BODY WATCH : No Sweat; It Isn’t That Hard

Lack of time--a favorite excuse to avoid exercise--isn’t the only obstacle to shaping up. Outdated beliefs are also to blame, according to the Shape Up America campaign, sponsored by the C. Everett Koop Foundation. A survey of 1,000 adults found that:

* 62% believe exercise has to be sustained continuously for at least 30 minutes a session. But accumulating 30 minutes over the course of a day is an option too, says Steven Blair of the Cooper Institute for Aerobics Research.

* 90% think exercise must be repeated three times a week for at least 20 minutes a session. Experts say those levels lead to cardiovascular fitness but that more moderate activity can also provide health benefits.

* 66% believe exercise must be vigorous enough to raise a sweat. But experts say activities that don’t normally result in profuse perspiration, like gardening and vacuuming, count as exercise too.