HIGH-INTENSITY WALKING EXERCISE REDUCES FRAILTY AMONG PREFRAIL AND FRAIL OLDER ADULTS

Abstract

Abstract Exercise is the most recommended therapeutic intervention for frailty, yet the precise exercise prescription remains elusive. The purpose of this study was to use a cluster randomized controlled trial to evaluate the impact of exercise intensity on frailty in older adults. We tested a high (HIW) vs. low (LIW) intensity walking intervention among n=165 pre-frail and frail residents from n=12 independent living communities. The 3x/week, 4 month supervised intervention targeted >70% heart rate reserve for HIW participants and < 50% heart rate reserve for LIW participants. The primary outcome was frailty category improvement as assessed by the SHARE-FI. We measured usual and fast gait speed, 6-minute walk test, Timed Up and Go, SPPB, Berg Balance, Falls Efficacy, and PROMIS Global Health. Participants were on average 79 years of age, 79% female, and 75% white. We analyzed outcomes based on a modified intention-to-treat principle using a linear or generalized linear mixed model with fixed arm, baseline outcome measure score and random cluster effects. We found increased odds of improving at least one SHARE-FI frailty category in the HIW group (OR=2.91 [reference group=LIW], 95% CI 1.19,7.13, p=0.02, N=103). Among secondary outcomes, there was a significant difference in change in usual gait speed (mean difference = 0.078, 95% CI = 0.026, 0.131, Hochberg adjusted P-value = 0.0357), as well as 6-minute walk test (mean difference = 160.72, 95% CI = 69.2, 252.2, Hochberg adjusted P-value = 0.0075). Results suggest that older adults should engage in more intensive/higher heart rate cardiovascular exercise to reduce frailty.