Caffeine is an incredible thing. It can help you wake up in the morning, get you through that mid-afternoon slump, or help you stay alert on a late-night drive.
But it’s also fickle: it can cause anxiety, digestive issues, and rapid heart rate. And on top of that, it’s addictive, meaning it can lead to a feedback loop in which you might crave caffeine not for its positive effects, but because you’ll feel unwell if you don’t have it.
Though caffeine is typically most associated with feelings of wakefulness and alertness, it’s a complicated substance with both positive and negative effects---and it even has a connection with fatigue and insomnia.
Does caffeine cause insomnia?
Caffeine’s ability to wake you up can, in fact, go too far. High caffeine intake can interfere with your ability to get restorative sleep. In other words, too much caffeine can negatively affect the quality and quantity of your sleep, causing insomnia.
And even though caffeine can help you feel more awake, it’s not a substitute for sleep. Attempting to replace restful sleep with increased caffeine intake will put your body under undue stress.
You might be tempted to double down on caffeine if you’re left with rebound fatigue, but this is a slippery slope. Caffeine offers a short-term boost to energy levels, but caffeine leaving your system as it metabolizes can actually result in feelings of fatigue. This rebound effect may lead you to consume more caffeine---which may lead to sleep disturbances---which may lead to even worse fatigue and more need for caffeine. It can be a vicious cycle.
In general, moderation is important when it comes to caffeine in order to avoid the undesired side effects of insomnia and fatigue.
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How much caffeine is too much?
What exactly does “too much caffeine” mean? It’s highly individual, and it depends on your genetics, your metabolism, and your sensitivity to caffeine.
According to the FDA, up to 400mg of caffeine per day (approximately the amount found in four to five cups of coffee) tends to be safe for healthy adults. That said, this daily limit differs for different people. Caffeine sensitivity is very personal and difficult to predict, and the best way to know whether you’ve had too much caffeine is if you’re experiencing negative side effects.
Aside from insomnia, these are some of the common symptoms of caffeine overconsumption:
- Jitters or anxiety
- Fast heart rate
- Digestive distress or nausea
- Headache
When it comes to caffeine, as with any stimulant, it’s best not to overdo it. And even if you’ve got a particularly stressful day ahead, you should avoid a sudden uptick in your caffeine consumption that could send your body into overdrive.
At what time should you cut off caffeine intake?
While it’s unlikely that a cup or two of coffee in the morning would result in insomnia, there’s caffeine in many other foods and drinks you might consume throughout the day: soda, chocolate, tea, energy drinks, and even some medications. Be careful of what you’re eating and drinking, and keep an eye on the clock.
Most advice says to cut off caffeine consumption by afternoon in order to avoid insomnia or sleeping issues, but this can be a bit vague and, annoyingly, can differ from person to person. Caffeine acts very quickly; you’ll reach peak blood levels around 30 to 60 minutes after consumption, but it usually takes three to five hours for your body to metabolize half of the substance.
Even though daily consumption of caffeine can lead to diminishing effects, it’s still important to be aware of the time of consumption. Studies show that caffeine intake even six hours before bed can reduce total sleep time by as much as an hour.
You should know your own limits when it comes to caffeine, but the earlier in the day you can stop consuming it, the better you’ll set yourself up for restful, restorative sleep.
The connection between caffeine, melatonin, and cortisol
Caffeine use is so pervasive in our day-to-day lives that its categorization as an addictive substance is often obfuscated. What feels more natural than a morning cup of coffee or an afternoon tea?
However, though naturally occurring, this stimulant has significant effects on the body beyond just boosting energy levels. It’s also related to your hormones---specifically, to the sleep hormone (melatonin) and the stress hormone (cortisol).
Caffeine and melatonin
Considering the link between caffeine and insomnia, it’s not too surprising that the stimulant affects melatonin production.
Melatonin is the hormone that regulates your circadian sleep/wake rhythm, allowing you to get sleepy when it gets dark. It’s necessary for falling and staying asleep, though many parts of modern life---including caffeine consumption---can interfere with it.
Research demonstrates that caffeine use suppresses melatonin secretion. And this isn’t necessarily related to the time at which caffeine is consumed: regular coffee consumption over time might decrease the body’s melatonin production, which can in turn worsen sleep quality and quantity. For that reason, if you have low melatonin levels and are a long-time caffeine user, the two might very well be related.
What happens if you take caffeine and melatonin together?
Since caffeine and melatonin perform opposite functions (keeping you awake versus helping you get to sleep), it seems counterintuitive to take them together. However, contrary to logic, caffeine appears to increase the bioavailability of melatonin, which means it helps melatonin have an active effect on the body.
That said, there’s not a lot of research on this, and conventional wisdom still holds true: it’s best to avoid caffeine as you approach bedtime in order to ensure quality sleep.
Caffeine and cortisol
Cortisol is what’s released in your body when you feel stress. It’s the “fight or flight” response that elevates your heart rate and blood pressure in response to perceived threats or stressors. This is an important hormone that helps the body with metabolism, immune response, blood pressure regulation, and more.
Despite its important role, too much cortisol can actually disrupt many of the body’s processes. These are some of the health conditions that can result from long-term cortisol activation:
- Sleep disturbances
- Anxiety and depression
- Headaches
- Digestive issues
- High blood pressure
Like many bodily functions, it’s all about healthy balance when it comes to cortisol. And while regulating this hormone may feel out of your control, you can control your caffeine consumption, which plays a part in cortisol production.
Because cortisol is related to alertness and focus, the body releases it naturally when you wake up. For most people, the hormone level peaks around 30 to 45 minutes after waking up and then declines slowly throughout the day. But this morning cortisol release often coincides with the time of day when people begin drinking coffee, tea, and other caffeinated drinks, which can further elevate your body’s levels of the stress hormone.
While the long-term health effects of caffeine-induced cortisol spikes are unknown, research suggests that elevated cortisol over extended periods can impair immune function and lead to health problems. Interestingly, the caffeine-related spike to cortisol does decrease over time for daily users of the substance, but as mentioned above, regular caffeine consumption can decrease melatonin production over time, so it’s a bit of a catch-22.
A final note on cortisol and melatonin: these two hormones need to work in harmony for the body to achieve a healthy sleep/wake cycle. If either one gets out of balance, sleep quality and energy levels can be negatively affected.
How do you know if caffeine is causing your sleep issues?
Our world isn’t built for sleep. Busy schedules, screens, stress---all of these interfere with our natural circadian rhythms. But with so much noise, how do you pinpoint the cause of your sleep issues? How can you tell if it’s caffeine or something else?
A data-driven approach is always best. Base’s personalized sleep testing plan can help you get answers about your hormone, nutrient, and vitamin levels so you can see what’s keeping you up at night. Instead of kicking caffeine to the curb without knowing whether that’s the real culprit, you can turn to Base’s personalized diet and lifestyle suggestions to guide you back to restful nights.
Tips for achieving more restful sleep
Positive sleep habits (also known as sleep hygiene) are important in getting a good night’s sleep. In addition to limiting your caffeine intake and managing stress, here are some achievable steps you can take toward better slumber:
- Create a comfortable, sleep-friendly bedroom space that’s dark, quiet, and relaxing.
- Make your bedroom an electronics-free zone to avoid blue light before bed.
- Develop a consistent routine. Aim to go to bed and wake up around the same time each day.
- Engage in some form of physical activity daily, even if it’s as simple as going for a walk.
- Don’t consume large/heavy meals or alcohol before bed.
These are just a few of many possible ways to adjust your lifestyle for better sleep hygiene. But if the issue is deeper---a hormonal imbalance or vitamin deficiency---these might not be enough. Base can connect you with answers and solutions that go beyond the generic, supporting you in whatever it is you need to get good sleep.
Struggling with sleep?
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