Supine lower body negative pressure exercise during bed rest maintains upright exercise capacity

2000 ◽  
Vol 89 (1) ◽  
pp. 218-227 ◽  
Author(s):  
Donald E. Watenpaugh ◽  
Richard E. Ballard ◽  
Suzanne M. Schneider ◽  
Stuart M. C. Lee ◽  
Andrew C. Ertl ◽  
...  

Bed rest and spaceflight reduce exercise fitness. Supine lower body negative pressure (LBNP) treadmill exercise provides integrated cardiovascular and musculoskeletal stimulation similar to that imposed by upright exercise in Earth gravity. We hypothesized that 40 min of supine exercise per day in a LBNP chamber at 1.0–1.2 body wt (58 ± 2 mmHg LBNP) maintains aerobic fitness and sprint speed during 15 days of 6° head-down bed rest (simulated microgravity). Seven male subjects underwent two such bed-rest studies in random order: one as a control study (no exercise) and one with daily supine LBNP treadmill exercise. After controlled bed-rest, time to exhaustion during an upright treadmill exercise test decreased 10%, peak oxygen consumption during the test decreased 14%, and sprint speed decreased 16% (all P < 0.05). Supine LBNP exercise during bed rest maintained all the above variables at pre-bed-rest levels. Our findings support further evaluation of LBNP exercise as a countermeasure against long-term microgravity-induced deconditioning.

2009 ◽  
Vol 106 (3) ◽  
pp. 919-928 ◽  
Author(s):  
Stuart M. C. Lee ◽  
Suzanne M. Schneider ◽  
Wanda L. Boda ◽  
Donald E. Watenpaugh ◽  
Brandon R. Macias ◽  
...  

We have shown previously that treadmill exercise within lower body negative pressure (LBNPex) maintains upright exercise capacity (peak oxygen consumption, V̇o2peak) in men after 5, 15, and 30 days of bed rest (BR). We hypothesized that LBNPex protects treadmill V̇o2peak and sprint speed in women during a 30-day BR. Seven sets of female monozygous twins volunteered to participate. Within each twin set, one was randomly assigned to a control group (Con) and performed no countermeasures, and the other was assigned to an exercise group (Ex) and performed a 40-min interval (40–80% pre-BR V̇o2peak) LBNPex (51 ± 5 mmHg) protocol, plus 5 min of static LBNP, 6 days per week. Before and immediately after BR, subjects completed a 30.5-m sprint test and an upright graded treadmill test to volitional fatigue. These results in women were compared with previously reported reductions in V̇o2peak and sprint speed in male twins after BR. In women, sprint speed (−8 ± 2%) and V̇o2peak (−6 ± 2%) were not different after BR in the Ex group. In contrast, both sprint speed (−24 ± 5%) and V̇o2peak (−16 ± 3%) were significantly less after BR in the Con group. The effect of BR on sprint speed and V̇o2peak after BR was not different between women and men. We conclude that treadmill exercise within LBNP protects against BR-induced reductions in V̇o2peak and sprint speed in women and should prove effective during long-duration spaceflight.


2005 ◽  
Vol 37 (Supplement) ◽  
pp. S36
Author(s):  
Stuart M.C. Lee ◽  
Suzanne M. Schneider ◽  
Donald E. Watenpaugh ◽  
Wanda L. Boda ◽  
Brandon R. Macias ◽  
...  

2007 ◽  
Vol 103 (6) ◽  
pp. 1964-1972 ◽  
Author(s):  
Donald E. Watenpaugh ◽  
Deborah D. O'Leary ◽  
Suzanne M. Schneider ◽  
Stuart M. C. Lee ◽  
Brandon R. Macias ◽  
...  

Orthostatic intolerance follows actual weightlessness and weightlessness simulated by bed rest. Orthostasis immediately after acute exercise imposes greater cardiovascular stress than orthostasis without prior exercise. We hypothesized that 5 min/day of simulated orthostasis [supine lower body negative pressure (LBNP)] immediately following LBNP exercise maintains orthostatic tolerance during bed rest. Identical twins (14 women, 16 men) underwent 30 days of 6° head-down tilt bed rest. One of each pair was randomly selected as a control, and their sibling performed 40 min/day of treadmill exercise while supine in 53 mmHg (SD 4) [7.05 kPa (SD 0.50)] LBNP. LBNP continued for 5 min after exercise stopped. Head-up tilt at 60° plus graded LBNP assessed orthostatic tolerance before and after bed rest. Hemodynamic measurements accompanied these tests. Bed rest decreased orthostatic tolerance time to a greater extent in control [34% (SD 10)] than in countermeasure subjects [13% (SD 20); P < 0.004]. Controls exhibited cardiac stroke volume reduction and relative cardioacceleration typically seen after bed rest, yet no such changes occurred in the countermeasure group. These findings demonstrate that 40 min/day of supine LBNP treadmill exercise followed immediately by 5 min of resting LBNP attenuates, but does not fully prevent, the orthostatic intolerance associated with 30 days of bed rest. We speculate that longer postexercise LBNP may improve results. Together with our earlier related studies, these ground-based results support spaceflight evaluation of postexercise orthostatic stress as a time-efficient countermeasure against postflight orthostatic intolerance.


Bone ◽  
2007 ◽  
Vol 40 (2) ◽  
pp. 529-537 ◽  
Author(s):  
Sara R. Zwart ◽  
Alan R. Hargens ◽  
Stuart M.C. Lee ◽  
Brandon R. Macias ◽  
Donald E. Watenpaugh ◽  
...  

2016 ◽  
Vol 4 (15) ◽  
pp. e12892 ◽  
Author(s):  
Suzanne M. Schneider ◽  
Stuart M. C. Lee ◽  
Alan H. Feiveson ◽  
Donald E. Watenpaugh ◽  
Brandon R. Macias ◽  
...  

2005 ◽  
Vol 37 (Supplement) ◽  
pp. S36 ◽  
Author(s):  
Stuart M.C. Lee ◽  
Suzanne M. Schneider ◽  
Donald E. Watenpaugh ◽  
Wanda L. Boda ◽  
Brandon R. Macias ◽  
...  

2005 ◽  
Vol 99 (1) ◽  
pp. 39-44 ◽  
Author(s):  
Peihong Cao ◽  
Shinji Kimura ◽  
Brandon R. Macias ◽  
Toshiaki Ueno ◽  
Donald E. Watenpaugh ◽  
...  

Astronauts experience spine deconditioning during exposure to microgravity due to the lack of axial loads on the spine. Treadmill exercise in a lower body negative pressure (LBNP) chamber provides axial loads on the lumbar spine. We hypothesize that daily supine LBNP exercise helps counteract lumbar spine deconditioning during 28 days of microgravity simulated by bed rest. Twelve sets of healthy, identical twins underwent 6° head-down-tilt bed rest for 28 days. One subject from each set of twins was randomly assigned to the exercise (Ex) group, whereas their sibling served as a nonexercise control (Con). The Ex group exercised in supine posture within a LBNP chamber for 45 min/day, 6 days/wk. All subjects underwent magnetic resonance imaging of their lumbar spine before and at the end of bed rest. Lumbar spinal length increased 3.7 ± 0.5 mm in the Con group over 28-day bed rest, whereas, in the Ex group, lumbar spinal length increased significantly less (2.3 ± 0.4 mm, P = 0.01). All lumbar intervertebral disk heights (L5–S1, L4–5, L3–4, L2–3, and L1–2) in the Con group increased significantly over the 28-day bed rest ( P < 0.05). In the Ex group, there were no significant increases in L5–S1 and L4–5 disk heights. Lumbar lordosis decreased significantly by 3.3 ± 1.2° during bed rest in the Con group ( P = 0.02), but it did not decrease significantly in the Ex group. Our results suggest that supine LBNP treadmill exercise partially counteracts lumbar spine lengthening and deconditioning associated with simulated microgravity.


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