NEW YORK (Reuters Health) - Obese children may have a hard time exercising because of the effort needed to move their larger bodies -- not because their hearts aren't up to the challenge, according to a new study. The findings, published in the journal Pediatrics, suggest that significantly overweight children should stick with low-intensity activities -- such as walking at an easy pace -- so that they don't fade quickly or ultimately give up on exercise. The study included 129 obese and 34 normal-weight teenagers who underwent fitness tests on a stationary bike. During higher-intensity cycling tests, both groups of...