HABITUAL PHYSICAL-ACTIVITY, AEROBIC CAPACITY AND METABOLIC CONTROL IN PATIENTS WITH NEWLY-DIAGNOSED TYPE-2 (NON-INSULIN-DEPENDENT) DIABETES-MELLITUS - EFFECT OF 1-YEAR DIET AND EXERCISE INTERVENTION

The aim of this study was to asses the effects of a 1-year intensified diet and exercise education regimen on habitual physical activity and aerobic capacity in middle-aged, obese patients with newly-diagnosed Type 2 (non-insulin-dependent) diabetes mellitus. In addition, we analysed whether the level and the changes in physical activity and aerobic capacity are related to the metabolic control of diabetes. After a 3-month basic education programme, 78 patients (45 men, 33 women) were randomly placed in an intervention or conventionally treated group. The intervention group received intensified diet education and continuous encouragement to increase physical activity which was monitored using exercise records and questionnaires. Aerobic capacity was assessed by measuring oxygen uptake at anaerobic threshold and at peak exercise. The proportion of patients with regular recreational exercise increased from 24% to 38% in the intervention men (0.10 < p < 0.20), remained at 54% in the conventionally treated men, increased from 53% to 70% in the intervention women (0.10 < p < 0.20) and from 31% to 50% (0.10 < p < 0.20) in the conventionally treated women. No measurable improvement was found in oxygen uptake in any of the groups. When the groups were combined, HbA1c showed an inverse correlation with oxygen uptake at an-aerobic threshold (r = - 0.27, p < 0.01) and maximum oxygen uptake (r = - 0.28, p < 0.01) at 12 months. The change in maximum oxygen uptake was linearly correlated with the change in HDL-cholesterol (r = 0.28,p < 0.01) and those patients with improved aerobic capacity (n = 37) had higher HDL-cholesterol level at the end of the study than those (n = 41) with unaltered or decreased aerobic capacity (1.27 +/- 0.27 vs 1.12 +/- 0.25 mmol.l-1, mean +/- SD;p < 0.05). In conclusion, in this long-term prospective study repeated encouragement and follow-up using exercise records was not sufficient to induce a significant increase in physical activity and an improvement in aerobic capacity in diabetic patients. Our results suggest, however, that high aerobic capacity is beneficial for glycaemic control, and on the other hand, even slight increase in aerobic capacity is associated with an increase in HDL-cholesterol level.