The new study data suggests that taking calcium and vitamin D before exercise influences how bones adapt to exercise - possibly preventing bone mineral losses that are often found in athletes that have participated in many years of intense training.
"The timing of calcium supplementation, and not just the amount of supplementation, may be an important factor in how the skeleton adapts to exercise training," said study lead author Dr Vanessa Sherk from the University of Colorado Anschutz Medical Campus, USA.
Speaking at The Endocrine Society's 95th Annual Meeting in San Francisco, USA, Sherk and her team investigated whether exercise induced decreases in blood calcium - which are believed to be responsible for losses in bone mineral density - occurred when a supplement was given to athletes either before or after training sessions.
They revealed that exercise-induced decreases in blood calcium occurred both in athletes supplemented before or after training - however they noted that pre-exercise supplementation resulted in less of a decrease.
"These findings are relevant to individuals who engage in vigorous exercise and may lose a substantial amount of calcium through sweating," Sherk said.
"Taking calcium before exercise may help keep blood levels more stable during exercise, compared to taking the supplement afterwards, but we do not yet know the long-term effects of this on bone density," she confirmed - adding that further research is now needed in order to determine whether the timing of calcium supplementation affects how the skeleton adapts to exercise training.