Leisure time physical activity improves the blood lipid profile, a marker of cardiovascular risk, of postmenopausal women.
This is the main takeaway of a new study that appears in the journal Frontiers in Endocrinology.
Sira Karvinen — a postdoctoral researcher from the Gerontology Research Center at the Faculty of Sport and Health Sciences, at the University of Jyväskylä in Finland — is the first and corresponding author of the study.
As Karvinen and colleagues explain in their paper, cardiovascular risk increases significantly and rapidly after the onset of menopause.
A person's lipid profile — comprising their total cholesterol, low density lipoprotein (LDL) cholesterol, high density lipoprotein (HDL) cholesterol, triglyceride, and fasting blood sugar levels — is a good marker of their cardiovascular health.
Menopause, the study authors explain, is associated with "unfavorable changes in lipid metabolism leading to an increased likelihood of developing metabolic syndrome and [cardiovascular disease]."
Researchers tend to agree on the above, just as they do on the notion that leisure time physical activity protects against cardiovascular disease.
However, there is less agreement regarding the relationship between leisure time physical activity, lipid profile changes, and cardiovascular risk after menopause.
So, Karvinen and her team set out to investigate 193 women who had enrolled in the Estrogenic Regulation of Muscle Apoptosis (ERMA) study. This is a cohort study of women ages 47–55.
'Sport-related hobbies' crucial in middle age
Study co-author Dr. Matthew Jergenson, from the University of Minnesota Medical School in Minneapolis, explains the motivation for the study.
He says, "It is well known that physical activity has health benefits, yet it is less clear to what extent physical activity can prevent the negative changes seen in blood lipid profiles during the menopausal transition."
"The present study," he adds, "examined menopausal women in the city of Jyväskylä, Finland, to explore the role of leisure time physical activity on [cardiovascular] risk factors."
The team used both questionnaires and accelerometers to monitor the women's levels of physical activity in general, and their leisure time physical activity levels in particular.
According to some definitions, leisure time physical activity describes "exercise, sports, or recreation that is not related to regular work, housework, or transport activities."
The researchers found a link between higher levels of leisure time physical activity and lower levels of total cholesterol, LDL ("bad") cholesterol, triglycerides, and fasting blood glucose. They also found a link with higher levels of HDL ("good") cholesterol.
"Based on our findings, leisure time physical activity was associated with a healthier blood lipid profile," reports Karvinen. However, the authors note that the positive changes in lipid profile are not enough to fully counter the negative changes in lipid profile that menopause often brings.
"[A]dvancing menopausal status predicted a less healthy lipid profile, suggesting that leisure time physical activity does not entirely offset the unfavorable lipid profile changes associated with the menopausal transition," explains Karvinen.
"However, leisure time physical activity may attenuate the unfavorable atherogenic changes in the serum [cardiovascular] risk factors of healthy middle aged women," add the authors.
"Hence one should not forget sport-related hobbies at middle age."
Strengths and limitations of the study
The study authors also lay out some strengths and limitations to their work. For example, they note that using the ERMA study is one strength, as the research is a "comprehensive cohort study" that specifically looks at postmenopausal changes.
The ERMA study used bleeding diaries and serum follice stimulating hormone levels, rather than just the participants' self-reporting, to assess the women's menopausal status.
The team also used comprehensive questionnaires, labotory tests, and physical measurements to assess the participants' cardiovascular risks.
The low discontinuation rates, as well as the larger number of participants compared with other studies that have addressed the same issues, are further strengths of the study.
The clinical relevance of the research, however, is somewhat limited. This is due to the fact that the team did not account for outcomes such as cardiovascular events, cardiovascular mortality, or all-cause mortality.
Furthermore, the study population was homogeneous; every woman was white. For this reason, the results may not apply to women of other ethnicities. They may also not apply to women with reduced access to healthcare.