Acute effects of a single session of aerobic exercise with or without weight-lifting on bone turnover in healthy young women.

This study aimed to investigate the acute effects of exercise on bone turnover and to determine whether brisk walking with or without weight-lifting makes a difference on bone metabolism. Nine healthy women performed two exercise bouts: brisk walking on a treadmill for 30 min (E), and similar exercise carrying 5 kg of weight in a backpack (WE). Serum parathyroid hormone (PTH), osteocalcin (OC), calcitonin (CT), procollagen type 1 carboxy terminal propeptide (PICP), procollagen type 1 amino terminal propeptide (PINP), type 1 collagen carboxy terminal telopeptide (ICTP), total alkaline phosphatase (ALP), and urine deoxypyridinoline (D-Pyr) levels were studied. Resting values served as control. Significant variances were observed only in serum ALP and PTH values. Variances in ALP values within subjects after exercise were statistically significant (analysis of variance in repeated measurements [AVRM], P=0.000). E caused a significant decrease, while WE caused a significant increase in ALP values at the 24th h (Bonferroni pairwise comparisons tests [BPC t-test]: P=0.028, P=0.000, respectively). Variances in PTH values within subjects after exercise were statistically significant (AVRM, P=0.029), while diurnal variation was not significant (P=0.981). E caused significant alterations in PTH levels (an increase at the 30th min, turned towards baseline at the 45th min) (BPC t-test, P=0.007). WE also caused alterations in PTH levels, though insignificant (BPC t-test, P=1.00). Brisk walking for 30 min has stimulating effects on bone turnover by various mechanisms without any additive effect of weight bearing.