Relationship of exercise volume to improvements of quality of life with supervised exercise training in patients with type 2 diabetes in a randomised controlled trial: the Italian Diabetes and Exercise Study (IDES)

Abstract

Aims/hypothesis: A positive impact of exercise intervention programmes on quality of life (QoL) may be important for long-term patient compliance to exercise recommendations. We have previously shown that QoL improves significantly with supervised exercise, whereas it worsens with counselling alone, in patients with type 2 diabetes from the Italian Diabetes and Exercise Study (IDES). Here, we report data on the relationship between changes in QoL and volume of physical activity/exercise in these individuals.

Methods: This multicentre parallel randomised controlled, open-label, trial enrolled sedentary patients with type 2 diabetes (n = 606 of 691 eligible) in 22 outpatient diabetes clinics. Patients were randomised by centre, age and diabetes treatment using a permuted-block design to twice-a-week supervised aerobic and resistance training plus exercise counselling (exercise group) versus counselling alone (control group) for 12 months. Health-related QoL was assessed by the 36-Item Short Form (SF-36) Health Survey.

Results: In the exercise group (n = 268 of 303 randomised), there was a trend for increasing QoL with increasing exercise volume, with significant improvement of the physical component summary (PCS) measure only above 17.5 metabolic equivalents h⁻¹ week⁻¹ and a clear volume-relationship for the mental component summary (MCS) measure. A relationship with volume of physical activity also was observed in the control group (n = 260 of 303 randomised), despite overall deterioration of all scores. Independent correlates of improvements in both PCS and MCS were exercise volume, study arm and, inversely, baseline score.

Conclusions/interpretation: This large trial shows a relationship between changes in physical and mental health-related QoL measures and volume of physical activity/exercise, with supervised exercise training also providing volume-independent benefits.