Here are the 11 biggest ways sleep gives your body a major assist.

Sleep keeps your heart healthy.
Add sleep deprivation to the list of risk factors that can leave you spending a lot of time in a cardiologist’s office. “Poor sleep quality is linked to heart health problems, from high blood pressure to heart attacks,” says Paruthi. Here’s why: Regularly shortchanging yourself on sleep can lead to a surge in stress hormones such as cortisol. The uptick in stress hormones compels your ticker to respond by working harder, and it doesn’t get the rest it needs, says Paruthi.

It prevents you from packing on pounds.
A good night’s rest won’t necessarily result in losing weight, but it can keep you from adding unwanted pounds. First, sleeplessness cranks up production of the hormone ghrelin, which boosts appetite, says Michael Breus, Ph.D., sleep specialist and author of The Sleep Doctor’s Diet Plan. “It also leads to a decrease in the hormone leptin, which signals feeling full,” says Breus. And by making you more stress-prone and low-energy, lack of sleep reduces your ability to fight junk food cravings. Give in to the office vending machine, and that candy bar will send your blood sugar surging, then crashing, leaving your appetite raging all over again.

It lowers your odds of a car crash.
Because a sleep debt slows your reaction time and reduces your ability to focus, “driving a car when you’re low on sleep is just as dangerous as driving drunk,” says Paruthi. Research backs this up: People who regularly sleep six to seven hours per night are twice as likely to get in an accident as those who usually score at least eight hours, according to a study from the AAA Foundation for Traffic Safety. Catch less than five hours, and your odds of a crash quadruple, reports the study.

Sleep strengthens your immune system.
Want to stay off the injury list and take fewer sick days? Make a habit of getting high-quality rest to keep the immune cells and proteins of your immune system in fighting shape. That, in turn, improves your ability to beat back colds, the flu, and other infections. Sleep also makes vaccines more effective. “After getting a shot, people with sleep issues don’t develop the same antibody response as well-rested people, and that leaves them more susceptible,” says Paruthi.

It keeps your brain from frying.
Remember that 1980s PSA that compared a cracked egg to your brain on drugs? Well, that sizzling egg is similar to your brain on sleep deprivation. While getting proper sleep is linked to improved concentration and higher cognitive functioning, even one sleepless night sets you up to feel fuzzyheaded, scattered and unfocused the next day. Your memory recall isn’t as sharp, and everything you do is in slow-mo, says Paruthi. That puts your job at risk. “You’re more likely to make mistakes at work, for example, but less likely to realize it and correct them,” she says.

It fires up your sex life.
Steady, quality shut-eye keeps testosterone levels high, prevents erection problems and ensures that you’re never too exhausted for sex. Cheat yourself out of sleep, however, and you cheat yourself out of great sex. Research shows that men who sleep less than six hours nightly have lower levels of testosterone, says Paruthi, and flagging testosterone can sink sex drive.

Read also – 8 Great Reasons To Get More Sleep

It can prevent headaches.
If you get stress headaches, scoring plenty of rest will help keep them from striking, says Paruthi. Sleep deprivation also plays an indirect role in making your head hurt as well by making you less able to cope with stress and anxiety, two things that can trigger a throbbing skull, even when you’ve had plenty of R&R.

It keeps you in top form at the gym.
Quality sleep is like nature’s sports supplement, improving your speed, hand-eye coordination, reaction time and muscle recovery. Thing is, even short-term sleep deprivation messes with these, throwing off your performance at the gym. Also, a 2013 study in the Journal of Strength and Conditioning Research found that sleep deprivation reduced muscle strength and power the next day, particularly if your workout was later in the afternoon.

It boosts your mood.
Think about the last time you slept really well: You probably woke up feeling brighter and optimistic, had more energy and drive and were less likely to let little challenges — like bad traffic or a heavy workload — lead to anger and frustration. Well, subpar sleep habits can have the opposite effect. “Even one night of sleeplessness can makes you cranky and irritable the next day,” says Paruthi. You’re also more vulnerable to stress and anxiety. All of these can make it harder to fall asleep the next night, so you become trapped in a cycle of sleeplessness and bad mood. The escape plan: vowing you’ll go to bed at a decent hour, and letting your system recharge and restore itself.

Sleep increases your pain threshold.
If you want to tough out physical pain, hit the sack. That’s the suggestion of a 2012 study from the journal Sleep, which divided study subjects into two groups, one that slept nine hours nightly and another that slept an average seven each night. Researchers then tested how long each participant could hold their finger to a radiant heat source. Subjects in the nine-hour group withstood the heat about 25 percent longer. It’s not clear why more sleep led to more pain tolerance, but the findings echo similar results in other studies and suggest that a long night’s sleep is a potent pain reliever.

It bolsters your relationships.
Considering that sleep deprivation contributes to crankiness and a crabby mood, it’s no wonder poor sleepers have more problems with their partner, including a greater likelihood of disagreements and a reduced ability to have empathy, says Paruthi. “Your sleep habits have a wider effect on the people around you than you think, contributing to relationship satisfaction and happiness,” she adds.

Read also – How Much Sleep You Really Need