Fasting morning exercise linked to higher blood glucose in individuals with T1D

Markedly different blood glucose responses and postexercise profiles are associated with fasting morning resistance exercise (RE) compared with afternoon RE in individuals with type 1 diabetes (T1D), a recent study has shown.

Blood glucose increased during fasting morning exercise (9.5±3.0–10.4±3.0 mmol/L) but decreased with afternoon exercise (8.2±2.5–7.4±2.6 mmol/L; p=0.031 for time-by-treatment interaction). An hour after exercise, blood glucose concentration was significantly higher after fasting morning vs afternoon exercise (10.9±3.2 vs 7.9±2.9 mmol/L; p=0.019).

Data from continuous glucose monitoring (CGM) revealed more glucose variability (2.7±1.1 vs 2.0±0.7 mmol/L; p=0.019) and more frequent hyperglycaemia (12 vs five events; p=0.025) after morning RE compared with afternoon RE.

This randomized, crossover study examined the effect of morning vs afternoon exercise in the fasting condition on blood glucose responses to RE.

Twelve participants with T1D (mean age, 31±8.9 years; nine females; diabetes duration, 19.1±8.3 years; HbA1c, 7.4±0.8 percent [57.4±8.5 mmol/mol]) performed approximately 40 minutes of RE (three sets of eight repetitions, seven exercises, at the individual’s predetermine eight repetition maximum at either 7 AM (fasting) or 5 PM. Sessions were performed at least 48 hours apart.

The investigators collected venous blood samples pre-exercise, immediately postexercise and 60 minutes postexercise. They also monitored interstitial glucose overnight postexercise by CGM.

“RE provides the human body with a multitude of benefits, including maintaining and/or building muscle mass, strength, and metabolism; increasing resting energy expenditure; improving bone mineral density; decreasing the risk of type 2 diabetes mellitus by increasing insulin sensitivity; and improving cardiovascular health,” the investigators said.