OBJECTIVE -We studied the association between leisure time physical activity (LTPA) and glycemic control, insulin dose, and estimated glucose disposal rate (eGDR) in type 1 diabetes.
RESEARCH DESIGN AND METHODS-This is a cross-sectional study of 1,030 type 1 diabetic patients participating in the Finnish Diabetic Nephropathy Study, a nationwide multicenter study. LTPA was assessed by a validated 12-month questionnaire and expressed in metabolic equivalent (MET) units. Patients were grouped as sedentary (LTPA Ͻ10 MET h/week, n ϭ 247), moderately active (LTPA 10 -40 MET h/week, n ϭ 568), and active (LTPA Ͼ40 MET h/week, n ϭ 215). Outcome measures were HbA 1c , insulin dose, and eGDR (estimate of insulin sensitivity based on waist-to-hip ratio, hypertension, and HbA 1c ).RESULTS -LTPA correlated with HbA 1c in women (r ϭ Ϫ0.12, P ϭ 0.007) but not in men (r ϭ Ϫ0.03, P ϭ 0.592). Sedentary women had higher HbA 1c than moderately active and active women: 8.8 Ϯ 1.4% vs. 8.3 Ϯ 1.4% vs. 8.3 Ϯ 1.4% (P ϭ 0.004), whereas HbA 1c in men was 8.4 Ϯ 1.3% vs. 8.2 Ϯ 1.4% vs. 8.2 Ϯ 1.3% (P ϭ 0.774), respectively. In men, insulin doses were 0.74 Ϯ 0.21 vs. 0.71 Ϯ 0.20 vs. 0.68 Ϯ 0.23 IU ⅐ kg -1 ⅐ 24 h -1 (P ϭ 0.003). In both sexes, sedentary patients had lower eGDRs than active patients [median (interquartile range) 5.5 (4.0 -8.2) vs. 6.8 (4.7-8.8) vs. 6.7 (4.6 -8.6) mg ⅐ kg -1 ⅐ min -1 ; P Ͻ 0.01 for sedentary vs. others]. Age, obesity, smoking, insulin dose, social class, diabetic nephropathy, or cardiovascular disease did not explain the results.CONCLUSIONS -Low levels of LTPA were associated with poor glycemic control in type 1 diabetic women. Men seem to use less insulin when physically active. Increased LTPA levels were associated with increased estimated insulin sensitivity. Longitudinal studies are needed to further clarify the effects of LTPA on type 1 diabetes.
Diabetes Care 28:777-782, 2005S everal recent studies have emphasized the importance of physical activity in the prevention of type 2 diabetes (1-4). These studies have shown that progression from the state of impaired glucose tolerance to overt diabetes can be inhibited, or at least postponed, by changing dietary habits and/or increasing the amount of physical activity. In a metaanalysis of 14 studies, exercise resulted in a clinically significant reduction in postintervention HbA 1c in type 2 diabetic patients (5). Type 1 diabetic patients present features of peripheral insulin resistance that can be improved by increasing physical activity (6 -8), rendering a theoretical basis for exercise to also improve glycemic control in type 1 diabetic patients.One recent cross-sectional study (9) and several intervention studies in the 1980s (6,7,10 -17) failed to show any significant improvements in glycemic control by physical activity in type 1 diabetic patients. Only a few studies have shown a positive effect on glycemic control (18 -21). Available studies were, however, limited by small numbers of patients or semiquantitative assessments of physical activity. Therefore,...