Exercise Dose and Insulin Sensitivity: Relevance for Diabetes Prevention
Medicine and Science in Sports and Exercise, 04/18/2012
Dube JJ et al. – This study identifies a graded dose–response relationship between exercise dose and improvements in insulin sensitivity. The implication of this observation is of importance for the adaptation of exercise prescription in clinical situations.Methods
- Fifty–five healthy volunteers participated in a 16–wk supervised endurance exercise intervention with a pre/postintervention design.
- Insulin sensitivity was assessed by euglycemic hyperinsulinemic clamp, peak oxygen uptake by a graded exercise test, and body composition by dual–energy x–ray absorptiometry.
- The exercise intervention consisted of three to five sessions per week with a minimum of three sessions supervised.
- A ramped exercise prescription protocol was used to achieve 75% of peak HR for 45 min per session.
- Exercise dose, expressed as average kilocalories expended per week, was computed as the product of exercise intensity, duration and frequency.
- Improved insulin sensitivity was significantly related to exercise dose in a graded dose–response relationship.
- No evidence of threshold or maximal dose–response effect was observed.
- Age and gender did not influence this dose–response relationship.
- Exercise intensity was also significantly related to improvements in insulin sensitivity, whereas frequency was not.