EFFECTS OF STRENGTH AND ENDURANCE EXERCISE ON CALCIUM-REGULATING HORMONES BETWEEN DIFFERENT LEVELS OF PHYSICAL ACTIVITY

Physical activity has shown to maintain bone mineral density (BMD) through the effects of mechanical loading on bone metabolism. However, the effects of exercise on the calcium-regulating hormones and other metabolic variables are not known. PURPOSE: To compare the effects of strength and endurance exercise on blood pH, total serum calcium, ionized calcium, parathyroid hormone (PTH) and calcitonin (CT) between males with different levels of physical activities. METHODS: The experimental group consisted of 9 physically active males (runners) and the control group consisted of 10 males who had not exercised regularly for the past year. Subjects were asked to perform both strength (eccentric action) and endurance exercises (VO2 peak). The blood pH, total serum calcium, ionized calcium, PTH and CT were measured before and after exercise. A two-way ANCOVA was used for data analysis. RESULTS: (1) When the control group did anaerobic exercise, the free ionized calcium increased significantly (p < 0.05). (2) Mode and intensity of physical activity have no significant effects on the body's calcium regulating hormones. (3) The level of physical activity plays a major role in increasing bone density. High levels of physical activities plus strength exercises can have an additive effect on bone density. CONCLUSION: Regular high intensity exercise will help increase bone density. Strength exercises can maintain bone density not only through mechanical loading, but also through blood pH and biochemical changes in free ionized calcium, which can positively affect bone density.