There is a common conception that osteoporosis only affects older women. For that reason, much of the preventive measures to protect against the condition -- things like weight lifting or consuming sufficient levels of calcium – are targeted to women. But osteoporosis, which is characterized by weakening bones due to thinning and increased porousness of bone tissue, affects about 20 percent of men over the age of 65.
Now, a new study reveals that young men can also use exercise to substantially increase their bone mass, which may in turn protect against osteoporosis later in life.
"Men who increased their load-bearing activity from age 19 to 24 not only developed more bone, but also had larger bones compared to men who were sedentary during the same period," said senior study author Dr. Mattias Lorentzon of the University of Gothenburg, in a statement.
In the largest study of its kind, Lorentzon and his team followed 833 Swedish men, who were 18- to 20-years old at recruitment, for a five year period. The researchers initially measured bone mass using scans and asked the study participants about their exercise habits. Then, after five years, they again completed bone scans and followed up about study habits.
They found that men who participated in load-bearing sports continuously during the entire period -- or who took up a load-bearing sport habit during the five year study -- faired better than those who were either sedentary from the start or who grew sedentary during the course of study. Those who participated in low-impact sports like swimming and bicycling saw other health benefits, but didn't have comparable bone-building results to the group of load-bearing athletes.
The term “load-bearing” refers to high impact sports that include quick starts and stops, jumping and other activities that require the body to bear weight down on the bones. That sort of movement forces young bodies to generate new bone tissue, increasing bone mass, said the researchers. They found that basketball and volleyball were the most strongly associated with increased bone mass, followed closely by tennis and soccer.
The greater the amount of exercise, the more substantial the results. For every added hour of physical activity per week, the study participants enjoyed an increase in bone mass. For example, reported the researchers, those who completed four or more hours of load-bearing exercise per week had a 1.3 percent increase in hip bone mass. By contrast, sedentary counterparts had a 2.1 percent decrease in mass.
The study was published in the Journal of Bone and Mineral Research.