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How Much is Enough

September 30, 2013

Eight glasses of water a day. Eight hours of sleep a night. We’ve all heard the advice about how much water, exercise, and sleep we need to stay healthy. There is some truth to the numbers, but there are differences from person to person, and even from season to season. Duke Primary Care providers help you understand what's important.

Numbers Don’t Lie (Down)

Inadequate sleep can do a number on our ability to get through the day. Should we aim for a solid eight hours?  Julie Lindsey, MD, a family medicine doctor in Chapel Hill, says, “There is no magic sleep number. The average adult needs 7 to 8 hours of sleep each night to feel their best.”

Sleep is best gauged by how you feel when you wake up, she explains. “If you feel refreshed after less than eight hours, then you are probably fine. If you feel refreshed after nine hours, then you may have a higher sleep requirement."

Your quality of sleep is just as important as quantity. “If you never feel refreshed no matter how much sleep you get, it’s time to make a change," Dr. Lindsey says. "Exercise and stress management are a good place to start, as inadequate physical activity and stress can disturb sleep." If the sleep disruption or fatigue persists, it’s time to see your doctor. “That could be a sign of a sleep disorder, a medical condition, or depression.”

Eight Times Eight

The other “eight” we often hear is in reference to glasses of water -- specifically eight, eight-ounce glasses a day. Like the sleep number, this one has some truth to it -- although it’s not a hard-and-fast rule. Michael Richards, MD, an internal medicine doctor, notes that typical drinking glasses hold more than eight ounces. If you’re using a 12- to 16-ounce glass, then drinking one glass of water at each meal may be sufficient.

There are good reasons for drinking all that H20. “Drinking enough water helps us maintain healthy blood pressure and good kidney function,” Richards says. “We lose water every day just by breathing -- especially when the weather is dry, as it is in the winter.”

If you’re eating plenty of fruits and vegetables, he adds, you’re getting water that way. In that case, four glasses may be all you need.

Take 30

When it comes to moving our bodies, the numbers you’ve heard are right. We need aerobic activity three or more times a week for at least 30 minutes at a stretch, and more is better.

“Exercise doesn’t have to involve sweating, straining, and discomfort,” Dr. Lindsey says. “A brisk walk with a friend counts, and keeping it fun makes it more likely that you will keep it up. Anything that gets your heart rate up counts towards heart health.”

Who’s Counting?

Dr. Lindsey cautions against obsessing over calories and the numbers on the scale. Weight loss efforts can be discouraging if you focus too much on restricting yourself and on short-term weight loss. “The best weight loss program is to fill your life with meaningful activities, set positive goals, and take steps every day toward those goals," she says. Rather than watching the scale, measure success by how many days a week you exercise and how many days a week you eat healthy meals at home. "By focusing on making permanent lifestyle changes, weight loss will ultimately happen. If you don't see results, seek out more accountability and support from a friend or a formal weight loss program. Your doctor is a good resource.

Counting calories can play a role when you're gaining weight, Dr. Lindsey says. “Generally, if you’re eating plenty of fruits and vegetables, your belly will be full and you’ll be getting adequate calories and the
 right nutrients.”

Daily Allowance

A diet rich in fruits and vegetables is the best way to get the vitamins you need. But in the winter, when access to fresh produce is limited, you may want to consider a multivitamin. “Even if you’re eating produce in the winter, it’s likely been shipped from the Southern Hemisphere or California,” Richards says. “It loses a lot of nutrients in transit.”

For women in their childbearing years, folic acid supplementation is important. “Nearly half of all pregnancies in America are unintended,” Dr. Lindsey says. “Women need to be on a vitamin with folic acid before becoming pregnant to help ensure the fetus develops properly.” Women who are trying to conceive or not using a reliable method of contraception should take a prenatal vitamin with 800 mcg of folic acid.

Everyone needs vitamin D, and most of us are deficient. The easiest way to get it is through direct access to sunlight. In the winter months, when our access to sunlight is diminished, we’ve got to make up the difference. A daily vitamin D supplement that’s 1,000 to 2,000 IUs should do the trick.

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