Optimising Caffeine For Waking, Working And Workouts

Introduction

Caffeine is the most widely consumed drug in the world, taken by over 80% of adults worldwide.^1,2 Whether it's a hot cup of coffee to kickstart our mornings, a relaxing cup of tea on our work lunch break, or an energy drink to fuel our exercise, caffeine has become a staple in our daily routines. But are we using caffeine optimally? By understanding how it interacts with our bodies, we can use caffeine strategically to maximise its benefits in our daily lives while minimising any downsides. In this article, we'll explore the science behind caffeine's effects on wakefulness, focus, and physical ability, as well as tips like timing your intake, finding the right amount to take, avoiding side effects, and stopping caffeine from losing its potency. Whether you're aiming to jumpstart your mornings, enhance your focus at work, or boost your performance in the gym, we’re here to help you make informed choices on your caffeine consumption to help you unlock your full potential.

What is caffeine?

Caffeine is a chemical produced by at least 60 different plants including tea (Camellia sinensis), coffee (Coffea arabica, Coffea canephora), and cacao (Theobroma cacao), the basis for chocolate.³ Historians believe caffeine was first used by humans in 2737 BC when the Chinese Emperor Shen Nung boiled water with leaves from a nearby bush, creating tea.³ We’ve been enjoying coffee, tea, energy drinks, soft drinks, chocolate, and some medications to improve our mental and physical performance.

How does caffeine affect the body?

So what does it mean to “improve our mental and physical performance”? Caffeine has several effects on the body, and the main ones are summarised in Table 1. The harmful effects won’t affect everyone but are more likely if you consume a lot or are not accustomed to caffeine. 

How does caffeine have these effects? 

Now that we’ve seen some of the effects of caffeine on the body, it’s useful to understand how it does this. 

The effects of caffeine are primarily due to one chemical; adenosine. Adenosine is a chemical messenger that works throughout the body, particularly in the brain, heart, and blood vessels. Adenosine works by acting on receptors present in the cells. Think of a receptor as a lock and adenosine as a key; only adenosine can fit into the adenosine receptor lock, and when it does it causes an effect. 

Consuming caffeine blocks the adenosine receptors, stopping adenosine from fitting into the lock and turning it on. This has downstream effects responsible for changes in our bodies mentioned earlier. For example, it increases our focus by enhancing dopamine and acetylcholine release in the brain.¹¹

Caffeine’s chemistry and pharmacological effects are too extensive (see here for more information) but how caffeine wakes us up is worth exploring. Adenosine accumulates in our brains throughout the day, binding to receptors to make us feel increasingly tired. It’s only when we sleep that adenosine is cleared out. Caffeine blocks these receptors to stop us from feeling tired. However, while these receptors are blocked, adenosine still accumulates. When caffeine wears off, we experience this adenosine backlog all at once, resulting in the energy ‘crash’ many of us associate with caffeine. Understanding this can help us avoid the crash. 

The general guidance for optimising caffeine

Dosage 

The FDA states that up to 400 mg of caffeine per day is safe for most people (roughly 4 cups of drip coffee). However, that doesn’t mean you should aim for this amount. Caffeine is found in a lot of drinks, some food (see Table 2) and some medications like painkillers, making it easy to overshoot this upper limit.

Stanford University Professor of Neuroscience Andrew Huberman recommends 1-3 mg of caffeine per kg of your weight, daily. This should maximise caffeine’s benefits without leaving you feeling irritable, anxious, or jittery. However, this amount will vary depending on factors like your genetics, anxiety, hydration, and how accustomed you are to caffeine. 

Timing

After consuming caffeine, you can expect to see benefits within 5 minutes, with its effects peaking between 15 and 120 minutes after ingestion. This is only an estimate; factors like genetics can change this, and absorption will be slower if you have coffee with food, particularly fibre.¹²

Caffeine for waking

Many of us who experience that initial morning grogginess when we wake up will immediately reach for a cup of coffee. However, experts suggest this may be deleterious, and point to the adenosine system to explain why. According to Huberman, everyone has some residual adenosine that is not cleared while you sleep. To address this, the body uses another chemical called cortisol, which peaks soon after waking to help clear out the remaining adenosine. However, immediately blocking the adenosine system with caffeine reduces the cortisol peak, stopping it from clearing adenosine.¹³ This creates a backlog, resulting in an ‘afternoon crash’. 

Instead, Huberman suggests that within around 30 minutes of waking, we should expose our eyes to bright light, and ideally do some gentle exercise. These activities amplify the cortisol peak, allowing complete removal of residual adenosine.¹⁴ Then roughly 90-120 minutes after waking, take your morning caffeine. These behaviours will maximise your alertness while minimising fatigue and a post-caffeine crash. 

Caffeine for productivity at work

The ability of caffeine to increase our alertness and focus makes it a powerful tool for productivity. Follow the guidance above for dosage and timing to experience caffeine’s peak benefits. Interestingly, taking caffeine immediately AFTER learning, has been shown to help us gain new information in our memory, so having a small espresso after an intense study session could help you with that next exam!^15,16

Based on this advice, you might be tempted to consume caffeine throughout your workday to stay at peak performance. However, this should be avoided for a few reasons. 

Firstly, sticking to the maximum of 400 mg per day will reduce any negative impacts on health. Furthermore, having too much caffeine too frequently will increase your chances of becoming tolerant to it, meaning you’ll need more and more to have the same beneficial effects. Finally, having caffeine too late in the day will impact your sleep. You might have had a late-night coffee before and fallen asleep just fine, but the quality of your sleep will have been markedly reduced.¹⁷ Sleep is crucial for many aspects of your well-being including aiding alertness and memory, so having too much caffeine to improve your productivity may be harming it.¹⁸ This leads to a vicious cycle; you take caffeine, you have worse sleep or an afternoon crash, so you take caffeine to combat it. 

If you have a coffee, half of the caffeine will still be in your blood roughly 6 hours later (caffeine’s ‘half-life’).¹² Experts recommend avoiding caffeine in the 6-12 hours before going to bed to avoid sleep disturbances. 

Caffeine for workouts

A study of over 20,000 elite athletes showed almost three-quarters used caffeine before or during national or international competitions, and it’s not surprising why; its benefits on strength, endurance, and coordination are well documented.⁵

The advice on dosage and timing of caffeine follows what we’ve already discussed. While we suggested not taking caffeine too early or late in the day, many of us choose to go on an early morning jog or an evening gym class to fit around our busy work schedules. Having caffeine will support this, but is not necessary to have a good workout, and will affect your sleep or fatigue during the day.

Summary

Caffeine is a powerful tool to jump-start our mornings, enhance our productivity at work, and energise our workouts. It's crucial to remember that moderation and strategic use are key to maintaining its effectiveness and minimising side effects or dependence. Experts recommend limiting yourself to 1-3 mg of caffeine per kg of body weight in one sitting and limiting yourself to 400 mg per day. Aim to take it 15-120 minutes before you’d like to experience its peak benefits. Avoid caffeine in the first 90-120 minutes after waking, and in the 6-12 hours before you sleep to minimise sleep disruptions. Although everyone responds differently, with this mindful approach you can make caffeine work for you, tackling all of life’s challenges with energy to spare.