Broom et al’s paper – ‘Acute effect of exercise intensity and duration on acylated ghrelin and hunger in men’ was the Journal of Endocrinology’s highest downloaded non – gold open access paper in 2017. It has now been acknowledged as one of the journals most highly citied in 2019.
Broom’s previous work showed that acute exercise transiently suppresses the orexigenic (appetite stimulating) gut hormone acylated ghrelin, but the extent to which exercise intensity and duration determine this response was not fully understood.
The effects of manipulating exercise intensity and duration on acylated ghrelin concentrations and hunger were therefore examined in two experiments.
In experiment A, nine healthy males completed three conditions being 1) resting control, 2) moderate-intensity running and 3) vigorous-intensity running.
In experiment B, nine healthy males completed three conditions being 1) resting control, 2) 45-min running and 3) 90-min running.
In both experiments, participants consumed standardised meals, and acylated ghrelin concentrations and hunger were measured throughout.
In experiment A, acylated ghrelin concentrations were lower than resting control in both running conditions and to a greater extent in the vigorous-intensity running condition. In experiment B, acylated ghrelin concentrations were lower than control in both running conditions. Hunger ratings were lower for longer after 90 minutes of running.
Exercise intensity and duration are key determinants of the acylated ghrelin response to acute exercise with a clear dose response effect. The higher the intensity and the longer the duration the greater the suppression of hunger and acylated ghrelin.
Research in this area is needed to identify effective doses of exercise to encourage weight loss and maintenance.
This work was in collaboration with academics from Loughborough University. We have recently submitted a paper examining swimming as a mode of physical activity which anecdotally increases hunger. Findings to follow once published.