Biologically relevant sex differences for fitness-related parameters in active octogenarians

The number of elderly people is growing in western populations, but only few maximal performance data exist for people >75 years, in particular for European octogenarians. This study was performed to characterize maximal performance of 55 independently living subjects (32 women, 81.1 ± 3.4 years; 23 men, 81.7 ± 2.9 years) with a focus on sex differences. Maximal performance was determined in a ramp test to exhaustion on a bicycle ergometer with ergospirometry, electrocardiogram and blood lactate measurements. Maximal isometric extension strength of the legs (MEL) was measured on a force platform in a seated position. Body composition was quantified by X-ray absorptiometry. In >25% of the subjects, serious cardiac abnormalities were detected during the ramp test with men more frequently being affected than women. Maximal oxygen consumption and power output were 18.2 ± 3.2 versus 25.9 ± 5.9 ml min⁻¹ kg⁻¹ and 66 ± 12 versus 138 ± 40 W for women versus men, with a significant sex difference for both parameters. Men outperformed women for MEL with 19.0 ± 3.8 versus 13.6 ± 3.3 N kg⁻¹. Concomitantly, we found a higher proportion of whole body fat in women (32.1 ± 6.2%) compared to men (20.5 ± 4.4%). Our study extends previously available maximal performance data for endurance and strength to independently living European octogenarians. As all sex-related differences were still apparent after normalization to lean body mass, it is concluded that it is essential to differentiate between female and male subjects when considering maximal performance parameters in the oldest segment of our population.