Why your blood pressure can spike when it's cold outside

By Ashley Williams, AccuWeather staff writer

Bundling up during the colder months will not only prevent you from shivering, but it’ll help keep your blood pressure down.

Lower temperatures narrow the blood vessels, which elevates blood pressure, since higher pressure is then required to push blood through the now-narrowed arteries and veins.

Although the constriction of blood vessels in colder conditions is actually a survival mechanism that helps conserve heat and maintain body temperature, it provides less room for blood to move around.

Blood pressure, which is the force of blood pushing against your artery walls, normally rises and falls throughout the day, according to the Centers for Disease Control and Prevention (CDC).

Hiking in snow

However, if it remains elevated for a long period of time, it can lead to heart damage, increased risk of stroke and other health issues, the CDC reported.

In 1961, researcher Geoffrey Rose studied seasonal variations in blood pressure and found that cold weather can increase a person’s blood pressure.

“Outdoor temperature is a major determinant of the observed seasonal fluctuations in blood pressure, with higher and lower blood pressure in winter and summer, respectively,” said Dr. Ragavendra Baliga, a cardiologist at The Ohio State University Wexner Medical Center.

Low environmental temperature is strongly associated with increased hospital admissions for acute heart attacks, stroke and higher cardiovascular mortality, Baliga added.

How much blood pressure increases in cold weather depends on variables including the current temperature, wind chill, how long a person is exposed to colder weather and the person’s health, according to researchers from the University of Florida.

University of Florida researchers found, however, that being exposed to a temperature of 52 degrees Fahrenheit for only five minutes can cause a significant increase in blood pressure.

Additional research has shown that cold weather can raise blood pressure despite your age or where you live, but the impact tends to be harder on people as they get older, according to AARP.

France’s National Institute of Health and Medical Research conducted a two-year study, which tracked 8,800 people aged 65 and older across three cities.

Blood pressure elevations in winter were highest among people aged 80 and older, the research found.

“In general, [blood pressure in older people] is already higher than those of the younger people, so a drop in temperature is more likely to elevate [an older person’s] blood pressure over the threshold level,” said Dr. Lu Shi, an associate professor of public health sciences at Clemson University.

People currently being treated for high blood pressure also face a higher risk of increased health problems, experts said.

“For people who have heart disease and those who are being controlled on blood pressure medicine, if they go out in extremely cold temperatures like blizzards or decide to shovel the snow, they may start to experience symptoms like shortness of breath and chest tightness,” said Dr. Nieca Goldberg, medical director of the Joan H. Tisch Center for Women’s Health at New York University’s Langone Medical Center.

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It’s possible that other weather and environmental-related conditions can also impact blood pressure, but the increase seems to relate more to a change in temperature and not sunshine or rainfall, experts said.

There’s a growing body of evidence that smog could elevate blood pressure, as the smog exposes the body to particulate matter,” said Shi.

“In addition, any weather condition – heat, for instance – that triggers stress response could elevate blood pressure,” he added.

The American Heart Association and the American College of Cardiology recently issued new guidelines which mean that 103 million adults are now considered to have high blood pressure, as opposed to 72 million people under the previous standard.

“Although more people will be considered to have high blood pressure, it’s an opportunity for lifestyle changes for many people, because it’s only estimated that there will be a 1.9-percent increase in those who will need medication as a result of the change,” Goldberg said.

To combat the impact of lower temperatures on blood pressure, physicians recommend keeping warm in colder weather and monitoring blood pressure levels, especially for the elderly and those who currently have hypertension.

For more safety and preparedness tips, visit AccuWeather.com/Ready.

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