Woman lies with sleeping mask in the bed

Hallie G. knew that she was a “poor sleeper,” some of it her own doing. She fought off sleep as long as possible at night to answer email or have some time to putter around the house while everyone else was already asleep. She knew that she woke up a lot during the night and didn’t feel rested in the morning. It wasn’t until she wore her Fitbit tracker to bed that she saw just poorly she slept. “I woke up 13 times and in total, probably slept around four hours. That’s just not enough!” she said, admitting that she couldn’t get through most days without continual caffeine fixes.

Hallie is one of some 70 million Americans who according to the National Sleep Foundation, suffer from chronic sleep problems, like insomnia, waking up frequently during the night, or waking up too early. Like Hallie, tens of millions of us are walking around in a chronic state of “sleep debt.” We are depriving our bodies of the full benefit of a good night’s sleep.

What exactly is a “good night’s sleep?”

We think of sleep in terms of the total amount of hours slept, but in reality, sleep is a far more complex process. We experience two different types of sleep: REM (rapid eye movement) and non REM. They are both important for our health and wellbeing.

Sleep consists of a series of repetitive cycles involving five different phases: There are three stages of non REM sleep followed by a briefer period of REM sleep during which we dream. (REM sleep accounts for about 20-25% of the sleep cycle, which means that we spend about two hours a night dreaming.) Each sleep cycle lasts between 90-110 minutes. On a good night, we seamlessly cycle in and out of these various stages of sleep about five or so times with few interruptions.

Stage 1

Your journey into sleep begins when you put your head down on your pillow and start to feel drowsy and relaxed. On average, within 10-20 minutes, you will fall into a light sleep. Muscle activity, eye movement and brain waves slow down. During this initial stage, you can be easily awakened by outside noise.

Stage 2

About half of your total sleep time is spent in Stage 2, a deeper form of sleep in which your eye movements and brain waves slow down even more. Body temperature drops and you become unaware of your surroundings.

Stage 3

Now you’re beginning to fall into an even deeper, more restorative sleep that is marked by the appearance of extremely slow brain waves ― called Delta Waves ― along with other smaller, faster waves. This stage of sleep is called delta or slow wave sleep. There are a series of physiological changes: blood pressure drops, metabolism slows down and your muscles are relaxed. During this stage, your body begins to perform its vital maintenance work to keep you and your cells functioning at your peak. During this part of the sleep cycle, your body releases a spurt of growth hormone, which is necessary for building muscle and bone, as well as tissue growth and repair.  A lack of delta sleep is associated with an increased risk for high blood pressure and cardiovascular disease.

REM Sleep Stage

You top off your sleep cycle with a bout of REM sleep — the time when you dream. During REM sleep, your eyes stay shut, but they are moving rapidly under your eyelids. Your muscles, on the other hand, stay very still in what is known as “sleep paralysis.” Although scientists don’t know for sure why we dream, REM sleep is believed to be vital for learning, mood and overall state of mind. The amount of REM sleep can fluctuate throughout a woman’s menstrual cycle. Lack of REM sleep is also linked to migraines. As you cycle through the various states of sleep throughout the night, your time spent in REM sleep increases.

How can you tell if you’re getting the proper rest? An at home sleep study can reveal some information. For example, you can see how many times you awaken during the night, and whether your sleep is “light” or “deep.”

At the very least, tracking your sleep at home can alert you to possible problems that you may be able to treat on your own with lifestyle changes. For Hallie, making an effort to go to bed earlier, restricting her caffeine intake to a cup or two in the morning, and focusing on relaxation at night instead of work, helped improve her sleep quality. If basic lifestyle changes don’t work, it’s a good idea to consult with a sleep specialist for further evaluation.