BOSTON - Pregnant 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, held in Boston from March 17-20, 2026, highlights 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. “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.
The study included 470 women, ages 18 to 45, enrolled from 2021 to 2024 at three health care centers in Iowa, Pennsylvania and West Virginia. Participants wore two monitors for 24 hours for seven consecutive days during each trimester to measure sedentary behavior, sleep and the 24-hour activity cycle. The results found that 18.6% of women developed hypertensive disorders of pregnancy. Sedentary behaviors and light physical activity were the strongest predictors of risk. The lowest-risk daily pattern included about six hours of sitting, nearly eight hours of light physical activity, four minutes of higher-intensity activity and roughly 10 hours of rest, associated with an 8% chance of developing hypertensive disorders compared to 16.9% with a typical pattern.
“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. “The researchers extend this to the pregnant population where nearly 20% of participants developed a hypertensive disorder of pregnancy. 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.”
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.”
The study had limitations, including a predominantly white, higher-educated and higher-income participant group, so results may not reflect other populations. Additionally, the number of hypertensive disorder cases was relatively small, preventing separate analysis of preeclampsia and gestational hypertension. The authors note that more research is needed to confirm findings and understand how specific activity patterns correlate to different disorders.
For more news from AHA EPI|Lifestyle Scientific Sessions 2026, follow on X at @HeartNews, #EPILifestyle26. Additional resources include the AHA news release on cardiovascular risk factors during pregnancy and the AHA science advisory on sedentary behavior and light-intensity physical activity during pregnancy.
