Why you are always tired between 1pm — 4pm

8 min readMar 3, 2021


Let me introduce you to the deadliest hospital in the world. In this hospital, patients are more likely to receive a fatal dose of anesthesia. They are also more likely to die within 48hours of surgery. Nurses and other caregivers, are less likely to wash their hands before treating patients. And cancerous growths are more likely to go undetected. If you were a patient, you probably wouldn’t want to enter this hospital. In fact, you would want everyone you know to stay far away. However, the hospital that I’m talking about, is actually located in your town. Everything that I’ve described is what happens in most medical centers around the world. To be more precise, it happens between 1pmto 4pm in the afternoon. And it’s not just the medical profession that suffers. When students in Denmark have to take national standardized tests, they take them on a computer. But because there are more students than computers, they have to take these tests at different times.

When researchers looked at 4 years of test results, they found an interesting correlation. Students who took the test in the morning, scored higher than those who took it in the afternoon. For every hour later in the day the students took the tests, the scores fell a little more. Timing of the test wasn’t everything of course, but it was a large component. So what exactly is going on here? Well, you might have noticed yourself that sometimes when the afternoon rolls around you become less productive. You’re not as motivated to do the work, you have a harder time focusing, and even the work that you do, is of lower quality. A lot of people around the globe experience this exact phenomenon every single day. And it has a name: the afternoon slump. There’s a biological reason why this happens. You see, a lot of our bodily functions are controlled by our circadian rhythm. This rhythm works kind of like an internal clock. It controls our hormones, body temperature, blood pressure and many other functions throughout the day. If you have ever wondered how your body knows when to go to sleep and when to wake up, it’s because of your circadian rhythm. When it’s time to go to bed, your body releases melatonin, to make you feel sleepy. When it’s time to wake up, melatonin secretion stops and your body releases cortisol to get you up and moving. Now the circadian rhythm also influences our alertness and mental ability, along with energy levels. Our cognitive abilities do not remain the same over the course of the day.

We are smarter and more energetic during some parts of the day, while during others, we’re the opposite. For example, during the night we experience a massive drop in energy and alertness, particularly between 2am to 4am. But we don’t usually notice this drop in mental ability, since most of us are asleep. However, upon awaking, our energy and alertness steadily increase over the course of the day, until they reach a peak in late morning. That’s when we tend to be at our cognitive best. But that peak is then followed by an afternoon low, which we call the afternoon slump. The low occurs approximately seven hours upon waking up, which is usually between 1pm to 4pm, for most people. This is what the afternoon slump is. A natural biological occurrence orchestrated by your circadian rhythm. This is why medical professionals make more mistakes, why students get lower scores and why you are unfocused and unmotivated during that time. The afternoon slump is then followed by another period of alertness, but as our body gets ready for sleep, we experience a slow decline in energy. Every person’s rhythm is slightly different, but the majority follow a similar pattern.

If I were to draw a 24 hour graph of your alertness, it would look something like this. You can see how it slowly rises after waking up, until it reaches a peak in the late morning. Then in the afternoon, it dips down. When the afternoon slump is over, it bounces up again. Then as bedtime approaches it slowly decreases. A big drop occurs in the middle of the night, which you most likely don’t notice. And as you wake up, the cycle repeats all over again. Now while the afternoon slump is natural, there are a few things that amplify it and make it worse. But there are also a few key habits that can help to reduce it. Let’s first take a look at what can make the dip worse. One of the things is lack of sleep. This shouldn’t be a surprise to anyone. When you get an insufficient amount of sleep, your mental alertness is severely reduced, especially during the afternoon slump. But if you’re getting an optimal amount of sleep on a regular basis, the circadian dip is going to be less intense. I know that a lot of people try to get more time in their day by cutting on their sleep. They hope to get more done, since they are awake longer. Which is a rookie mistake. What those people don’t realize is that they’re functioning sub-optimally throughout the day. Sure, they have more time, but they have a harder time focusing and thus it takes them longer to get their work done.

Likewise, people who get optimal sleep, might have slightly less time in their day. But they have more energy and they function much better as a result. Getting more high-quality sleep is necessary for optimal mental and physical performance. So get your sleep. 7 to 9 hours per night has been shown to be the healthiest for most adults. But optimally you should be sleeping without an alarm clock and let your body wake up naturally, instead of forcefully. Another thing that can amplify the afternoon slump is a big carbohydrate lunch. You know how grandma usually forces food down your throat when you visit her? Then you probably know that feeling of drowsiness that follows. You’re lethargic, you can’t move and you feel like you’re going to explode. Digestion can take up a lot of energy. Especially big meals, give your stomach quite a workload. However, what can make it even worse, are meals that are made out of simple carbs, such as sugar. When you eat simple carbohydrates your blood glucose tends to spike up, giving you temporary energy. But that spike is then followed by a decrease in glucose levels, which results in a crash below your usual levels.

When you pair this sugar crash with an afternoon slump, an irresistible urge to sleep might overcome you. So to avoid this massive crash at lunch time, avoid big and heavy meals, made out of simple carbs. Instead go for smaller portions, with a variety of different nutrients such as protein, fat and fiber. I mentioned before how students who took the tests in the afternoon, scored lower than those who took them in the morning. And many people believe that the solution to this problem would be to move all the tests before noon. However, the researchers who studied those test results, also discovered something else. Students who had a 20–30minute break, before the test, to eat, play and chat, did not see a decline in their scores. In fact, they increased. Scores went up after a break, even if the test was taken in the afternoon. These days, taking a break is looked down upon. Others quickly label us as “lazy” if we do. And often we even label ourselves this way. That’s because most people believe that to get more work done, they should just keep on working.

However, when we stick with a task for too long, it eventually leads to mental fatigue. We’re not as focused, we do our work slower, and we make more mistakes. I’m sure you’ve noticed this yourself. You’re trying to focus on your work, but your mind just keeps on wandering and thinking about something else. Deliberate breaks are extremely underrated, since they can help us minimize and avoid all of that. Especially when a break is taken during the afternoon slump. So, what does a proper break consist of? There are 4 things. First is detachment. On your break, you don’t want to think about work or whatever you were doing, otherwise you might intensify your mental fatigue further. Instead you want to psychologically detached think about something that’s not related to work and isn’t cognitively demanding. Second is movement. Taking a walk will boost your energy levels, sharpen your focus and reduce the feelings of fatigue in the afternoon. One study found that walking around for 5minutes, roughly every hour during the workday, is more effective than a single 30minute walk. So if you have an option, take shorter walking breaks frequently. If not, a longer walk is still better than nothing. Third go outside.

Taking a short walk outdoors, will rejuvenate you more than if you take a walk inside. Not only will you get more sun exposure, you will also physically detach from work. Fourth is company. Spending time with others, particularly with people you like, is a great way to recharge. However if your job requires you to deal with other people, it might be better to spend the break alone. Especially if you’re more of an introvert. So if you’re looking for an ideal restorative break, consider a short walk outside, with a friend, during which you discuss something other than work. Yet another way to recharge during the afternoon slump, is to take a power nap. Napping can lead to considerable benefits in terms of alertness and cognitive performance. A 5minute nap has no effect. But a 10 to 20minute nap is proven to increase mental alertness for three hours. A lot of people who try napping make one big mistake and end up feeling even worse after it. That’s because when a nap is longer than 20minutes, our brain begins to fall into deeper stages of sleep.

If that happens you experience something called sleep inertia. You know that feeling in the morning when you wake up and feel groggy, disoriented and sluggish? That’s sleep inertia and if you nap for too long, you are going to feel more tired and sleepy, than before you took the nap. So keep your power naps short. You don’t want to fall asleep during the nap, and you shouldn’t think of napping as sleeping. Instead you can think of it more like a relaxing meditation, where you close your eyes, lay down and just let your mind disconnect for 15 minutes. Now I understand that not everyone has the option to take a nap, or a longer break during the afternoon slump, because your workplace doesn’t offer that flexibility. Or you might be one of those people who just want to power through it. If you fall into this category, I at least recommend not doing any important work during the slump. Instead, you should switch to something that doesn’t require as much concentration. Things that are familiar, mundane, not as important and can be done on auto-pilot. Easy tasks basically. Your most important and difficult work should be done before or after the slump. That’s when your cognitive abilities are at their peak and you don’t compromise your work.

Hopefully you now have a better idea, about why the afternoon slump happens and what you can do about it. If you have the option, experiment with your schedule a bit and see how you could implement the tips I’ve talked about. Thanks for reading and I hope this made you better than yesterday.