Ss. Gilbert et al., Peripheral heat loss: A predictor of the hypothermic response to melatoninadministration in young and older women, PHYSL BEHAV, 66(2), 1999, pp. 365-370
Core hypothermia following daytime melatonin administration typically displ
ays significant interindividual variability. As this hypothermia has been a
ssociated with significant increases in skin temperature, the mechanism by
which melatonin decreases core temperature may involve increasing periphera
l heat loss. If so, the interindividual variability in this effect may refl
ect concomitant interindividual variability in heat loss capacity at the di
stal periphery. For six younger (mean +/- SEM: 23.4 +/- 0.3 years) and 10 o
lder women (mean +/- SEM: 65.6 +/- 0.7 years), the maximum decrease in core
body temperature following a 5-mg (p.o.) dose of melatonin was correlated
with the capacity to lose heat. This was determined by the maximum increase
in contralateral hand temperature following a mild positive thermal challe
nge (PTC). The regression analysis yielded a significant (p < 0.01)correlat
ion of 0.80, suggesting that the individual magnitude of hypothermia follow
ing melatonin administration may reflect the capacity of an individual to d
issipate heat at the distal periphery. (C) 1999 Elsevier Science Inc.