Fitness and low blood glucose have to be achieved independently in type 1 diabetes

This study examined whether physical activity is associated with improved fitness and improved blood glucose levels.

Physical activity and good control of blood glucose levels are known to reduce the risk of developing cardiovascular disease. Diabetics tend to have lower physical activity as physical activity can result in low blood glucose levels. It is not clear whether increasing physical activity can improve control of blood glucose levels. 

This study aimed to determine whether physical activity is associated with cardiorespiratory fitness (ability of the heart and lungs to supply oxygen to muscles during exercise) and improved blood glucose levels. This study involved 23 T1D patients (12 women and 11 men). The total energy expenditure (indication of physical activity) was recorded for up to 12 days via a sensory armband. Blood glucose levels were recorded for up to 12 days using a continuous glucose monitor. The continuous glucose monitor measured blood glucose levels every few minutes. Participants were free to carry out any exercise they wished. Participants kept a food and insulin diary throughout the 12 days.

Higher daily physical activity was associated with greater cardiorespiratory fitness and less body fat. There was no association between daily physical activity and blood glucose levels. There was also no association between improved cardiorespiratory fitness and blood glucose levels.

This study concluded that physical activity is associated with improved cardiorespiratory fitness. However, physical activity is not associated with improved control of blood glucose levels, and so patients should not rely on fitness level alone to reduce blood glucose levels. 

The sample size of 23 participants was quite small and a greater sample size would have been ideal. The 12 day assessment period could have been extended to see if long-term physical exercise had an effect.

Consult your physician to discuss the health benefits of physical exercise.