Abstract
Background Menopausal symptoms can affect women's health and wellbeing. It is important to develop interventions to alleviate symptoms, especially given recent evidence resulting in many women no longer choosing to take hormone replacement therapy. Exercise may prove useful in alleviating symptoms, although evidence on its effectiveness has been conflicting.
Aim To examine the association between exercise participation, body mass index (BMI), and health-related quality of life in women of menopausal-age.
Design of study Survey of women of menopausal age.
Setting West Midlands, England.
Method Women aged 46–55 years (n = 2399) registered with six general practices in the West Midlands were sent a questionnaire containing items relating to demographics, lifestyle factors, weight, height, exercise participation, menopausal bleeding patterns, and health-related quality of life (including vasomotor symptoms).
Results One thousand two hundred and six (50.3%) women replied. Women who were regularly active reported better health-related quality of life scores than women who were not regularly active (P<0.01 for all significant subscales). No difference in vasomotor symptoms was recorded for exercise status. Women who were obese reported significantly higher vasomotor symptom scores than women of normal weight (P<0.01). Women who were obese reported significantly higher somatic symptoms (P<0.001) and attractiveness concern scores (P<0.001) than women of normal weight or those who were overweight.
Conclusion The data suggest a positive association between somatic and psychological dimensions of health-related quality of life and participation in regular exercise. Women with BMI scores in the normal range reported lower vasomotor symptom scores and better health-related quality of life scores than heavier women. Further evidence from high-quality randomised controlled trials is required to assess whether exercise interventions are effective for management of menopausal symptoms.
INTRODUCTION
A high proportion of middle-aged women will experience vasomotor symptoms, such as hot flushes, due to changes in endogenous hormone levels.1 Flushes and night sweats are of concern to women, and they can also disrupt sleep patterns and alter daily activities, which can lead to fatigue, irritability, and decreased quality of life.2 Interventions that help women through the menopausal phase of their lives, such as engagement in regular exercise,3 are important for improving symptoms.4
The extent to which exercise may have a positive impact on vasomotor symptoms and subsequent quality of life in women who are menopausal is not known, although there are reasons for assuming that exercise may be useful. General population trials and reviews5,6 have found exercise to have a positive effect on menopausal-related health outcomes related to cognitive functioning, depression, sleep patterns, bone density, and cardiovascular diseases.
With a few notable exceptions,7,8 observational studies designed to address the association between exercise and menopausal symptoms have included small samples and have taken place before the availability of new evidence linking hormone replacement therapy (HRT) with adverse events. Several observational studies7–10 have been supportive of a positive relationship between exercise, vasomotor symptoms, and health-related quality of life in women of menopausal age, but findings have not always been consistent; several studies have reported no associations11 or mixed findings.12 Trials13,14 have examined the effects of exercise interventions on vasomotor symptoms but these have been of low quality, women with atypical presentations, and contained several methodological flaws and/or small samples, thus limiting the reliability of their conclusions.
Contradictory evidence exists regarding the effect of body mass index (BMI) on menopausal symptoms, particularly hot flushes. Some studies have reported that heavier women are at increased risk of experiencing hot flushes,8,15 whereas others have reported the opposite effect or no association.2,16 In terms of potential explanations, a high BMI implies greater amount of adipose tissue which converts adrenal androgens to oestrogens. This may, in turn, alleviate symptoms. In this way, exercise may increase vasomotor symptoms by reducing adipose tissue.
Other authors17,18 have proposed that exercise, (which theoretically should lower BMI), may have a similar effect to HRT in the amelioration of vasomotor symptoms by increasing the presence of peripheral serum levels of ß-endorphins, and by stabilising the thermoregulatory centre, thereby reducing symptoms. These conflicting studies highlight the need for additional research.
Menopausal symptoms can affect women's health and wellbeing. Although HRT remains the most effective treatment for menopausal symptoms, acceptance and long-term continuation of HRT use is low.19 This has been the case, particularly since the publication of studies highlighting that HRT may be linked to an increased risk of particular diseases, including certain cancers.20–22 It is important, therefore, to investigate alternative interventions to alleviate these symptoms, such as exercise.
The primary aim of the study was to examine the simultaneous association between exercise participation, BMI, health-related quality of life, and vasomotor symptoms in women aged 46–55 years.
RESULTS
Characteristics of the study population
An overall response rate of 50.3% (1206/2399) was obtained. A further 26 questionnaires were not completed and therefore not included in the analyses. The mean age of responders was 50.5 years (standard deviation [SD] = 2.8), of whom approximately half were post-menopausal with the remainder being pre- or peri-menopausal. The sample was predominately white (90.2%), with low alcohol consumption and did not smoke. Only 11.8% reported using HRT: 5.5%, 6.9%, and 17.7% in pre-, peri-, and post-menopausal women, respectively. Approximately half the sample was considered overweight or obese (Table 1). A total of 59.2% of the sample was categorised as not regularly active and 40.8% as regularly active.
Table 1 Prevalence statistics for demographics according to exercise status.
Preliminary analyses
Multivariate effects were significant for menopausal status (F[7,1040] = 7.23, P<0.001), age category (F[7,1053] = 3.16, P<0.01), alcohol consumption (F[7,1054] = 1.78, P<0.02). These variables were subsequently used as covariates in the main study analyses.
Exercise status and health-related quality of life
No significant interactions were recorded. Regarding exercise status, analyses revealed significant effects favouring participants who were regularly active for depressed mood (F[1,1070] = 27.13, P<0.001), anxiety (F[1094] = 6.45, P<0.01), somatic symptoms (F[1,1075] = 14.34, P<0.01), and attractiveness concern scores (F[1,1002] = 8.73, P<0.01).
Data were analysed in accordance with each of the stages of change for exercise. Analyses revealed a similar pattern of significant effects to those reported, with the exception of anxiety scores. Specifically, women at the maintenance stage of change reported significantly lower depressed mood and somatic symptom scores than those at pre-contemplation (P<0.002), contemplation (P<0.001), and preparation (P<0.001). Women at pre-contemplation also reported significantly higher attractiveness concern scores than women who were at the contemplation (P<0.001), preparation (P<0.001), action (P<0.001), and maintenance (P<0.001) stages of change (Table 2).
Table 2 Exercise status, body mass index category, and health-related quality of life.
Body mass index and health-related quality of life
Significant BMI effects were found for the subscales vasomotor symptoms (F[2,1109] = 3.57, P<0.03), somatic symptoms (F[2,1075] = 5.10, P<0.01), and attractiveness (F[2,1086] = 18.10, P<0.001). Follow-up tests revealed that women who were obese reported significantly higher vasomotor symptoms (P<0.01) scores than women of normal weight. Women who were obese also reported significantly higher somatic symptom scores than women of normal weight or those who were overweight (all P<0.01). Women who were obese reported significantly higher attractiveness concern scores than women of normal weight and those who were overweight. Women who were overweight reported higher scores than women of normal weight in the attractiveness concern scores (Table 2).
DISCUSSION
Summary of main findings
Women who were regularly active reported better health-related quality of life than their less active counterparts. There was no significant difference in vasomotor symptom scores between participants who were active regularly and those who were not. It was also found that women who were obese reported higher vasomotor symptom scores than women of normal weight, and lower health-related quality of life scores than women of normal weight and those who were overweight.
Strengths and limitations of the study
It is not possible to determine from observational study designs whether women reported better health-related quality of life scores because they were active or whether they were less active because they were symptomatic. Exercise participation was measured by self-report and individuals tend to overestimate this. The simple classification of women as regularly active or not regularly active on the basis of their stage of change for exercise score may be considered somewhat crude, although sensitivity analyses confirmed this did not alter the main findings.
It is possible that the findings of the study could be explained by the selfselection of healthy women responding to the questionnaire. However, a large proportion of responders were women who were sedentary/not regularly active and/or were overweight or obese. These proportions are concordant with the Million Women Study,22 which reported that 65% of women in their sample exercised once per week or less, or not at all.
Although the overall response rate was relatively low, the age distribution (50.4% = 46–50 years; 49.6% = 51–55 years) and ethnicity distribution (non-white = 9.6%) of the sample coincides with data from the West Midlands region 2001 Census for this age group (48% = 45–49 years; 52% = 50–54 years, 8% of non-white ethnicity).23 Thus, despite a low response rate, our data should be less prone to bias regarding these variables.
The strengths of the study are that a number of factors known to influence both symptoms and exercise participation were controlled in the analyses and that a much larger sample was included, when compared with many previous studies. To the best of our knowledge this is the first British study to focus specifically on these outcomes in a sample of women of menopausal age.
Comparison with existing literature
Unlike some studies7–10 but similar to others,11,12 exercise participation was not significantly associated with vasomotor symptoms, although it was associated with some dimensions of health-related quality of life. It is interesting to note that exercise was not related to an increase of vasomotor symptoms, which is not inconceivable given that the process of exercise typically causes individuals to produce heat and sweating/perspiration. This may be one reason why some women of menopausal age avoid doing exercise.
It is also possible that the relationship between exercise and menopausal symptoms is mediated by exercise intensity, as it has been suggested that the production of ß-endorphins is more likely to occur during high-intensity rather than low-intensity exercise.26 Middle-aged women are more likely to engage in low- to moderate-intensity exercise than vigorous forms,27 which may explain the lack of significant relationships for vasomotor symptoms and other WHQ subscales. Despite these issues, the positive association between exercise and the other health-related quality of life outcomes should not be underestimated, particularly for somatic symptoms, which typically also cause a great deal of distress and discomfort to women who are menopausal. The findings for the somatic and psychological dimensions of health-related quality of life in the present study are in line with previous research.7
Similar to past research,8,15 data indicate that women who were obese reported higher vasomotor symptom scores and lower health-related quality of life scores than women with normal BMI scores. A recent longitudinal study28 has documented that increases in weight of more than 5kg were associated with significant increases in somatic symptoms.
The use of HRT in the sample was low (11.8%), which provided the opportunity to examine the outcomes of interest in a sample largely free of hormonal treatment. The prevalence of HRT use in the UK increased steadily19 in the 25 years prior to the publication of several major studies, including trials that reported adverse effects of HRT.20–22 In post-menopausal women alone, the prevalence of HRT was 17.7%, considerably lower than the figures recorded some years earlier by the Million Women Study (33%)22 and the UK General Practice Research Database29 (27% in 1996; 28% in 1997–1998). The role of exercise as an alternative to HRT may become more critical in the coming years because large numbers of women are no longer choosing to use HRT.
Implications for future research
The menopause transition can represent a ‘teachable moment’ in women lives, a time for women to consider ways to improve their overall health status. High-quality trials that examine the effects of exercise on menopausal symptoms is urgently required. Although exercise was not associated with vasomotor symptoms, it was associated with fewer psychological and psychosomatic health problems which can affect women of menopausal age. Furthermore, women who were obese reported higher vasomotor symptom scores than women who displayed normal BMI scores. The examination of exercise as an alternative to HRT is timely given women's changing attitudes towards HRT.
