The Influence of Prolonged Strength Training Upon Muscle and Fat in Healthy and Chronically Diseased Elderly Close to Retirement Age

Abstract

Background: Physical and cognitive function declines with age, accelerating after the age of 60. Strength training over a few months improves physical function, but less is known about how long-term strength training affects physical and cognitive function. Therefore, we aimed to investigate the effect of 1 year strength training of two different intensities upon muscle mass, function, and cognition in retirement-age individuals. Methods: In this randomized controlled trial (clinicaltrials.gov: NCT02123641), participants were allocated to either a) supervised, heavy resistance training (HRT, n=149, 3/wk), b) moderate intensity resistance training (MIT, n=154, 3/wk) or c) non-exercise activities (CON, n=148). 451 participants were randomized (62-70 yrs, women 61%, ≈80% with a chronic medical disease) and 419 were included in the intention-to-treat analysis (n=143, 144 and 132; HRT, MIT and CON). Changes in muscle power (primary outcome), strength and size, physical function, body composition, hippocampus volume and physical/mental well-being were analysed. Findings: Of the participants (HRT+MIT), 83% completed training at least 2/wk. Leg extensor power was unchanged in all groups, but strength training had positive effects on isometric knee extensor strength and muscle mass, whereas an increased cross-sectional area of vastus lateralis muscle, a decreased whole-body fat percentage and visceral fat content occurred in HRT only. Further, chair-stand performance and 400 m walking time improved in all groups. Hippocampus volume decreased in all groups over time with no influence of strength training, whereas mental health (SF-36) improved more in HRT than MIT. Interpretation:Together, the results indicate that long-term supervised strength training in both healthy and chronically diseased elderly individuals can be implemented with good compliance and induces consistent changes in physiological parameters of muscle and fat. Trial Registration: Clinicaltrials.gov (NCT02123641). Funding Statement: Nordea Foundation (Centre for Healthy Ageing grant). Declaration of Interests: Dr. Gylling reports grants from Nordea Foundation (Centre for Healthy Ageing grant), during the conduct of the study. All other authors declare no conflicts of interest. Ethics Approval Statement: All participants signed an informed consent before participating in the study. The study was approved by the regional ethical committee (Capital Region, Copenhagen, Denmark, No. H-3-2014-017), and complied with the declaration of Helsinki, and the study was approved by the Danish Data Protection Agency.