What Is Slow-Wave Sleep?

What Is Slow-Wave Sleep?

Slow-wave sleep, also referred to as deep sleep, is the stage of sleep when the body is in its most restful state. This stage is vital for growth, memory, and immune function. That said, the impact of deep sleep on our overall health, sleep issues, and potential medical conditions is remarkable. So, if you want to find out more, continue reading below.

Slow-Wave Sleep Basics

As already noted, slow-wave sleep is also called deep sleep, but it is also known as the third stage of sleep. Namely, during a night of sleep, a person goes through four sleep stages – three non-rapid eye movement (NREM) sleep stages and only one rapid eye movement (REM) sleep stage. And, each of these stages is characterized by distinctive changes in brain activity. In general, a person moves through these stages four to six times a night.

When it comes to Slow-wave sleep, is characterized by electrical brain activity changes as the body progresses into a deep and restorative state. Each slow-wave sleep cycle lasts for about 20 to 40 minutes and most of it occurs early in the night, making 10% to 20% of the total amount of sleep each night.

However, it’s important to mention that our slow-wave sleep needs change with age. In other words, we need less slow-wave sleep as we get older. On the other hand, if we’ve experienced sleep loss, the body, and the brain make up for it by increasing the proportion of slow-wave sleep. Plus, chronic insomnia patients tend to spend less time in deep sleep.

Slow-Wave Sleep Effects on the Body and Brain

Brain waves are basically the brain’s electrical activity represented visually. They are measured by special equipment and show what is happening in the brain at different times. Regarding the third stage of sleep, these waves slow down and start a pattern showing a person is in deep sleep.

But, along with slowed down brain waves, other bodily functions slow down as well such as breathing, heart rate, and blood pressure. The decrease in blood pressure is significantly important for heart health and helps in protection against high blood pressure, stroke, and heart failure.

Plus, during slow-wave sleep, muscles are relaxed, and it is more difficult to wake up a person during this stage. Another important thing to mention is the production of hormones. For instance, during the third stage of sleep, the production of the growth hormone increases, which is vital for metabolism, bones, and muscles.

Slow-Wave Sleep Function

Finally, let’s have a closer look at why is slow-wave sleep so important for us and what’s its function. Experts have found that slow-wave sleep has a great variety of vital functions, but more research is still needed to understand its purpose completely. In short, here are the most notable functions of slow-wave sleep:

  • Makes sleep refreshing and restorative and reduces pressure throughout the day.
  • Supports memory by helping newly acquired memories become part of long-term memory.
  • Facilitates learning by restoring brain cell connections.
  • Supports tissue growth and repair thanks to the hormonal changes that occur during the third stage of sleep.
  • Boosts immunity also thanks to the changes in hormone levels.
  • Enables the elimination of waste products found in the fluid surrounding the brain and spinal cord, such as amyloid-beta proteins.