A common concern amongst many women is how their hormones affect their exercise training and diet. Women’s bodies are influenced by fluctuations in hormones not only throughout the normal monthly reproductive cycle, but also throughout their entire lives. Both men and women experience a significant change in hormones at the onset of puberty and sexual maturation. For the remainder of their lives, men normally have less significant fluctuations in their sex hormone levels until approaching middle age. Studies document a gradual decline in sex hormones past the age of 40 years. Women, however, may see great fluctuations in sex hormone levels throughout their adult lives depending on physiological state, contraceptive methods, and menopause.
There are many physiological dysfunctions that may affect sex hormones levels, and to address these issues is far beyond the scope of this present column. Women that feel they may have abnormal hormone levels should consult with a competent physician or endocrinologist. Nevertheless, many women are prescribed hormones for contraceptive purposes or for hormone replacement therapy. Can hormone therapy affect exercise and the female athlete? Let’s find out.
Because many contraceptive methods and menopause therapies influence a woman’s hormonal milieu, both will be addressed here and are referred to as ‘hormone therapy.’ First, let’s briefly look at some of the hormone preparations, their components and the different routes of administration. Then we will discuss the implications they have relative to training and diet.
Sex hormones are not created equal
Throughout the month, a woman’s estrogen and androgen hormone levels vary in a complex dance of spikes, dips and feedback loops to ultimately regulate the reproductive system. As women age, this regulation system quietly changes and women enter menopause, accompanied by a significant decline in estrogen production and estrogen: androgen ratio. Historically, women shoulder the major responsibility of birth control and child rearing. With the advent of pharmacological developments, women now have the ability to exercise more control of their reproductive choices and to alter the side effects that often accompany menopause later in life.
Rather than writing an entire article devoted to the pharmacology of hormone therapy, a summary is presented. The two most commonly manipulated sex hormone levels in a woman’s body are estrogen and progesterone. These hormones are typically associated as ‘female hormones,’ although they are present in men as well albeit at lower levels. However, both contraceptive and menopause hormone therapies may involve androgens or hormones with some androgenic activity, as well as the estrogenic and progestational components.
Several formulations and preparations of hormone therapy are available with varying composition and hormone activity. Both contraceptive and replacement therapies may combine variable dosages of estrogen and progestins with different efficacy and side effects. A new generation of hormone therapy, called ‘phasic’ agents, are designed to deliver estrogen and progestin components in a physiological manner and to decrease the total amount of hormones given during a cycle. In these preparations, the estrogen and progestin ratios will change during the cycle in attempt to mimic the natural ratios in the body. It is this combination of different estrogens and progestins in varying dosages that results in a broad range of hormonal effects: estrogenic, progestational and androgenic.
As we would suspect, the dosage of estrogen greatly influences the degree of estrogenic activity. Conversely, the degree of progestational potency and androgenic activity is related to the particular progestin and its dosage in the formulation. Quite often, the progestin determines the cardiovascular and metabolic side effects of the formulation.
The most popular route of hormone therapy is traditionally by oral administration. When administered orally, our bodies’ natural hormones are easily degraded in the intestinal tract and rapidly metabolized in the liver. Therefore most oral hormone therapies are formulated with compounds (hormones) that are structurally altered to avoid rapid degradation and metabolism. Unlike the progestins, estrogens have relatively similar potency and efficacy. Progestins are derived from progesterone and 19-nortestosterone and therefore differ in their progestational, antiestrogenic and androgenic activities. Consequently, the side effects associated with combination-type hormone formulations can be attributed to the dosage of estrogen, and dosage and type of progestin.
Many of the side effects that are reported with combination-type formulations can be attributed to the balance between the estrogenic and progestational effects. Adverse effects may reflect excess or a deficiency of estrogen or progestin. Some common side effects reported are breast tenderness, water retention, noncyclic weight gain, and acne. Although the benefits of oral contraceptives for women are obvious, current debate in the medical literature centers on benefits and side effects of hormone replacement therapy for postmenopausal women.
Many studies document changes in carbohydrate metabolism and body composition in women during hormone therapy. Recent literature claims that these changes are not as evident in women who use transdermal (either patches or dermal ointments) administration versus those who use oral formulations. Oral hormone therapy is known to produce significant effects on liver function with accompanying shifts in cholesterol levels and insulin sensitivity. Depending on the oral formulation, women may experience a rise in bodyfat and possibly a decrease in muscle mass. Lipid levels may also be influenced by oral hormone therapy with a rise in triglyceride levels and possibly LDL (the ‘bad’ cholesterol) concentrations. Although many studies demonstrate that combination-type oral hormones produce cardiovascular and hematological (blood clotting) effects, recent studies refute this. As well, oral hormones may worsen hypertension and increase risk of stroke, especially in women over 35 years of age.
How does hormone therapy affect diet?
Some side effects noted with some hormone therapy are increased appetite, weight gain and water retention. Undoubtedly, weight gain in women on hormone therapy is dependent upon the formulation used and predisposing conditions. Many women report gains in body weight or body fat, many do not. The research literature follows suit: some studies report weight gain, shifts in body composition, and some report no such changes. Nevertheless, changes in carbohydrate metabolism are well established in women taking oral contraceptives. Formulations with the more androgenic progestins are more likely to cause increases in glucose levels and insulin resistance than formulations with less androgenic progestins. As well, oral estrogen resulted in an increase in body fat mass and a decrease in lean mass in postmenopausal women. Similar changes are not seen in women using transdermal administration.
Oral hormone therapy with androgenic progestins may be responsible for the changes in carbohydrate metabolism, although one study has shown that oral estrogen reduced fat metabolism after a mixed meal. These effects are attributed to changes in liver function caused by oral hormones and are less when non-oral hormones are used, such as transdermal patches. Consequently, women receiving oral hormone therapy (depending on the formulation) may not be able to reduce body fat levels by dieting as readily as women who do not use oral hormones.
Although there has been no research providing any specific evidence, a diet lower in carbohydrates than the typical American diet may hinder the insulin resistance that can occur with oral hormone use. Since the average woman typically eats a diet low in protein, increasing dietary protein may help prevent the loss of lean body mass that is sometimes reported with hormone therapy. Women athletes on hormone therapy should ensure their daily protein intake is adequate considering their daily requirements are higher. Not surprisingly, some studies have shown that combined dietary and exercise intervention lowered serum cholesterol in women on hormone therapy. Although not demonstrated specifically in the literature, such a combined intervention strategy would most likely prevent insulin resistance as well.
How does hormone therapy affect exercising?
When a woman is placed on hormone therapy (for whatever reason), she should discuss with her physician if there is any contraindication in her exercising program. Some of the studies have noted changes in electrocardiographs during exercise tolerance tests in women who are taking estrogen. As well, women who are predisposed to hypertension may be advised to closely monitor their heart rate during aerobic/cardio exercise. Although little research investigates other hormonal changes during sex hormone therapy, some studies report a high association of low back pain with women receiving hormone therapy. Authors speculate that hormonal effects on joints and ligaments may be involved and could have implications in heavy weight lifting.
Some women typically experience varying degrees of breast tenderness during part of the hormone therapy cycle. These women are encouraged to provide good breast support by wearing a well-constructed sports bra. For small to average sized breasts, a well-fitting bra that constricts movement of the breasts while exercising should reduce breast soreness. Women with large breasts may have to search for specialty sports bras that provide support in all directions (underneath, diagonally and upper) for comfort. Restriction of breast movement, especially during aerobic exercising, will reduce exercise-associated breast soreness during these times.
Ultimately, hormone therapy does not affect how a woman should exercise as much as it increases the importance of exercise. Few studies assess if the reported changes in lean body mass affect physical fitness and strength. Considering the reports of increased lipid profiles and reduced insulin sensitivity in women receiving hormone therapy, exercise may modulate these effects. Several studies have shown that exercise, both resistance training and aerobic, reduce many of the side effects previously mentioned. Since resistance training increase glucose transport and insulin sensitivity in muscle tissue, we could safely speculate that it might be employed to help prevent the increase in body fat that sometimes accompanies use of hormone therapy. As well, resistance training may have an additive effect on preserving bone mineral density, thereby reducing risk of osteoporosis in later life.
Endurance training has been shown to lower lipid levels and reduce body weight in overweight women on hormone therapy compared to women who do not train at all. However, the weight loss included lean body mass as well as body fat. Resistance training, in addition to endurance training, helped preserve lean body mass (both bone and muscle mass) in a similar group of women. Whether resistance training alone would produce the same reductions in both body fat and serum lipid levels has not been investigated. Consequently, it may be prudent to incorporate both aerobic and weight lifting in an exercise program for a woman on hormone therapy to control weight gain and increased lipid levels.
Living and exercising with hormone therapy
As discussed, hormone therapy may induce shifts in normal metabolic functioning such as favoring higher serum lipid levels and bodyfat accumulation. Women are encouraged to inquire as to what their hormone therapy formulations consist of, what side effects they may produce, and what their alternatives are if they are dissatisfied with their current therapy.
Exercise becomes increasingly important during hormone therapy to modulate any changes that may occur. As well, women should be aware of the shifts in appetite, lipid levels, water and body weight so that they can control changes before or as they occur rather than wait several months or years later, when it may become more difficult to reverse them. Also be aware of new patterns of connective tissue soreness or pain so that changes in weight lifting can be instituted to protect against possible injuries. Hormone therapy can provide many benefits if you educate yourself on what is available to you and how to minimize the side effects. It’s your body; listen to it and treat it well.