Why you're tired in the afternoon, and how to beat the 3pm slump

Why am I so tired in the afternoon?

Your body has a natural dip in alertness in the early afternoon. Sleep researchers describe the so-called post-lunch dip as largely unrelated to lunch [1]. You'd feel it at 2 or 3pm even if you skipped the meal.

That doesn't mean lunch is off the hook. In the same study, people did a long, boring drive in a simulator after either a light lunch or a heavy one. The heavy lunch made them drift out of their lane more and showed more signs of sleepiness in their brainwave readings [1]. The researchers also found a bad night's sleep makes the dip worse.

So the slump is a mix of 3 things. Your body clock sets it up, and a big lunch and short sleep make it hit harder. Sitting still in front of a screen for hours doesn't help either.

Does moving help more than coffee?

For a quick boost, it might. A 2017 study had 18 young women who were short on sleep try 3 different things on different days [2]. One day they took a 50 mg caffeine pill, about what's in a can of some sodas. Another day they took a placebo. On the third, they walked up and down stairs at an easy pace for 10 minutes.

The stair walking gave them a bigger jump in how energetic they felt than the caffeine did. The boost didn't last forever though. An hour later, the stair and caffeine groups felt about the same. And neither one made a difference on memory or attention tests.

It's a small study, and 50 mg is a lot less caffeine than a cup of coffee, so I wouldn't throw out your coffee maker. But it's a good reason to try a walk first.

Does breaking up sitting help with afternoon fatigue?

Another study had 19 adults sit for a full 7-hour day in a lab, twice [3]. One day they sat straight through. The other day they got up every 30 minutes for 3 minutes of light walking.

On the walking day, people reported feeling less tired at the 4-hour and 7-hour marks. That's right when most of us are fighting the afternoon slump. Like the stair study, it didn't find any change on memory or thinking tests. So moving made people feel less wiped out, but it didn't turn them into geniuses.

That's still a win. Feeling less tired at 3pm is the whole point.

How to beat the afternoon slump

Here's what I'd try, roughly in order of how easy it is.

The first two are the ones I'd focus on if you sit at a desk. They don't take much time, you don't need any gear, and you can do them in work clothes. 10 squats, a few desk push-ups, or a lap around the house all count.

Why "I'll just get up at 3" doesn't happen

The trouble with the afternoon slump is that it's the exact moment you least feel like moving. You're tired, you've got 4 tabs open, and getting up sounds like a lot of work. So you grab another coffee or open your phone instead.

That's why it helps to have something outside your own head make the call for you.

How Sporadic helps

Our Office Breaks stack sends you light, desk-friendly stretches at 9am, 12pm, and 2:30pm, Monday to Friday. That last one lands right in the middle of the slump. You get a notification, do some neck rolls, shoulder rolls, and stretches, and mark it complete.

If you'd rather get your heart rate up, Walk Reminders sends 1-3 walking challenges a day with a 2-hour window to finish each one. And the free Get Up, Get Active stack sends 2-4 random challenges a day, like squats or push-ups, which is about the best caffeine replacement I know of.

For more ideas, read exercises for people who sit all day, or see how Sporadic fits a desk job on our movement at work page.

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