8 behaviors that indicate someone isn’t getting enough sleep at night, according to psychology

I’ve pulled more than a few all-nighters in my day.

Whether it was cramming for exams in college or chasing a looming work deadline, I used to believe that sacrificing a few hours of shuteye was no big deal.

But the more I delved into psychology—and the more I personally experienced the fallout—the clearer it became that missing out on quality rest can wreak havoc on both mind and body.

If you or someone you know is stumbling through the day, keep reading.

Below are eight key behaviors that often suggest a person isn’t catching enough Z’s.

Understanding these signs can be the first step toward better sleep hygiene and a happier, healthier life.

1. Constantly relying on caffeine to stay functional

I once had a routine that involved a triple-shot latte before 9 a.m., then another coffee (or two) in the afternoon to beat the slump.

If you’re gulping down multiple cups of caffeine just to feel remotely awake, you might be running on less sleep than your body really needs.

Caffeine is a temporary fix that masks the underlying issue. It’s like taping over a warning light on your car’s dashboard—it doesn’t solve the problem.

As noted by the National Sleep Foundation, excessive caffeine intake can even backfire by making it harder to fall asleep at night, creating a vicious cycle.

If you notice that you’re constantly chasing that next caffeine boost to keep your eyes open, consider it a wake-up call that you’re not well-rested in the first place.

2. Becoming uncharacteristically irritable

Ever snap at a friend for no real reason, only to realize you were running on four hours of sleep?

I’ve definitely been there.

Chronic lack of rest can strip away our emotional resilience, making small annoyances feel like huge personal affronts.

According to research, people who are sleep-deprived tend to have heightened emotional reactivity.

That means everyday stressors—traffic, a slow internet connection, or even a mild critique—can spark an oversized reaction.

If you find yourself in a persistent bad mood or lashing out more than usual, it’s worth asking whether you’re simply missing out on decent shuteye.

Feeling edgy isn’t a personality flaw; it’s often the result of an overwhelmed brain struggling to cope without enough rest.

3. Struggling to concentrate or remember simple details

I can’t count how many times I’ve blanked on a friend’s name or spaced out in the middle of a conversation after a rough night.

Sleep is crucial for cognitive functioning.

The brain consolidates memories and processes information while we snooze, so it’s no surprise that shortchanging sleep can cause us to be scatterbrained.

Ever wonder why after a solid night’s rest, your mind feels sharper and you can recall details more effortlessly?

Studies show that adequate sleep helps “cement” new information and experiences into the brain.

On the flip side, chronic drowsiness can make it hard to remember even simple things—like where you left your keys or the tasks on your to-do list.

4. Feeling persistently low on energy, no matter what

We’ve all heard about that famous “afternoon slump.”

But if you find yourself drained from the moment you wake up, it might be a sign you’re not recharging enough at night.

I remember a time when I tried to self-medicate with energy bars, sugary snacks, and motivational music playlists—basically anything to push through the day.

But none of that truly tackled the root issue: lack of proper rest.

If you’re stumbling around feeling half-dead, it’s not a willpower problem; it’s a signal you’re ignoring your body’s natural calls for replenishment.

Even practicing mindfulness, which I’m a huge advocate for, can’t fully compensate for not getting enough hours in bed.

5. Relying on sugary or carb-heavy foods to stay alert

I’ve noticed that whenever I’m short on sleep, my cravings go off the charts—especially for carbs and sugary treats.

Turns out, there’s a biological reason for that. When you’re tired, your body craves quick energy, and simple carbs or sugar provide a temporary rush.

This is backed by experts like Dr. Michael Breus, a clinical psychologist and sleep specialist, who has noted that sleep deprivation can skew hunger hormones (like leptin and ghrelin), making you feel hungrier than normal.

Even though those donuts might feel comforting in the moment, they’ll probably lead to an energy crash later on.

And that crash only amplifies the fatigue you’re trying to outrun in the first place.

6. Dozing off or zoning out unexpectedly

Ever been in a meeting or lecture where your head starts bobbing without warning?

Been there, done that, and it’s both embarrassing and revealing.

Micro-sleeps—those brief involuntary episodes of dozing—are the body’s desperate attempt to catch up on lost rest.

And zoning out completely, where you lose track of an entire conversation, can be just as telling.

If you find yourself daydreaming to the point of blankness, that’s your brain hitting the “emergency pause” button.

It’s sending a clear message: we’re not firing on all cylinders here because we didn’t get the downtime we needed.

I’ve talked about this before, but pushing yourself to function while you’re operating on fumes is only sustainable for so long.

Eventually, the mind finds ways to shut down, even when you’re technically awake.

7. Becoming sick more often

In the early days of Hack Spirit, I was juggling writing, reading about Buddhism, and traveling across a few countries.

It was a thrilling time, but my sleep took a hit.

Before long, I noticed a pattern: colds, aches, and general malaise came knocking on my door far too often.

Why does this happen?

Well, insufficient rest can weaken your immune system, leaving you more susceptible to viruses and infections.

So if you’re catching every bug that’s going around, you might want to look beyond your vitamin intake or hygiene practices.

Improving your nightly rest could be the missing piece of the puzzle.

8. Overreacting to stress or feeling overwhelmed

To wrap things up, let’s talk about stress.

Whether it’s work deadlines or family drama, life throws curveballs at all of us.

But when you’re operating on little sleep, even minor hiccups can feel like an existential crisis.

Carl Rogers once said, “The good life is a process, not a state of being.”

Part of that process involves building resilience to handle life’s ups and downs. Sleep deprivation, however, chips away at that resilience.

It’s like trying to climb a mountain with worn-out boots—eventually, the smallest rock can trip you up.

If you notice your anxiety level skyrockets at the slightest challenge, it could be a strong hint that your mind and body are craving a deeper, longer rest.

Final words

We live in a world where being busy is often glamorized, but the truth is that consistent exhaustion comes at a steep price.

If you recognize these behaviors—constant irritability, endless coffee refills, snack binges, or random daytime dozing—it’s worth pausing to see if you’re neglecting what could be your most powerful ally: a good night’s sleep.

In my own journey, I’ve learned that no amount of productivity hacks or mindfulness tricks can replace the simple magic of proper rest.

I even touch on this in my book, Hidden Secrets of Buddhism: How To Live With Maximum Impact and Minimum Ego by highlighting the importance of grounding routines and mindful living.

At Hack Spirit, we’re all about practical transformation, and learning to honor your body’s need for rest is perhaps the most practical transformation of all.

If you spot any of these signs in yourself, don’t wait for burnout to strike.

Start by setting a consistent bedtime, cutting back on caffeine later in the day, and creating a relaxing pre-sleep ritual.

These little actions can have a massive impact on your mental clarity, emotional balance, and overall well-being.

And trust me—it feels pretty amazing to wake up in the morning ready to take on the day instead of dragging your feet.