Sleep Physiology: The Restorative Power of Rest

We spend about one-third of our lives asleep, making it no surprise that sleep is a favorite activity for many. Yet, few of us consider the internal processes at work as we settle into bed and drift into dreamland.

This is where sleep physiology comes into play. It delves into the biological processes behind sleep, exploring how our bodies regulate it, its effects on bodily functions and the different stages of sleep.

So, grab your favorite pillow and join us as we uncover the essentials of sleep physiology and discover how to enhance your sleep habits for optimal rest and renewal.

The Sleep Cycle

Each night, we cycle through two primary phases of sleep:

Nonrapid Eye Movement (NREM)
NREM sleep accounts for approximately 75% of your sleep time and consists of three stages:
- Stage one: This brief phase occurs as you start to fall asleep and lasts about five minutes.
- Stage two: After we nod off, we enter a light sleep for around 25 minutes.
- Stage three: This is the deepest phase of NREM and often the hardest to wake from. Waking up during this phase can lead to mental fogginess and reduced performance for up to an hour. It is also the most restorative phase, where the body repairs tissues and boosts the immune system.

Rapid Eye Movement (REM)
Following NREM, REM sleep begins with rapid eye movements and accounts for about 25% of your total sleep time. This phase is famous for creating vivid dreams — like that one where your cat juggled baby mice before a crowd of elderly lions in 1980s punk rock gear. Despite its rich dream content, REM sleep is the least restorative phase.

Throughout the night, we cycle through these two phases, with the first NREM cycle lasting about 70 minutes and lengthening with each subsequent cycle. The initial REM cycle lasts around 10 minutes, with later cycles extending up to an hour. In total, we experience approximately four to six sleep cycles a night.

Effects of Impaired Sleep

Have you ever struggled through a few rough nights of sleep? Whether it’s due to caring for a new baby or giving in to that third cup of coffee, various factors can lead to restless nights.

You might have noticed the effects of impaired sleep, like difficulty retaining new information, decreased coordination or mood swings. If so, you’re not alone. According to the National Council on Aging, 30% of Americans suffer from insomnia, and 10% say it affects their daily lives.

Psychological risks of continued poor sleep may include:

Hallucinations

Mania

Impulsive behavior

Anxiety

Depression

Paranoia

Suicidal thoughts

The Benefits of Restorative Rest

We’ve all experienced waking up from a blissful eight (or even ten) hours of solid sleep. On those mornings, we often feel well-rested, with increased mental clarity, heightened energy and a renewed drive to tackle the day. Oh, the power of a good night’s sleep.

While sleep needs vary based on genetics, adults aged 18 to 60 generally require seven or more hours each night to experience the following benefits:

Improved immune response

Reduced stress levels

Enhanced metabolism

Better heart health

Lower risk of chronic conditions, such as Type 2 diabetes, high blood pressure and stroke

Improved attention span

Greater ability to remember information

Tips for Optimizing Sleep

Even under the best circumstances, not every night will provide the perfect amount of zzz’s — but you can still significantly increase the number of nights you enjoy rejuvenating rest. Here are some tips to improve the quality of your sleep:

Establish a bedtime routine
Go to bed at the same time each night. Develop a consistent pre-sleep routine, such as showering, brushing your teeth and reading a book in bed, to help you wind down and prepare for rest.

Maintain a sleep-positive environment
Minimize auditory distractions by closing the door or using a sound machine. Maintain a cool room temperature to enhance thermoregulation, which may help you remain in REM sleep for longer periods.

Turn off electronic devices before bed
While scrolling through social media or catching up on news might seem like a relaxing end to your day, the blue light emitted by phones can interfere with sleep. Instead, replace screen time with relaxing activities like journaling, meditating, stretching or reading.

Turn Your Passion Into a Rewarding Career

If you’re intrigued by what your brain and body are up to while you sleep, or if you’re considering a career dedicated to improving the sleep health of others, there are several paths to explore within this segment of the healthcare industry.

The University of Florida offers a variety of online graduate programs in the medical sciences designed to help you achieve your professional goals. These programs provide an excellent foundation, whether you’re ready to enter the workforce or plan to apply to professional school for further education.

Explore the online graduate certificates and master’s degrees below to find the program that best suits your interests and career aspirations.