OBJECTIVE -To compare the response of blood glucose levels to intermittent highintensity exercise (IHE) and moderate-intensity exercise (MOD) in individuals with type 1 diabetes.
RESEARCH DESIGN AND METHODS-Seven healthy individuals with type 1 diabetes were tested on two separate occasions, during which either a 30-min MOD or IHE protocol was performed. MOD consisted of continuous exercise at 40% VO 2peak , while the IHE protocol involved a combination of continuous exercise at 40% VO 2peak interspersed with 4-s sprints performed every 2 min to simulate the activity patterns of team sports.RESULTS -Both exercise protocols resulted in a decline in blood glucose levels. However, the decline was greater with MOD (Ϫ4.4 Ϯ 1.2 mmol/l) compared with IHE (Ϫ2.9 Ϯ 0.8 mmol/l; P Ͻ 0.05), despite the performance of a greater amount of total work with IHE (P Ͻ 0.05). During 60 min of recovery from exercise, glucose levels remained higher in IHE compared with MOD (P Ͻ 0.05). Furthermore, glucose levels remained stable during recovery from IHE, while they continued to decrease after MOD (P Ͻ 0.05). The stabilization of blood glucose levels with IHE was associated with elevated levels of lactate, catecholamines, and growth hormone during early recovery from exercise (P Ͻ 0.05). There were no differences in free insulin, glucagon, cortisol, or free fatty acids between MOD and IHE.CONCLUSIONS -The decline in blood glucose levels is less with IHE compared with MOD during both exercise and recovery in individuals with type 1 diabetes.
Diabetes Care 28:1289 -1294, 2005E xercise is generally recommended for individuals with type 1 diabetes for the same reasons as the rest of the population. That is, regular physical activity has physiological benefits, including improved physical work capacity, body composition, blood pressure, and blood lipid profile (1-3) and is associated with less risk of diabetes complications and mortality in individuals with type 1 diabetes (4). In addition, exercise has psychological benefits, including increased sense of well-being, quality of life, and ability to cope with stress (3). Particularly in children, participation in sports is an important recreational and social activity that benefits both social interaction and peer group assimilation (5).Unfortunately, participation in exercise can also increase the risk of experiencing hypoglycemia in individuals with type 1 diabetes, both during exercise (6,7) and for up to 31 h of recovery (8). Consequently, many individuals with type 1 diabetes feel negatively toward physical activity (9) and are discouraged from participating in sports and games by their parents, school staff, or physicians (10).Existing guidelines to minimize the risk of hypoglycemia associated with exercise are often general (11) and fail to take into account that different precautions are required for exercise of varying type, duration, and intensity. Specifically, there are no evidence-based guidelines for individuals wanting to participate in intermittent high-intensity exercise (IHE...