Treadmill aerobic training improves glucose tolerance and indices of insulin sensitivity in disabled stroke survivors - A preliminary report

Background and Purpose - Insulin resistance and glucose intolerance are highly prevalent after stroke, contributing to worsening cardiovascular disease risk and a predisposition to recurrent stroke. Treadmill exercise training (T-AEX) increases aerobic capacity (VO2 peak) in chronic stroke patients, suggesting intensity levels that may be adequate to improve glucose metabolism. We compared the effects of a progressive T-AEX intervention to an attention-matched stretching intervention (CONTROL) on glucose tolerance and indices of insulin sensitivity in stroke survivors. Methods - Participants had hemiparetic gait after remote (> 6 months) ischemic stroke. They were randomized to 6-month T-AEX or a duration matched reference CONTROL program of supervised stretching exercises. Main outcome measures were glucose and insulin responses during a 3-hour oral glucose tolerance test (OGTT). Results - Forty-six subjects (T-AEX = 26, CONTROL = 20) completed OGTT testing before and after the interventions. T-AEX increased VO2 peak (+ 15% versus-3% Delta, P < 0.01) compared with CONTROL. There were significant reductions in fasting insulin (-23% versus + 9% Delta, P < 0.05) and the total integrated 3-hour insulin response (-24% versus-3% Delta, P < 0.01) in T-AEX compared with CONTROL. In patients with abnormal glucose tolerance at baseline, T-AEX resulted in a significant 14% decrease in 3-hour glucose response (n = 12, P < 0.05). Fifty-eight percent of T-AEX participants with abnormal baseline OGTT (7 of 12) improved glucose tolerance status at 2 hours compared with < 10% (1 of 11) of impaired CONTROLS (P < 0.05). Conclusions - These preliminary findings suggest that progressive aerobic exercise can reduce insulin resistance and prevent diabetes in hemiparetic stroke survivors. Larger clinical trials are needed to definitively establish the use of structured exercise training for stimulating metabolic improvement poststroke.