Exercise improves learning and memory impairments in sleep deprived female rats

Inadequate sleep is a common problem in modern societies. It has been previously shown that female rats are more vulnerable to the deleterious effects of sleep deprivation on cognitive functions. Physical exercise has been suggested to attenuate the cognitive impairments induced by sleep deprivation in male rats. The objective of the current study was to investigate the effects of physical exercise on cognitive functions of female rats following paradoxical sleep deprivation. Intact and ovariectomized (OVX) female Wistar rats were used in the present study. The exercise protocol was 4 weeks of treadmill running. The multiple platform method was applied for the induction of 72h paradoxical sleep deprivation and the cognitive function was evaluated using Morris water maze (MWM). Plasma corticosterone level was evaluated in separate groups of study. ANOVA and repeated measures were used to analyze the data and P<0.05 was considered statistically significant. Throughout the investigation, significant learning impairment was observed in sleep-deprived OVX rats compared to the intact and the other OVX groups. Short term memory impairment was observed in both sleep-deprived OVX and intact groups. Physical exercise alleviated the PSD-induced learning and memory impairments in both intact and OVX groups. Corticosterone levels were not statistically significant among the different groups. The results of our study confirmed the negative effects of PSD on cognitive functions in female rats and regular physical exercise seems to protect rats from these effects. Further studies are suggested to be carried out in order to evaluate the possible underlying mechanisms, and also to evaluate the possible interactions between sex hormones and PSD-induced cognitive impairments.