Heat production and heat loss responses to cold water immersion after 35 days horizontal bed rest
Mekjavic IB, Kounalakis SN, Keramidas ME, Biolo G, Narici M, Eiken O
Aviation, space, and environmental medicine · 5 citations
Review labels
Neutral facts our review recorded about how this study was done. They describe method, never whether we like the result.
How it was studied
- Design
- Controlled clinical trial (indexed by PubMed)
- Studied in
- People
- Main outcome
- Health markers and function
Who paid for it
- Funding
- Funding not disclosed
Publication
- Published
- 2012-04-30 · Aviat Space Environ Med · vol. 83 · issue 5 · pp. 472–476
- Publisher
- Aerospace Medical Association
- Cited
- 12 citations · more than 64% of similar papers · 0.5× the field average
- References
- 0 works
- Access
- Paywalled
- Research areas
- Spaceflight effects on biology · Thermoregulation and physiological responses · Cardiovascular and exercise physiology
- Keywords
- Bed rest, Shivering, Deconditioning, Biceps, Thermoregulation, Rest (music), Chemistry, Anatomy, Leg muscle, Medicine, Internal medicine, Surgery
- MeSH
- lower extremity, muscle, skeletal, humans, muscular atrophy, ultrasonography, analysis of variance, immersion, oxygen consumption, body temperature regulation, skin temperature, heart rate, prone position, supine position, rest, male, cold temperature, young adult
6 authors
From SI
- Igor B. MekjavićJožef Stefan Institute
- Stylianos N. Kounalakis
- Michail E. Keramidas
- Gianni Biolo
- Marco Vincenzo Narici
- Ola Eiken
Abstract
Introduction
Bed rest is a terrestrial experimental analogue of unloading experienced during exposure to microgravity. Such unloading causes atrophy predominantly of the postural muscles, especially those of the lower limbs.
Methods
We tested the hypothesis that 35 d horizontal bed rest alters thermoregulatory responses of subjects (N = 10) immersed in 15 degrees C water, particularly the heat produced by the shivering tremor of the skeletal muscles. Before and after bed rest we measured the thickness of the gastrocnemius medialis (GM), vastus lateralis (VL), tibialis anterior (TA), and biceps brachii (BB) muscles by ultrasonography. During the immersions, we monitored rectal and skin temperatures, heat flux, heart rate, and oxygen uptake.
Results
After bed rest, muscle thickness decreased significantly by 12.2 +/- 8.8% and 8.0 +/- 9.1% in the GM and VL, respectively. No changes were observed in the TA and BB muscles. The 35-d bed rest caused a significant reduction in aerobic power, as reflected in maximal oxygen uptake. There were no significant differences in any of the observed thermoregulatory responses between the pre- and post-bed rest immersions.
Conclusions
Cardiovascular and muscular deconditioning had no effect on the heat production and heat loss responses. Due to the significant reduction in the mass of the muscles in the lower limbs, concomitant with no change in heat production, we conclude that leg muscles do not play a significant role in shivering thermogenesis.
Abstract via Europe PMC. Copyright remains with the authors or publisher.
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