No Effect of Exercise Timing on Daily Glycaemia Despite Shifts in Acute Glucose Dynamics in Participants with Normal Glucose Tolerance: A Randomised Crossover Trial

In 29 healthy adults with normal glucose tolerance, exercising in the evening (16:00–19:00) versus morning (07:00–10:00) does not change overall daily mean glycaemic exposure.

• Why it matters: The key uncertainty is whether exercise timing alters daily glucose regulation in healthy free-living adults, beyond short-term glucose effects.
• What they did: In a randomized crossover trial, participants completed one 30-minute moderate-intensity bout in each time window, while continuous glucose monitoring and wrist activity tracking supported an 8-day free-living comparison.
• The result: Evening exercise caused a larger acute glucose reduction (P < 0.001) and greater within-day glycaemic variability (day × timing interaction: SD P = 0.00939; CV P = 0.00766), without timing differences in appetite.

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