Exercise outcomes in prevalent users of stimulant medications

Background: To compare users of stimulant medications with matched nonusers on exercise outcomes during a maximal treadmill exercise test. Methods: A cross-sectional study of a community-based cohort comparing propensity-score-matched stimulant medication users (n=245) and nonusers (n=735) who underwent a maximal treadmill exercise test in the Cooper Center Longitudinal Study cohort from January 1, 1995 to December 31, 2013. Main Outcomes were peak systolic blood pressure (SBP), average rise in SBP, peak heart rate (HR), and estimated VO₂max during exercise. A linear mixed model analysis was used to evaluate the effect of stimulant exposure on each of the exercise outcomes. In a sensitivity analysis, users were compared against nonusers for risk of chronotropic incompetence. Analyses were adjusted for relevant covariates and multiple testing. Results: Peak HR during exercise was significantly lower in stimulant medication users (least square mean estimate 170.2 beats/minute) compared to nonusers (174.4 beats/minute; p<0.0001). Moreover, stimulant medication users had an increased risk of chronotropic incompetence compared to nonusers (adjusted odds ratio 3.28, 95% confidence interval 1.70 to 6.34, p=0.0008). No significant differences were observed in the outcomes of peak SBP, average SBP rise, and estimated VO₂max between matched groups. Conclusions: Stimulant medication use was associated with a significant decrease in peak HR and an increased risk of chronotropic incompetence. Further investigation is required to understand the clinical significance of chronotropic incompetence in stimulant medication users. Concerns that stimulant medication use may increase peak SBP and average SBP during exercise were not supported by this study.