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Daily Supine LBNP Treadmill Exercise Maintains Upright Exercise Capacity During 14 Days of Bed RestExposure to microgravity or bed rest reduces upright exercise capacity. Exercise modes, durations, and intensities which will effectively and efficiently counteract such deconditioning are presently unresolved. We that daily supine treadmill interval training with lower body negative pressure (LBNP) would prevent reduction in upright exercise capacity during 14 days of 6 deg. head-down bed rest (BR). Eight healthy male subjects underwent two 14 day BR protocols separated by 3 months. In a crossover design, subjects either remained at strict BR or performed 40 min of daily exercise consisting of supine walking and running at intensities varying from 40-80% of pre-BR upright peak oxygen uptake (VO2). LBNP during supine exercise was used to provide 1.0 to 1.2 times body weight of footward force. An incremental upright treadmill test to measure submaximal and peak exercise responses was given pre- and post-BR. In the non-exercise condition, peak VO2 and time to exhaustion were reduced 16 +/- 4% and 10 +/- 1% (p less than 0.05), respectively, from pre-BR. With LBNP exercise these variables were not significantly different (NS) from pre-BR. During submaximal treadmill speeds after BR, heart rate was higher (11 +/- 11 bpm, p less than 0.05) and respiratory exchange ratio was elevated (p less than 0.05) in the no exercise condition. Both were maintained at pre-BR levels in the LBNP exercise condition (NS from pre-BR). Since this supine treadmill interval training with addition of LBNP maintained upright exercise responses and capacity during BR, this countermeasure may also be effective during space flight.
Document ID
20020039734
Acquisition Source
Headquarters
Document Type
Conference Paper
Authors
Ertl, Andy C.
(Vanderbilt Univ. Nashville, TN United States)
Watenpaugh, D. E.
(NASA Ames Research Center Moffett Field, CA United States)
Hargens, Alan R.
(NASA Ames Research Center Moffett Field, CA United States)
Fortney, S. M.
Lee, S. M. C.
Ballard, R. E.
William, J. M.
Date Acquired
August 20, 2013
Publication Date
January 1, 1996
Subject Category
Aerospace Medicine
Meeting Information
Meeting: Aerospace Medicine Association Meeting
Location: Chicago, IL
Country: United States
Start Date: May 11, 1997
End Date: May 15, 1997
Sponsors: Aerospace Medical Association
Funding Number(s)
PROJECT: RTOP 199-26-12-38
PROJECT: RTOP 199-14-11-13
CONTRACT_GRANT: NAGW-4031
PROJECT: RTOP 199-26-12-34
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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