Transient dissociation of bone metabolism induced by high performance exercise: A study in elite marathon runners

Bone metabolism parameters were studied in 18 elite marathon runners (11 me n and 7 women) who participated in the Marathon World Cup held at San Sebas tian, Spain in 1993. Measurements were made before the race, immediately af ter the race, and 24 hours after the race. The most interesting finding was increased alkaline phosphatase (P < 0.0001) and decreased tartrate-resista nt acid phosphatase (P = 0.0035), which suggests that exercise produced unc oupling of the bone cell metabolism. Serum calcium corrected for proteins d id not increase with exercise and at the end of the race there was a negati ve correlation between cortisol, which was significantly higher (P < 0.0001 ), and corrected serum calcium(r = 0.53, P = 0.026) that was not present at baseline. Running time showed a significant negative correlation with base line serum cortisol (r = -0.67, P = 0.0015) and a significant positive corr elation with body mass index (r = 0,53, P = 0.0207). The increase in alkali ne phosphatase persisted 24 hours after the race, which suggests that exerc ise produced an intense and sustained effect on osteogenic capacity.