Sex Differences in the Relationship between Exercise and the Brain

Abstract

IntroductionExercise is an effective, non‐pharmacological therapy to promote brain health. Sex differences in cognitive changes through the lifespan and in response to exercise training are documented, yet more information is needed to characterize these disparities. We hypothesized that aerobic exercise training would improve memory, coordination, and muscular strength in female rats and have no significant effect in male rats.MethodsThirty‐two Fisher 344 animals (16 males and 16 females) were housed 2 per cage, on a 12:12 light:dark cycle with food and water ad libitum. At two months old, following a 1‐week acclimatization period where the non‐compliant runners were identified, they were randomly assigned to sedentary or exercise training groups. Those in the exercise training group completed a 10 week treadmill training protocol. The protocol was administered during the animal’s dark cycle and began at 15 cm/s for 15 minutes and increased up to 35 cm/s for 60 minutes. Animals in the sedentary group were restricted to cage activity. Memory (Morris water maze), coordination (Rotarod) and muscular strength (grip strength) were assessed following the exercise intervention.ResultsA significant exercise training effect was seen in females but absent in males. Female runners showed greater performance in the Morris water maze (9.2 sec. vs 32.7, p <.05) and in the Rotarod (69 sec. vs 47.5, p <.05). No significant training effect was documented in the male groups. Also, no training effect was documented in grip strength in either males or females.ConclusionIn the present study, memory and coordination improvements as a result of aerobic exercise training were seen in female but not male rats. This work adds to existing literature which investigates sex differences in cognitive health and adaptations to exercise training.