Exercise After Overnight Fasting Stabilizes Glucose Levels in Type 1 Diabetes

women exercising
women exercising
The effect of high-intensity interval training with a bout of moderate-intensity continuous training on glucose levels was examined in T1D.

A single episode of high-intensity interval training (HIT) or a bout of moderate-intensity continuous training (MICT) after fasting did not increase the risk for hypoglycemia in individuals with type 1 diabetes, according to findings published in the Journal of Clinical Endocrinology & Metabolism.

Moderate-intensity physical activity is recommended for individuals with type 1 diabetes, but marked declines in blood glucose levels have been associated with a single bout of moderate intensity exercise. In the current study, researchers assessed the effects of a single bout of HIT and MICT after an overnight fast on both acute and 24-hour glucose concentrations in 14 individuals with type 1 diabetes.

Glucose levels were monitored after a single bout of HIT (6 × 1-minute intervals) and 30 minutes of MICT on separate days, and then were compared with a control day of no exercise. Participants exercised after an overnight fast without short-acting insulin, and blood glucose samples were obtained both pre- and postexercise.

There were no differences in the incidence of/percentage of time that was spent in hypoglycemia, hyperglycemia or the target glucose range between HIT, MICT and the control day without exercise (P >.05). In addition, blood glucose concentrations were not significantly (P =.49) different between pre- and postexercise with HIT (+0.39 ± 0.42 mmol/L) or MICT (−0.39 ± 0.66 mmol/L).

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“Based on our findings it appears that exercising following an overnight fast before using short-acting insulin helps to maintain blood glucose stability, irrespective of the mode or intensity of the exercise, which means that patients do not need to consume carbohydrate to avoid [hypoglycemia] during exercise,” wrote the researchers.


Scott SN, Cocks M, Andrews RC, et al. Fasted high-intensity interval and moderate-intensity exercise do not lead to detrimental 24-hour blood glucose profiles [published online September 24, 2018]. J Clin Endocrinol Metab. doi:10.1210/jc.2018-01308