July 29, 2025, 5:20 pm | Read time: 5 minutes
Exercise protects the heart—this is well-known. But how do exercise habits change over a lifetime, especially around cardiovascular diseases like heart attack, stroke, or heart failure? A new long-term study from the U.S. shows: Activity levels often begin to decline about twelve years before cardiovascular disease—and remain permanently lower afterward. The study found that African American women were particularly affected, consistently showing the lowest levels of physical activity.
Study Goal: Determine the Link Between Exercise and Heart Disease
Regular physical activity of moderate to vigorous intensity—known as MVPA (“moderate to vigorous physical activity”)—is considered a key protective factor against cardiovascular diseases. However, little was known about how exercise behavior develops over decades, especially in relation to the onset of a disease. This is precisely where the current study comes in.
The study examined how MVPA changes from young adulthood to older age, whether a decline in activity is evident before a cardiovascular event, how activity behavior develops afterward, and whether there are differences by gender and ethnicity.
Study Design and Methods
The analysis is based on data from the CARDIA study (Coronary Artery Risk Development in Young Adults), an ongoing prospective U.S. cohort study in four cities since 1985. The current evaluation includes a cohort analysis with 3,068 participants and an embedded case-control study with 236 individuals who experienced a cardiovascular disease during the study. These 236 subjects were each compared with a control person of the same age, gender, and ethnicity.1
Physical activity was recorded in up to ten surveys between 1985/86 and 2020 to 2022 using a validated questionnaire. MVPA was measured in so-called Exercise Units (EU). Three hundred EU correspond to about 150 minutes of exercise per week—the internationally recommended minimum for health-effective activity. Those who reported less than 300 EU per week were considered physically inactive in the study.
Activity patterns were modeled over the entire adult life span and in relation to cardiovascular events. Additionally, the likelihood of insufficient exercise after a disease was calculated—meaning values below 300 EU per week.
How Exercise Levels Develop Over a Lifetime
Physical activity decreased over the course of adulthood in all groups: It was high in youth, dropped significantly in middle age, and then stabilized at a lower level. However, there were significant differences between population groups. African American women consistently showed the lowest activity, while African American men experienced the greatest decline over time.
Heart Patients Showed Reduced Activity 12 Years Prior
Among the 236 individuals with a cardiovascular event, it was found that the decline in activity began about twelve years before the event. In the two years immediately preceding the event, this downward trend accelerated significantly. After the event, activity levels remained permanently lower than those of healthy control subjects. This decline was particularly pronounced in people with heart failure.
What Do the Numbers Mean Specifically?
The analysis revealed that those affected by a cardiovascular event were significantly more likely to remain physically inactive afterward. The so-called Odds Ratio (OR) was 1.78—meaning the risk of achieving less than 300 EU per week (thus falling below the recommended minimum activity) was 78 percent higher for those affected than for the control subjects.
The associated 95 percent confidence interval ranged from 1.26 to 2.50. This means the researchers are very confident—95 percent, in fact—that the actual risk is somewhere between 26 percent and 150 percent higher than for healthy individuals. Such values indicate that the difference is not random but very likely truly exists.
The situation was even more pronounced for African American women: Their Odds Ratio was 4.52—they were more than four times as likely to be inactive after a cardiovascular event compared to healthy women of the same ethnic group.
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After a Heart Disease, Activity Often Remains Permanently Reduced
The study vividly shows that while physical activity generally decreases with age, it declines much earlier and more sharply in people with later cardiovascular disease. The period about ten years before the event could be a potential early warning signal or a modifiable risk factor.
After a heart event, activity often remains permanently low—even though it is particularly important for recovery, quality of life, and prognosis during this phase. This suggests that rehabilitation and follow-up programs should focus more on long-term promotion of physical activity.
The particularly high impact on African American women also points to structural health inequalities. In addition to medical measures, targeted societal, financial, and cultural approaches are needed to better support disadvantaged groups.
Context of the Study and Possible Limitations
The combination of long-term cohort data and embedded case-control design provides valuable insight into activity patterns over several decades. The large number of participants, repeated surveys, and differentiated consideration by population groups increase the study’s significance.
However, limitations exist in that the data on physical activity are based on self-reports, which can lead to over- or underestimations. Objective measurement methods, such as motion sensors, were not used. Additionally, the study was conducted exclusively in the U.S.—its applicability to other countries with different health systems or cultural differences in exercise behavior is therefore limited.
Another important point: Lack of exercise can be both a cause and a consequence of a developing disease process. Thus, the study shows correlations but not causality.