E. Kristalboneh et al., PHYSICAL PERFORMANCE AND HEAT TOLERANCE AFTER CHRONIC WATER LOADING AND HEAT ACCLIMATION, Aviation, space, and environmental medicine, 66(8), 1995, pp. 733-738
Heat acclimation (HA) and forced water intake (FWI) have both been fou
nd to improve the endurance of human subjects working in hot environme
nts. Therefore, we studied the interaction between HA and FWI. Prior t
o any treatment (control, AI and BI) the subjects (n = 9) underwent a
heat tolerance (HT) test. Thereafter, they were divided into two group
s. The first (n = 5) were heat-acclimated (AII), underwent a second HT
test, doubled their normal daily water intake for 1 week (AIII), and
underwent a third HT test; the second group (n = 4) were subjected to
the same protocol, except that the FWI came before and during HA (BII)
. It was found that both regimens (phases AII and BII) significantly i
ncreased work duration. Although the results of the two methods were s
imilar, their combination somewhat lengthened work tolerance time (pha
ses AIII, BIII). Maximal oxygen uptake did not change after HA (BII) o
r FWI (AII), but the maximal values were attained at significantly low
er heart rates, both after BII alone or combined with HA (BIII). In an
additional experiment, the time needed to ''ride'' 15 km on a bicycle
ergometer was reduced by 10% after FWI as compared to control time.