Training, Acclimatization and Heat Tolerance

[Weib]

http://www.pubmedcentral.nih.gov/picren ... obtype=pdf

SUMMARY
The data obtained in these studies indicate that a
strenuous interval training program (repeated fast
runs alternating with one- to four-minute periods of
rest or slower activity) in a cool environment is
more effective in preconditioning physically fit
young men for work in the heat than training by
continuous moderate work.
Interval training provides more powerful and
frequent stimulation of the temperature regulatory
responses (sweating and vasomotor adjustments of
blood flow to the skin) than does moderate continuous
work. In one hour of alternating periods of
strenuous treadmill work (10 mets) and rest in a
cool environment, men showed elevations of rectal
and gastrocnemius muscle temperatures of 390 C.
and 39.4° C. respectively. Marked cutaneous vasoconstriction
and lowering of skin temperature occurred
during the work periods, with rapid reflex
flushing of the skin and with blood during the rest
periods and sweat rates ranged from 1 to 1.5 kg./hr.
in the second half-hour.
Strenuous games such as handball and basketball
may be alternated with interval training in the preconditioning
program. An increase in the intensity
and duration of daily work-outs as the men gain
endurance would probably have improved heat
tolerance even more than the one-hour work-outs
used in this study. Evidence of this is provided by
the superior heat tolerance of trained distance runners,
whose work-outs are normally more severe and
longer than untrained men can tolerate.