
You’re more likely to get sick

Your body needs sleep to keep its immune system ticking along nicely. If you fail to sleep for over 24 hours, you’re more likely to catch the common cold due to your weakened defenses. Sleep – or a lack thereof – can also affect how quickly it takes for you to recover from illnesses.
You’ll experience bouts of anger

Failing to get the right amount of shut-eye is likely to make you irritable, easily aggravated, and all-around angry. Forgoing sleep for an extended amount of time leads to a lack of emotional regulation, resulting in unnecessarily snappy responses and sudden, unexplained bouts of severe anger.
It’ll be hard to concentrate

We all know how hard it is to concentrate the day after spending a night tossing and turning – imagine how it’d feel after 2 days! Sleep drastically affects the part of your brain that controls your cognitive functions, meaning a lack of sleep leaves your brain running on mere metaphorical fumes.
Your memory will be impaired

Studies show that if you go without catching a wink of sleep for just one night, your ability to learn new things will drop by up to 40%. This is because sleep affects the hippocampus – the part of your brain that’s responsible for memory. Two nights of full sleep are required to fully restore memory function.
Anxiety levels will increase

Sleep and mental health go hand in hand. Poor snoozing habits can trigger anxiety, paranoia, and depression, creating a miserable waking life. Ironically, anxiety can cause you to stay awake for longer periods of time, resulting in an endless vicious cycle of exhaustion and stress.
You may experience appetite changes

After going without sleep for 24 hours or more, you should expect severe changes to your appetite. Normally, your appetite would increase, with your body desperately seeking any form of sustenance to keep it going. Occasionally, appetites can decrease, usually a symptom born from depression.
You’ll experience depersonalization

Failing to sleep for 48 hours will cause you to feel dissociated from reality in your waking life, believing that everything around you is a meaningless illusion. You’ll also experience depersonalization – feeling as though your thoughts and actions are inherently disconnected from your mind and body.
You’re at risk of chronic disease

Aside from the mental effects, a deficiency in sleep can have very real physical side effects. After staying conscious for 48 hours straight you’re at a much higher risk of developing numerous chronic health problems, including kidney disease, heart disease, diabetes, stroke, and high blood pressure.
Extreme fatigue will take over

It goes without saying that if you forgo sleep, you’ll experience fatigue. But just how far will this fatigue go? To put it simply, it’ll impact every second of your day. It’ll make daily tasks exceedingly difficult to fulfill, while you’re at a much higher risk of sustaining an injury.
You’ll hallucinate

In the most extreme cases, going without sleep can cause vivid – and sometimes scary – hallucinations. Around 80% of people will experience either visual or audio hallucinations after missing one night’s sleep, caused by a signficant drop in your brain’s dopamine levels. Without sleep, parts of your brain work together in chaotic ways, causing these vivid imaginary images.