NEW YORK (Reuters Health) - The more time young men spend engaging in high-impact physical exercise, the greater their bone mineral density, a new study of medical students shows.
But among their female peers, there was no link between high-impact workouts and bone mineral density, Dr. Peter Nordstrom of the University Hospital of Northern Sweden in Umea and colleagues found. Instead, the young women’s body weight, lean body mass and fat mass predicted the density of their bones.
The findings “suggest that present physical activity level has a stronger relation to different aspects of bone mass in the male compared to the female adult skeleton,” Nordstrom and his team conclude in current issue of the International Journal of Sports Medicine.
Activity appears to play the strongest role in building bones in childhood and adolescence, the researchers note. To better understand the influence of exercise on bone mass in young adults, they looked at 62 male medical students whose average age about 28, and 62 female medical students whose average age was about 25.
The amount of time the men spent each week in high-impact physical activity and being active was associated with both their bone mineral density and their bone mineral content.
But for women, the type of physical activity performed and the amount of time spent being active had no association with either bone mineral density or bone mineral content. The total body weight, however, was associated with bone mass measurement.
It’s possible the female study participants weren’t engaging in enough high-impact exercise for their bone density to be affected, the researchers note; high-impact activity averaged 1.5 hours weekly for females, and consisted mainly of aerobic workouts and gymnastics.
While exercising heavily can interrupt women’s menstrual periods, and thus affect bone health, they add, this likely wasn’t a factor because women with menstrual problems were excluded from the study.
SOURCE: International Journal of Sports Medicine, May 2007.