Are Improvements in Skeletal Muscle Oxidative Capacity Possible in the Elderly?

Abstract

Loss of skeletal muscle function is a key factor contributing to the reduced quality of life and mobility in aging individuals. While several mechanisms have been implicated, reduced skeletal muscle oxidative capacity is thought to play a major role. Exercise training is known to improve skeletal muscle oxidative capacity in young healthy populations. Whether exercise training can improve skeletal muscle oxidative capacity in elderly individuals, with associated cardiovascular risk factors, remains unclear. To address this question, we recruited 8 elderly participants from the local Dallas‐Fort Worth community (73 ± 7 yrs; m/f: 2/6; BMI: 25.9 ± 3.1 kg). Subjects completed two baseline visits to establish our day‐to‐day reproducibility, followed by 4‐weeks of handgrip exercise training at 30% of maximal voluntary contraction (MVC, non‐dominant arm), five (5) days a week. MVC was reassessed each week, and the total number of contractions was gradually increased, for a total of 600, 900, 1200, and 1500 grips per day, respectively. Skeletal muscle oxidative capacity was assessed using a well‐established near‐infrared spectroscopy (NIRS) protocol, expressed as the post‐exercise muscle oxygen consumption recovery time constant (i.e. tau, in seconds). To date, we have completed data collection on 5 of 8 participants. All five participants increased their MVC with exercise training (pre‐training MVC: 23.1 ± 17.2 kg; post‐training MVC: 26.8 ± 16.1 kg, or 16.0% increase). Despite measurable increases in muscle strength however, skeletal muscle oxidative capacity was unchanged from baseline (pre‐training tau: 45.9 ± 16.5 s; post‐training tau: 49.6 ± 13.5 s, or 8.1% increase). These data are in contrast to at least two prior reports showing an improvement in skeletal muscle oxidative capacity in young, healthy subjects, and elderly participants at least 10 years younger than those studied here. We interpret these data to reflect an upper limit to the training adaptation previously reported.Support or Funding InformationThis work was supported by a UT Arlington Interdisciplinary Research Program grant.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.