Abstract

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 <10 MET h/week, n = 247), moderately active (LTPA 10–40 MET h/week, n = 568), and active (LTPA >40 MET h/week, n = 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 = −0.12, P = 0.007) but not in men (r = −0.03, P = 0.592). Sedentary women had higher HbA_1c than moderately active and active women: 8.8 ± 1.4% vs. 8.3 ± 1.4% vs. 8.3 ± 1.4% (P = 0.004), whereas HbA_1c in men was 8.4 ± 1.3% vs. 8.2 ± 1.4% vs. 8.2 ± 1.3% (P = 0.774), respectively. In men, insulin doses were 0.74 ± 0.21 vs. 0.71 ± 0.20 vs. 0.68 ± 0.23 IU · kg^–1 · 24 h^–1 (P = 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 · kg^–1 · min^–1; P < 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.