The influence of ambient temperature on sleep characteristics in the aged cat.

Sleep characteristics were compared in young adult and aged cats over a range of environmental temperatures from 5 to 35 degrees C. Although both groups exhibited sleep disruptions as ambient temperatures decreased, transient arousals were increased at temperature extremes in the aged group compared to young adults. Declining efficiency of thermoregulatory control and increased sensitivity to environmental temperature in the elderly may contribute to the changes in sleep quality which occur during the aging process.