Calcium and phosphorus supplemented diet increases bone volume after thirty days of high speed treadmill exercise in adult mice

Weight-bearing exercise increases bone mass and strength. Increasing bone loading frequency during exercise can strengthen bone. Combining exercise with a calcium- and phosphorus-supplemented diet increases cortical area more than exercise alone in mice. Thus, we hypothesized that combining high-speed treadmill exercise while feeding mice a mineral-supplemented diet would lead to greater cortical area than high-speed exercise on a standard diet and low-speed exercise on a supplemented diet. Fifteen-week old male C57BL/6 mice were assigned to seven groups—(1) baseline, (2) non-exercise fed a control diet, (3) non-exercise fed a supplemented diet, (4) low-speed exercise fed a control diet, (5) low-speed exercise fed a supplemented diet, (6) high-speed exercise fed a control diet, and (7) high-speed exercise fed a supplemented diet. Mice exercised thirty days for 20 min/day at 12 m/min or 20 m/min. Tibiae were assessed by micro-CT and 4-point bending. Cortical area fraction and trabecular bone volume fraction (BV/TV) were significantly increased by the supplemented diet. High-speed exercised mice had significantly lower body weight, with no detrimental effects to bone health. Increasing running speed can decrease body weight while maintaining the benefits of exercise and nutrition on bone health. Running can lower body weight without harming bone health.