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Winter Months Bring Elevated Blood Pressure, Experts Say

Here’s what you need to know about seasonal and other variations in blood pressure

It turns out blood pressure has a chill factor: Hypertension is harder to control in colder weather, according to a study that used the Veterans Administration’s (VA) storehouse of 1.8 billion vital statistics records.

The five-year study covered almost 1.2 million Veterans Administration patients cared for at 15 VA hospitals located at different latitudes: Anchorage; Baltimore; Boston; Chicago; Fargo, ND; Honolulu; Houston; West Los Angeles; Miami; Minneapolis; New York City; Philadelphia; San Juan, Puerto Rico; Portland, Oregon; and Washington, DC.

The average age of participants was 66. Fifty-one percent were Caucasian, 21 percent were Hispanic, and 27 percent were African American. Less than 4 percent were female.

Within the sample, almost 444,000 veterans had high blood pressure (based on readings of more than 140/90 on three separate days).

And, regardless of their locale, patients experienced an average difference of almost 8 percent in getting their high blood pressure back to normal between winter and summer, with that feat being much tougher in winter.

What’s behind this ‘chill factor’?
Jefferson cardiologist Matthew V. DeCaro, MD, says the study is valid – but shouldn't be cause for alarm.

He says there could be a number of reasons to explain a blood-pressure increase in cold weather. One possible reason is the vasoconstriction, or narrowing of the blood vessels, that occurs in cold weather. Another possible explanation is that cold medicines, as well as non-steroidal anti-inflammatory painkillers, can raise blood pressure.

Dr. DeCaro says a third possibility is that anxiety and depression are more common in the winter and holiday months. He notes that for some people, anxiety and depression may lead to more alcohol and coffee consumption, both of which can raise blood pressure.

Dr. DeCaro also points out a more obvious reason: “Most people are more sedentary in the winter,” he explains. “If you’re staying inside and eating more, this can lead to weight gain, which also contributes to hypertension.”

Variations are common throughout the year
Above all, Dr. DeCaro encourages people not to panic about the potential for elevated blood pressure during the winter.

“People mistakenly believe that blood pressure is constant, but in reality, it’s highly variable,” he notes, adding that when hospital patients have intra-arterial cannulas that read blood pressure second to second, it’s not unusual to see variations of 30 mmHg a minute.  

“These instantaneous readings can be misleading. The blood pressure literature focuses on average blood pressure over a long timeframe and correlates this with risk of adverse events, such as strokes and heart attacks,” Dr. DeCaro explains.

He cautions against becoming too fixated on measuring blood pressure. That kind of obsession can actually contribute to blood-pressure elevation.

“One needs to be careful in anxious individuals who become ‘BP nuts,’” he says. “Their anxiety over perceived elevations actually makes it go higher – at times, very much so – and sometimes they’re checking it over 20 times a day.”

The bottom line: In winter or any other season, Dr. DeCaro advises patients to get an automated blood-pressure cuff and get readings on a pre-determined schedule – not based on how they feel.

For more information
Make an appointment with a Jefferson physician online or by calling 1-800-JEFF-NOW.