How do I reset my tolerance?

Halve your daily dose for four or five days, then halve it again, rather than quitting outright. You keep the withdrawal headaches manageable and most people find the performance effect returns noticeably within two weeks. Then reintroduce it as a tool on hard training days rather than a default every morning.

Caffeine and Training Performance

Caffeine and Training Performance from CrossFit BC. How much caffeine helps performance, when to take it, why it wrecks your sleep six hours later, and how to reset a tolerance that has crept out of control.

Written by:: CrossFit BC Coaching Team
Section:: Nutrition
Reading time:: 9 min
Topics:: caffeine, coffee, performance, sleep, supplements, energy
Published:: Saturday, August 15, 2026
Last updated:: Sunday, August 16, 2026

Caffeine and Training: How to Use It Without It Using You

This article is part of the CrossFit BC journal, written by the coaching staff who run our classes in Olympic Village, Vancouver. We publish what we teach on the floor: training decisions, recovery, nutrition, and the honest tradeoffs behind them.

Common questions

How much caffeine improves performance?

Roughly 3 to 6 mg per kilogram of body weight taken 45 to 60 minutes before training. For a 75 kg person that is about 225 to 450 mg, or two to four cups of brewed coffee. Beyond that range the performance benefit plateaus while the jitters, elevated heart rate and sleep disruption keep climbing.

How late is too late for coffee?

Caffeine's half-life is about five to six hours, longer if you are a slow metaboliser or on certain medications. A 400 mg dose at 4pm still leaves roughly 100 mg circulating at 4am. A practical cut-off is eight to ten hours before bed, which for most Vancouver schedules means nothing after about noon or 1pm.

Does caffeine dehydrate you?

Not meaningfully at normal intakes. The mild diuretic effect is offset by the fluid in the drink itself, and habitual consumers adapt further. Coffee counts toward your daily fluid intake.