Comparing the reinforcing value of high intensity interval training versus moderate intensity aerobic exercise in sedentary adults

Authors: EPSTEIN, LEONARD - University At Buffalo; O’DONNELL, SARA - University At Buffalo; BIONDILLIO, MATHEW - University At Buffalo; HOSTLER, DAVID - University At Buffalo; Roemmich, James

Submitted to: Physiology & Behavior
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/19/2021
Publication Date: 5/24/2021
Citation: Epstein, L.H., O’Donnell, S., Biondillio, M., Hostler, D., Roemmich, J.N. 2021. Comparing the reinforcing value of high intensity interval training versus moderate intensity aerobic exercise in sedentary adults. Physiology and Behavior. 238. Article 113468. https://doi.org/10.1016/j.physbeh.2021.113468.
DOI: https://doi.org/10.1016/j.physbeh.2021.113468

Interpretive Summary: Exercise is reinforcing for both animals and humans. Exercise activates brain reward pathways and adults who find exercise more reinforcing engage in more exercise behavior. The majority of research on exercise reinforcement has studied moderate intensity aerobic exercise (MIAE). There is limited research on how reinforcing high intensity interval training (HIIT) may be. HIIT is often reported to be a preferred form of exercise in comparison to MIAE. Scientists and the Grand Forks Human Nutrition Research Center in collaboration with University scientists discovered that adults were more likely to substitute sedentary behaviors with HIIT than with MIAE. These results suggest inactive people may be more likely to adhere to the physical activity guidelines referenced in the USDA Dietary Guidelines for Americans if the exercise program includes a majority of HIIT rather than MIAE.

Technical Abstract: Exercise is a reinforcer for both animals and humans, as they will work progressively harder to gain access for the opportunity to exercise. Exercise activates brain reward pathways similar to drugs of abuse, and the magnitude of the reinforcing value of exercise is a predictor of exercise behavior. The majority of research on exercise reinforcement has studied moderate intensity aerobic exercise (MIAE) or resistance training. There is limited research on the relative reinforcing value (RRV) of high intensity interval training (HIIT), which is often reported to be a preferred form of exercise in comparison to MIAE. Experiment 1 was a pilot study of 20 sedentary females designed to compare the reliability of differences in RRV HIIT vs RRV MIAE over two sessions, assess protocols comparing different volumes of HIIT in comparison to MIAE, and estimate sample sizes needed for a fully powered study to assess which type of exercise protocol was a better substitute for a highly liked sedentary activity. Experiment 2 studied 44 participants to assess whether HIIT or MIAE would be better substitutes for highly liked sedentary activities. Experiment 1 showed that measures of RRV HIIT or RRV MIAE were reliable, and that volume of HIIT did not influence RRV HIIT, even if it was of equal amount or duration to MIAE. Experiment 2 showed that HIIT was a more preferred substitute for sedentary behaviors than MIAE. Predictors of RRV MIAE were liking of MIAE and pleasantness of affect post MIAE. These results suggest inactive people may find interval training to be more reinforcing than MIAE, and may be more likely to adopt and maintain an exercise program involving HIIT rather than MIAE. The next stage of research should be to understand how to sensitize the RRV of exercise to motivate sedentary people to be more active.