Q. What usually happens when someone goes to sleep?

A. Adults typically experience several rounds of sleep cycles of around 90 minutes throughout the night. They enter sleep through Stage 1 sleep, a very light sleep. Then we go into Stage 2 sleep and it has a higher arousal threshold than Stage 1 sleep. Then comes Stage 3 sleep, also known as slow wave sleep or deep sleep. That has the highest arousal threshold of all.

If you’ve ever seen a child at a carnival or state fair and the child is asleep on the parent’s shoulder and you wonder ‘How in the world can this child sleep through this?’ That child is in slow wave sleep.

Q. What is REM sleep?

A. Non-REM sleep is in stages 1, 2 and 3. REM sleep is [in] a very active part of the brain and a very active stage of sleep neurologically. That’s when we tend to do most of our vivid dreaming. The body is ideally paralyzed during that time. We lose muscle tone throughout the body except for the diaphragm, eye muscles and a small muscle in the ear. This prevents us from acting out our dreams at night. Rapid eye movement sleep would typically occupy 20-25% of the night.

Q. Who experiences the most slow wave sleep?

A. Young people and women tend to have more slow wave sleep than men. And in each of us, as we get older, we tend to have less slow wave sleep.

Q. What should you do if you cannot fall asleep because your brain starts spinning the minute you turn off the light?

A. Like any bad habit, you learn to stop doing that. First of all, you have to understand that you’re ultimately in control of what you think, and that’s called mindfulness (UVA’s Mindfulness Center is a good place to start learning how to manage stress and sleep disturbances).

There are three parts of the brain. The brain of wakefulness, the brain of non-REM sleep and the brain of REM sleep. When people are thinking at night, they are feeding the brain of wakefulness and it’s giving negative input to the brain of sleep.

You need to clear your mind in whatever way you can and allow the brain of non-REM sleep to take over. Counting exercises can help. With each normal exhalation you count a number. When an intrusive thought enters your mind, you start over again. What you are doing when you do this is you are gaining insight into the fact that you have control over your thoughts. What you are doing by showing some discipline and helping to clear out your mind is you’re allowing the brain of non-REM sleep to get balance.

Q. What are your pro tips for healthy sleep habits in adults?

A. I think it’s to have a regular bedtime and a regular wake time and not to have a big shift between workdays and non-workdays. I’d get regular exercise. Some people are sensitive to exercise within three hours of going to bed, so you might want to monitor for that. Avoid caffeine after 2 p.m. Get tested for sleep apnea if you think there might be an issue with that.

Q. What about the environment of the room you’re sleeping in?

A. It’s important to sleep in a cooler room. It’s important to sleep in a dark room. It’s important to sleep in a quiet room. I know all those things seem very evident, but we’ve built a lot of nice houses near some very busy highways.

You want to set aside the bed as a safe zone. It’s not another wing of your office. It’s not a time to review things for the following day. You need to partition your life and set boundaries.

Q. How does family life figure in sleep hygiene and what about pets?

A. It’s important to have a quiet bed partner and to set boundaries with children. It’s not okay for little kids to come in at night and interrupt your sleep. It’s not okay for pets to come into bed at night. We had a psychology professor at Oregon Health and Science University, where I used to be, and he said, “Have your pets sleep outside the room. You both will sleep better.”

Q. What are the most common types of sleep disorders in adults?

A. We see all types of sleep disorders. There are more than 80 of them.

Eighty percent of people have insomnia from time to time.

Another is obstructive sleep apnea. We lose neuromuscular tone as we fall asleep and for some of us, it results just in snoring. In others, it gets to the point where there’s more intrusive airflow limitation that interrupts our sleep, leading to a recurrent arousal during the night, and sometimes these arousals can be associated with oxygen desaturations. The most common cause of that would be obstructive sleep apnea.

Some people have neurologic problems like restless leg syndrome, which is also associated sometimes with periodic limb movement disorder.

Q. Can apps like Calm, where for example someone with an Irish accent is reading you a bedtime story, help you drop off to sleep?

A. I think they can be very successful in certain individuals. If you have a tendency toward worry or stress, those can help to get you focused on something different.

Q. Why is sleep so important?

A. We need sleep for rejuvenation of the brain and recovery of the brain processes. It’s the only way to get some of this rest. It’s unachievable in any other way other than getting sleep. Sleep is very important for cognition. It’s very important for immunological processes. It’s very important for hormonal and endocrine balance.

Q. What can happen if you don’t get enough sleep?

A. Sleep deprivation can lead to all kinds of poor health consequences – increased motor vehicle accidents, a decreased quality of life, family and interpersonal discord. It can lead to, in some cases, even increased rates of some cancers, which we are just starting to understand, and increased rates of stroke, increased rates of diabetes and increased rates of obesity. All kinds of bad things can happen.

Q. When should someone visit a sleep disorder doctor?

A. The best piece of advice is don’t hesitate to talk to your primary care provider about sleep and see if they can help you. They can ask questions like “Do you snore? Do you snore to the point that your bed partner leaves the room? How well do you sleep at night? When you go to sleep, do you stay asleep? Do you wake up multiple times a night? Do you wake up in the morning after eight or nine hours of sleep still feeling very tired?” If there are lots of “yeses,” then it would be time to refer to a sleep doctor.