Researchers link high blood pressure to cool indoor temps

Aug. 23 (UPI) -- Cool indoor temperatures have been tied to high blood pressure, according to a new study.

Researchers at University College London studied low temperatures in homes and blood pressure. Their findings were published Tuesday in the Journal of Hypertension.

"Among other diet and lifestyle changes people can make to reduce high blood pressure, our findings suggest that keeping homes a bit warmer could also be beneficial," senior author Dr. Stephen Jivraj of the UCL Institute of Epidemiology & Health Care, said in a press release.

For every one-third degree Fahrenheit decrease in indoor temperature, there was a rise of 0.48 mmHg in systolic blood pressure and 0.45 mmHg in diastolic blood pressure. Normal blood pressure is less than 120/80 mmHg, according to guidelines from the American College of Radiology and the American Heart Association. Systolic pressure -- the first number -- measures the force of the heart's contraction, and diastolic pressure is the resistance in the blood vessels.

"Our research has helped to explain the higher rates of hypertension, as well as potential increases in deaths from stroke and heart disease, in the winter months, suggesting indoor temperatures should be taken more seriously in diagnosis and treatment decisions, and in public health messages," Jivraj said.

Researchers analyzed data on people 16 and older that participated in the Health Survey for England in 2014. Nurses visited 4,659 participants in their homes, including taking their blood pressure and checking indoor temperature readings in their living rooms.

The researchers accounted for social deprivation and outdoor temperature to identify an independent association with indoor temperature.

The average systolic was 126.64 mmHg and diastolic blood pressure 74.52 mmHg compared with 121.12 mmHg and 70.51 mmHg in the warmest homes.

The effect of indoor temperature on blood pressure was stronger among people who don't exercise regularly.

"We would suggest that clinicians take indoor temperature into consideration, as it could affect a diagnosis if someone has borderline hypertension, and people with cooler homes may also need higher doses of medications," said co-author Hongde Zhao, a researcher at the institute.

The researchers noted the need to adequately heat homes during the winter months. They said their advisable temperature is 69.8 Fahrenheit.