Figure 2.

A-D, Combined violin and bar plots showing treadmill stress testing measurements after nicotine-containing product challenge: peak metabolic equivalents (A), peak rate-pressure product (B), heart rate reserve (C), and 60-s heart rate recovery (D). Age-, sex-, and race- or ethnicity-adjusted analysis of covariance tests to compare the within-group and between-group differences after product challenge. Violin plots show distributions of observed outcomes for within each group. Bar plots depict model-estimated marginal means and associated 95% CIs with covariates fixed at their mean values. P value annotations reflect pairwise group comparisons following significant omnibus main effects. False discovery rate correction using the Benjamini and Hochberg procedure was applied to all four tests. All nominally significant effects in this set survived false discovery rate correction and were followed by specific group contrasts. ENDS = electronic nicotine delivery system; MET = metabolic equivalent.