Effect of physical activity on calcium homeostasis and calciotropic hormones: a review.

Physical exercise has frequently been shown to improve bone mass, especially at load-bearing bone sites. It is widely acknowledged that the anabolic effects of exercise on bone tissue are related to the application of mechanical constraints, but part of the osteogenic response may be due to other factors. In particular, various hormonal parameters that are modified by training, such as insulin-like growth factor-1 and sexual hormones, may modulate the bone response. In contrast, little is known about the involvement of calciotropic hormones in the adaptation mechanism of bone tissue. These hormones, which include parathyroid hormone, vitamin D metabolites, and calcitonin, are highly implicated in the regulation of both bone remodeling and calcium homeostasis. In addition to their direct action on bone cell activity, these hormones act on various target tissues such as kidney and intestine. This article describes the acute and long-term effects of exercise on both calcium homeostasis and calciotropic hormones in various populations. It clearly shows that exercise modifies calcium homeostasis and calciotropic hormone levels and that the variations in response are modulated by parameters related to exercise, including duration and intensity, as well as by individual characteristics such as age, sex, and training status.