Research Highlights:
- In a study including nearly 500 pregnant women in three U.S. cities from 2020-2025, sedentary behavior, sleep and physical activity across a 7-day, 24-hour timeframe during each trimester were measured. The amount of time spent sitting and doing light physical activity were found to be the main predictors of developing blood pressure-related conditions (hypertensive disorders) of pregnancy, such as gestational hypertension and preeclampsia.
- Women who limited their sedentary time to about eight hours a day and engaged in at least seven hours of light physical activity, and on average, 22 minutes of higher intensity activity and nine hours of sleep daily had a 30% lower risk of developing hypertensive disorders of pregnancy.
- The researchers say more research is needed to test whether helping pregnant women sit less and move more throughout the day can reduce their risk of developing a hypertensive disorder of pregnancy.
- Note: The study featured in this news release is a research abstract. Abstracts presented at the American Heart Association's scientific meetings are not peer-reviewed, and the findings are considered preliminary until published as a full manuscript in a peer-reviewed scientific journal.
BOSTON, March 19, 2026 — During pregnancy, women can reduce their risk of developing a hypertensive disorder by nearly 30% by limiting sedentary time to no more than eight hours a day and increasing light, everyday physical activity to at least seven hours a day, according to preliminary research presented at the American Heart Association's EPI|Lifestyle Scientific Sessions 2026. The meeting is in Boston, March 17-20, 2026, and offers the latest science on population-based health, epidemiology, prevention, lifestyle and cardiometabolic health.
"Our study suggests that in the real world, where daily routines vary widely, it may actually be the balance of sitting time and light intensity movement across the entire day that matters most," said lead study author Kara Whitaker, Ph.D., M.P.H., FAHA, an associate professor in the department of health, sport and human physiology at the University of Iowa in Iowa City, Iowa. "This doesn't mean exercise isn't beneficial—rather, that when it comes to hypertensive disorders of pregnancy, everyday movement and limiting long periods of sitting may play a bigger role than we previously understood."
According to the American Heart Association, high blood pressure during pregnancy and other adverse pregnancy conditions are associated with an increased risk of future cardiovascular disease. While physical activity and sleep patterns are related to cardiovascular disease risk, there has not been a lot of research on how 24-hour activity patterns during pregnancy can impact the risk of hypertension.
High blood pressure develops in up to 5%-10% of all pregnancies and is the leading cause of fetal and maternal disease and death. This study aimed to identify optimal 24-hour behavioral and activity patterns across pregnancy trimesters that are associated with the lowest risk of hypertensive disorders of pregnancy.
The study results found:
- Of the 470 study participants, 18.6% of the women developed hypertensive disorders of pregnancy (gestational hypertension or preeclampsia).
- Sedentary behaviors and light physical activity were the strongest predictors of hypertensive disorders of pregnancy risk across all trimesters of pregnancy.
- The lowest-risk daily pattern of activity included about six hours of sitting, nearly eight hours of light physical activity, four minutes of higher‑intensity activity (traditional exercise) and roughly 10 hours of time spent resting. This daily pattern was linked to an 8% chance of having hypertensive disorders of pregnancy, compared to 16.9% observed among those with a typical daily pattern.
- Compared to typical daily movement patterns, the optimal combination of activity reduced a woman's risk of high blood pressure-related conditions during pregnancy by more than half. When compared to the least healthy daily movement patterns measured in the study, the optimal activity combination reduced risk by nearly 80%.
- The risk of hypertensive disorders of pregnancy rose for those who sat more than 10 hours per day or if there was less than five hours per day of light activity.
- These findings highlight sitting time and light physical activity as key modifiable behaviors that may help prevent the development of hypertensive disorders of pregnancy, which, in turn, may have important implications for women's lifelong heart health.
"Both sedentary behavior and hypertension in pregnancy are increasingly common, and in non-pregnant individuals we know that physical activity is associated with reductions in blood pressure," said Natalie A. Bello, M.D., M.P.H., an American Heart Association volunteer expert and member of the writing groups for AHA's scientific statement, Prevention and Treatment of Maternal Stroke in Pregnancy and Postpartum, as well as Guideline for the Prevention, Detection, Evaluation and Management of High Blood Pressure in Adults. "The researchers extend this to the pregnant population where nearly 20% of participants developed a hypertensive disorder of pregnancy. They saw incremental associations between more physical activity and lower risk of developing preeclampsia or gestational hypertension. It remains to be seen whether this association is causal, and future studies designed to increase physical activity and reduce sedentary behavior in pregnancy are needed." Bello, who was not involved with this study, is an associate professor of cardiology at the Smidt Heart Institute at Cedars-Sinai Medical Center and director of women's cardiovascular health & cardiology at Atria Health and Research Institute, both in Los Angeles.
The study results align with the American Heart Association's Life Essential 8 for Pregnancy recommendations, which encourage women to find ways to move throughout the day, get adequate sleep, eat healthy foods, manage cholesterol and blood sugar, as well as monitor blood pressure.
"These findings have the potential to shift how we think about physical activity and sleep during pregnancy," said Whitaker. "Right now, there are no clear, quantitative guidelines for how much sitting or light intensity movement is healthiest during pregnancy, and our results provide early evidence that could help shape those recommendations in the future. Ultimately, this line of research could give patients and clinicians more practical, achievable ways to support healthier pregnancies."
Study details, background and design:
- The study included 470 women, ages 18 to 45 years; 83% self-reported as non-Hispanic white. The participants were enrolled in the study from 2021 to 2024 at three health care centers in Iowa, Pennsylvania and West Virginia.
- The women were all in their first trimester of pregnancy (prior to 13 weeks gestation) at enrollment, and they were followed until 6 weeks after delivery.
- Each study participant wore two monitors for 24 hours for seven consecutive days during each trimester of their pregnancy to measure sedentary behavior, sleep and the 24-hour activity cycle (composition of sedentary behavior, physical activity and sleep). This data was analyzed with health records related to hypertensive disorders and other adverse pregnancy outcomes.
- Activity was measured using a small, wearable monitor that tracked the amount of time spent lying down, sitting, standing and walking. A watch assessed the participants' sleep duration.
- The rates of gestational hypertension and preeclampsia were noted from the study participants' medical records, and statistical models were used to predict the risk of hypertensive disorders of pregnancy based on data from the 24-hour movement behaviors and calculated by trimester.
The study had several limitations, including that the study participants were mostly white and tended to have higher education and income levels, so the results may not reflect the experiences of people in other population groups. In addition, because the number of cases of hypertensive disorders of pregnancy was relatively small, study researchers were not able to analyze rates of preeclampsia and gestational hypertension separately, and these two medical conditions may have different relationships with physical activity. The authors note that studies with more participants and people from other population groups are needed to confirm the findings and to better understand how specific physical activity patterns may correlate to different hypertensive disorders of pregnancy.
Co-authors, disclosures and funding sources are listed in the abstract.
Statements and conclusions of studies that are presented at the American Heart Association/American Stroke Association's scientific meetings are solely those of the study authors and do not necessarily reflect the Association's policy or position. The Association makes no representation or guarantee as to their accuracy or reliability. Abstracts presented at the Association's scientific meetings are not peer-reviewed, rather, they are curated by independent review panels and are considered based on the potential to add to the diversity of scientific issues and views discussed at the meeting. The findings are considered preliminary until published as a full manuscript in a peer-reviewed scientific journal.
