NSSC information and J. McFather/JSC (Ed., 7/8/19)

Current exercise countermeasures are insufficient to prevent muscle atrophy, cardiovascular deconditioning, and bone loss associated with long-duration spaceflight. A known limitation has been the inability of the International Space Station (ISS) exercise hardware to provide sufficient loads to the human body that are required for maintaining physiological function. New flight exercise hardware, including the advanced resistance exercise device (ARED) and 2nd generation treadmill (T2), are designed to provide astronauts with the ability to exercise at higher intensity. This opens an array of new possibilities for exercise programming in long-duration spaceflight. While the ability to do resistance exercises at heavier loads, the ability to run faster and potentially with more body loading are obvious improvements in exercise capabilities, the details of how this new equipment should be used are not so obvious. Towards this end, two workshops were held, the NASA Muscle Workshop in June 2008 and the NASA International Space Station Exercise Prescription Workshop in October 2008. Intramural and extramural experts concluded that using higher intensity resistance exercises and interval aerobic exercise would help to maintain physiological function while simultaneously decreasing total exercise time and volume. The panel then recommended that this evidence-based approach to the development of a novel exercise prescription for use on ISS should immediately be proposed. Therefore the purpose of this research is to evaluate the efficacy of a new integrated resistance and aerobic training (iRAT) program designed to minimize loss of muscle, bone, and cardiovascular function during ISS missions.

Highlights of the iRAT include an increase in the intensity and a reduction in the volume of resistance exercises, inclusion of very short, but high intensity interval-type aerobic exercises, and starting the exercise countermeasures as early as possible in the flight, preferably in the first week. Pre-, in-, and post-flight testing, and data sharing with selected on-going medical assessment tests, will be used to assess the effectiveness of this candidate prescription. Tests include detailed measurements of lower body muscle structure and function (MRI, ultrasound, muscle performance testing, shared muscle medical tests), maximal aerobic capacity, ventilatory threshold, left ventricular mass and cardiac contractility, and bone mineral density. Twenty (20) long duration crewmembers will be recruited as active subjects in iRAT; and 20 will be asked to serve as controls that perform the standard care exercise prescription and the pre-post flight testing.

This proposal is sponsored by the Exercise Physiology and Countermeasures Project and directly addresses the Human Research Program (HRP) Integrated Research Plan (IRP) Risks of Impaired Performance Due To Reduced Muscle Mass, Strength and Endurance and Risk of Reduced Physical Performance Capabilities Due To Reduced Aerobic Capacity, and Risk of Accelerated Osteoporosis. This proposal addresses Gap M7: Can the current in-flight performance be maintained with reduced exercise volume? The proposal addresses IRP Gap M8 (What is the minimum exercise regimen needed to maintain fitness levels for operationally relevant tasks?) and Gap M9 (What is the minimum set of equipment needed to maintain those (M8) fitness levels?).

A more thorough understanding of how cardiovascular, skeletal muscle, and bone health is affected by exercise.

The effectiveness of high intensity/low volume training (HIT) has been extensively documented in populations ranging from elite athletes to clinical patients. In addition to the time savings of shorter exercise sessions, there is evidence to suggest that HIT may elicit superior physiologic adaptations compared to traditional lower intensity/higher volume training. For instance, over a 6-week period (5 d/wk), Tabata et al. compared 60 min bouts of continuous exercise (70% VO2peak) to 7-8 intervals (20 s at 170% VO2peak /10 s rest). Despite cumulative exercise time of only ~2 h compared to 30 h for the continuous group, the HIT group increased both aerobic and anaerobic capacity whereas the continuous, high volume group only improved aerobic capacity. Somewhat longer duration intervals of 2-4 min have been shown to maintain or improve aerobic capacity during bed rest unloading and athletic training.

In light of the potential for similar if not superior physiologic protection despite diminished exercise volume, the purpose of this investigation was to compare physiologic outcomes after long-duration (~six months) spaceflight on the ISS in crewmembers who performed exercise countermeasures consisting of either 1) lower intensity/higher volume exercise (6 d/wk resistance exercise and 6 d/wk aerobic exercise) or 2) high intensity/lower volume exercise (3 d/wk resistance exercise and 6 d/wk aerobic exercise).

Tabata I, Nishimura K, Kouzaki M et al. Effects of moderate-intensity endurance and high-intensity intermittent training on anaerobic capacity and VO2max. Med Sci Sports Exerc. 1996;28(10):1327-30.

Current exercise countermeasures are insufficient to prevent muscle atrophy, cardiovascular deconditioning, and bone loss associated with long-duration spaceflight. A known limitation has been the inability of the International Space Station (ISS) exercise hardware to provide sufficient loads to the human body that are required for maintaining physiological function. New flight exercise hardware, including the advanced resistance exercise device (ARED) and 2nd generation treadmill (T2), are designed to provide astronauts with the ability to exercise at higher intensity. This opens an array of new possibilities for exercise programming in long-duration spaceflight. While the ability to do resistance exercises at heavier loads, the ability to run faster and potentially with more body loading are obvious improvements in exercise capabilities, the details of how this new equipment should be used are not so obvious. Towards this end, two workshops were held, the NASA Muscle Workshop in June 2008 and the NASA International Space Station Exercise Prescription Workshop in October 2008. Intramural and extramural experts concluded that using higher intensity resistance exercises and interval aerobic exercise would help to maintain physiological function while simultaneously decreasing total exercise time and volume. The panel then recommended that this evidence-based approach to the development of a novel exercise prescription for use on ISS should immediately be proposed. Therefore the purpose of this research is to evaluate the efficacy of a new integrated resistance and aerobic training (iRAT) program designed to minimize loss of muscle, bone, and cardiovascular function during ISS missions.

Highlights of the iRAT include an increase in the intensity and a reduction in the volume of resistance exercises, inclusion of very short, but high intensity interval-type aerobic exercises, and starting the exercise countermeasures as early as possible in the flight, preferably in the first week. Pre-, in-, and post-flight testing, and data sharing with selected on-going medical assessment tests, will be used to assess the effectiveness of this candidate prescription. Tests include detailed measurements of lower body muscle structure and function (MRI, ultrasound, muscle performance testing, shared muscle medical tests), maximal aerobic capacity, ventilatory threshold, left ventricular mass and cardiac contractility, and bone mineral density. Twenty (20) long duration crew members will be recruited as active subjects in iRAT; and 20 will be asked to serve as controls that perform the standard care exercise prescription and the pre-post flight testing.

This proposal is sponsored by the Exercise Physiology and Countermeasures Project and directly addresses the Human Research Program (HRP) Integrated Research Plan (IRP) Risks of Impaired Performance Due To Reduced Muscle Mass, Strength and Endurance and Risk of Reduced Physical Performance Capabilities Due To Reduced Aerobic Capacity, and Risk of Accelerated Osteoporosis. This proposal addresses Gap M7: Can the current in-flight performance be maintained with reduced exercise volume? The proposal addresses IRP Gap M8 (What is the minimum exercise regimen needed to maintain fitness levels for operationally relevant tasks?) and Gap M9 (What is the minimum set of equipment needed to maintain those (M8) fitness levels?).

A more thorough understanding of how cardiovascular, skeletal muscle, and bone health is affected by exercise.

ED. NOTE (October 2016): Continuation of "Integrated Resistance and Aerobic Training Study (Sprint)," which was an internal project at Universities Space Research Association/NASA Johnson Space Center, while Principal Investigator was affiliated there.