How long until lack of sleep kills

Most people notice that when they're sleepy, they're not at the top of their game. People playing sports that require precision — like shooting, sailing, or cycling — also make more mistakes when they've been awake for extended periods. You know those great things your immune system does when you get a wound but don't immediately get an infection, or you come near a sick person but don't get ill yourself?

Prolonged sleep deprivation and even one night of sleeplessness can impede your body's natural defenses against infection. Sleep deprivation also seems to make newly received vaccines less effective. If you're wondering why you're sick all the time and seem to pick up every bug that travels around the office, it's probably because you're not getting enough sleep. Sleep-deprived people are almost three times as likely as well-rested people to catch a cold , according to one study. Testosterone is an important component of sexual drive and desire in both women and men.

Sleeping increases testosterone levels, while being awake decreases them. Sleep deprivation and disturbed sleep, consequently, are associated with reduced libido and sexual dysfunction. People with sleep apnea are particularly at risk.

In a classic study led by the Nobel Prize-winning psychologist Daniel Kahneman , a group of working women kept detailed logs of their moods and day-to-day activities. The other was tight deadlines at work. Another study reported higher marital happiness among women with more peaceful sleep, though it's hard to say whether happy people sleep better, or good sleep makes people happier. Most likely, it's some combination of the two. Insomniacs are also twice as likely to develop depression , and research suggests that treating sleep problems may help treat depressive symptoms.

Being awake when your body wants you to be asleep messes with your metabolism, which in turn increases your risk for insulin resistance often called "prediabetes" and type 2 diabetes.

Several studies in adults have found a strong association — though not a cause-effect relationship — between regular sleep loss and the risk of developing diabetes. More sleep may also help reduce diabetes risk for adolescents, according to researchers.

Other researchers have found that severe sleep deprivation impairs people's ability to follow preestablished procedures for making a "go" or "no-go" decision, something that researchers say contributed to the explosion of the space shuttle Challenger, the Chernobyl meltdown, and the Exxon Valdez disaster. If you want to stay alert and attentive, sleep is a requirement. Otherwise, you enter "an unstable state that fluctuates within seconds and that cannot be characterized as either fully awake or asleep," researchers said.

In that state, your ability to pay attention is variable at best. Severe sleep deprivation seems to affect your ability to carry on a conversation — much like having too much to drink. Pilots, truck drivers, medical residents, and others required to stay awake for long periods "show an increased risk of crashes or near misses due to sleep deprivation," it said. When people sleep, the body slows down its normal urine production.

But when someone is sleep-deprived, that doesn't happen, leading to what researchers call "excess nocturnal urine production. This condition may be linked to bed-wetting in children.

In adults, it's tied to what's called nocturia, the need to use the bathroom many times during the night. Lack of sleep causes hormonal changes that make it harder for your body to build muscle and heal. This makes it more difficult to recover from muscle damage caused by exercise, and it worsens conditions related to muscle atrophy.

Other research has found that the reverse is also true — that during sleep, your body releases growth hormone and heals damage.

That's why fitness advocates will always point out that sleep is an essential part of getting in shape. People in pain — especially those who have chronic pain — tend to not get enough sleep. This makes sense, since pain can wake you up in the night and make it hard to fall asleep in the first place. But recently, researchers have begun to suspect that sleep deprivation may actually cause pain or at least increase people's sensitivity to pain. Patients with Crohn's disease have been found to be twice as likely to experience a relapse when they don't get enough sleep.

Scientists don't yet know exactly why sleep deprivation leads to headaches, but it's a connection doctors have noticed for more than a century. Our sleep cycle or body clock doesn't just determine when we're tired or awake — it also affects the function of every cell in our body. Researchers have started to figure out how disruptions in sleep schedules prevent cells from fighting inflammation, which could explain why tired people often have many problems from inflammatory conditions, including asthma , arthritis, multiple sclerosis, and cardiovascular disease.

Snoring can be an indication that you are dealing with sleep apnea , a sleep disorder that can cause other medical problems over time. It's caused by decreased airflow, which can strain the heart and cause cardiovascular problems. The condition is also linked to weight gain. A study shed some light on why sleep is tied to so many different aspects of our health and wellness: Poor sleep actually disrupts normal genetic activity.

Although Gardner exhibited physical, mental and emotional degeneration and experienced severe insomnia decades later , he's alive in his 70s today. Gardner's day experiment didn't kill him, but anyone who's experienced total sleep deprivation can likely vouch that the end feels near.

Symptoms of sleep deprivation are progressive: The more sleep debt you rack up, the worse you feel. After a night or two of poor sleep, you feel irritable, cranky, unmotivated and sluggish.

After a week of short slumbers, you may find yourself snapping at people, crying over nothing, battling headaches, losing focus, overeating or under-eating and scraping by on stimulants. Go without sleep longer than that, and you may begin to experience hallucinations, paranoia, delusions and other scary symptoms. How long will your body allow you to survive on short sleep? And what about complete lack of sleep -- can it really kill you? CNET talked to sleep specialists to find out.

One extremely rare, hereditary disease seems to cause death via sleep deprivation. Fatal familial insomnia FFI starts with mild insomnia but progresses quickly, eventually leading to a complete inability to sleep. FFI patients also exhibit symptoms of dementia, difficulty controlling the body and degeneration of autonomic functions, such as digestion and temperature regulation.

Still, this is a neurodegenerative disease that affects the brain, Miller says, and "it's more likely that FFI patients die from neural degeneration, as opposed to lack of sleep. Interestingly, Miller encourages people not to be afraid of sleep deprivation, despite the known ill effects.

We are built to withstand a certain degree of sleep deprivation. Stay awake for long enough, and you will be highly prone to microsleeps - temporary, unintended episodes of unconsciousness that may be just a fraction of a second long. While microsleeps do serve a purpose, they are also part of the reason why you shouldn't drive when tired.

So how does going without sleep actually affect your health? Groeger points out that very little gets better when we lose sleep. Your resistance to bugs reduces, and if you were ill to begin with, your recovery slows. These changes are slight at first, but accumulate over time. Unfortunately, many of us are in this state much of the time whether due to insomnia, a busy life, or small children. Although we may attempt to compensate with caffeine, sugar etc, the only real antidote to sleep loss is sleep itself.

You don't need to put back all, or even most, of what you've lost. Over the long term, the effects of sleep deprivation are compounded, with chronic sleep loss playing a clear role in a number of physical diseases and mental health conditions.

While the amount of sleep you need is highly individual - it will depend on your age, sex, health, lifestyle, etc - if you're not getting enough, you will know about it.

If prolonged lack of sleep is a problem, see your doctor, who will be able to give you an evaluation and may refer you to a sleep clinic if necessary. After all, lack of sleep may not kill you, but it's worth addressing as soon as it starts to affect your quality of life. What is biphasic or polyphasic sleep and is it good for you? Disclaimer: This article is for information only and should not be used for the diagnosis or treatment of medical conditions.

Egton Medical Information Systems Limited has used all reasonable care in compiling the information but make no warranty as to its accuracy. Consult a doctor or other health care professional for diagnosis and treatment of medical conditions.

For details see our conditions. How long do bouts of insomnia last? Our picks for Can you really die from lack of sleep? Do naps count as sleep? Tips for better sleep in summer. How much screen time is too much? How getting older affects your sleep.