Blood Pressures Changes From Winter/Summer

Blood pressure systematically worsens in the winter and improves in the summer, U.S. researchers found.

Lead study author Dr. Ross D. Fletcher, chief of staff at the VA Medical Center in Washington, analyzed electronic health records from 15 VA hospitals in warmer and colder cities throughout the United States. The researchers identified 443,632 veterans with high blood pressure -- readings of more than 140 mm Hg systolic or more than 90 mm Hg diastolic on three separate days.

The study found a significant variation in every city, warmer or colder, in return to normal blood pressure in winter compared to summer. The average significant difference in percent of patients returning to normal was 7.76 percent between the two seasons.

"The bottom line is that regardless of whether you're in Anchorage, Alaska, or San Juan, Puerto Rico, there is a difference in high blood pressure returning to normal in the winter compared to the summer," Fletcher said in a statement.

The findings were reported at the American Heart Association's Scientific Sessions in Orlando, Fla.