Changes in drug sensitivity following acute and chronic exercise

Abstract

A number of factors are known to influence drug sensitivity. These include biological variables such as genetics, age, endocrine status and gender, as well as environmental variables such as operant schedules, ambient temperature and sleep deprivation. Additional factors function as either biological or environmental variables in different situations. For example, chronic drug administration can produce tolerance and cross tolerance and function as a biological variable. Acute administration of the same compound can function as an environmental variable. The present study examined exercise as both a biological and an environmental variable influencing drug sensitivity. Chronic exercise leads to relatively long term changes in physical fitness level, and functions as a biological variable. Fitness level did not influence drug sensitivity when physically conditioned animals and non-exercised control subjects were compared under rested conditions. Mild acute exercise, an environmental variable, increased sensitivity to muscarinic antagonists in the control subjects but not in the exercise trained animals. These results indicate that exercise state should be considered as an environmental variable capable of influencing drug response and that biological fitness level modifies this effect.