Prolonged head-down tilt exposure reduces maximal cutaneous vasodilator and sweating capacity in humans

C. G. Crandall, M. Shibasaki, T. E. Wilson, J. Cui, B. D. Levine

Research output: Contribution to journalArticle

35 Citations (Scopus)

Abstract

Cutaneous vasodilation and sweat rate are reduced during a thermal challenge after simulated and actual microgravity exposure. The effects of microgravity exposure on cutaneous vasodilator capacity and on sweat gland function are unknown. The purpose of this study was to test the hypothesis that simulated microgravity exposure, using the 6° head-down tilt (HDT) bed rest model, reduces maximal forearm cutaneous vascular conductance (FVC) and sweat gland function and that exercise during HDT preserves these responses. To test these hypotheses, 20 subjects were exposed to 14 days of strict HDT bed rest. Twelve of those subjects exercised (supine cycle ergometry) at 75% of pre-bed rest heart rate maximum for 90 min/day throughout HDT bed rest. Before and after HDT bed rest, maximal FVC was measured, via plethysmography, by heating the entire forearm to 42°C for 45 min. Sweat gland function was assessed by administering 1 × 10-6 to 2 M acetylcholine (9 doses) via intradermal microdialysis while simultaneously monitoring sweat rate over the microdialysis membranes. In the nonexercise group, maximal FVC and maximal stimulated sweat rate were significantly reduced after HDT bed rest. In contrast, these responses were unchanged in the exercise group. These data suggest that 14 days of simulated microgravity exposure, using the HDT bed rest model, reduces cutaneous vasodilator and sweating capacity, whereas aerobic exercise training during HDT bed rest preserves these responses.

Original languageEnglish (US)
Pages (from-to)2330-2336
Number of pages7
JournalJournal of Applied Physiology
Volume94
Issue number6
StatePublished - Jun 1 2003

Fingerprint

Head-Down Tilt
Bed Rest
Sweating
Vasodilator Agents
Weightlessness
Skin
Forearm
Sweat Glands
Sweat
Blood Vessels
Microdialysis
Exercise
Ergometry
Plethysmography
Vasodilation
Heating
Acetylcholine
Hot Temperature
Heart Rate
Membranes

Keywords

  • Deconditioning
  • Microdialysis
  • Skin blood flow
  • Spaceflight
  • Thermoregulation

ASJC Scopus subject areas

  • Physiology
  • Endocrinology
  • Orthopedics and Sports Medicine
  • Physical Therapy, Sports Therapy and Rehabilitation

Cite this

Prolonged head-down tilt exposure reduces maximal cutaneous vasodilator and sweating capacity in humans. / Crandall, C. G.; Shibasaki, M.; Wilson, T. E.; Cui, J.; Levine, B. D.

In: Journal of Applied Physiology, Vol. 94, No. 6, 01.06.2003, p. 2330-2336.

Research output: Contribution to journalArticle

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