The effect of aging on relationships between lean body mass and VO₂max in rowers

Aging is associated with a fall in maximal aerobic capacity as well as with a decline in lean body mass. The purpose of the study was to investigate the influence of aging on the relationship between aerobic capacity and lean body mass in subjects that chronically train both their upper and lower bodies. Eleven older rowers (58±5 yrs) and 11 younger rowers (27±4 yrs) participated in the study. Prior to the VO₂max testing, subjects underwent a dual energy X-ray absorptiometry scan to estimate total lean body mass. Subsequently, VO₂max was quantified during a maximal exercise test on a rowing ergometer as well as a semi-recumbent cycle ergometer. The test protocol included a pre-exercise stage followed by incremental exercise until VO₂max was reached. The order of exercise modes was randomized and there was a wash-out period between the two tests. Oxygen uptake was obtained via a breath-by-breath metabolic cart (Vmax™ Encore, San Diego, CA). Rowing VO₂max was higher than cycling VO₂max in both groups (p<0.05). Older subjects had less of an increase in VO₂max from cycling to rowing (p<0.05). There was a significant relationship between muscle mass and VO₂max for both groups (p<0.05). After correcting for muscle mass, the difference in cycling VO₂max between groups disappeared (p>0.05), however, older subjects still demonstrated a lower rowing VO₂max relative to younger subjects (p<0.05). Muscle mass is associated with the VO₂max obtained, however, it appears that VO₂max in older subjects may be less influenced by muscle mass than in younger subjects.