The effect on deep body temperature of infants co-sleeping (with eithe
r or both parents) is investigated in this case control study. Overnig
ht continuous recordings of rectal temperature were made from 34 babie
s co-sleeping with one or both parents throughout the night and 34 inf
ants matched for age, feeding regimen, parental smoking, thermal envir
onment, sleeping position, and sex who slept alone. The co-sleeping in
fants had significantly higher rectal temperatures hom two hours after
bedtime, when the initial fall in sleeping body temperature was compl
ete. The mean rectal temperature of co-sleeping infants between two an
d eight hours was 0.1 degrees C higher than that of infants sleeping a
lone (p < 0.04). Given the very small variance in rectal temperature t
his probably reflects a considerable physiological difference between
the two groups.