Blood pressure, heart rate, blood cholesterol, blood glucose (sugar): it’s good to know your numbers

May 17, 2011

Doctor checking blood pressure

"I'm running out of gas." "I feel like I've got a flat tire." These days, sometimes it's hard to tell whether a person is talking about their car or their health. Then again, we need both our bodies and our cars running right if we want to get around.

That's why we're here to talk about our bodies' "dashboard signs." These are numbers or measurements that show whether our health is good, or whether we need attention – sometimes right away. To take the link a little further, you could even say our bodies have "check engine" lights.

Bottom line? It's important to know the signs of good health and the signs that something's wrong. It's just part of keeping your body running smoothly. So let's take a look at the human "health dashboard" and see what some of these numbers mean.

Blood pressure

If there's a true "check engine" light on the human dashboard, it's our blood pressure readings. Good news: blood pressure is one of the easiest numbers to keep an eye on. If you've been into a drugstore or even the grocery, you've seen the machines that test your blood pressure for you. Our advice? Use them! The more you keep track of your health, the better your chances are of heading off any problems in their early stages.

So what is blood pressure? The American Heart Association describes it as the force caused by blood going through your arteries as your heart beats. (Think of water in a garden hose. The higher the water pressure, the more strain on the hose.) One number, the systolic number, shows the pressure of blood when your heart is pumping. The second, or diastolic, number shows the pressure on your arteries when your heart rests between beats. WebMD says it's easy to think of them as "top" and "bottom" numbers: systolic is the "top" or "beating" number, and diastolic is the "bottom" or "resting" number.

Using this method, normal blood pressure would be "120/80." It's usually spoken as "120 over 80." This means when a healthy heart is beating the pressure in the arteries is 120 mm Hg ("mm Hg" is a medical measurement that means "millimeters of mercury") and when it's resting between beats the pressure drops to 80 mm Hg.

High blood pressure is when the systolic (top) number is higher than 140 and the diastolic (bottom) number is 90 or more.

"Borderline" high blood pressure is when systolic (top) pressure is between 120 and 139 and diastolic (bottom) pressure is between 80 and 89.

Consistently high blood pressure is almost always a sign something's wrong. Your blood pressure may be high after exercise or emotional stress. That is normal. That's the way the body uses the blood pressure to force oxygen out to the tissues. But consistently elevated blood pressure takes its toll on your heart, kidneys and brain. So it's important to know your blood pressure. If it's normal, have it checked at least once every two years. If your blood pressure is high, see a doctor right away. High blood pressure is both a symptom and a cause of heart problems, and it's one of our country's top causes of death. But it can be controlled more easily than you might think.

A chart of normal, "borderline," high, and "crisis zone" blood pressure levels from the American Heart Association is at http://bit.ly/dvvdCv.

Heart Rate

Your heart rate is how many times your heart beats each minute. This number changes as your level of activity changes. After all, a heart at rest doesn't have to work as hard as a heart that's under stress.

The first thing to know is your resting heart rate. The Mayo Clinic describes a simple method: First, sit still for a few minutes. Then turn your hand palm up and check your pulse by putting your index and third fingers on top of your wrist. You can also put them on the side of your neck near your windpipe. Count the number of times you feel your pulse beat in 10 seconds. Multiply this number by 6, and this should be your resting heart rate.

The Mayo Clinic says a normal resting heart rate is between 60 to 100 beats per minute. The American Heart Association says it's between 60 and 80. What's best for you? See your doctor and find out.

Remember that stress, weight, fitness level, any medicines you're taking, the air temperature, and your body position all change your resting heart rate. So if your heart rate's up, you may want to check again after a few minutes of rest.

Also, people who work out and are fit often have lower heart rates, sometimes as low as 40 beats per minute.

So now you know your resting heart rate. Great! What next? Well, depending on what your doctor says about your fitness, you may need to know about your target heart rate, too. This rate is about how fast your heart needs to beat during exercise to get healthier.

The American Heart Association says target heart rates depend on age and fitness level. To find yours, measure your pulse as you exercise. Then, try to keep the number you come up with somewhere between 50 percent and 85 percent of your maximum heart rate. (To get your maximum heart rate, subtract your age from 220.)

Blood glucose

Blood glucose measures a kind of sugar, or glucose, in your blood. Glucose comes from foods with carbohydrates, and is the main way your body gets energy. Your blood glucose affects other functions in your body, including insulin production. Your pancreas releases insulin to control blood glucose levels.

This is why knowing your blood glucose numbers really counts. If your pancreas doesn't make enough insulin to control your glucose, you could be in danger. Long-term high blood glucose can hurt kidneys, nerves, blood vessels, and the eyes. Glucose is also the key sign of diabetes. And diabetes is the disease behind all kinds of health problems.

Glucose testing is used not only to check for diabetes, but also to check on and control diabetes in people who already have it. WebMD has a very good article on glucose and glucose testing. It lists the following numbers as normal for adults without diabetes.

Fasting blood glucose (glucose measured after not eating for at least 8 hours): 70-99 milligrams per deciliter (3.9-5.5 mmol/L)

Postprandial blood glucose (glucose measured 2 hours after eating): 70-145 mg/dL (3.9-8.1 mmol/L)

Random or "Casual blood glucose" (glucose measured throughout the day): 70-125 mg/dL (3.9-6.9 mmol/L)

Another new number: "Prediabetes" glucose levels

Lately we've been hearing another new term: "prediabetes." Basically, it's what people have before they're diagnosed with Type 2 diabetes. Prediabetes means you have all the risk factors for diabetes but just hasn't quite into diabetes yet (though research says you usually will within 10 years).

Prediabetes is tricky. It doesn't have symptoms, at least not the way we think of them. On the plus side, knowing you have higher-than-normal blood glucose (blood sugar) levels and controlling them can stop the downward slide into diabetes. An article on the popular health website SparkPeople.com says that fasting glucose levels between 100 mg/dL and 125 mg/dL are called "Impaired Fasting Glucose." For glucose tolerance (measured after drinking a glucose-rich beverage), levels between 140 mg/dL and 199 mg/dL are seen as "Impaired Glucose Tolerance."

Blood cholesterol

The last number that's good to know is actually three numbers. We're talking about the three numbers that make up your overall blood cholesterol. The American Heart Association says all adults over the age of 20 should have a total blood cholesterol test done once every five years.

Healthy cholesterol is very important. It plays a major part in avoiding heart disease, stroke, and even diabetes. The American Heart Association lists the three basic kinds of cholesterol and their healthy ranges as:

LDL ("Bad") Cholesterol

Less than 100 mg/dL is "optimal"

100 to 129 mg/dL is called "near or above optimal"

130 to 159 mg/dL is "borderline high"

160 to 189 mg/dL is "high"

190 mg/dL and above is "very high"

HDL ("Good") Cholesterol

Levels of 60 mg/dL or above are healthy.

HDL levels of less than 40 mg/dL for men or less than 50 mg/dL for women are risk factors for heart disease or stroke.

Triglycerides (the most common form of fat in the body)

Less than 150 mg/dL is "normal"

150-199 mg/dL is "borderline high"

200-499 mg/dL is "high"

500 mg/dL and above is "very high"

Total Cholesterol

Less than 200 mg/dL means a lower risk for heart or artery disease.

220-239 mg/dL is seen as "borderline high"

240 mg/dL or above is "high blood cholesterol." People with high blood cholesterol have twice the risk of heart diease than people with total blood cholesterol below 200 mg/dL.

The American Heart Association website has a very helpful quiz about cholesterol. You can take the quiz here.

A note about Metabolic Syndrome

"Metabolic syndrome" is a group of risk factors that place people at a greater risk for cardiovascular disease and diabetes. When all the risk factors are seen together, the chances for problems like heart attack or stroke are much higher than if a person has only one or two of them. The American Heart Association says about 34% of Americans have metabolic syndrome. The main signs of metabolic syndrome are

  • Abdominal obesity
  • Triglyceride level of 150 mg/dL or greater
  • HDL cholesterol of less than 40 mg/dL in men or less than 50 mg/dL in women
  • Systolic blood pressure (top number) of 130 mm Hg or greater
  • Diastolic blood pressure (bottom number) of 85 mm Hg or greater
  • Fasting glucose of 100 mg/dL or greater

Is it time to go in for a tune-up?

If you don't know your numbers, why take chances? Your doctor can help you learn what you need to know and help keep your body running smoothly. And if you're heading for trouble? Your doctor can help you get back on the road to good health, too. It's easy once you know how.

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