The effects of long term swim training on physiological stress levels in the rat

Abstract

Swim training is used in rats as an exercise model of cardioprotection, for skeletal muscle studies, for rehabilitation studies in muscle and neural atrophy. However, acute swimming is also used to induce psychological stress in rats in many studies. There is little data on the effect of long term swim training on the stress levels in rats. Male Wistar rats were randomly divided into sedentary (Sed) or exercised (Ex) groups. Ex groups were exercise trained by swimming for a period of 8 weeks, 5 days per week, starting at 5 minutes per day and incrementally increasing to 60 minutes per day. At the end of the 8 weeks the open field test was performed and blood corticosterone levels were measured by RIA to determine whether the swim training protocol had any effects on stress behaviour and hormone levels of the rats. Neither the behavioural studies nor the corticosterone levels showed any increase above control levels in the groups investigated. Corticosterone levels for Sed (133.3 ± 37.1 ng/ml) and Ex (130.4 ± 30.1 ng/ml) groups were similar, and this was also reflected in the behavioural data collected. In our study, long term swim training did not elicit a physiological stress response in the rat model at the end of the 8 weeks training program.