BOSTON — Pregnant women may significantly reduce their risk of developing hypertensive disorders by limiting sedentary time to no more than eight hours a day and increasing light physical activity to at least seven hours daily, according to preliminary research presented at the American Heart Association’s EPI|Lifestyle Scientific Sessions 2026 in Boston.
The study, which included nearly 500 pregnant women across three U.S. cities, measured sedentary behavior, sleep and physical activity across a 7-day, 24-hour timeframe during each trimester. The findings indicate that the amount of time spent sitting and doing light physical activity are the main predictors of developing blood pressure-related conditions such as gestational hypertension and preeclampsia.
“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 at the University of Iowa in Iowa City. “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 affects up to 5%-10% of pregnancies and is a leading cause of fetal and maternal disease and death. The study aimed to identify optimal 24-hour behavioral patterns associated with the lowest risk of hypertensive disorders.
Among the 470 participants, 18.6% developed hypertensive disorders of pregnancy. 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. This pattern was linked to an 8% chance of developing hypertensive disorders, compared to 16.9% among those with a typical daily pattern. Compared to typical movement patterns, the optimal combination reduced risk by more than half, and compared to the least healthy patterns, risk was reduced by nearly 80%.
“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 associate professor of cardiology at the Smidt Heart Institute at Cedars-Sinai Medical Center. “The researchers extend this to the pregnant population where nearly 20% of participants developed a hypertensive disorder of pregnancy.”
The study results align with the American Heart Association’s Life Essential 8 for Pregnancy recommendations, which encourage movement throughout the day, adequate sleep and healthy eating.
“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 included women aged 18 to 45, with 83% self-reporting as non-Hispanic white. Limitations include a relatively homogeneous sample and small number of hypertensive cases, preventing separate analysis of preeclampsia and gestational hypertension. The authors note that more research is needed to confirm findings and understand specific patterns.
