A new study published in the International Journal of Environmental Research and Public Health aimed to determine whether thermoregulatory responses (sweating and cutaneous vasodilation) after isomaltulose drink ingestion differ from those of sucrose and water during exercise in a hot environment.

This study enrolled ten young healthy males, who consumed 10% sucrose, 10% isomaltulose or water drinks. All participants cycled for 15 minutes—at 75% peak oxygen uptake in a hot environment (30 °C, 40% relative humidity-)—35 minutes after ingestion. 

The findings showed that sucrose ingestion induced greater blood-glucose concentration and insulin secretion at the pre-exercise state, compared to isomaltulose and/or water, with no differences in blood-glucose during exercise. Change in plasma volume did not differ between the three trials throughout the experiment, but both, sucrose and isomaltulose ingestions similarly increased plasma osmolality, as compared with water—a key response that potentially delays the onset of heat loss responses. Core temperature thresholds and slopes for heat loss responses were not different between the trials during exercise. 

Hence, ingestion of isomaltulose beverages induces low glycemic and insulinemic states before exercise but does not alter thermoregulatory responses during exercise in a hot environment, compared to sucrose or water.

Source: International Journal of Environmental Research and Public Health. 2021 Jun; 18(11): 5760. doi: 10.3390/ijerph18115760