Habitual preexercise caffeine supplementation prevents exercise training-induced attenuation of exercising systolic blood pressure and double product

We examined the effect of habitual preexercise caffeine supplementation on training-induced adaptations to exercising systolic blood pressure (SBP), diastolic blood pressure (DBP), pulse pressure (PP), heart rate (HR), and double product (DP). Young women (means ± SD; 24 ± 7 yr) were randomized to a caffeine (120 mg) supplement (CAF; <i>n</i> = 17) or placebo (PLA; <i>n</i> = 16) group, completed 6 wk of high-intensity exercise training on three nonconsecutive days per week, and supplemented with CAF or PLA 30-60 min before exercise or else upon waking. Before (PRE) and after (POST) the intervention, SBP, DBP, and HR were measured and PP and DP were calculated, at rest and during fixed-power exercise at 50 and 75 W. Statistical analyses included three-way mixed-factorial ANOVAs with post hoc comparisons as necessary. Group × intensity × time interactions were observed for SBP (<i>P</i> = 0.0105) and DP (<i>P</i> = 0.003). SBP and DP increased with increasing exercise intensity at PRE and POST in both groups. However, although SBP and DP decreased PRE to POST at 50 and 75 W in PLA, SBP and DP did not change at any intensity from PRE to POST in CAF. An intensity × time interaction was observed for DBP (<i>P</i> = 0.006) indicating no change in resting DBP, but reductions from PRE to POST at 50 and 75 W that were independent of group. Main effects of intensity (<i>P</i> < 0.0001) and time (<i>P</i> = 0.03) were observed for HR, and a main effect of intensity was observed for PP (<i>P</i> < 0.0001). Habitual caffeine supplementation blunted training-induced reductions in exercising SBP and DP. Individuals may wish to avoid preexercise supplementation if seeking to maximize the BP-lowering benefits of exercise.<b>NEW & NOTEWORTHY</b> Habitual preexercise caffeine consumption prevented reductions in exercising systolic blood pressure and double product induced by 6 wk of high-intensity exercise in women. Therefore, our findings indicate that habitual preexercise caffeine supplementation may impede beneficial hemodynamic adaptations of exercise training in healthy, young women.