Exercise, nutrition are complementary


September 06, 1994|By Colleen Pierre | Colleen Pierre,Special to The Sun

Nutrition and fitness are so intertwined that it's often hard to tell where one ends and the other begins. Eating well provides all the building blocks for a healthy body. Exercise without good nutrition has limited ability to improve body parts and body function.

But food alone won't do it, either. Even when you're eating all the right stuff, you need a well-tuned delivery system to get the building blocks to muscles, heart, lungs and other "building sites." Your cardiovascular system is often touted for its ability to protect against heart disease and deliver oxygen to exercising muscles. And it's also responsible for delivering amino acids, vitamins, minerals and water to all your body's cells.

But fitness can be hard on your health.

We learned that years ago. In the midst of the running frenzy, which spilled over into the aerobic dancing craze, shin splints and stress fractures created the sports medicine boom. To be injured was to be alive.

Our battle scars offered war-story material, excuses for poor race performance and medically enforced reasons to take a day off. (Although one of my friends did hobble a mile on crutches . . . just to maintain a daily running string of several years.)

Then masochism took a back seat, and "low-impact" was born. To our amazement we found we could reduce injuries. All we had to do was stop hitting the ground so hard.

Newcomers were encouraged to walk, not run. Runners lowered impact by choosing better shoes and softer surfaces, and by running fewer miles.

Some cross-trained, mixing in swimming and cycling. Others just switched to cross-country ski machines or a variety of stationary equipment. Aerobic dancers learned to keep one foot on a "suspended" floor at all times -- no more jumping, leaping or bouncing on tile-over-concrete gymnasium floors.

But we didn't want to give up the cardiovascular power we developed through high-intensity workouts. With heart rates at 60-80 percent of maximum, we were pumping plenty of blood, strengthening heart muscle and squeezing out the most fitness for the time invested.

Could low-impact and high-intensity co-exist peacefully? Absolutely. Impact is about how hard you hit the ground. Intensity is about how hard your heart beats. We learned that we could get the same intensity by using our upper bodies more. By including big arm motions or using light weights, we could get our heart rates into target range without hitting the ground so hard.

We also learned to take some time off. Research confirmed what our bodies were telling us. Rest is critical to prevent injuries. We learned to take one day off each week. Beginners began by exercising every other day. Veterans got hooked on "hard-easy" training -- working out intensely one day, and lightly, for recovery, the next.

Occasionally, some of these lessons get lost in the translation.

You can judge the impact of others' workouts just by watching. You can see how hard they hit the ground. You can observe whether they keep one foot on the ground, as in a step aerobics workout, or go leaping off into space as in old-style aerobic dancing.

But it's nearly impossible to judge the intensity of someone else's workout, because intensity is about heart rate. Out-of-condition beginners often develop high heart rates quickly, although they appear to be doing very little work. They're moving slowly. Not keeping up with the group. Not covering as much ground.

But their hearts are beating rapidly, because the heart, itself, is just a muscle, and it, too, gets out of shape. It has to pump faster to deliver oxygen to other muscles that are trying to get in shape. Beginners should be encouraged to take their time and go at a comfortable pace, rather than trying to keep up with the group. Although their bodies are going slowly, their hearts are working hard.

For beginners, any exercise day is a "hard" day, even if they don't go very far or last very long, and will require a rest day tomorrow. Gradually, they'll build endurance, so workouts get longer. At the same time, the heart muscle will be getting sturdier. Each beat will be stronger, pumping more blood and delivering more oxygen with each contraction. So it doesn't have to beat as fast to do the same amount of work. and it will take more and more activity to achieve the same target heart rate.

Before long, beginners will be veterans, going as long and as strong as everyone else in the class, but the intensity of the workout will be the same as it was in the beginning. Their bodies will be going faster, but their hearts will beat comfortably at 60-80 percent of maximum heart rate, delivering body-building nutrients along with all that oxygen.

Colleen Pierre, a registered dietitian, is the nutrition consultant the the Union Memorial Sports Medicine Center and Vanderhorst & Associates in Baltimore.

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