Smart Caffeine Timing: Boost Performance and Protect Your Sleep

Key Points

• Caffeine is a proven ergogenic aid, improving endurance, strength, and reaction time while reducing fatigue.

• Timing is crucial: avoid caffeine within 9 hours of bedtime to protect sleep.

• Moderate doses (3–6 mg/kg body weight) deliver benefits for performance.

• Pre-workouts offer precise doses of caffeine for strategic use.

• Balancing performance and recovery means maximising caffeine’s benefits while protecting sleep.

Dr. Crionna Tobin (CT): Caffeine is such a hot topic in performance nutrition. At Optimum Nutrition, I see athletes using it to gain an edge in training and competition every day. But here’s the big question we always come back to: how do you get the benefits without compromising sleep and recovery?

Professor Shona Halson (SH): That’s exactly the challenge. Caffeine is one of the most well-researched ergogenic aids. It can improve endurance, strength, and reaction time, while also reducing fatigue and perceived exertion. But the flip side is that caffeine can significantly disrupt sleep if taken too late in the day or in excessive amounts.

How Caffeine Works

CT: Before we go deeper into timing and dosage, can you explain how caffeine actually works in the body?

SH: Of course. The main mechanism is through the blockade of adenosine receptors in the brain. Adenosine is a chemical that builds up during the day and makes us feel sleepy. By blocking adenosine from binding to its receptors, caffeine essentially “switches off” that drowsy signal.

CT: So, that’s why people feel more alert and focused after caffeine?

SH: Exactly. And in a sporting context, this effect reduces perceived exertion — so exercise feels easier — while also enhancing motor unit recruitment, reaction time, and cognitive function. That’s why caffeine works across endurance, strength, and even skill-based tasks.

Timing of Caffeine Intake

CT: So, it’s not just about whether you take caffeine, but when you take it. With athletes training at different times of the day, timing becomes crucial.

SH: Absolutely. Caffeine has a half-life of about three to six hours in healthy adults, though genetics can make that shorter or longer. Essentially, it means caffeine stays in the body for quite some time. For example, even a cup of coffee with ~100 mg of caffeine should ideally be consumed at least nine hours before bedtime to protect sleep.

CT: That’s why pre-workouts can be so useful. They allow athletes to take caffeine in a targeted, evidence-based way —in the morning— so the benefits for training are maximised but sleep later that night isn’t disturbed. And if someone really enjoys coffee socially in the late afternoon, switching to decaf is a smart swap.

Caffeine Dosage

CT: What about the amount of caffeine? I know athletes sometimes assume more equals better.

SH: Yes, but that’s not the case. Moderate doses of around 3–6 mg per kg of body weight are typically enough to enhance performance. Going higher doesn’t usually improve outcomes, but it does increase the chance of side effects — things like anxiety, stomach upset, and of course, more pronounced sleep disruption.

CT: And again, that’s where pre-workout formulations can be a real advantage. They’re designed to deliver those effective doses without athletes guessing how much they’ve consumed. That makes it easier to enjoy the performance benefits without pushing into the negative effects.

Summary

CT: So really, it comes down to smart use: right product, right dose, right time. That way, athletes can unlock the proven benefits of caffeine and still protect recovery through sleep.

SH: Exactly. Limiting caffeine to earlier in the day, sticking with moderate doses, and being aware of your own sensitivity are the key strategies. Otherwise, there’s the risk of relying too heavily on caffeine just to counter poor sleep, which becomes a vicious cycle.

CT: At Optimum Nutrition, our approach is always to help athletes use tools like caffeine effectively — enhancing performance and supporting long-term recovery. Sleep, nutrition, and training all go hand in hand.

References

• Spriet, L. L. (2014). Exercise and sport performance with low doses of caffeine. Sports Medicine, 44(Suppl 2), 175–184.

• Dunican, I. C., Higgins, C. C., & Jones, M. J. (2018). Caffeine use in athletes: Insights into the role of genetics, habitual intake and sleep. Sports Medicine, 48(1), 1–8.

• McLellan, T. M., Caldwell, J. A., & Lieberman, H. R. (2016). A review of caffeine’s effects on cognitive, physical and occupational performance. Neuroscience & Biobehavioral Reviews, 71, 294–312.

• Clark, I., & Landolt, H. P. (2017). Coffee, caffeine, and sleep: A systematic review of epidemiological studies and randomized controlled trials. Sleep Medicine Reviews, 31, 70–78.

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