Your Levels May Rise as the Temperature Drops

docbp As we enter the shortest, coldest days of the year, it’s natural to keep an eye on outside temperatures to make decisions about outdoor apparel and transportation. If you are among the one in three adults in the United States with high blood pressure, you should also check your blood pressure frequently, particularly in winter. Based on the numbers, you may need adjustments in your lifestyle as well.

A study conducted by the VA Medical Center in Washington, D.C., revealed that blood pressures are higher in winter months. Published earlier this year inCirculation, a journal of the American Heart Association, the study reviewed health records of 443,632 veterans nationwide during a five-year period. The research showed that blood pressures were consistently higher during the winter in 60 percent of the veterans studied.

Because the study’s data also revealed that the pattern held true even in southern climates with milder winters, the researchers speculated that perhaps sedentary lifestyles and weight gain during winter months might be partly to blame. Other physicians and researchers feel that stress and food choices with high fat or sodium may be potential culprits for higher blood pressure at this time of year.

Let’s Talk Numbers

High blood pressure (also called hypertension) involves blood that travels through arteries with an increased force.

Fish “If the heart is pumping against high pressure for a long time, like any other muscle it thickens and eventually becomes less effective," says Airley E. Fish, MD, MPH (right), a cardiologist at Beth Israel Deaconess Medical Center (BIDMC) who sees patients in both Boston and Chelsea. "Damage can occur to the heart or other organs such as the brain, kidneys, and eyes. Over time, hypertension raises the risk for stroke, heart attack, heart failure and kidney disease.”

Blood pressure is measured as systolic pressure (when the heart is contracting) over diastolic pressure (when the heart relaxes between heart beats). A normal blood pressure reading is less than 120/80. Hypertension is diagnosed at 140/90 or higher (130/80 if you are diabetic or have kidney disease). If your systolic blood pressure is between 120 and 139, or your diastolic pressure is between 80 and 89, you are considered at risk or “pre-hypertensive.”

Should You Be Worried?

“High blood pressure is often referred to as the ’silent killer’ since it may occur for decades with no symptoms,” according to Fish.

More than 20 percent of those with high blood pressure are unaware that they have it, and more than half of those with hypertension are not treating it, according to the American Heart Association.

While most people have no symptoms at all, if blood pressure rises to very high levels, you may experience headache, dizziness, blurred vision, shortness of breath, or abdominal or chest pain. Unfortunately, a number of people only find out that they have hypertension after they suffer a heart attack or stroke.

Knowing the risk factors for high blood pressure is one way to evaluate your chance of developing the disorder.

“Age is one of the biggest risk factors, since arteries narrow with the years, which naturally increases blood pressure. So, even if your blood pressure has been fine in the past, regular checks are still needed,” explains Fish.

The following factors can increase your chance of developing high blood pressure:

  • Age: Generally, both systolic and diastolic blood pressure increase up to middle age. By age 50, the diastolic pressure levels off, while the systolic pressure continues to increase.
  • Gender: High blood pressure is more common in men up to middle age. Women are more prone to hypertension after menopause.
  • Genetics: High blood pressure often runs in families.
  • Race: More than 40 percent of blacks have hypertension, and it often develops earlier in life.
  • Weight: Those who are overweight or obese have a larger volume of blood, which increases pressure on artery walls.
  • Alcohol: Having more than two drinks a day can elevate blood pressure.
  • Smoking: Chemicals in tobacco can damage and narrow arteries.
  • Sedentary lifestyle: Inactivity causes higher heart rates, which elevates pressure on arteries and makes the heart work harder.
  • Poor diet: A diet that is high in salt, fat and sugar can raise the risk of both high blood pressure and obesity.
  • Other conditions: High cholesterol, sleep apnea, diabetes and kidney disease all increase the risk of hypertension.

For assistance in assessing your risk, check out the High Blood Pressure Health Risk Calculator from the American Heart Association.

Frequent Testing is Key

bpcuff You know the drill; every time you visit the doctor, a nurse checks your blood pressure. This is not just a formality — it’s an important medical precaution. And for those who have a high risk for hypertension or already have high blood pressure, once a year is not enough.

“If you have borderline or high blood pressure, it’s well worth investing in an at-home blood pressure kit,” says Fish. “You are more apt to take regular readings if you can do so at home.”

Fish recommends that those with blood pressure monitors take them to their physicians to check the monitor's accuracy as well.

“I also recommend that patients check their blood pressure at various times of the day and in different situations," Fish adds. "If you take medication and your reading is lower in the morning and higher later, you may need to speak with your doctor about changing the time that you take your medication. Additionally, if you start to identify stressful situations that trigger elevations in your blood pressure, it may serve as a motivation to make positive lifestyle changes such as exercising and general stress reduction.”

A number of pharmacies have in-store blood pressure equipment as well. While these can work in a pinch, there’s no way to calibrate them with your physician.

“For those with medical conditions like atrial fibrillation, a machine may not even pick up high blood pressure,” says Fish. “If you have cardiovascular issues or risks, I recommend staggering your twice-yearly appointments with your cardiologist and primary care physicians so that you are seen by a physician every three months if possible.”

Improving Your Numbers

The reason for frequent blood pressure readings is to aim for early diagnosis and treatment. If your reading is high, you’ll also need to come back for more frequent checks, and your physician will discuss lifestyle changes with you. Actions that can help to reduce blood pressure readings include:

  • Maintain a healthy weight.
  • Exercise regularly (30 minutes of moderate intensity activity, such as brisk walking, five days a week).
  • If you smoke, quit.
  • Eat a heart-healthy diet, such as the DASH (Dietary Approaches to Stop Hypertension) Diet, which is low in fat and sodium and rich in fruits, vegetables, whole grains and low-fat dairy.
  • Avoid excess alcohol, having no more than one drink daily for women and two for men.
  • Manage stress.
When Medication is Needed

If your blood pressure readings exceed 140/90 on two occasions or more (or 130/80 if you have diabetes or kidney disease), and lifestyle improvements have been attempted or are in place, your physician will likely prescribe medication to lower or control levels and reduce health risks and complications.

“Many patients are surprised when they are given more than one medication,” explains Fish. “Sometimes we need to add a second agent because despite being on the maximum dose of an antihypertensive medication, the patient’s blood pressure is still not well controlled. In other cases, side effects are an issue. Some patients tolerate lower doses of two medications better than a higher dose of a single agent.”

While there are many options for medication to reduce blood pressure, here is an overview of some of the types of medications you may be prescribed.

Diuretics: Likely one of the oldest drugs used to treat high blood pressure, they help the body to eliminate excess salt and water. This makes it easier for the heart to pump and decreases the risk of heart attacks, strokes and blood clots.

Beta blockers: These medicines reduce the amount of blood used by the heart by decreasing the effect of adrenaline.

Calcium-channel blockers: These medicines enhance blood flow by reducing calcium absorption in cells of the heart and arteries, reducing the force of the heart’s contraction, and opening narrowed blood vessels.

ACE inhibitors: This medicine blocks the body’s chemical actions that constrict blood vessels, helping to ease both cardiac and kidney functions.

Alpha-2 receptor agonist: This medication works by decreasing the adrenaline-producing activity of the involuntary nervous system.

Raising Awareness, Lowering Risk

Because blood pressure counts rise in winter, frequent checks and wise lifestyle choices are even more imperative now.

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

With the right choices, whether you are currently hypertensive or not, you can be in fine shape to emerge from the winter doldrums and greet the spring!

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

December 2012