When Temps Go Down, Blood Pressure Can Go Up

Keep close tabs on BP during the winter months

You’re probably aware of some of the well-known risk factors of high blood pressure, such as genetics and age. Lifestyle factors including unhealthy diets and stress are also associated with this widespread condition, known as hypertension.

What you may not know is that high blood pressure tends to be more difficult to control during the winter months.

In a large nationwide study published several years ago, researchers reviewed health records of more than 400,000 veterans over a five-year period. The research showed that among 60 percent of the participants studied, blood pressure readings were consistently higher during the winter. This followed an earlier study that indicated increases in blood pressure during winter months might be particularly problematic for the elderly.

“One reason for increased winter blood pressure may be that cold temperatures trigger a ‘fight or flight’ response,” says Airley E. Fish, MD, MPH , a cardiologist at Beth Israel Deaconess Medical Center (BIDMC) who sees patients in both Boston and Chelsea . “This causes the heart to beat faster and can cause blood vessels to constrict and blood pressure to rise.”

But cold temperatures may not be the only factors underlying blood pressure increases: Sedentary lifestyles and winter weight gain — as well as decongestants and cold medications — can also raise blood pressure.

“No matter what the underlying cause, we recommend that patients take extra care to monitor their blood pressure throughout the winter months,” says Fish (right).

 Know Your Numbers

Blood pressure measures the force of blood pushing against the heart’s arteries. Blood pressure readings are given in two numbers: systolic pressure (when the heart is contracting) over diastolic pressure (when the heart relaxes between beats).

According to the American Heart Association , a normal healthy blood pressure reading is less than 120/80. Hypertension is diagnosed at 140/90 or higher (130/80 for patients with diabetes or kidney disease). A systolic blood pressure reading between 120 and 139, or diastolic pressure reading between 80 and 89, is considered “pre-hypertensive.”

“High blood pressure affects one in three adults in the U.S.,” says Fish. “It’s often referred to as a 'silent killer' since it often has no symptoms and can go undetected for decades.”

In fact, the AHA reports that more than 20 percent of those with high blood pressure are unaware that they have the condition, and more than half of those diagnosed with hypertension are not being treated for it.

“If the heart is pumping against high pressure for a long time, like any other muscle it thickens and eventually becomes less effective," says Fish. “Uncontrolled hypertension raises a person’s risk for stroke, heart attack, heart failure and kidney disease.”

Know the Risk Factors

Because arteries narrow over time, age is one of the biggest risk factors for high blood pressure. Until a person reaches middle age, both systolic and diastolic pressures can be expected to increase; around age 50, diastolic pressure tends to level off, while systolic pressure often continues to rise.

“Even if your blood pressure reading has been normal in the past, regular checks are necessary as you get older,” explains Fish.

To assess your risk, check out the AHA’s High Blood Pressure Health Risk Calculator .

Other risk factors include:

  • Gender: High blood pressure is more common in men until middle age. Women are more prone to hypertension after menopause.
  • Genetics: High blood pressure often runs in families.
  • Race: More than 40 percent of African Americans have hypertension, and it often develops earlier in life.
  • Lifestyle factors: Excess weight, poor diet, lack of activity, smoking and stress can all contribute to high blood pressure.
Know How to Control Blood Pressure

Lifestyle changes are the first step in controlling blood pressure, says Fish. According to guidelines from the AHA, the following steps can help keep blood pressure in check:

When Do You Need Medication?

If blood pressure readings are higher than 140/90 on two or more occasions (or 130/80 for individuals who have diabetes or kidney disease), and lifestyle changes have not led to any improvements, one or more medications may be prescribed to lower or control blood pressure levels. There are a number of different types of blood pressure medications, including diuretics, beta blockers, calcium-channel blockers, ACE inhibitors and alpha-2 receptor agonists.

“Some patients tolerate lower doses of two medications better than a higher dose of a single agent, and therefore, in some cases, we may recommend two different medications to control blood pressure,” says Fish, who also recommends patients buy an at-home blood pressure monitor to keep close tabs on their readings, and suggests patients first visit with their physicians to make sure the monitors are accurate and carefully calibrated.

“See your physician regularly, exercise and eat well, and — if you need hypertensive medication — take it as prescribed,” says Fish. “Prevention is the best medicine to keep blood pressure in check and avoid life-changing cardiac events — in winter months, and throughout the year.”

Above content provided by the CardioVascular Institute at Beth Israel Deaconess Medical Center. For advice about your medical care, consult your doctor.

February 2017

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