The Effects of Exercise, Heat, and Microclimate Cooling on Terminal Stroke Volume in Men and Women
Abstract
We have previously reported that in lieu of the more common end-of-test criteria such as core temperature < 39 deg C, and heart rate (HR) < 180 bpm (2,3), volitional fatigue for men exercising in the heat appears to occur with a reduction in stroke volume (SV) to a value of approximately 75 ml/beat/min (1). Since it has been established that females have a lower absolute SV (4) it is doubtful that a terminal stroke volume (TSV) of 75 ml/beat/min would be observed in females. It was hypothesized that using either body surface area (BSA), which would account for an increased peripheral blood circulation and the exchange between the skin and the environment, or fat free mass, which represents the body mass to be perfused would provide a physiological metric to normalize SV results between males and females. Additionally, we observed that while the use of a microclimate cooling garment (ice vest) attenuated the rate of cardiovascular drift, the fall in terminal SV (TSV) was independent of temperature and ice vest usage for males exercising in the heat. This paper provides results from acomparison evaluation of male and female SV responses to exercising in the heat both with and without the use of microclimate cooling.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 07, 2000
- Accession Number
- ADA431729
Entities
People
- James A. Hodgdon
- Jay H. Heaney
- Micheal J. Buono
Organizations
- Naval Health Research Center