Athletes May Benefit from Supplemental Calcium Immediately Before or During Workouts

Calcium is one of the main minerals in the human body. It is not only necessary for teeth and bone health, but is also critically involved in muscular force production. Astongishingly there are relatively few studies investigating the immediate effect of calcium supplementation on exercise performance in athletes. A recent study by Barry et al. (Barry. 2010) is among the few which investigate the immediate (pre/during exercise supplemtation) on para-tyhroid hormone (PTH) and thus calcium resorption from bone:

Male endurance athletes (n=20) completed three 35-km cycling time trials under differing calcium supplementation conditions: 1) 1000 mg calcium 20 minutes before exercise and placebo during, 2) placebo before and 250 mg calcium every 15 minutes during exercise (1000 mg total), or 3) placebo before and during exercise. [...] When compared to placebo, calcium supplementation before exercise attenuated the increase in PTH (55.8 +/- 15.0 vs. 74.0 +/- 14.2; mean +/- SE; p=0.04); there was a similar trend (58.0 +/- 17.4; p=0.07) for calcium supplementation during exercise.

Although this warrants further investigations, the various recommendation to take ones calcium supplementation in the evening, with meals, without meals, without magnesium etc. have to be extended by "take your calcium supplement before or in the course of your workouts".