Study suggests hour of daily exercise

A 30-minute exercise routine and one-size-fits-all dietary rules are no longer the best guidelines for a healthy lifestyle, according to a new study from the Food and Nutrition Board. Its report, however, has garnered mixed reviews from the Duke community.

The Food and Drug Administration-funded study proposed an hour of moderately high-intensity exercise daily, as well as a new range for consumption of the various macromolecules found in food--carbohydrates, fats and proteins--in an effort to maintain good health and protect against diseases.

Previously, the Office of the Surgeon General had recommended 30 minutes of moderate-to-high-intensity exercise three to four days a week.

Researchers determined the baseline for exercising to be an hour of walking at four miles per hour every day, and only higher-intensity exercise would allow for shorter workouts. They found this optimal level of exercise by measuring subjects' use of water and energy for three weeks, concluding that healthy people expended an amount of energy corresponding to an hour each day spent walking at four miles per hour.

Joanne Lupton, chair of the Food and Nutrition Board, said people must exercise every day to reap its full benefits.

"There is a carryover effect from the exercise that is saved in your metabolic rate," Lupton said. She added that taking a day off from exercise would require both compensating for the break on the other days and a decrease in caloric intake for that day.

Lupton cautioned that the "hour-a-day" exercise recommendation includes activities such as walking up the stairs or doing housework, but that these activities would probably not be intense enough to satisfy the requirement without additional exercise.

The current dietary recommendations endorsed by the Food and Drug Administration are represented by the food pyramid and recommended daily allowances for vitamins and minerals. The new guidelines, released Sept. 5, are different in that they suggest a range of macromolecules for ideal consumption, allowing greater leeway in acceptable diets.

Eisenson said the liberalization of the food guidelines allowed a wider variety of diets to be included. However, he said the ranges were more a guide to health care workers than to the general public, saying most people will not be able to correlate the ranges to their diet and apply the guidelines properly.

Franca Alphin, student health services dietitian, was encouraged by the new findings. "I certainly think we had to make a change in the dietary guidelines," she said.

But in regard to exercise, Alphin said an hour a day is an excessive recommendation, particularly for less active people.

"The only fear I have is the group that we are trying to target are the sedentary, and they are going to be blown away," she said.

Alphin also criticized the study's recommendation to exercise seven days a week. Exercisers should either take one day off or, if they are going to exercise, take an easy day at the gym, she said. In direct contrast to Lupton's comments, Alphin said people should not have to make up a missed day or cut back on calories on a day they do not exercise.

She also emphasized that consistency is more important than quantity. "The bottom line is what you are willing to do on a regular basis," she said.

Many students had similar reactions to the new findings.

"I just don't think people should work out every day--it seems too destructive," sophomore Megan Marshall said. "I don't think it's that necessary."

On the other hand, varsity volleyball player Krista Dill was impressed with the guidelines. "I feel that exercise is so important. Sometimes we forget about treating our bodies well."

Dill, a junior, said being an athlete makes her more conscious of what she eats. "The problem with nutrition is that they try to set these percentiles," she said. She added that one's optimal weight is body-specific, and that finding it is important to leading a healthy life.