Exercise Plus Calcium Keeps Bones Strong
Density can sometimes be improved, Arizona study finds
MONDAY, Sept. 29, 2003 (HealthDayNews) -- Women who have quit hormone replacement therapy (HRT) often worry about losing the protective effect that estrogen had on their bone density.
But a new study suggests that getting regular weight-bearing and resistance exercise and taking plenty of calcium can help maintain bone density, at least in the hip, without taking HRT.
Researchers looked at the effect of exercise and calcium in two populations of women, those already on HRT and those who were not, says study author Timothy Lohman, a physiology professor at the University of Arizona.
"So we weren't evaluating the HRT but the exercise, and we found it was effective in both groups, that exercise and calcium together can be effective," he says.
The effects on bone were better with HRT, especially in the spine area, Lohman concedes, but adds, "in the hip area, it looks good just with exercise and calcium."
When the Women's Health Initiative was halted last year after unacceptably increased risks of breast cancer and heart attack were found among women on HRT compared to those not on the regimen, many women decided to discontinue the daily treatment and many others opted not to start it.
But one potential downside was losing the known protective effect estrogen has on maintaining bone density and decreasing the risk of osteoporosis, the gradual loss of bone density that can lead to fractures of the hip, spine and wrist.
In the Arizona study, known as The Bone, Estrogen and Strength Training (BEST) study, researchers evaluated 159 women who were on HRT and 161 who had not used it, dividing those two groups into an exercising group or a non-exercising group, for a total of four groups.
The exercise regimen, done three days a week, included 20 to 25 minutes of resistance training, two sets of six to eight repetitions, with six exercises. They include back extension, leg press, squats, the lateral pulldown, dumbbell press and seated row.
Women also did seven to 10 minutes of cardiovascular weight-bearing activity, such as jumping rope, jogging or skipping, during each session.
All women took a total of 800 milligrams of calcium citrate daily, with two pills spaced at least four hours apart.
Those who took HRT, calcium and who exercised increased their bone density in more body sites, increasing it by 1 percent to 2 percent in the hip and spine, Lohman says.
Bone density in the hip also increased about 1 percent in those who exercised and took calcium but didn't take HRT, according to the findings, which were published recently in the journal Osteoporosis International.
"HRT was critical for improving spine bone density, but not hip density," says Linda Houtkooper, another member of the research team. And, she stresses, it was the combination of both types of exercise and getting calcium from both food and supplements that appeared critical.
As a woman ages, just keeping the bone mass she has can be good news. "If a woman in her 50s can just maintain her bone mass, she goes a long way toward warding off osteoporosis," Lohman says.
"Exercise helps you whether you are on HRT or not," he adds.
The study "confirms what we have known," says Dr. Robert P. Heaney, a veteran osteoporosis researcher at Creighton University in Omaha. "It shows that if you exercise and are given adequate calcium and are on hormones, you will preserve bone."
He views the preservation of bone as a "three-legged stool. One is hormones, one is nutrition, one is exercise."
"I think hormones are still important," Heaney adds, although he recommends that estrogen be given by patch rather than orally to preserve bone after menopause.
Women who use weight-training must progress to heavier weights to achieve the benefit, Lohman says. And he advises them to check in first with their doctor and with a physical therapist. The physical therapist can alert them to any physical limitations and instruct them in how to do the exercises.
Lohman also recommends that all women get a baseline bone density test in their 40s or 50s, then repeat it annually, even if their insurance won't pay for it.
Depending on age, a daily calcium intake of 1,000 to 1,300 milligrams is recommended, according to the National Osteoporosis Foundation. If women have trouble taking in that much from calcium-rich foods such as dairy products, supplements are recommended.
The BEST study was funded by the National Institutes of Health and Mission Pharmacal provided the calcium supplements.