Aquatic Exercise Training in Warm vs. Cold Water in Elderly Patients with Type 2 Diabetes

Introduction: Older adults with type 2 diabetes face increased risks of macrovascular and microvascular complications. Aquatic exercise offers a joint-friendly alternative in this population. However, the influence of water temperature on exercise outcomes remains unclear. Purpose: This study compared the effects of warm-water versus cold-water aerobic exercise on physical fitness, glycemic control, and vascular function in elderly patients with type 2 diabetes. Methods: Thirty-two sedentary older adults (aged 60–75) with type 2 diabetes were randomized into warm-water (36°C; n=16) or cold-water (20°C; n=16) cycling exercise groups, training three times per week for 12 weeks. Results: Fifteen participants in the warm-water group and twelve in the cold-water group completed the study. Both groups demonstrated improvements in peak aerobic fitness, HbA1c, lipid profiles, pulse wave velocity, flow-mediated dilation, and skin microvascular function (p<0.05). Warm-water exercise produced greater improvements in all indices of foot microvascular reactivity than the cold water group. Warm water training additionally improved isometric leg strength, trunk flexibility, plasma nitric oxide, and reduced oxidative stress (p<0.05), while cold-water exercise led to reductions in blood pressure (p<0.05). Conclusion: Both warm- and cold-water aerobic exercise effectively improved both macro- and micro-vascular function and metabolic health in older adults with type 2 diabetes. However, warm-water exercise conferred extra benefits in muscle strength, flexibility, and oxidative stress, while cold water exercise reduced blood pressure.