Cardiovascular responses to daily activity and exercise countermeasures on the International Space Station
- Paper number
IAC-11,A1,2,15,x9471
- Author
Ms. Katelyn Fraser, University of Waterloo, Canada
- Coauthor
Mrs. Danielle Greaves, University of Waterloo, Canada
- Coauthor
Dr. Andrew Blaber, Simon Fraser University, Canada
- Coauthor
Prof. Kevin Shoemaker, University of Western Ontario, Canada
- Coauthor
Dr. Richard Hughson, University of Waterloo, Canada
- Year
2011
- Abstract
Cardiovascular and Cerebrovascular Control upon return from the International Space Station (CCISS) is a project that sought to investigate cardiovascular deconditioning associated with long-duration space flight (55-199d). PURPOSE: To examine changes in cardiovascular control during long-duration missions we monitored heart rate (HR) during normal daily activities that could include up to 2.5 hours/day of aerobic (AE) and resistance (RE) type exercises while on the International Space Station (ISS). METHODS: Ankle activity (Actiwatches) and HR (Holter monitoring) were collected for 24-hour periods before, during and within 24-48 hours after space flight (n=7). Data were analyzed in 3-4 hour segments during the night, morning, afternoon and evening (excluding exercise sessions). HR and ankle activity were monitored during the AE and RE sessions. RESULTS: Compared to on Earth, night HR was unchanged on the ISS (55.5+/-7 bpm compared to 55.7+/-8 bpm in-flight). Daily activity HR on Earth in the morning, afternoon and evening was 71.0+/-13 bpm, 71.5+/-9 bpm, and 72.8+/-10 bpm, respectively. In-flight daily activity HR during the morning, afternoon and evening was reduced to 66.8+/-13 bpm, 69.2+/-11 bpm and 65.9+/-9 bpm reflecting the lower physical demands as indicated by the dramatic reduction in the full-day ankle activity counts (14+/-9 in space compared to 107+/-44 on Earth, p$<$0.001). As a countermeasure to prevent cardiovascular deconditioning, astronauts performed regular AE and RE. During these in-flight exercise sessions which lasted from 29 to 56 minutes, the average HR was 128+/-11 bpm during AE and 92+/-17 bpm during RE. The peak HR observed during these sessions ranged from 130-171 bpm for AE and from 112-163 bpm for RE. Upon return to Earth, HR was elevated to 59.7+/-8 bpm, 76.6+/-10 bpm, 81.4+/-9 bpm and 77.5+/-11 bpm during the night, morning, afternoon and evening, respectively. CONCLUSION: In contrast to predictions made after the first long-duration space flights that 80\% of astronauts would experience orthostatic intolerance upon return to Earth, the astronauts of this study maintained their cardiovascular health and had only minor increases in HR post-flight. These data suggest that the exercise prescriptions currently used on the ISS challenge the cardiovascular system and offer protection against deconditioning. Supported by the Canadian Space Agency.
- Abstract document
- Manuscript document
(absent)