SLEEP | CAFFEINE
Healthy from the Start Resources for Shiftworkers
What we put into our bodies can impact our sleep more than many people realise.
A few substances to be mindful of are caffeine, alcohol, sleep medication, and recreational drugs.
In general, what we put into our bodies, and when we consume it, can impact the quality and duration of our sleep. You can read more about nutrition and its relationship with sleep, health, and wellbeing as a shiftworker here. Below we cover off some of the substances that can be most impactful to your sleep: caffeine, alcohol, sleep medications and recreational substances.
Caffeine is a natural stimulant found in various foods and beverages and is widely used for its ability to enhance alertness and combat fatigue. Common sources include coffee, tea, energy drinks, soft drinks, chocolate, and certain supplements like caffeine tablets and pre-workout products (66). As a stimulant, caffeine is a popular fatigue management tool amongst shiftworkers, but the appeal of caffeine extends more broadly; it's one of the most consumed stimulants worldwide (67).
Caffeine is a useful tool for managing fatigue as a shiftworker, but it should be consumed with caution. Limit intake to 400mg per day, which is about 2-3 cups of coffee, or an energy drink, plus a serving of pre-workout and some dark chocolate. You’ll get the most out of caffeine if you consume it in 100-200mg doses at a time, and avoid caffeine before sleep as it remains active in your body for several hours.
When consumed, caffeine takes about 45 minutes to be fully absorbed into your system, and its effects can start to kick-in within 15 minutes to 2 hours – this varies based on things like age, health, and gender. It’s important to note that caffeine can linger in your system for quite a while, with half of the contents remaining active even 5 hours post-consumption! (67)
For shift workers, caffeine's ability to temporarily block adenosine (68)—a substance that builds up while you’re awake and contributes to sleepiness—is particularly beneficial. However, the length of time that caffeine hangs around in your body means that timing of consumption is crucial. To avoid caffeine keeping you awake when you’re trying to sleep, avoid consuming caffeine in the hours leading up to your sleep time. Be mindful of the amount as well; excessive caffeine can lead to anxiety, agitation, and other nasty side effects. Staying within the 400mg daily limit, preferably in smaller doses of 100-200mg, is recommended for optimal benefits without the adverse effects (69).
Below is a guide on how much caffeine you may be consuming (70):
