Peripheral effects of endurance training in young and old subjects

Abstract

The effects of 12 wk of endurance training at 70% peak O2 consumption (VO2) were studied in 10 elderly (65.1 +/- 2.9 yr) and 10 young (23.6 +/- 1.8 yr) healthy men and women. Training had no effect on weight or body composition in either group. The elderly had more adipose tissue and less muscle mass than the young. Initial peak VO2 was lower in the elderly, but the absolute increase of 5.5-6.0 ml.kg-1.min-1 after training was similar for both groups. Muscle biopsies taken at rest showed that, before training, muscle glycogen stores were 61% higher in the young. Before training, glycogen utilization per joule during submaximal exercise was higher in the elderly. Glycogen stores and muscle O2 consumption increased significantly in response to training in the elderly only. After training, the proportion of energy derived from whole body carbohydrate oxidation during submaximal exercise declined in the young only. The absolute changes that training produced in peak VO2 were similar in both age groups, but the 128% increase in muscle oxidative capacity was greater in the elderly, suggesting that peripheral factors play an important role in the response of the elderly to endurance exercise.

The effects of age on kinetics of oxygen uptake and phosphocreatine in humans during exercise

“…Although peak VO2 was not above untrained levels for our older group, we have previously demonstrated that moderate training of older individuals can result in large improvements in muscle metabolism (Marsh, Paterson, Thompson, Cheung, MacDermid & Arnold, 1993b) (Coggan et al 1992b) with a program of moderate walking and jogging exercise. The oxidative capacity of skeletal muscle, determined in vitro, has been shown to be elevated in older individuals to levels similar to those found in younger individuals, after each has undergone similar aerobic training programmes (Meredith et al 1989). In both of the above training studies (Meredith et al 1989;Coggan et al 1992a), older individuals still had levels for peak 1/2 which were lower than those of the younger individuals.…”

The prevalence and risk factors for age-related macular degeneration in rural–urban India, Sankara Nethralaya Rural–Urban Age-related Macular degeneration study, Report No. 1

“…Meredith et al (175) examined the responses of initially sedentary young (age 20-30) and older (age 60-70) men and women to three months of aerobic conditioning (70% of maximal heart rate, 45 minutes/day, three days per week). Absolute gains in aerobic capacity were found to be similar between the two age groups, although the mechanism for adaptation to regular submaximal exercise appears to be different.…”

Resting metabolic rate, body composition and aerobic fitness comparisons between active and sedentary 54 –71 year old males

“…Five longitudinal studies of 8±12 wk duration have been conducted on mixed groups of males and females whose ages approximated those of our subjects: two reported signi®cant increases in RMR (MJad) with no signi®cant changes in mass and FFM (Berke et al, 1992;; one reported a signi®cant increase in absolute (MJad) and relative RMR (MJ Á kg FFM 71 Ád 71 ) with no signi®cant change in mass and FFM (Poehlman & Danforth, 1991); one reported a signi®cant increase in RMR (MJad) and RMR per kg of mineral and protein with negligible change in body mass (Goran & Poehlman, 1992b); and, one found no change in RMR (MJ Á kg 71 Ád 71 ) with non-signi®cant changes in body mass and relative body fat of 0.1 kg and 1.3%, respectively, over the twelve week training programme (Meredith et al, 1989). Interestingly, this latter study used the lowest intensity training programme and also Poehlman et al (1992b) only found a signi®cant increase in RMR when the exercise intensity increased from light ( $ 60% y Pm x ) to moderate ( $ 75% y Pm x ).…”

“…Nevertheless, all (Nichols et al, 1990;Poehlman et al, 1990Poehlman et al, , 1992a but one (Lundholm et al, 1986) cross-sectional study on older males and all (Berke et al, 1992;Poehlman & Danforth, 1991;Poehlman et al, 1992b) but one (Meredith et al, 1989) longitudinal investigation, which were conducted on mixed groups of older males and females, support the hypothesis that aerobic training increases the RMR. However, were the only researchers to use other than the two compartment hydrodensitometric body composition model, or the two compartment total body potassium body composition model (Lundholm et al, 1986), to estimate the FFM which can be used when statistically analysing RMR data for between group differences or treatment effects.…”