Pregnant women may significantly reduce their risk of developing hypertensive disorders such as gestational hypertension and preeclampsia by limiting sedentary time and increasing light physical activity, according to preliminary research presented at the American Heart Association’s EPI|Lifestyle Scientific Sessions 2026 in Boston.
The study, which included 470 pregnant women across three U.S. cities from 2021 to 2024, 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 were the main predictors of developing hypertensive disorders of pregnancy.
Women who limited their sedentary time to about eight hours a day and engaged in at least seven hours of light physical activity, along with an average of 22 minutes of higher-intensity activity and nine hours of sleep daily, had a 30% lower risk of developing hypertensive disorders of pregnancy compared to those with typical daily patterns.
“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 and other adverse pregnancy conditions increase the risk of future cardiovascular disease. Hypertensive disorders affect 5% to 10% of pregnancies and are 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.
The study found that of 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 time resting, linked to an 8% chance of developing these disorders compared to 16.9% in those with typical patterns. The risk rose for those sitting more than 10 hours per day or with less than five hours of light activity.
Natalie A. Bello, M.D., M.P.H., an American Heart Association volunteer expert, noted that the study extends findings from non-pregnant populations to pregnant women, showing incremental associations between more physical activity and lower risk. “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,” said Bello, who was not involved in the study.
The results align with the American Heart Association’s Life Essential 8 for Pregnancy recommendations, which encourage moving throughout the day, adequate sleep, and healthy eating. Whitaker emphasized the potential for these findings to shape future guidelines: “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 mostly white, higher-educated participant group, and the small number of hypertensive disorder cases prevented separate analysis of preeclampsia and gestational hypertension. More research is needed to confirm findings and test whether interventions to reduce sitting and increase movement can causally lower risk.
This research was presented at the American Heart Association’s EPI|Lifestyle Scientific Sessions 2026, and the findings are considered preliminary until published in a peer-reviewed journal.
