Exercise and Menopause: A Time for Positive Changes
Mona M. Shangold, MD, with Carl Sherman
Series Editor: Nicholas A. DiNubile, MD
THE PHYSICIAN AND SPORTSMEDICINE - VOL 26 - NO. 12 - DECEMBER 98
In Brief: Exercise may help control a number of physical and psychological problems and changes associated with menopause and midlife, including depression, weight gain, loss of muscle mass and bone density, the risk of coronary artery disease, and possibly vasomotor symptoms. The basic prescription of aerobic exercise (20 to 60 minutes 3 to 5 days per week) and strength training (2 to 3 days per week) should be adapted to the patient's medical condition, fitness level, motivation, experience, and preferences. Exercise effects can be supplemented by estrogen therapy, a low-fat diet, and adequate calcium and vitamin D intake.
Menopause and the surrounding years are times of change for women. (See "The Years Surrounding Menopause: Practical Terms for a Complex Time," below.) Hormonal alterations can produce symptoms such as hot flushes, night sweats, and vaginal dryness. General signs of aging, such as diminished strength and endurance, may become more pronounced and lead to reduced activity, increased weight, and depression. Serious health risks, such as cardiovascular disease and osteoporosis, may arouse concern.
Exercise—along with proper diet and, if advisable, hormone therapy—can help prevent or minimize many of the problems associated with menopause. Fortunately, midlife changes themselves may make women more aware of their health and more motivated to make positive lifestyle changes than they were when younger. Thus, the climacteric interval (the decade or so surrounding the cessation of menses, which occurs at an average age of 52 (1)) is an excellent time for physicians to talk to their patients about the benefits of exercise, encourage those who exercise to continue, and help those who don't exercise to begin. Positive changes at midlife can yield lasting benefits.
Effects of Exercise
A number of physical and emotional manifestations have been associated with menopause, including depression, weight gain, irritability, insomnia, and loss of concentration. However, only two—vasomotor flushes and vaginal dryness—have been shown to be due to hormonal changes (2). Exercise does not seem to influence vaginal dryness, but it does have a demonstrated or at least possible influence on many of the other phenomena associated with menopause.
Vasomotor symptoms. There is some evidence that exercise reduces reports of hot flushes and night sweats, but it is not conclusive. A controlled, cross-sectional, population-based study (3) of over 1,600 women found that sedentary women were twice as likely to report hot flushes as physically active women. Another study (4) reported a drop in the incidence of hot flushes immediately following a 45-minute aerobic workout (but not subsequently), suggesting that exercise had only an acute effect. And two cross-sectional studies (4), involving 267 active and sedentary women, suggested that exercise-related reductions in reports of vasomotor symptoms may largely reflect the effect of exercise on mood. At present there is no evidence that exercise has a lasting or consistent effect on vasomotor symptoms.
Depression. Although depression and depressive signs are actually no more common at menopause than in any other period of a woman's life (5), many menopausal women report mood disturbances. These may be related to sleep deprivation caused by hot flushes and to neurotransmitter changes associated with aging (6). Regular aerobic exercise may be helpful, and many depressed people have treated themselves, often unknowingly, by exercising regularly.
Weight gain. Though many menopausal women report weight gain, objective studies (7) suggest that body mass index actually increases at a steady rate from the third through the seventh decades of life, with no acceleration in the perimenopausal period.
What appears to influence weight gain in middle age and after is not hormonal status, but a loss of muscle mass and the accompanying decline—1% to 2% per decade—in metabolic rate (8). Caloric restriction, the centerpiece of weight-loss efforts for most women, depresses metabolism still further, often leading to frustration and failure.
Exercise is particularly helpful for middle-aged women who want to control their weight because it reverses the diet-induced reduction in metabolic rate and also increases fat-free mass. In fact, physical activity of sufficient magnitude can largely offset age-related changes in body composition. A cross-sectional study (9) of female athletes and sedentary women, aged 18 to 69, found no difference in body fat percentage and fat-free mass between the youngest and oldest athletes. In addition, the resting metabolic rate of the older exercisers was closer to that of the young athletes than to that of sedentary, age-matched women.
Research has also shown that midlife women who increase their physical activity gain the least weight and subcutaneous fat. One study (10) followed 507 women, aged 42 to 50, for 3 years. Those who were least active at baseline and those whose activity declined during the study period gained the most weight.
Muscle mass. Maintaining muscle mass with exercise can also prevent the decline in strength that affects many women in menopause and beyond. Strength training is the most effective in this regard, and ample evidence shows that 8 to 12 weeks of progressive weight training can substantially increase muscle strength in women (as well as men) aged 50 and above, even into their 90s (11).
Bone loss. More ominous than the decline of muscle mass is the loss of bone in midlife. About 80% of the 25 million Americans who have osteoporosis are women. Women's vertebral and femoral bone loss begins after about age 30, and they lose about 0.5% to 1.0% of total bone mass annually from age 40 until menopause, when bone loss accelerates. During the first 5 to 10 years after menopause, annual bone loss averages about 2%. Thus, a woman can easily lose 15% to 30% of her peak bone mass by age 60 (12,13).
Estrogen deficiency appears to be the most important cause of this bone loss. Exercise is not a substitute for hormone replacement or other pharmacologic interventions when osteopenia is marked, but it plays an important role in preventing bone loss or increasing bone density (14,15). Indeed, athletic activity has been associated with bone hypertrophy of up to 40% (16).
In one controlled study (17) of 25 women aged 49 to 61, lumbar spine bone mineral density (BMD) was significantly higher in those who jogged or played volleyball than in those who had no regular physical activity. Walking has been shown to be beneficial as well. A 12-month study (18) of more than 200 postmenopausal women found that those who walked 7.5 miles per week had a higher average BMD of the trunk, legs, and whole body than those who walked less than 1 mile each week.
Although weight-bearing exercise is usually recommended for bone maintenance, any activity that stresses the bones or skeletal muscles appears to increase bone density. Swimmers, for example, have higher vertebral bone mineral content than age-matched sedentary persons (19). However, more recent studies indicate that nonimpact exercise is not as beneficial for bone density as medium-impact (walking) or high-impact activities (volleyball). Even though swimming is better than no exercise, it should probably be augmented with strength training to have a greater effect on BMD (20).
Coronary artery disease. The risk of coronary artery disease increases with age for both men and women, but it rises abruptly in postmenopausal women because of adverse lipid and vascular changes induced by estrogen deficiency. To some extent these changes can be reversed by aerobic exercise (21). A 3-year study (10) found that the high-density lipoprotein cholesterol level of healthy middle-aged women remained unchanged in those who increased their exercise over 3 years, while it fell in those who decreased their exercise.
Population studies have generally shown a strong inverse relationship between physical activity and heart disease risk and between cardiorespiratory fitness and risk of heart disease (22). While much of this research has focused on men, the findings are generally the same for women. For example, a study (23) of nearly 1,500 38- to 60-year-old Swedish women found that those who were inactive during leisure time had a nearly threefold greater incidence of coronary artery disease than those who were active.
An 8-year study (24) of more than 3,000 women showed that an increase in aerobic capacity resulted in a decrease in the risk of death from cardiovascular disease; those in the lowest quintile had nearly 10 times the risk of those in the highest quintile. Women can achieve a significant increase in aerobic capacity with a relatively modest exercise program, such as 30 minutes of running, walking, or cycling three times a week for 20 weeks (25).
The Exercise Prescription
A prescription for exercise should be given to virtually every woman at menopause—not to address specific symptoms of hormonal changes, but to initiate or reinforce patterns for general health maintenance. These patterns are important because women who are about 50 years old and inactive will lose muscle strength, bone density, and functional capacity at an accelerated pace as the effects of disuse are added to those of aging. The longer exercise is delayed, the more difficult it will be to begin.
Basic guidelines. The basic prescription should include aerobic and strength training. Ideally, a postmenopausal woman would do 20 or more minutes of aerobic exercise—brisk walking, stationary bicycling, swimming, or rowing—7 days a week. However, following the American College of Sports Medicine's (ACSM) guidelines (26) is certainly adequate: 20 to 60 continuous or accumulated minutes of aerobic exercise 3 to 5 days per week and strength training, using free weights or machines, 2 to 3 days per week. The ACSM also recommends flexibility training 2 to 3 days per week.
Individualizing the program. No single approach, however, is right for all women. When explaining the value of exercise, it's important to focus on the concerns of the individual. If a woman wants to reduce weight, emphasize that she can lose fat much more effectively through exercise than through dieting. If correcting abnormal lipids is the goal, exercise and diet are more effective than either alone (27). If fatigue is a concern, the patient may need to be reassured that a higher level of activity will boost rather than deplete energy and strength. Women who were brought up to equate inactivity with femininity—including many in their 50s and older—may need reassurance that exercise will not make them less feminine and will enhance their health and well-being.
A daily exercise schedule isn't for everyone. Many women who do not have concrete goals (such as weight loss) are likely to prefer three aerobic sessions per week, which is sufficient to improve cardiovascular fitness and maintain bone health. A woman who has been sedentary for years will need to start with an easy program—a comfortable 15-minute walk several times a week, for example.
Patients who are beginning a new exercise program should start slowly and increase the intensity and duration gradually. Those who are unfamiliar with strength training should have help in designing a workout and supervision in performing exercises correctly—a physician's or physical therapist's office is generally less intimidating than a crowded health club. Doing too much exercise or doing it incorrectly can cause musculoskeletal injuries that will disrupt progress. In training for health and fitness, it's better to err on the side of too little rather than too much.
Discuss the program with the patient to help her choose activities that are comfortable, pleasurable, and compatible with her lifestyle. Simple, practical suggestions—such as moving a stationary bicycle from the basement rec room to the living room—may substantially improve compliance.
Hormone Replacement Therapy
A comprehensive approach to menopause demands more than exercise. Estrogen remains the best overall treatment for these patients: Hormone replacement therapy (HRT) will reduce the rate of bone loss and probably memory loss and the risk of heart disease, as well as improve sleep and relieve vasomotor symptoms. Although previous observational studies have shown that HRT reduces cardiovascular mortality rates even in women with pre-existing heart disease, a large, placebo-controlled, randomized 4-year investigation demonstrated that HRT does not prevent vascular events in women who already have heart disease (28).
Most women will benefit from HRT, although not all women need it. Women who have a uterus and are treated with estrogen therapy should also be treated with progesterone or a synthetic progestin to protect the endometrium (this is the only proven indication for progesterone currently accepted by the general scientific community). Although most women need both hormones, some need only estrogen or projesterone alone. Because of the complexity and uniqueness of each woman's hormonal status and therapeutic needs in midlife, decisions about HRT are probably best discussed with a woman's gynecologist or reproductive endocrinologist.
Exercise is not a substitute for estrogen therapy but an essential adjunct. All women in this age-group will benefit from regular exercise, and all physicians should be recommending it. It has been shown that the combination of resistance exercise and estrogen therapy leads to a greater improvement in bone density than either alone does (29). Exercise also appears to augment the effects of estrogen therapy and calcium supplementation, so diet modifications should be discussed when exercise is prescribed. Bone maintenance requires both physical activity and adequate daily intakes of calcium (1,500 mg for estrogen-deficient women or 1,000 mg for estrogen-replete women), which can come from dietary sources like dairy products or from supplements, and vitamin D (400 IU). A low-fat diet will further reduce cardiovascular risk.
Phytoestrogens. Eating a diet rich in phytoestrogens should be discouraged as a treatment for menopause. Some women who want to avoid HRT attempt to relieve hot flushes and other symptoms by consuming large quantities of foods—primarily soybean products—that contain estrogen-like compounds. The safety and efficacy of these foods, however, have not been studied sufficiently. The intake of phytoestrogens in such a regimen varies according to the food sources, and high concentrations may, in fact, be less safe than an approved pharmaceutical product, especially if progesterone is not provided for endometrial protection, as would routinely be done with HRT.
Women who intend to remain healthy, vital, and independent as they age need a well-rounded approach to health maintenance. Physicians who understand the effects of regular exercise on the physical and psychological problems of women in midlife and beyond can help them find the right balance of exercise, diet, and, if necessary, hormone therapy to achieve this goal.
The Years Surrounding Menopause: Practical Terms for a Complex Time
The meaning of the term "menopause" is clear—it refers to a woman's final menstrual period. However, the hormonal dynamics of the time surrounding menopause are complex, and the language used to describe this time is confusing.
Women between the ages of 40 and 60 are gynecologically very heterogeneous. Some are still ovulating and menstruating regularly and producing normal quantities of estrogen and progesterone. Others may bleed regularly or irregularly but have consistent or sporadic deficiencies of estrogen and/or progesterone. The remainder have ceased menstruating completely and have deficiencies of both estrogen and progesterone.
Further, in a study (1) of hormonal dynamics in the few years immediately preceding menopause, the authors showed that serum estrogen concentrations and urinary estrogen excretion tend to be higher than before or after these years, and progesterone concentrations and urinary progesterone excretion tend to be lower. While these findings may be very important in the development of gynecologic disorders (uterine myomata and abnormal bleeding, for example), their relationship to other aspects of midlife health, such as cardiovascular disease and bone loss, remains unclear. (The complex endocrinology of the perimenopause is beyond the scope of this article, but more information is available in a comprehensive and eloquent review (2).)
The World Health Organization (WHO) has recommended (3) the use of the term "perimenopause" to refer to "the period immediately before the menopause (when the endocrinological, biological, and clinical features of approaching menopause commence) and the first year after menopause." The WHO defines "menopausal transition" as "only the portion of the perimenopause before the final menstrual period."
These definitions, however, are impractical because they can be applied only in retrospect. A woman does not know that a menstrual period is her last until she fails to have another. An entire year must pass before she can be considered definitely postmenopausal.
Given this impracticality and the complex ovarian hormonal changes and gynecologic heterogeneity of 40- to 60-year-old women, "perimenopause" and "menopausal transition" are not used in the accompanying article. Instead "midlife" and "climacteric" are used interchangeably to refer to years immediately before and after menopause, in most cases covering the age range from about 40 to 60 years.
Dr Shangold is director of The Center for Women's Health and Sports Gynecology in Philadelphia. She is a fellow of the American College of Sports Medicine and the American College of Obstetricians and Gynecologists. Mr Sherman is a freelance writer in New York City. Dr DiNubile is an orthopedic surgeon in private practice in Havertown, Pennsylvania, specializing in sports medicine and arthroscopy. He is the director of Sports Medicine and Wellness at the Crozer-Keystone Healthplex in Springfield, Pennsylvania; a clinical assistant professor in the department of orthopedic surgery at the University of Pennsylvania in Philadelphia; the orthopedic consultant to the Philadelphia 76ers basketball team and the Pennsylvania Ballet; and a member of the editorial board of The Physician and Sportsmedicine. Address correspondence to Mona M. Shangold, MD, 1601 Walnut St, Ste 1200, Philadelphia, PA 19102.
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