BOSTON — Pregnant women may reduce their risk of developing hypertensive disorders such as gestational hypertension and preeclampsia by nearly 30% if they limit sedentary time to no more than eight hours a day and increase 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.
“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.”
The study included 470 pregnant women from three U.S. health care centers in Iowa, Pennsylvania and West Virginia. Participants wore monitors for 24 hours over seven consecutive days during each trimester to measure sedentary behavior, sleep and physical activity. Of the participants, 18.6% developed hypertensive disorders of pregnancy. The analysis identified that the lowest-risk daily pattern included about six hours of sitting, nearly eight hours of light activity, four minutes of higher-intensity exercise, and roughly 10 hours of rest, which was linked to an 8% chance of developing such disorders compared to 16.9% for typical patterns.
Compared to typical daily movement, the optimal combination reduced risk by more than half. When compared to the least healthy patterns, risk was reduced by nearly 80%. Risk increased for those sitting more than 10 hours per day or engaging in less than five hours of light activity. The findings underscore sedentary behavior and light physical activity as key modifiable behaviors for preventing hypertensive disorders of pregnancy, which may have long-term implications for women’s heart health.
Natalie A. Bello, M.D., M.P.H., an American Heart Association volunteer expert, noted, “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.”
The study aligns with the American Heart Association’s Life Essential 8 for Pregnancy recommendations, which encourage moving throughout the day and adequate sleep. Limitations include a predominantly white, higher-education sample, and the small number of hypertensive cases prevented separate analysis of preeclampsia and gestational hypertension. Further research with diverse populations is needed to confirm findings.
The research is considered preliminary until published in a peer-reviewed journal.
