Short-term Aerobic Exercise with and without a Weighted Vest: What’s the Effect on Bone Metabolism?

Researchers from Iran recently published on article called “Effects of short-term aerobic exercise with and without external loading on bone metabolism and balance in postmenopausal women with osteoporosis.”  It was published online (ahead of print) on March 24, 2012, and it will soon appear in the journal Rheumatology International.
The researchers’ goal was to determine the effect submaximal aerobic exercise (with and without external loading) had on bone metabolism and balance.  They were looking specifically at postmenopausal women with osteoporosis. 

There were 36 women in the study; all joined voluntarily and were sedentary and postmenopausal.  The researchers randomly divided them into 3 groups:

• Aerobic exercise group
• Aerobic exercise with weighted vest group
• Control group

This was a 6-week study.

For both the aerobic exercise and aerobic exercise with weighted vest groups, they did 18 sessions of submaximal treadmill walking—30 minutes daily, 3 times a week.  The weighted vest was 4% to 8% of a subject’s body weight.

The control group did no aerobic exercise.

Before and after the 6 weeks, body composition, bone biomarkers, bone-specific alkaline phosphatase (BALP), N-terminal telopeptide of type 1 collagen (NTC), and balance (Near Tandem Stand [NTS]; Star-excursion [SE]) were measured by the researchers.

For the weighted-vest group, fat decreased (p = 0.01) and fat-free mass increased (p = 0.005) significantly after the 6-week exercise program.

Both aerobic exercise groups experienced a significant increase in BALP (p ≤ 0.05); they also both saw a significant decrease in NTX (p ≤ 0.05).

There was a difference in post-study NTS results for the 2 aerobic exercise groups versus the control group:  the NTS increased in the exercise groups, but it decreased in the control (aerobic exercise group:  + 49.68%; aerobic exercise with weighted vest group: + 104.66%; control group: - 28.96%).

Also in the effect on balance, a significant increase in SE values (for all directions) was seen in the weighted vest group.

In conclusion, this study showed that aerobic exercise stimulates bone synthesis and decreases bone resorption in postmenopausal women with osteoporosis.  If an osteoporotic postmenopausal woman wears a weighted vest during aerobic exercise, her balance can also improve.