Exercise and Women's Health

Some of the top ten leading causes of death in women are chronic diseases modifiable by behavior such as exercise participation. Evidence of the benefits of exercise for women’s health is strong. Exercise can assist in the prevention of cardiovascular disease, diabetes, depression, hypertension, and some cancers. However, women continue to be inactive at rates that increase their risk for chronic illness. To improve women’s health, a concerted effort between professionals of all health disciplines is necessary to encourage women of all ages and ethnicities to increase their engagement in exercise participation.

EXERCISE CAN CONTRIBUTE TO QUALITY OF LIFE AND OVERALL HEALTH AND WELL-BEING OF WOMEN

There is ample empirical evidence that a regular physical activity (PA) regimen can assist in the prevention of many chronic diseases such as cardiovascular disease (CVD), diabetes, depression, hypertension, osteoporosis, and some cancers (Farag et al., 2010; Warburton, Nicol, & Bredin, 2006). Four of the top ten leading causes of death in women are chronic diseases that could be modified by behavior such as participation in physical activity. Decreasing the burden associated with chronic diseases would increase quality of life of those affected (Ahmed et al., 2011; Wang, McPherson, Marsh, Gortmaker, & Brown, 2011). In fact, one of the new goals set for Healthy People 2020, the initiative that sets goals and objectives for health promotion and disease prevention in the United States, is to improve health-related quality of life and well-being of all individuals (United States Department of Health and Human Services [HHS], Healthy People 2020, 2011). Exercise could contribute to reaching this goal.

Williams et al. (2007) showed that participation in regular PA increased bone mineral density, decreased body fat percentage, and increased muscular strength. Other benefits of PA include decreased basal insulin levels while increasing insulin sensitivity (Macias-Cervantes, Malacara, Garay-Sevilla, & Díaz-Cisneros, 2009); it also decreases fasting insulin in expecting mothers (Liu, Mayer-Davis, Pate, Gallagher, & Bacon, 2010). Furthermore, there is evidence that high density lipoprotein (HDL) is increased while low density lipoprotein (LDL) is decreased as a result of exercise participation (Wise, 2010). However, despite the numerous health messages highlighting the importance of PA, based on Leisure-Time Aerobic Activity from the 2011 National Health Interview Survey, 55.4% of women 18 years and older do not meet the PA guidelines for aerobic activity, which recommends the accumulation of 150 minutes of moderate or 75 minutes of vigorous activity per week (HHS, 2008).

LEADING CAUSES OF DEATH

According to the Centers for Disease Control and Prevention (CDC, 2012b), in 2010, the leading causes of death among women of all races was heart disease (23.5%), followed by cancer (22.1%) and strokes (6.2%). What follows is a brief discussion of the positive effect of exercise on cardiovascular disease, hypertension, blood lipid profile, and cancer in women.

CARDIOVASCULAR DISEASES

In a review of the effects of PA and CVD in women, Oguma and Shinoda- Tagawa (2004) found an association between PA participation and a reduced risk of CVD in women. Oguma and Shinoda-Tagawa noted accumulation of 60 minutes of walking per week is sufficient to reduce the risk of CVD among women. This dose-response relationship was also reported by others. Li and Siegrist (2012) conducted a review of studies spanning 30 years, from 1980 to 2010, on the relationship between PA and incident of CVD. The sample size was over 650,000 which included nearly 130,000 women. The authors looked at leisure time PA as well as moderate occupational PA. Among women, for the group with a high level of leisure time of PA, the relative risk (RR) of overall CVD was 0.73 (p<0.0001, 95% CI [0.68-0.78] compared to the group with a low leisure time of PA (Li & Siegrist, 2012). As well, Li and Siegrist reported a reduction of overall risk of coronary heart disease and stroke of 10 to 20% in women. 

For occupational PA, the relationship was strong, but not statistically significant, with RR of 0.83 (p= .089, 95% CI [0.67–1.03]) for women with a moderate level occupational PA compared to the group with a low occupational PA (Li & Siegrist, 2012). Similar results regarding intensity of PA for women was reported by Diep, Kwagyan, Kurantsin-Mills, Weir, and Jayam-Trouth (2010). Diep et al. (2010) reported a reduction of risk by 24% for women participating in high levels of PA groups (RR = 0.76, CI 0.64-.89, p < 0.01); however, the risk of reduction related to moderate PA level was not statistically significant for women. One of the limitations of these reviews was the self-reported nature of the data and the diverse methods used to measure and classify PA in low, moderate, and high categories (eg: average frequency of activities; average frequency combined with duration of activities; combination of frequency, duration, and intensity of activities). Li and Siegrist (2013) only used data collected by objective measures to categorize occupational and leisure-time PA while Diep et al. (2010) used self-reported data.

Nonetheless, Sofi, Capalbo, Cesari, Abbate, & Gensini (2008) indicated health benefits of PA are not compromised even though PA data obtained by self-report lack validity compared to measured data.

The take home message for health professionals who devise PA interventions for women is that they must ensure the programs they develop reflect the appropriate intensity to elicit cardiovascular health benefits for women. This could be done by using metabolic equivalent of tasks (MET). One MET is equivalent to using 3.5 ml of O2/Kg/min (Jetté, Sidney, & Blumchen, 1990). Exercising at moderate intensity reflects utilizing between 3 and 6 METs (eg., brisk walking, shovelling snow, and cycling). Activities that require utilization of 6 METs or more are categorized as vigorous intensity (eg., jogging, cross-country skiing, and weight lifting; Jetté et al., 1990). It would seem appropriate to give women a list of examples of activities and their associate intensity coupled with the recommended guidelines of PA for optimal health which are a minimum of 150 minutes of moderate or 75 minutes of vigorous intensity PA each week (HHS, 2008).

HYPERTENSION

Blood pressure levels are categorized as normal (systolic <120mmHg, diastolic 80mmHg), prehypertensive (120 mmHg < systolic < 139 mm Hg; 80 mmHg < diastolic < 89) mm Hg) or high (systolic >140mmHg, diastolic > 90mmHg. The risk for stroke and heart disease increases in those who are hypertensive (Wassertheil-Smoller et al., 2000). 

According to the CDC (2012a) 32.7% of American women live with hypertension. The rates vary by ethnicity with the highest rates found in African American women (45.5%), followed by European American women (31.3%) and Mexican American women (28.9%) (CDC, 2012a). In all ethnicities combined, the highest rates are found among older women, 53.3% for those aged 55- 64 years, 69.3% and 78.5% for those aged 65-74 years and 75 years and older, respectively (CDC, 2012a). In pregnancy, 10% of women are affected by hypertension which is a leading cause of illness and even death in both mother and fetus (Garovic & Hayman, 2007).

As seen, a regular PA regimen is beneficial for reducing the risk of CVD in women. The same benefits were found for the risk of hypertension. As previously discussed, African American women have disproportionately higher rates of obesity and physical inactivity than their European counterparts which put them at higher risk of elevated blood pressure (Staffileno, Minnick, Coke, & Hollenberg, 2007). An 8-week home-based intervention with 24 African American women (N = 14 experimental, N = 10 control) aged 18 to 45 years resulted in an inverse association between participation in lifestyle PA and systolic blood pressure (r = -0.620, p = .024) (Staffileno et al., 2007). On average, systolic blood pressure was reduced by 6.4 mm Hg, and diastolic went from 90.8 to 87.4 mm Hg (Staffileno et al., 2007).

The importance of appropriate diet for those with hypertension cannot be understated. Nearly a decade ago, a modified lifestyle that included weight loss and regular aerobic exercise was recommended by the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC; Chobanian et al., 2003). In their seventh report, the JNC recommended individuals include fruit and vegetables as well as food rich in fibers and low in fat, including low-fat dairy products (Chobanian et al., 2003). The Dietary Approaches to Stop Hypertension (DASH) has been proven to be an effective means to reduce blood pressure (Conlin et al., 2000). However, with regard to blood lipid profile, exercise is an important component of interventions focusing on helping women achieve appropriate blood lipid levels. 

Blood Lipid Profile

Women with high levels of blood lipid profile such as high levels of LDL and triglycerides are at increased risk of heart disease compared to those with normal levels of blood lipid profile (Collins, 2008). Although higher levels of HDL have a protective effect against the risk of heart disease, those levels decline after menopause due to the decline in estrogen (Collins, 2008). PA, more specifically aerobic exercise, has proven to have beneficial effects in the management of blood lipid profile. To illustrate, Blumenthal et al. (2010) conducted an intervention that used DASH alone, DASH combined with PA and caloric restriction, and usual diet controls. Blumenthal et al. (2010) reported a decreased level of glucose, better sensitivity to insulin, and lower levels of total cholesterol and triglycerides in participants in the combined group of DASH and PA and caloric restriction compared to those in the DASH diet alone and the usual diet controls groups. In addition, the PA group had lower level of LDL cholesterol and lower fasting glucose than the participants in the usual diet controls group (Blumenthal et al., 2010). These results are promising given the supervised exercise consisted of three 30-minute sessions per week at intensity levels varying from 70% to 85% of heart rate reserve (Blumenthal et al., 2010).

When discussing heart health with women, health professionals could leverage the small weekly volume of aerobic exercise needed, notably 90 minutes, to elicit some positive changes in blood lipid profile. In addition, it has been shown that aerobic exercise can be accumulated in increments of 10 minutes to meet the recommended guidelines (HHS, 2008). Tackling a shorter duration of exercise per session may be more palatable to the new exerciser. During pregnancy, the American College of Gynecologists (ACOG) recommends accumulating at least half an hour of exercise daily at moderate intensity for healthy pregnant women (ACOG, 2003). In some situations, such as persistent second- or third-trimester bleeding or preeclampsia/pregnancy- induced hypertension, aerobic exercises are not recommended. In fact, The ACOG lists several conditions during which aerobic exercise participation is contraindicated. Moreover, there are certain warning signs that demand complete cessation of all types of exercise. Sharing the ACOGguidelines with expecting mothers should be on the checklist of all childbirth educators (ACOG 2003).

CANCER AND EXERCISE

Several factors are contributing to the continuing rise in the prevalence of cancer in the United States. Indeed, factors such as growth in the aging population and early detection (Siegel, Naishadham, & Jemal, 2012) translate to more cancer survivors. The probability of women receiving a cancer diagnosis in their lifetime is 38% (Siegel et al., 2012). However, although most cancers are diagnosed in individuals aged 65 and older (Rowland, 2008), according to the American Cancers Society breast cancer tends to be diagnosed at a younger median age than other cancers (Siegel, 2012). Thus, there is a higher probability of women receiving a diagnosis of breast cancer prior to the age of 60. In addition, Siegel et al. (2012) reported African American women have a lower incidence rate (6%) but a higher death rate (16%) than European American women.

Evidence shows exercise can help reduce the risk of cancer recurrence (Holmes, Chen, Feskanich, Kroenke, & Colditz, 2005; Meyerhardt et al., 2006). For example, Holmes et al. (2005) conducted a study of 2987 registered nurses diagnosed with cancer between 1984 and 1998. There was an unadjusted reduction of mortality risk of 6% at 10 years for survivors who walked nine or more metabolic equivalent of task (MET)-hours compared with those who walked less than three MET-hours. Holmes et al. (2005) defined three MET-hours as walking for one hour at a speed averaging between 2 to 2.9 miles per hour. In another study, Meyerhardt et al. (2006) found recreational exercise post stages I to III colorectal cancer diagnosis may reduce mortality specific to colorectal cancer. Meyerhardt et al. (2006) compared pre- and postdiagnosis value for women (N = 573) who increased their engagement in exercise. 

The results showed colorectal hazard ratios of 0.48 (95% CI [0.24-0.97]) and 0.51 (95%, CI [0.30- 0.85]) for colorectal cancer deaths and any-cause death, respectively, for women who increased their exercise activities compared to those who did not change their activity regimen (Meyerhardt et al., 2006). In addition, exercise was shown to have a positive effect on rate of infection, rate of recurrence, and overall survival of solid tumor patients (Bellizzi et al., 2009, Elter et al., 2009; Holmes et al., 2005; Meyerhardt et al., 2006).

When counselling women cancer survivors, it will be important to share the positive effects of being physically active, even though it may seem a surmountable task when one has to deal with the debilitating effects of cancer treatment. Consistently, research has shown exercise has some physical and psychological benefits for survivors at all stages of cancer (Courneya & Friedenreich, 2007).

EXERCISE, WOMEN’S HEALTH, AND PREGNANCY 

Physical activity participation to improve health is also important for women who are planning on becoming pregnant. Optimum health prepregnancy will aid in managing the changes that occur not only during pregnancy but also after pregnancy. For example, according to the American Diabetes Association, exercise is beneficial in the management of gestational diabetes when diet alone cannot normalize blood glucose levels (Jovanovic-Peterson, & Peterson, 1996). In addition, exercise participation has been linked to prevention and reduction of depression in early pregnancy (Downs, DiNallo, & Kirner, 2008) and postpartum (Daley, Macarthur, & Winter, 2007). Once cleared for exercise by their physician expecting mother should modify their exercise regimen to conform to the revised guidelines for exercise during pregnancy and the postpartum period developed by the American College of Obstetricians and Gynecologists.

In the industrialized world, the most frequent cause of death during pregnancy is cardiovascular disease partly because advancements in medicine have increased the number of women of reproductive age with this disease (Nickens, Long, & Geraci, 2013). According to the American Heart Association, among nonpregnant women, those aged 20 to 39 years had a prevalence of cardiovascular disease of 10.1% which tripled to 34.4% for women aged 40 to 59 years Go et al. (, 2013). In addition, the increased number of women with compromised blood lipid profiles, diabetes, obesity, and hypertension has contributed to a larger number of women who enter pregnancy with heart disease or develop the condition while pregnant (Nickens et al., 2013). For ex.ample, Nickens reported the 4% of expecting mothers may experience complications due to cardiovascular disease. 

CONCLUSION

As seen, the evidence of the benefits of exercise for women’s health is strong. However, women continue to be inactive at rates that increase their risk for many chronic diseases which can negatively impact their childbearing years. An active lifestyle should start in early life and continue throughout adulthood As a pathway to increase women’s health before, during, and after pregnancy, a concerted effort between professionals of all health disciplines is necessary to encourage women of all ages and ethnicities to increase their engagement in exercise participation as a preventive measure to reduce the risk of chronic diseases associated with inactivity.

– references available on request. 

-This article was originally published in the International Journal of Childbirth and Education, and in the Fitness Informer, July, 2017