Why Do I Sleep Better During the Day? 4 Possible Reasons

It’s common for people that have a tough time sleeping at night to find it much easier to sleep during the day.

Unfortunately, napping during the day can make it even harder to fall asleep at night.

Understanding why sleeping can be easier during the daytime can reveal underlying sleep problems that need to be corrected.

There are 4 main reasons why sleeping during the day can be easier than at night. Let’s look at them from most likely to least likely.

1. Circadian Rhythm Disorders Can Make You Sleepy During the Day

Some people don’t get particularly sleepy at night when they would expect to. This is often a signal of a circadian rhythm disorder.

How sleepy you are is governed by 2 internal systems:

• Circadian rhythm - A biological clock that controls when many processes (e.g. sleep hormone regulation) occur. Factors like exposure to sunlight, when you eat, and time of the day regulate your circadian rhythm.
• Homeostatic sleep pressure - The longer you are awake, the higher the pressure to sleep builds up in your body.

When both of these systems line up and say “it’s time to sleep”, that’s when sleeping is the easiest.

Here’s what it’s supposed to look like, with the circadian rhythm as the bottom line, and homeostatic pressure as the top line (1):

When a certain threshold is reached, you go to sleep, and the homeostatic sleep pressure is relieved.

A circadian rhythm disorder describes when your circadian rhythm is shifted significantly out of sync with your homeostatic sleep pressure (2).

In other words, you feel sleepy after being awake for a certain amount of time, but your circadian rhythm says it’s not time to sleep yet - you don’t reach your sleep pressure threshold.

This results in feeling the need to sleep at strange times, including the day (there are a few times during the day when your circadian rhythm may peak high enough to sleep).

What Causes a Circadian Rhythm Disorder?

For some unlucky people, circadian rhythm disorders are caused by genetics.

In most cases, however, a circadian rhythm disorder is caused by poor sleeping habits:

• Not having a regular sleep schedule
• Blue light exposure at night
• Too much caffeine (which for some people can be any at all)
• Anxiety
• Depression
• Night shift work

What Are the Signs of Circadian Rhythm Disorders?

There are 2 types of circadian rhythm disorders:

• Advanced sleep phase disorders - Where you feel the need to go to sleep earlier and wake up early.
• Delayed sleep phase disorders - Where you don’t get sleepy until very late (i.e. early morning) and tend to sleep in.

Most people can’t get enough sleep because of this and get sleepy during the day.

How is Circadian Rhythm Disorder Treated?

Fixing sleep hygiene is the simplest place to start, but the treatment for circadian rhythm disorders varies based on the case.

It may involve:

• Lifestyle and sleep hygiene changes
• Light therapy
• Melatonin supplements or blue light blocking glasses
• Temporary sleep restriction

Sleep is vital to good health, so if you are personally experiencing regular daytime fatigue, this is something that you should consult your doctor about. There could be concerns about narcolepsy that need to be confirmed and treated appropriately.

2. There’s No Sleep Anxiety When Sleeping During the Day

Many people get anxiety when trying to go to sleep, and not surprisingly it makes it harder to sleep at night.

This anxiety is typically caused by worrying about:

• Getting enough sleep
• What needs to be done the next day
• Stressful things in life that you want to solve

This can lead to a lack of sleep or poor sleep quality.

During the day, you’re less likely to worry about these things. And with that anxiety gone, it’s easy to doze off when your mind is occupied by something more menial (e.g. boring work task, watching TV, sitting in a lecture).

Sleep anxiety is typically treated with cognitive behavioral therapy (CBT). It allows you to re-examine what’s causing you anxiety, and find healthy ways to react instead.

3. Sleepiness Can Be A Response to Eating

If you start getting sleepy during the day at a similar time, there’s a possibility that it’s a response to eating something earlier.

Studies have shown that people get sleepier about 2-3 hours after eating either a high fat or high carbohydrate meal (3).

In the picture above, the high fat meal is the open circle, while the high carbohydrate meal group is the filled in circle.

Many people eat an unhealthy meal in the morning at about 8 am, and then start to get sleepy around 10 or 11 because of this.

Other things like caffeine can also have a “crash” effect at some point in the day.

SummaryIf you suspect that you’re getting tired during the day because of your eating habits, try eating a different type of meal or eating at a different time of day and seeing if it changes when you get sleepy.

4. Your Lack of Sleep At Night is Catching Up to You

Ultimately, most people who sleep well during the day are just tired.

If you don’t sleep enough, that homeostatic sleep pressure that we looked at builds up and eventually needs to be released.

If you’re not sleeping 7-10 hours regularly (and the amount each person needs differs), you’re likely just not sleeping enough.

In that case, you either need to:

• Prioritize making time for sleep
• Improving your sleep hygiene so that you feel sleepy at appropriate times
• Solve any underlying issues like anxiety that limit your sleep.

Summary: Sleeping During the Day

These 4 reasons for sleeping easily during the day cover the vast majority of situations.

However, if none of those seem possible, you may have an underlying condition like narcolepsy.

A doctor will be able to run a sleep study if needed in order to rule out conditions like narcolepsy and other sleep issues.

References

1. Sleep-Wake Regulation and Its Impact on Working Memory Performance
2. Circadian Rhythm Disorders
3. Influences of Fat and Carbohydrate on Postprandial Sleepiness, Mood, and Hormones