Mixed

Caffeine ingestion (median 6.0 mg/kg) significantly reduces Rating of Perceived Exertion (RPE) during constant-load exercise compared to placebo, an effect that partially explains the subsequent improvement in exercise performance.

Take approximately 6mg of caffeine per kg of body weight about 60 minutes before exercise. Ensure you have abstained from caffeine for at least 24 hours beforehand. This will likely lower how hard the exercise feels during the activity, allowing you to sustain higher intensities or durations, particularly if you are well-trained. Note that this reduction in perceived effort does not necessarily persist at the very end of an all-out exhaustion test.