Human rights and the older worker: changes in work capacity with age.

The aging of physical working capacity affects the employability of older individuals in heavy work through such factors as a decline in aerobic power, muscular strength, and tolerance of thermal load. Difficulties in setting an appropriate criterion for enforced retirement include, on the one hand, a tremendous inter-individual variation in the rate of aging, and on the other, the problem that a standard appropriate for older men cannot be met by even the youngest women. Vigorous training can reduce some components of biological age by as much as 20 yr, and it is manifestly unfair to require the retirement of those employees who have chosen a lifestyle that has conserved their physical condition. However, the development of reliable, valid, and convincing tests that will distinguish such individuals remains a fascinating medico-legal challenge.