It seems that we’re always talking about the importance of high quality sleep, but what does that actually mean? What makes sleep “high quality”? Can your sleep quality be affected by poor sleep quantity? How do you improve your sleep quality? What do sleep experts really mean when they talk about getting 8 hours of “quality” sleep each night?
According to the Sleep Research Society, “sleep quality” is the subjective term given to a combination of tiredness upon waking, ease of sleep onset, sleep maintenance (how well you stay asleep), and total sleep time. Based on their studies, sleep quality is directly linked to how efficiently you progress through the four sleep stages. The easier you can float uninterrupted through the natural progression of sleep, the more rested you’ll feel in the morning!
The Stages of High Quality Sleep
Quality sleep occurs when your body can proceed through all four stages of the sleep cycle; transitions from stage to stage must be smooth, uninterrupted, and take place several times each night. Since it’s such a natural, unconscious progression, it seems odd that we would have difficulty getting the high quality sleep we require. However, sleep interruptions (that commonly arise from alcohol consumption or sleeping with a partner) can send our sleep cycle spinning!
The Stages of Sleep
To take control of your sleep quality, it’s important to have an understanding of each of the sleep cycles:
Stage 1 sleep is the lightest of the four and normally lasts anywhere from one to ten minutes. During this stage, you may drift in and out of consciousness, be aware of noises around you, and typically awaken quite easily. Many sleepers report involuntary muscle contractions known as hypnic myoclonia. This scientific term is the feeling of falling and the “jump” you may experience as you wake up. Stage 1 sleep is the lowest quality and if you wake up during it, you’ll feel completely unrested….even if you’ve been sleeping for hours!
During Stage 2 sleep cycles, your brain waves will start to slow down with an occasional burst of waves from time to time. Your heart rate continues to slow, and your body temperature begins to decrease as you prepare to enter a deeper sleep state. You’ll be harder to wake up, and you’ll be largely unable to absorb external input such as the sounds of a conversation. On average, you’ll spend around 50% of your total sleep in Stage 2 sleep.
Starting around thirty-five to forty-five minutes after you fall asleep, Stage 3 sleep is the deepest non-REM level. Your brain waves continue to slow down as your body releases hormones that serve to keep your limbs still. You might sleep through disturbances that would have woken you if you’d been in Stage 1 or 2, but it’s REM sleep that’s most important to sleep quality.
Rapid eye movement (REM) sleep is the deepest level of sleep, and it typically occurs 70 to 90 minutes after you fall asleep. Your breathing will become more rapid and shallow, and, if someone were to hold open your eyelids, they would see your pupils rapidly darting in random directions. During the first three stages, your muscles began to relax, but during REM sleep, your muscles will become unresponsive and temporarily paralyzed as a mechanism to prevent waking. The average sleep cycle typically takes between 90 and 110 minutes, so, if you’re getting in a full eight hours, you’ll reap the rewards of multiple cycles of REM sleep!
High quality sleep is dependent on your ability to efficiently move through the four sleep stages. One of the easiest ways to increase the quality of your sleep is to limit external factors that affect your sleep efficiency. Caffeinated drinks, drugs, cigarettes, and decongestants are stimulants that can cause irregular brain wave patterns which make it difficult to enter the appropriate stage of sleep. External sounds, lights, and smells may also interrupt your sleep cycles. Limiting these external influences allow your body to establish a natural sleep cycle which contributes to a higher overall quality of slumber.