Sleep studies are tests that watch what happens to your body during sleep. Sleep studies can also determine whether you have a problem with your stages of sleep. The two stages of sleep are non-rapid eye movement (NREM) and rapid eye movement (REM). Normally, NREM and REM alternate 4 to 5 times during a night's sleep. A change in this cycle may make it hard for you to sleep soundly.

Sleep studies allow doctors to measure how much and how well you sleep. They also help show whether you have sleep problems and how severe they are. Sleep studies are important because untreated sleep disorders can increase your risk of high blood pressure, heart attack, stroke, and other medical conditions. Sleep disorders also have been linked to an increased risk of injury due to falls and car accidents.

People usually aren't aware of their breathing and movements while sleeping. They may never think to talk to their doctors about sleep- and health-related issues that may be linked to sleep problems. Or if you often have trouble falling or staying asleep, or if you wake up too early and aren't able to go back to sleep. These are common signs of a sleep disorder.

The most common sleep studies are:

• Polysomnography - This test records several body functions during sleep, including brain activity, eye movement, oxygen and carbon dioxide blood levels, heart rate and rhythm, breathing rate and rhythm, the flow of air through your mouth and nose, snoring, body muscle movements, and chest and belly movement.
• Multiple sleep latency test (MSLT) - This test measures how long it takes you to fall asleep. It also determines whether you enter REM sleep.
• Maintenance of wakefulness test (MWT) - This test measures whether you can stay awake during a time when you are normally awake.

Sleep studies usually are done in a sleep lab. Sleep labs are often located in hospitals. But sleep studies also can be done with portable equipment you use at home/ spahotel.