Voiceover: I’m sure we’ve all had trouble sleeping at one point or another, maybe trouble falling asleep, staying asleep or waking up or maybe you're forcing yourself to sleep less because you have too much to do to lie in bed. But sleep deprivation can be a serious issue. People who don't get enough sleep are more irritable and perform worse on memory and detention tasks than people who do. So all this can be just a minor annoyance in everyday life, imagine the long-term implications for let's say, airline pilots, firefighters, security officers or the person driving next to you on the freeway. For example, one study in Canada showed that the Monday after the Spring time change, so when people lose an hour of sleep, the number of traffic accidents increases sharply compared to the Monday after the Fall time change when people get an extra hour of sleep, the number of accidents decreases sharply. So that's just one example, but sleep deprivation also makes people more susceptible to obesity. When you're sleep deprived you're body produces more cortisol which is a hormone that tells your body to make more fat. You also produce more of the hormone that tells your body you're hungry, so you end up eating more and turning more of what you eat into fat which can contribute to weight gain. And finally sleep deprivation can also increase your risk for depression and one theory about this link is that REM sleep helps your brain process emotional experiences, which in turn helps protect against depression though we're still not entirely sure about this link. Most people, now most people experience sleep deprivation at some points in their lives, but the good news is that most people can get back on track by getting a few nights of good sleep, sort of paying back your sleep debt. Your next question might be then, "How much sleep is enough sleep?" That's kind of a hard question to answer, but most adults need about 7-8 hours of sleep, but the exact number varies by individual and by age. Babies need a lot more sleep, for example, than older adults often sleep less than 10 or 8 hours without severe detriments. Again everyone has trouble falling asleep at some point, but people who have persistent problems in falling or staying asleep have a more serous sleep disorder called insomnia. There are various medications that can help people fall asleep, but taking them for too long can result in dependence and tolerance, which is if a person continues to rely on the medication then their body will get used to it and they'll eventually need more and more to get the same affects. Now, that can often be a bad thing because there are side effects to drugs, but so treatment for insomnia often involves psychological training as well as or sometimes instead of medication and some lifestyle changes might also be necessary. For example, exercise regularly but not right before bed or spend some time just relaxing before bed and these can people with insomnia. On the other end of the spectrum is narcolepsy, which is a disorder when people can't help themselves from falling asleep. So about 1 in 2,000 people suffers from narcolepsy and most of the time people with narcolepsy will have these spontaneous fits of intense sleepiness occasionally lapsing into REM sleep and these fits last about five minutes and can occur really any time. Although the cause of narcolepsy is still under investigation, there are indications that it's genetic and it's linked to the absence of a certain neurotransmitter that helps with alertness suggesting that neurochemical interventions may help some people overcome this problem. A more common sleep disorder is sleep apnea, which affects about 1 in 20 people. This one is a little scary because people who have apnea are really unlikely to be aware of it. What happens is that people stop breathing while they sleep. After about a minute of not breathing, your body realizes you're not getting enough oxygen and you wake up just long enough to gasp for air and then fall back asleep without really being aware of what happened and this can actually happen as many as hundreds of times each night, which is a lot and because you're constantly drifting kind of between sleep and wakefulness, you don't really get enough of your deeper stages of sleep so this prevents you from going into the N3 stage or the slow-wave sleep. Snoring can be an indication of sleep apnea, so if you've ever been told that you snore and you often feel fatigued in the morning even after what you think is a full night sleep then you might be one of the 1 in 20 people with sleep apnea, but it's very treatable so don't worry. Sleep walking and sleep talking are the last sleep disorders we're going to talk about. Like narcolepsy, these are mostly genetic and they occur during N3 stage sleep and are usually harmless as long as you don't walk into a dangerous situation or reveal any deep dark secrets. Sleep walking and talking occur more frequently in children, partially because children experience more N3 stage sleep than adults, but as you grow these nighttime adventures become much less frequent.