A new study suggests that pregnant women can reduce their risk of developing hypertensive disorders 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. The findings were presented at the American Heart Association’s EPI|Lifestyle Scientific Sessions 2026 in Boston, March 17-20, 2026.
“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. “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.”
High blood pressure develops in up to 5%-10% of all pregnancies and is a leading cause of fetal and maternal disease and death. The study aimed to identify optimal 24-hour behavioral and activity patterns across pregnancy trimesters associated with the lowest risk of hypertensive disorders of pregnancy, including gestational hypertension and preeclampsia.
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 rates of gestational hypertension and preeclampsia were obtained from medical records.
Results showed that 18.6% of participants 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. This pattern was linked to an 8% chance of developing hypertensive disorders, compared to 16.9% among those with a typical 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%.
Risk rose for those who sat more than 10 hours per day or had less than five hours of light activity. “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.”
The study aligns with the American Heart Association’s Life Essential 8 for Pregnancy recommendations, which encourage moving throughout the day, adequate sleep, healthy eating, and monitoring 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.”
The study had limitations, including a predominantly white, higher-education participant group, so results may not reflect other populations. Additionally, the number of hypertensive disorder cases was small, preventing separate analysis of preeclampsia and gestational hypertension. More research is needed to confirm findings and explore causal relationships.
