Whether you’re cramming for an exam or trying to beat the clock on a job deadline, there are times when you may be tempted to work straight through the night. You probably already know that you won’t feel and function at your best after losing out on sleep. And you should also know that you are yourself and others if you get behind the wheel of a car. But beyond simply making you tired, all-nighters affect your health and performance in ways you may not realize—until it comes back to haunt you.
A sleepless night will wreak havoc on your cognitive function. It can distort your memory, leaving you susceptible to false memories or simply cause fogginess and forgetfulness. It can impair your concentration and problem-solving abilities. And it can lead to a degradation of your brain’s white matter, crucial for forming neural connections and enhancing learning.
Lack of sleep can adversely affect your metabolism by triggering changes in the hormones that regulate satiety and appetite—namely, leptin and ghrelin—which can make you feel hungrier and crave more carbohydrates and sugary foods than usual. Over time, this can increase your risk of obesity. In addition, sleep loss may throw other hormones (such as insulin and cortisol) out of whack, putting you at risk for type 2 diabetes.
Pulling an all-nighter can send your emotions on a roller-coaster ride. It’s no secret that sleep deficiency can make you moody and irritable. But it also can trigger short-term euphoria, impairing your judgment and encouraging impulsive or risky behavior. How it happens: Sleep loss shuts down the prefrontal cortex, the brain area responsible for decision-making and smart planning, while heightening activity in the brain’s pleasure-driven pathways. Think of it as feeling a constant impulse to have another glass of wine, without any signals telling you to stop now or face a horrible hangover tomorrow.
Too little sleep throws off your circadian rhythm, the 24-hour internal clock that resides inside your brain and regulates alertness, blood pressure, hormones, body temperature, and other key bodily functions. That misalignment between your body’s circadian rhythm and your sleep schedule can have a snowball effect, making it harder to sleep well the next night, and the night after that. Indeed, even a single all-nighter can change the genes that control the biological clocks in your cells, which could have a variety of harmful effects including impaired blood sugar regulation.