No Effect of Exercise Timing on Daily Glycaemia Despite Shifts in Acute Glucose Dynamics in Participants with Normal Glucose Tolerance: A Randomised Crossover Trial
- 1Rowett Institute, University of Aberdeen, Aberdeen, UK; Aberdeen Cardiovascular and Diabetes Centre, University of Aberdeen, Aberdeen, UK
Abstract
Exercise is a well-established modulator of glucose regulation, but whether the time of day it is performed matters for healthy, free-living adults remains unresolved. In a randomised crossover trial, 29 healthy adults completed a single 30-minute bout of moderate-intensity exercise in the morning (07:00-10:00) and in the evening (16:00-19:00), with continuous glucose monitoring and wrist-worn activity tracking used to capture responses over an 8-day free-living protocol. Evening exercise produced a significantly greater acute reduction in blood glucose (P < 0.001) compared to morning exercise, but this did not translate into consistent differences in overall daily mean glycaemic exposure, whether measured over the calendar day or over a window aligned with exercise onset. Evening exercise was linked to greater within-day glycaemic variability than morning exercise, with the clearest evidence coming from the circadian-aligned analysis (day x timing interaction, SD: P = 0.00939; CV: P = 0.00766). Appetite rose after exercise in both conditions, with no difference by time of day. Taken together, these results show that exercise timing does not change how much glucose exposure a healthy adult accumulates over a day, but it does change the shape of the glucose response around the exercise bout itself, a distinction only visible when glucose is examined at a finer temporal resolution than daily averages allow.
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BibTeX
@misc{dasar2026effect,
title = {{No Effect of Exercise Timing on Daily Glycaemia Despite Shifts in Acute Glucose Dynamics in Participants with Normal Glucose Tolerance: A Randomised Crossover Trial}},
author = {L. T. Dasar and M. Hamilton and D. Borisova and I. Lewis and V. Kjellin-Bennett and V. Gargano and R. Prakash and K. Beaulieu and B. M. Gabriel},
howpublished = {bioRxiv},
year = {2026},
month = oct,
doi = {10.64898/2026.10.30.763114},
url = {https://www.biorxiv.org/content/10.64898/2026.10.30.763114v1},
note = {CC BY},
}
RIS
TY - UNPB
TI - No Effect of Exercise Timing on Daily Glycaemia Despite Shifts in Acute Glucose Dynamics in Participants with Normal Glucose Tolerance: A Randomised Crossover Trial
AU - L. T. Dasar
AU - M. Hamilton
AU - D. Borisova
AU - I. Lewis
AU - V. Kjellin-Bennett
AU - V. Gargano
AU - R. Prakash
AU - K. Beaulieu
AU - B. M. Gabriel
PY - 2026
DA - 2026/10/30
PB - bioRxiv
DO - 10.64898/2026.10.30.763114
UR - https://www.biorxiv.org/content/10.64898/2026.10.30.763114v1
AB - Exercise is a well-established modulator of glucose regulation, but whether the time of day it is performed matters for healthy, free-living adults remains unresolved. In a randomised crossover trial, 29 healthy adults completed a single 30-minute bout of moderate-intensity exercise in the morning (07:00-10:00) and in the evening (16:00-19:00), with continuous glucose monitoring and wrist-worn activity tracking used to capture responses over an 8-day free-living protocol. Evening exercise produced a significantly greater acute reduction in blood glucose (P < 0.001) compared to morning exercise, but this did not translate into consistent differences in overall daily mean glycaemic exposure, whether measured over the calendar day or over a window aligned with exercise onset. Evening exercise was linked to greater within-day glycaemic variability than morning exercise, with the clearest evidence coming from the circadian-aligned analysis (day x timing interaction, SD: P = 0.00939; CV: P = 0.00766). Appetite rose after exercise in both conditions, with no difference by time of day. Taken together, these results show that exercise timing does not change how much glucose exposure a healthy adult accumulates over a day, but it does change the shape of the glucose response around the exercise bout itself, a distinction only visible when glucose is examined at a finer temporal resolution than daily averages allow.
ER -