Effect of stimulant medication use by children with ADHD on heart rate and perceived exertion.

The effect of stimulant medication use by children with attention deficit/hyperactivity disorder (ADHD) on the rating of perceived exertion (RPE)-heart rate (HR) relationship was examined. Children with ADHD (n=20; 11.3±1.8 yrs) and children without ADHD (n=25; 11.2±2.1 yrs) were studied. Children with ADHD were examined while on their usual dose of medication on the day of study. HR and RPE, using the OMNI RPE scale, were assessed during a graded exercise to peak voluntary effort. The RPE-HR relationship was determined individually and the intercept and slope responses were compared between groups. The intercept was 132.4±19.5 bpm for children with ADHD and 120.6±15.7 bpm for children without ADHD. The slope was 7.3±1.9 bpm/RPE for the children with ADHD and 8.1±1.6 bpm/ RPE for the children without ADHD. For the group with ADHD the intercept and slope values fell outside of the 95% CI observed in the control group. The altered relationship between RPE and HR with stimulant medication use in children with ADHD has practical implications with respect to the use of HR and RPE to monitor exercise intensity.