Eight Weeks of Intermittent Exercise in Hypoxia, with or without a Low-Carbohydrate Diet, Improves Bone Mass and Functional and Physiological Capacity in Older Adults with Type 2 Diabetes.

Plain Language Summary

Individuals with type 2 diabetes mellitus (T2DM) have an up to 3 times higher risk of fractures compared to non-diabetics which may be mediated through the effects of hyperglycaemia on collagen cross-linking and advanced glycation end products. Exercise in hypoxia (EH) has been shown to have benefits for both bone health and glucose metabolism in patients with T2DM. The aim of this 8-week randomised controlled trial, including 42 patients with T2DM aged over 65 years, was to investigate the effects of EH (3 times per week, equivalent to an altitude of 3000m) alone or in combination with a low carbohydrate diet (LCD, 40% carbohydrate, 20% protein, 40% fat) compared to control diet (60% carbohydrate, 20% protein, 20% fat) and exercise in normal oxygen levels. Outcome measures included glycaemic control, body mass index (BMI), body fat and bone mass content (BMC), cardiorespiratory fitness, functional mobility, and strength. After 8 weeks, HbA1c, blood glucose, weight, hip and waist circumference, waist-hip ratio and body fat improved in all 3 groups, with no statistical difference between groups, whilst HOMA-IR and lean mass did not significantly change in any group. BMC significantly increased in all groups, with the groups exercising in hypoxia improving significantly more than controls. Functional tests showed that hand grip strength and 6-minute walk test improved in all groups, with significantly greater improvement in 6MWT in those exercising in hypoxia. All physiological measures (VO2 peak, time to exhaustion, peak workload, basal heart rate, basal and peak lactate) improved in all groups, except maximum heart rate which decreased in the 2 control diet groups but increased in the LCD group.