the main page)
"Jim's cooling system was working in his suit. He
did not select enough cooling temperature for the suit. (He) said he wished he
had selected a little cooler (temperature ).But then Jim always liked the heat
and the direct sunshine." (Personal communication- Irwin's widow
In Irwin's autobiography (2) he describes
"heavy perspiration" while working on the lunar surface (extra vehicular
Exposure to excessive heat is conducive to magnesium ion deficits
(3) and in turn adrenaline elevations with rapid heart rate (4) and a
vicious cycle.( see Fig. 1 Interplanetary
Travel and Permanent Injury to Normal Heart ).
heart rate up to 167 per minute, i.e. above
85% of his maximum predicted heart rate for his age of 41, would increase the
risk of sudden death, complicating a fatal exercise- induced rhythm disturbance
(ventricular fibrillation). (5)
1. Stendig-Lindberg G, Moran D, Shapiro Y,
How significant is magnesium in thermoregulation ?J Basic Clin
Physiol Pharmacol 9: 73-85, 1998.
2. Irwin JB, Emerson WA.To Rule The Night .The
Discovery Voyage Of Astronaut Jim Irwin . Holman, Lippincott, Philadelphia.
3. Beller GA, Maher JT, Hartley LH et al. .Changes
In Serum And Sweat Magnesium Levels During Work In The Heat . Av Space
Environ Med 46:709-712,1975.
4. Apte CV,Dikshit MB, Prasad BA
Beta-adrenoreceptor blockade attenuates heat-induced tachycardia but not the
tolerance to the stress. Indian J Physiol Pharmacol 36:149-154,1992.
5. Bayes de Luna A ,Coumel P ., Leclereq JF.
Ambulatory sudden cardiac death:mechanisms of production of fatal arrhythmia
on the basis of data from 157 cases. Am Heart J 117:151-159,1989.
AN INCREASE IN BODY TEMPERATURE DURING RUNNING HAS BEEN NOTED BY
NASA IN MICROGRAVITY. ( PERSONAL COMMUNICATION ANDERS HANSSON, Ph.D ) AUTHOR OF
"MARS AND THE DEVELOPMENT OF LIFE" 1995.
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