HIIT as a Preventative Measure for Age-Related Cognitive Decline

Abstract

PURPOSE: The relationship between aging and cognition is multifaceted, and the effects of exercise on age-related cognitive decline seem promising. Exactly how exercise promotes cognitive health, and which form of exercise promotes it the most, is still uncertain. This study's main purpose was to assess the effects of High-Intensity Interval Training on functional and cognitive performance in a group of middle-aged mice, compared to a sedentary control group. HYPOTHESES: First, we expect the high-intensity interval trained group (HIIT; n = 8) to exhibit greater resistance to age-related cognitive decline, pre- to post-, than the sedentary control group (SED; n = 7). Second, we predict the HIIT mice maintain physical function compared to the SED group. METHODS: Using C57BL/6 mice, the present study utilized a 12-week treadmill HIIT protocol as the intervention, assessing functional and cognitive performance with the Comprehensive Functional Assessment Battery (CFAB) and a Cognitive Assessment Battery (CAB). CFAB consists of tasks including Treadmill, Inverted Cling, Grip Meter, Volitional Wheel Running, and Rotarod. CAB is comprised of tasks including Open Field, Novel Object Recognition, Y-maze, and Puzzle Box. Cognitive and physical function batteries were performed pre- and post-intervention. EchoMRI and in vivo contractile physiology were used to measure body composition and plantar flexor torque, respectively, at baseline and post-intervention. RESULTS: The 12-week HIIT protocol resulted in significant aerobic capacity improvements for the HIIT group, increasing treadmill time by 28%, while the SED group demonstrated a 41.4% decline in treadmill time (within-subjects effects of time*group F=21.381, p<0.001; between-subjects effects of time*groups F=5.572, p=0.035). No significant differences between the groups' cognitive function tests were observed pre- to post-training. Differences in body mass, fat, and fat% pre- to post-training, measured at the time of EchoMRI, were significantly larger within groups (2x2 Repeated Measures ANOVA: F=20.062, 46.845, and 35.899, respectively; all p<0.001). DISCUSSION: Contrary to previous research, the current study found little effect of HIIT on body composition. Regarding the lack of cognitive maintenance observed, at only 17 months of age the mice may not experience any cognitive deterioration. Thus, the HIIT intervention may not have had an opportunity to influence cognitive function maintenance. Our next step is to assess young adult mice to establish a CAB baseline, and evaluate older adult cognitive response to HITT.