Insulin sensitivity in response to a single resistance exercise session in apparently healthy individuals

Regular resistance exercise completed for a number of weeks has been shown to increase insulin sensitivity and reduce the risk of diabetes related complications. However, the acute responses to resistance exercise have not been adequately investigated in relation to training frequency. Aim: To investigate the changes to insulin sensitivity in apparently healthy individuals following a single session of unaccustomed resistance exercise. Subjects and Methods: Ten sedentary, apparently healthy individuals performed a baseline oral glucose tolerance test and maximal strength testing. Participants then performed a single session of moderate-high intensity resistance exercise which was followed by four consecutive days of oral glucose tolerance testing, for which participants replicated their initial diet. Mean estimated insulin sensitivity change scores from baseline values and their 95% confidence intervals were compared to the previously determined values for a clinically meaningful change. Results: Two participants were identified as having hyperinsulinaemia and their data were therefore removed from the main analysis. There was a clinically meaningful increase in insulin response (mean >7,237 pmol.L-1.120mins-1) on all days following the exercise session and a clinically meaningful increase in glucose response (mean >81 mmol.L-1.120mins-1) on only the third day following exercise. These changes suggest a potentially adverse short-term effect. Additionally the two individuals with hyperinsulinaemia displayed more extreme results. Conclusion: These results suggest that insulin sensitivity may be impaired following a single session of unaccustomed resistance exercise for approximately four days in healthy untrained, older individuals. Further research is required for individuals with hyperinsulinaemia