Exercise

By Dean Ornish, MD

Moderate exercise provides much of the health benefits of more intensive exercise but with a lower risk of injury or sudden cardiac death during exercise. The greatest reduction in premature death is between those who walk and those who are sedentary.

Walking is the preferred form of exercise, 30 minutes per day or one hour three times per week at 50% to 80% of their maximum heart rate.

From a fitness standpoint, more is better, but only if you do it on a regular basis. What gets people in trouble is when they are weekend warriors -- being sedentary six days a week and exercising intensively (e.g. shoveling snow, playing basketball) on the seventh.

Tips - Simple Choices, Powerful Changes

Do what you like. Do you prefer to be inside or outside? By yourself or with others? Be creative. Is there a walking group in your community or at a club, a mall, or a rec center? Put on a favorite CD while doing household cleaning to start tapping your feet and moving your body with more vitality; make it fun. While you take the kids to a lesson at their dance studio or skating rink, take a walk or a lesson yourself.

Set a routine. Pick a time that works for you to exercise, then make it a habit, like brushing your teeth.

Find a reason to walk or exercise. If you work at a computer, step up and out of your station every hour. Even a few minutes here and there add up, so if you walk to the water cooler and up and down a flight of stairs once, you are burning calories that can shed a pound or two of fat over time. Participating in charity fund-raising walks with friends is a fun way to share time while contributing to a benefit.

Build in Rewards. You are much more likely to stick to an exercise routine if you find something that makes you look forward to your workout. Many gyms have televisions where you can watch favorite sitcoms, get the daily news, or catch sports highlights. Bring your Walkman and listen to favorite music, audio books, or anything that will give an inspirational or devotional tone to your exercise routine.

Another viewpoint - How It Works

When exercising, your body uses one of two systems to produce energy --the aerobic system and the anaerobic system.

The aerobic system uses oxygen to convert carbohydrates in your body to energy, and it can fuel long, sustained exertion. The anaerobic system, by contrast, grabs energy stored in your muscles in the form of glycogen to fuel short bursts of activity like sprinting or lifting heavy objects. This system doesn't draw on oxygen and only provides energy for brief activities. It also pours out lactic acid as a byproduct and causes that achy, used-up feeling.

According to the American Council of Exercise (www.acefitness.org), interval training may allow you to enjoy the benefits of anaerobic exercise without the burning muscles. It involves alternating high-intensity and lower-intensity exercise within a single workout. The Swedes have given it the name fartlek, which means, "speed play."

In the Laval University study, for example, participants alternated between 3 minutes of moderate-intensity step aerobics and 1 minute of high-intensity stepping, repeating the cycle eight to ten times.

According to Wayne L. Westcott, PhD, fitness research director at the South Shore YMCA in Quincy, Massachusetts, interval training is "absolutely the best" for both beginners and high-end athletes. "High-end athletes all train that way," he says. "It's not necessarily the easiest, but it is the best."

Heart and Mind Benefit

"The most important phase of exercise for heart health," Westcott explains, "is immediately after the bout of exercise -- the recovery period. In interval training, you get multiple recovery periods [as you switch to low-intensity bouts] and thus an enhanced heart response."

Another important advantage of interval training is that it can help combat boredom. "Go into the standard gym," Westcott says: "Everyone is walking on treadmills or riding exercise bikes. Although these are expensive machines with readouts of every kind, usually the dials are covered by a towel or newspaper. The exercisers don't want to know how much longer they have or how much farther they need to go. They are bored."

Contrast this, he says, with getting on the bike and setting it for the first 5 warm-up minutes at 50 watts, then jumping to 4 minutes at 125 watts. "That's 4, not 30," he emphasizes. "It's hard but you can do it."

For the next 4 minutes, dial down to 75 watts. "Suddenly, this seems easy, almost fun," Westcott exclaims. "You start enjoying it, instead of waiting for it to be over." Then back to 125 watts! "You should do three sets of the 125, 75, then a cool-down of 50 watts."

Boost Your Immune System

How do you decide your maximum? "Most people exercise at 70% of their maximum heart rate," Westcott says. "You can use the talk test: At maximum, all-out effort, you should not be able to talk except to say yes or no. At mid-effort, you could probably utter a sentence or two. And at low, effort, you should be able to hold a conversation."

To interval train for 30 minutes on the treadmill, Westcott says, don't walk 3 1/2 miles per hour for 30 minutes but instead try doing five intervals of 6 minutes each. Begin with 6 minutes at 3 miles per hour, then 6 minutes at 4, then another 6 minutes at 3, then 6 at 4, and finally a cool-down of 6 minutes at 3.

This gives you the same workout--30 minutes at an average of 3 1/2 miles per hour--but with more work effort than your body would normally produce.

As an added benefit, you may even boost your immune system. Researchers at Texas Christian University in Fort Worth recently did a small study on 10 volunteers. Exercisers had significantly higher counts of immune cells, and that immunity was highest after the second round of bike riding.