The Effects of Exercise on Appetite-Regulating Hormone Concentrations over a 36-h Fast in Healthy Young Adults: A Randomized Crossover Study

Abstract

Hunger and satiety are controlled by several physiological mechanisms, including pancreatic and gastrointestinal hormones. While the influence of exercise and fasting have been described individually, in relation to these hormones, there is a paucity of work showing the effects of the two modalities (fasting and exercise) combined. Twenty healthy adults (11 males, 9 females) completed both conditions of this study, each consisting of a 36-h water-only fast. One of the fasts began with treadmill exercise, and the differences between the conditions on various appetite hormones were measured every 12 h. The difference in the area under the curve between conditions for ghrelin was 211.8 ± 73.1 pg/mL (F = 8.40, p < 0.0105), and, for GLP-1, it was −1867.9 ± 850.4 pg/mL (F = 4.82, p < 0.0422). No significant differences were noted for areas under the curve between conditions for leptin, PP, PYY, insulin, or GIP. Initiating a fast with exercise lowers ghrelin concentrations and elevates GLP-1 concentrations. Given that ghrelin elicits feelings of hunger and GLP-1 signals feelings of satiety, adding exercise to the beginning of a fast may reduce some of the biological drive of hunger, which could make fasting more tolerable, leading to better adherence and more significant health outcomes.

The Effects of a High-Carbohydrate versus a High-Fat Shake on Biomarkers of Metabolism and Glycemic Control When Used to Interrupt a 38-h Fast: A Randomized Crossover Study

“…Knowing their impact on glycemic control and metabolic switching, our lab recently reported the effects of beginning a fast with and without exercise on concentrations of insulin, GLP-1, and GIP, noting that insulin and GIP reach minimal concentrations by 12 h of fasting and remain low regardless of whether exercise was used to initiate the fast [ 59 ]. We also reported that GLP-1 was elevated for up to 36 h after exercise compared to the non-exercise group.…”

Physical Activity and Excess Body Weight and Adiposity for Adults. American College of Sports Medicine Consensus Statement

“…Although the data are limited, the addition of exercise to a period of fasting has been shown to possibly enhance the beneficial effects on cardiometabolic markers of health (e.g., lipids, inflammation) and possibly liver health (87). It has also been suggested that the addition of exercise at the beginning of a fasting period may allow for the fasting period to be more tolerable by reducing the biological drive for hunger (88); however, the data are very limited to support this potential effect. Although data on the safety of combining intermittent fasting with exercise are limited, caution should be applied if implementing this strategy, particularly for individuals who may be at risk for hypoglycemia or other related conditions that may be impacted with this intervention strategy.…”

Gestational Diabetes Mellitus and Colostral Appetite-Regulating Adipokines

“…It was reported that appetite and satiety regulation are profoundly complex and involve the endocrine and the central nervous system [76,77]. The changes in appetite-regulating hormone pattern cause disturbances in the molecular signaling involved in control of food intake and feeling of satiety, which might translate into milk intake and possibly offspring growth [78][79][80][81]. The work groups [39,42] reported that the appetite-regulating molecules are a critical window for adiposity programming during the first 6 months of an infant's life and predispose it to higher risk of obesity and metabolic disorders in later life.…”