The Effect of Acute Aerobic Exercise On the Time Spent in Hypoglycaemia After Bariatric Surgery (The BariEX Study)

To determine whether a pre-lunch single bout of moderate-intensity aerobic exercise (AEX) alters time spent in hypoglycaemia (<3.0 mmol/L) during the subsequent 24 hours (24-h) and parameters of glucose homeostasis in individuals without diabetes after metabolic/bariatric surgery (MBS).

In a randomised crossover study, 15 participants completed two conditions: 30min treadmill walking at 60% V̇O₂peak (AEX) and time-matched sitting (CON). After an overnight fast and a standardised breakfast, participants performed AEX or CON, and both conditions were followed by an identical lunch administered as a mixed-meal tolerance test (MMTT). Continuous glucose monitoring (CGM) assessed glucose levels for 24-h post-intervention, during which participants consumed standardised meals. CGM data were available for analysis in 11 participants. The primary outcome was time spent with glucose <3.0 mmol/L during the 24-h post-intervention. Secondary outcomes included other CGM-derived glucose metrics and plasma glucose and insulin responses during the 3-h MMTT.

Only one isolated hypoglycaemic event (<3.0 mmol/L) occurred, precluding statistical analysis of the primary outcome. Mean 24-h glucose (AEX: 6.4 (1.0); CON: 6.5 (0.9) mmol/L; p = 0.57) and time <3.9 mmol/L (AEX 0 (0.0, 0.5); CON 0 (0.0, 0.5) %; p = 0.68) did not differ between conditions. AEX reduced glucose coefficient of variation (p < 0.01). During the MMTT, nadir, peak, and AUC_0-180 glucose, as well as pre-MMTT insulin concentrations, were higher following AEX (all p < 0.05).

A pre-lunch 30-min bout of AEX did not increase the 24-h risk of hypoglycaemia post-MBS but elevated post-MMTT glucose levels.