The current findings suggest significant differences in the quality of life between the moderate and high PA groups and the low PA group in postmenopausal women; the EQ-5D index score also showed a significant difference. In particular, compared to the low PA group, the moderate PA group showed a significantly higher quality of life index in the age groups above 60 with normal or high BMI. Although a number of previous studies have reported the positive aspects of PA in postmenopausal women, no study has compared the quality of life according to the level of PA in large groups to the best of our knowledge. Therefore, this study was the first attempt in analyzing the HRQoL and perceived health status in different PA level groups involving 8,122 postmenopausal women who participated in the sixth and seventh edition of the National Health and Nutrition Survey (2014–2018).
Postmenopausal women may experience reduced quality of life due to physical, psychological, and social issues. In particular, PA subsequently decreases due to weight gain and decadence of the musculoskeletal system. However, it must be noted that PA level, along with the quality of life, can still be increased through regular and well-controlled exercise . The current study also found significant differences between the moderate and high PA groups and the low PA group in all five dimensions of the quality of life, namely exercise ability, self-management, daily activities, pain/discomfort, and anxiety/depression on top of the EQ-5D index score. In particular, when compared to the low PA group, the moderate PA group showed significantly higher quality of life index in the age groups above 60 with normal and high BMI. This is consistent with the meta-analysis reported by Pucci GC et al.  who revealed a higher quality of life in the high PA level elderly groups when compared to low PA level elderly groups. Similarly, a positive correlation between elevated PA and high quality of life in groups with underlying diseases such as diabetes and cancer [21, 22] has been previously reported. Studies investigating the relationship between menopause and HRQoL in middle-aged women revealed that postmenopausal women had lower EQ-5D index values than pre-menopausal women, which suggests that the deterioration of physical function happening mostly within five years of menopause is a major factor for this difference . However, according to a randomized control study by Moriyama CK et al., a significant difference existed in the changes in physical function in the group with moderate PA levels regardless of undergoing hormone replacement therapy. Furthermore, PA was observed to improve the quality of life along with the alleviation of menopausal symptoms.
The effects of exercise and PA in postmenopausal women on their health outcomes have been reported in several studies; e.g., exercise can lower the risk of cardiovascular disease, prevent osteoporosis, and lower BMI and blood pressure [24–27]. Exercise can also alleviate hot flushes and menopausal symptoms since PA has been attributed to increased blood beta-endorphins, which is known to decrease after menopause , resulting in the relief of vasomotor symptoms . The current findings are also consistent with previous results. Furthermore, the current study found that moderate PA showed a more significant difference than high PA when compared to low PA. In previous studies investigating the level of PA and the quality of life, the group that performed moderate or high intensity (23METs/hour/week) PA levels showed significantly higher quality of life than those who did not . Morimoto T, et al. notably reported that a higher PA level would lead to positive effects on the quality of life in both men and women and, in particular, the highest intensity of PA showed a significant difference in various dimensions of the quality of life in women .
The change in PA itself was not observed to have a direct relation to the alleviation of vasomotor or psychological symptoms . However, the weight loss that resulted from increased PA was correlated with the alleviation of overall symptoms of menopause. Thus, it is believed that a moderate level of PA may have led to weight loss and an increased awareness of health levels, which could have influenced the results. In particular, in the comparative analysis of EQ-5D according to BMI, only the moderate PA group had a significant difference compared to low PA group in the normal and high BMI groups. This was not found in the low BMI group, which suggests that factors such as varying weight loss due to difference in PA levels may be related to the observed result. This study did not include analysis of the weight loss among the three comparison groups. Thus, further studies involving additional comparative analysis on this topic would be useful.
It has been previously reported that a clear association was found between menopausal symptoms, including vasomotor symptoms, and the resulting low quality of life . Therefore, it can be inferred that the alleviation of menopausal symptoms with the increase in beta-endorphin levels through PA or weight loss improves the quality of life. Additionally, the psychological and social effects of PA, which improves the quality of life, should also be considered. The EQ-5D evaluation dimensions also reflect certain psychological and social factors, such as self-management and anxiety/depression. The corresponding factors resulting from the PA level, including social connectedness and reinforcement of self-esteem must also be considered. On the other hand, in the comparison by age groups, no significant difference according to the PA level in the age groups under 60 years of age was found. The researchers believe that the PA level in those groups produced a different effect on the quality of life because, unlike the age group over 60 years of age, the postmenopausal symptoms and durations differed depending on the duration after menopause.
Our study had several limitations. First, the cross-sectional study design prevented the explanation of the clear causal relationship between the level of PA and quality of life. Second, since the quantification of PA level was based on a self-report survey, it may be more or less inaccurate. In particular, recall bias could not be completely ruled out. Lastly, reflecting on the persistence of PA was difficult due to the analysis of the PA level being only conducted at the time of the survey. Analyzing the persistence and long-term effects of PA through subsequent studies is highly recommended. Despite these limitations, our study was more extensive than many previous studies, as this study used a nationally representative study population. Furthermore, a greater number of sociodemographic factors, including residence, household income, and marital status, were taken into account as opposed to previous studies. Finally, this was the first attempt to consider PA levels in comparing the quality of life in postmenopausal women.