# Effect of β-blockade on measures and reproducibility of heart rate, oxygen uptake and work rate across repeated bouts of short-duration, RPE-regulated exercise

## TL;DR

This study shows that beta-blockers reduce heart rate and oxygen uptake during exercise but do not affect relative exercise measures, making RPE-regulated workouts reliable for people on these medications.

## Contribution

The study demonstrates that beta-blockade does not impair reproducibility of RPE-regulated exercise despite reducing absolute physiological responses.

## Key findings

- Beta-blockade significantly reduced heart rate, oxygen uptake, and work rate during exercise.
- Exercise responses were consistently higher at RPE 15 than RPE 13.
- Reproducibility of exercise measures remained high despite beta-blockade.

## Abstract

We examined the effect of β-blockade on measures and reproducibility of heart rate (HR), oxygen uptake (\documentclass[12pt]{minimal}
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\begin{document}$${\dot{\rm{V}}}{\rm{O}}_{2}$$\end{document}V˙O2) and work rate (WR) across repeated bouts of short-duration, RPE-regulated exercise.

Participants completed an RPE-regulated, interval-based exercise session under control and β-blockade conditions with six 3-min bouts alternating between RPE 13 and RPE 15, separated by 2-min active recovery periods. Participants adjusted treadmill speed/grade to meet the target RPE. Linear mixed effects models assessed the effect β-blockade on exercise responses for each RPE, while intraclass correlation coefficients (ICC) and coefficients of variation (CV) evaluated reproducibility across bouts.

β-Blockade significantly reduced HR (− 36.5 beat min−1, p < 0.001), \documentclass[12pt]{minimal}
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\begin{document}$${\dot{\rm{V}}}{\rm{O}}_{2}$$\end{document}V˙O2 (− 4.2 mL kg−1 min−1, p < 0.001) and work rate (− 0.6 METs, p = 0.022) during exercise. Differences between conditions remained significant for %HRpeak (p < 0.001) but not %\documentclass[12pt]{minimal}
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\begin{document}$${\dot{\rm{V}}}$$\end{document}V˙O2peak or %WRpeak (p > 0.05). Exercise responses were consistently higher at RPE 15 than RPE 13 (all p < 0.001). A significant interaction showed greater HR reduction at RPE 15 (45.5 beat min−1) than RPE 13 (40.0 beat min−1) under β-blockade (p = 0.041). ICC values indicated good to excellent reproducibility across bouts, with no significant difference between conditions. Variability across bouts was low (mean CV = 2–8%) and unaffected by β-blockade.

Our findings suggest that despite significant reductions in absolute responses, β-blockade does not affect relative measures of \documentclass[12pt]{minimal}
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\begin{document}$${\dot{\rm{V}}}$$\end{document}V˙O2 or work rate. RPE-regulated exercise may facilitate highly reproducible exercise intensities, making it particularly valuable for populations where β-blocker use is prevalent.

The online version contains supplementary material available at 10.1007/s00421-025-05818-x.