The effects of brisk walking on markers of bone and calcium metabolism in postmenopausal women

Abstract

Weight-bearing exercise has been shown to maintain or increase bone mass in younger as well as older individuals but the mechanisms by which mechanical loading affects bone metabolism are not known in detail. Twelve postmenopausal women participated in a single bout of brisk walking (50% of VO2 max) for 90 minutes. Calciotropic hormones and markers of type I collagen formation (PICP) and degradation (ICTP) were measured before the exercise, and 1, 24, and 72 hours following the exercise. Total body bone mineral content (BMC) and density (BMD) were measured by dual energy X-ray absorptiometry (DXA). Brisk walking did not induce any significant changes in the concentrations of ionized calcium, parathyroid hormone (PTH), calcitonin, or osteocalcin. A significant increase of PICP was noted 24 and 72 hours (P < 0.01) after exertion and a significant decrease in the concentration of serum ICTP at 1 hour (P < 0.05) was followed by an increase at 72 hours (P < 0.001). There was no significant difference between the increases in the concentrations of PICP and ICTP at 72 hours. Strong inverse correlations between the basal levels of PTH and BMD (r = -0.78; P < 0.01) as well as between osteocalcin and BMD (r = -0.83; P < 0.01) were noticed. The changes in serum levels of bone collagen markers indicate an altered bone collagen turnover due to this moderate endurance exercise. The results also support the fact that serum levels of PTH as well as those of osteocalcin are associated with total body BMD in postmenopausal women.

Is Walking Exercise a Protective Factor for Osteoporosis in Young Obese Women?

“…This loss is 52% less for lumbar BMD in women reporting walking as their sole form of weight-bearing exercise. Thorsen et al (1996), similarly, found that brisk outdoor walking for 90 minutes at 50% of VO2max had significant positive effect on the markers of collagen metabolism. Consequently, there may be a therapeutic role for walking exercise in the prevention and management of osteoporosis.…”

Animal models of osteoporosis - necessity and limitations

“…Future studies using OVX sheep should investigate other newer biochemical markers indicative of fragments of type I collagen synthesis and degradation that are most likely to reflect bone turnover (DeSouza et al, 1996;Thorsen et al, 1996;O' Connell, 1999). Such markers include the carboxy-terminal propeptide (PICP) to reflect bone matrix synthesis and the carboxy-terminal telopeptide (Ctelopeptide or ICTP) which reflects bone matrix degrada-Running title: Animal models -osteoporosis tion.…”

Clinical Usefulness of the Measurement of Bone Mineral Content by Radiographic Absorptiometry in the Young Thoroughbred

“…No significant sex difference was noted in the present study. The differences among these reports suggest that the bone metabolism markers depend on the bone growth stage [17], type of the horse [17], sex hormone [6], and exercise intensity [38,40]. However, the reasons remain unclear and further study to elucidate them is necessary.…”