The effects of muscle-building exercise on vitamin D and mineral metabolism.

Exercise and muscle strength are important determinants of bone mass. Studies were carried out in normal young adult white males to determine the effects of exercise on vitamin D and mineral metabolism. Fourteen men who had engaged in regular muscle-building exercises for at least 1 year and 14 age-matched controls (age range, 19-36 year) were hospitalized on a metabolic ward and were given a constant daily diet estimated to contain 400 mg of calcium, 900 mg of phosphorus, 110 mEq of sodium, 65 mEq of potassium, and 18 mEq of magnesium.

Heart Rate and Lactate Levels During Weight-Training Exercise in Trained and Untrained Men.

In brief: The effects of squatting exercise on heart rate and blood lactate levels were studied in five trained and five untrained men between the ages of 22 and 37. The subjects performed squats (sets of ten repetitions until exhaustion), resting for 2 1/2 minutes between sets. Total positive work was estimated with the following formula: (bar mass + body mass) X vertical displacement X repetitions.