How Lack Of Sleep Makes You Energetic

Sleep is an essential part of a healthy lifestyle, but many people report feeling more energised after a night of poor sleep. This can be attributed to a variety of factors, including a surge in cortisol and adrenaline, the brain's reward system firing up, or subjective adaptation to sleep loss. While you may feel more alert, your performance and health may suffer. Research shows that sleep loss increases the reactivity in your brain, making you feel more energetic, but this can lead to hyperactivity, impulsivity, and symptoms similar to ADHD. Additionally, your body's natural production of cortisol, the stress hormone, may increase, leading to negative consequences for your health.

Your cortisol and adrenaline levels increase

When you don't get enough sleep, your body produces more of the alertness-boosting hormones cortisol and adrenaline to get you through the day. Research shows that pulling an all-nighter significantly increases cortisol levels, but even sleeping for 5.5 hours can increase cortisol levels the next evening.

Cortisol is often referred to as the body's caffeine. It is a stimulant that our bodies produce naturally. When you feel yourself perk up while interacting with someone interesting, for example, that's your cortisol level going up. It enables you to focus on the other person and join the conversation in a lively manner.

However, high cortisol levels can have negative consequences. These include difficulty concentrating, weight gain (especially belly fat), and anxiety and depression. Cortisol is a stress hormone, and when you don't get adequate sleep, your cortisol production gets out of whack. It remains elevated instead of naturally decreasing, sometimes providing the illusion that you feel better with less sleep. But in reality, our stress increases, and we lose the ability to have relaxed control.

Adrenaline is another stimulant hormone that increases when you don't get enough sleep. It is part of the body's sympathetic nervous system response, which is responsible for active behaviour, such as saving our lives through fight-or-flight responses. When you're in danger, your sympathetic nervous system pumps cortisol and adrenaline through your body, telling you that escape is paramount.

While these hormones can make you feel more energised after a night of poor sleep, it's important to remember that this energy is false and unsustainable. Relying on cortisol and adrenaline to get you through the day can lead to negative consequences for your health and well-being.

Your brain's reward system fires up

Research shows that sleep loss increases reactivity in your brain's reward system. This means you may react better to both positive and negative stimuli, or you may experience giddiness or euphoria, making you feel better when you sleep less. Sleep loss can even improve the moods of those with depression. Research has shown that an all-nighter can improve depressive symptoms in 40% to 60% of cases. However, these improvements disappear when people get more sleep.

The brain gets more active the longer it goes without sleep. After an all-nighter, or even after sleeping for just 5.5 hours, your body produces more of the alertness-boosting hormones cortisol and adrenaline to get you through the day. These hormones give you a false sense of energy and can make it hard to sleep at night as you're stuck in fight-or-flight mode, leading to even more sleep loss.

The excitability of your frontal cortex (a part of your brain) increases with time awake and decreases when you get more sleep. So your brain may be working in overdrive. Sleep deprivation is linked to hyperactivity and impulsivity and can lead to symptoms that mimic ADHD, making you feel like you have more energy.

This extra energy is not healthy or sustainable. As one sleep expert puts it, "it could be viewed similarly to a manic state".

Your dopamine levels increase

A 2023 study on mice found that sleep loss enhances dopamine release in the brain. Dopamine is the "feel-good" hormone. In sleep-deprived mice, this led to hyperactivity, aggression, fewer depressive-like behaviours, and more social and sexual behaviour.

While more research is needed to determine if this also happens in humans, it could be a contributing factor to the "tired-but-wired" feeling you get after a night of poor sleep.

The brain becomes more active and sensitive the longer it goes without sleep. This is because our brains are constantly forming new connections while we are awake. The longer we are awake, the more active our minds become. This can lead to manic thinking that feels more energised but is much less effective.

This extra energy is not sustainable or healthy. As one doctor puts it, "it could be viewed similarly to a manic state."

You subjectively adapt to sleep loss

Our brains are adept at tricking us. When we don't get enough sleep, we can subjectively adapt to some of the effects of chronic sleep deprivation. While we feel fine on less sleep, we are not doing well at all.

One study found that participants' performance on cognitive tests got significantly worse the more sleep-deprived they became. But their ratings of sleepiness only increased slightly at first and then levelled out. The study stated that:

> "Sleepiness ratings suggest that subjects were largely unaware of these increasing cognitive deficits, which may explain why the impact of chronic sleep restriction on waking cognitive functions is often assumed to be benign."

Another sleep study found that people who said they got enough sleep slept more than three hours longer when they got the chance — meaning they were probably sleep-deprived and didn't know it.

And you might simply be missing the signs of sleep deprivation. It's not just low energy — sleep loss can cause everything from weight gain to acne, digestive issues to mental exhaustion. It's easy to blame a bad diet or stress over poor sleep for these symptoms.

Research from 2016 states that people who think they do fine on little sleep may actually need environmental stimulation to stay awake and underestimate how sleepy they really are.

You might also be in sync with your circadian rhythm, which is boosting your energy levels. If you were hitting snooze on weekends and waking up during a natural dip in energy, or now you're honouring your night owl ways or have a regular sleep routine, you may be more in sync with your body clock.

You do energy-boosting things when you get less sleep

When you don't get enough sleep, you may feel the need to reach for stimulants like caffeine or sugar to help you get through the day. While these may provide a temporary energy boost, they are not a substitute for a good night's sleep. In fact, too much caffeine can give you the jitters and make it even harder to fall asleep at night.

Instead of relying on stimulants, try getting some morning sunlight and fresh air, which can promote wakefulness and alertness. A light jog or walk can also help stimulate alertness in the brain, but be sure not to overdo it—vigorous exercise when you're exhausted can increase your risk of injury. If you have the time, a short nap of up to 25 minutes can help recharge your body and mind.

It's also important to pay attention to your diet when you're sleep-deprived. While sugary snacks and simple carbohydrates may be tempting, they can lead to energy crashes later on. Instead, opt for a balanced diet with an emphasis on protein-rich foods like nuts, lean meats, and Greek yogurt.

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