Age and sleep modify finger temperature responses to facial cooling.
BACKGROUND
The increased incidence of hypothermia with age suggests that healthy 80-year-olds might show impaired responsivity to transient, localized thermal stimulation. Such a deficit might be particularly clear during sleep, when behavioral thermoregulation is less likely.


METHODS
We examined finger temperature cooling in response to local cooling of the face--a response presumed to be centrally mediated. Nineteen healthy 80-year-olds (12 female) and twenty-seven 20-year-olds (10 female) were exposed to repetitive 20-minute cooling and rewarming cycles across a night of sleep deprivation and a night of sleep occurring three nights later. We sought to determine whether thermal responsivity was altered by age and sleep, but by design avoided inducing core temperature hypothermia.


RESULTS
In response to facial cooling during sleep deprivation, finger temperature decreased significantly more in the young than in old. This suggested relatively greater heat retention in the young. During non-REM sleep the thermal responsivity of both groups decreased and age-related differences were no longer present. Changes in core temperature induced by the stimulation were minimal.


CONCLUSIONS
The results suggest that the capability of retaining heat via peripheral vasoconstriction while awake decreases with age. Despite this vulnerability, responsivity during non-REM sleep as well as average core temperature were comparable between age groups.
Jennings
J R
JR
Western Psychiatric Institute and Clinic, Department of Psychiatry, University of Pittsburgh School of Medicine.
Reynolds
C F
CF
Houck
P R
PR
Buysse
D J
DJ
Hoch
C C
CC
Hall
F
F
Monk
T H
TH
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D001833:Body Temperature Regulation; D003080:Cold Temperature; D004569:Electroencephalography; D005145:Face; D005260:Female; D005385:Fingers; D006801:Humans; D008297:Male; D012890:Sleep / Q000502:physiology*; D012892:Sleep Deprivation