NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
WISE-2005 Protective Effect of Exercise within LBNP Countermeasure Detected by Heart Rate Response to Low Levels of LBNPSixteen women were studied before, during and after a 60 day, continu ous 6" head-down bed-rest (HDBR). Subjects were randomly assigned to two groups: Control (no countermeasures) and Exercise+LBNP (supine ru nning within an LBNP chamber for 40-min followed by 10-min passive L BNP for 3-4 days/week, plus flywheel resistive training of the legs e very third day). Cardiovascular responses were observed before bed re st, on day 50 of HDBR and R+8 after bed rest. Subjects were supine in the LBNP device with suction applied at 0, -10, -20 and -30 mmHg LBN P for 2-min per stage. In the pre-bed rest testing, there was no diff erence in HR between the groups at rest or at -30 mmHg. On HDBR day 50, HR was elevated at supine rest for the Con not the Ex group, whil e at -30 mmHg HR was elevated above pre-HDBR for both groups, but the magnitude of increase from Pre- to HDBR day 50 was less for the Ex g roup than for the Con group. The change in HR on HDBR day 50 is an im portant indicator as it was less than 24-hours after the Exercise+LBN P countermeasure on day 49. After bed rest, no specific countermeasu res were provided in the first week, so HR responses on day R+8 refle cted the effects of bed rest with or without countermeasure plus any recovery from simply returning to the upright posture. Relative to th e Pre-bed rest responses, HR on day R+8 had recovered in the Ex group but was still elevated in the Con group. These results indicate that the cardiovascular response to LBNP is preserved to a greater degre e during bed rest by the countermeasures, and further that the cardio vascular response returned to pre-bed rest much more rapidly in the E xercise+LBNP group than hi the group that received no cardiovascular countermeasures.
Document ID
20070022702
Acquisition Source
Ames Research Center
Document Type
Reprint (Version printed in journal)
Authors
Hughson, R. L.
(Waterloo Univ. Ontario, Canada)
Shoemaker, J. K.
(University of Western Ontario London, Ontario, Canada)
Hargens, A. R.
(California Univ. San Diego, CA, United States)
Mattar, L.
(Waterloo Univ. Ontario, Canada)
Edgell, H.
(Waterloo Univ. Ontario, Canada)
Kerbeci, P.
(CHU Tours, Hospital France)
Arbeille, Ph.
(CHU Tours, Hospital France)
Date Acquired
August 23, 2013
Publication Date
July 1, 2006
Publication Information
Publication: Journal of Gravitational Physiology, Volume 13, No. 1
Subject Category
Aerospace Medicine
Distribution Limits
Public
Copyright
Other

Available Downloads

There are no available downloads for this record.
No Preview Available