Peak Oxygen Uptake and Physical Activity in 11- to 16-Year-Olds.

The present study examined the relationship between peak V̇O₂ and habitual physical activity in 11- to 16-year-old students. The peak V̇O₂ of 111 girls and 85 boys was determined using treadmill or cycle ergometry. Habitual physical activity was estimated from minute-by-minute heart rate monitoring over three 12-hr periods during normal school days. Over half of the girls and one third of the boys failed to sustain a single 10-min period with their heart rate at or above 140 bpm. Only one boy sustained a daily 20-minute period with a heart rate at or above 160 bpm. During Saturday monitoring over 90% of the girls and 75% of the boys failed to sustain a single 10-min period with their heart rate at or above 140 bpm, and only one girl and four boys sustained a 20-min period with their heart rate at or above 160 bpm. No significant relationship was detected between peak V̇O₂ and heart rate indicators of habitual physical activity. This study suggests that few children have periods of physical activity of sufficient intensity and duration to stress the cardiopulmonary system.