A recently developed technique for examining thermal sensitivity durin
g sleep was used to assess whether skin and core temperature responses
to thermal stimulation were altered by sleep state. The technique was
designed to probe thermal responsivity without altering core body tem
perature or inducing awakening. Twenty-seven young men and women were
studied during a sleep deprivation night and a sleep night three night
s later. Cold water stimulation of the face alternated with an equal p
eriod of rewarming across a 40-min cycle throughout the night. Skin te
mperature from the finger and rectal temperature were continuously ass
essed. Sleep continuity and architecture were largely uninfluenced by
the thermal stimulation. Finger skin temperature decreased during cold
facial stimulation in both sleep and waking states. Skin temperature
changes during sleep were approximately one-fifth the magnitude of tho
se during waking. Core temperature was minimally influenced. REM sleep
was associated with a greater amplitude decrease in finger temperatur
e than was non-REM (NREM) sleep. The results support the utility of th
e technique as a probe of thermal responsivity during sleep and sugges
t a reduction of thermal responsivity during sleep and, more tentative
ly, an altered responsivity during REM versus NREM sleep.