Do you fall asleep easily, but still find yourself awakening during the night, only to stare at the ceiling? If you do, you’re in good company. Many people experience fragmented, or interrupted sleep. They may not consider themselves an insomniac, as they drift off to sleep in a reasonable time. Yet they struggle to stay asleep or wake up numerous times before sunrise. You might also wonder what impact fragmented sleep has on your health and well-being. More than you might think! Before we explore these issues, let’s ensure you understand the basics of sleep.
Architecture of Sleep: Stages of Sleep
Sleep is not a uniform state. Instead, it’s a dynamic process that consists of multiple stages and cycles you move in and out of. During your sleep journey, you enter two main types of sleep: non-rapid eye movement (NREM) and rapid eye movement (REM) sleep.
First, let’s look at NREM sleep. Scientists divide this phase of sleep into three substages:
- N1: This is the lightest stage of sleep, serving as a transition between wakefulness and deeper sleep.
- N2: Characterized by sleep spindles and K-complexes, this stage represents about 45% of total sleep time
- N3: Also called slow-wave sleep (SWS), this is the deepest and most restorative stage of NREM sleep.
Now, REM sleep. This is the stage of sleep when you are most likely to experience vivid dreams and even nightmares. If you don’t get enough sleep during this phase, you’re more likely to be irritable. Also, you consolidate memories during this stage, so you could be more forgetful too.
Sleep Cycles
As you sleep, you cycle through the stages of life every 90 to 120 minutes. During a night’s sleep, you might cycle through these stages 4 to 6 times. As the night goes on, the length of REM sleep increases.
When Your Sleep Is Disrupted or Fragmented
Fragmented sleep is when something disrupts your natural sleep cycle, and you wake up more frequently. This can affect how well you sleep and how much sleep you get. What causes it? Some of the causes include
- Outside disturbances. This could include a hot sleeping area, interruptions due to noise, or too much light in your room.
- Internal factors. Any type of discomfort, like pain, worry, or anxiety can cause you to awaken during the night.
- Sleep disorders. If you have a sleep disorder, like sleep apnea, you may wake up many times during the night.
- Lifestyle choices. Lifestyle is another common cause. One of the most important is having an irregular sleep schedule.
The Physiological Impact of Interrupted Sleep
Sleep is your body’s time to rest, recover, and repair. So, it’s not surprising that when it’s fragmented, it negatively affects your health and mood. Since you’re spending less time in deep sleep, you don’t feel refreshed when you wake up. Instead, you feel tired, disoriented, and groggy. Plus, tissue and cellular repair may be sub-optimal as well. So, what specific effects does it have on your body?
Hormonal Changes
When you toss and turn and awaken frequently, it places substantial stress on your body. In response, your adrenal glands produce more stress hormones, like cortisol and adrenaline, leading to anxiety and other mood changes. When these hormones are higher longer term, they can trigger or worsen metabolic issues, like obesity and insulin resistance. Research shows that poor sleep reduces insulin sensitivity and disrupts blood sugar control. Lack of adequate rest also activates appetite hormones, like ghrelin, that cause you to eat more. Over time, this increases the risk of type 2 diabetes and obesity.
Cardiovascular Effects
When you wake up repeatedly throughout the night, it activates your sympathetic nervous system. When your sympathetic pathways are fired up, it causes a rise in blood pressure and a decline in heart rate variability. Both are harmful to the health of your heart. Over time, these nightly changes place you at higher risk of cardiovascular disease.
Immune Function
Your immune system repairs during sleep too. As you slumber, your immune system produces critical production cytokines—proteins that your immune system uses to moderate the inflammatory response and protect against foreign invaders. When you toss and turn and have sleep interruptions, it interferes with function. Think of sleep as your body’s nightly reset button. Unless it’s high quality, your immune defenses may suffer. So, prioritizing restful sleep is not just a luxury; it’s a must for health!
Cognitive and Psychological Consequences
The effects of interrupted sleep extend beyond physical health, significantly impacting our cognitive abilities and emotional well-being. Since we process and consolidate memories during the deep stages of sleep, disrupted sleep can affect your memory. A 2021 study found that fragmented sleep and less N2 stage affected working memory, learning, and recall. Participants demonstrated deficits in working memory after fragmented sleep.
Attention and Performance
Even a single night of fragmented sleep can result in decreased attention span, slower reaction times, and impaired decision-making abilities. These effects can be particularly dangerous in situations requiring high levels of alertness, such as driving.
Mood Disorders
To top it all off, studies link fragmented sleep to mood disorders, like anxiety and depression. This isn’t surprising as who feels calm and upbeat when you’ve had poor-quality sleep? Mood issues are more likely to be a problem if you have fragmented sleep night after night. But also know that mood disorders can worsen sleep issues, so it’s a two-way street that can create a vicious cycle of fragmented sleep and mood changes.
Cognitive Decline
One of the most serious concerns with fragmented sleep is the effect it has on brain health. Some studies show that sleep disruptions place an added burden on the brain and increase the risk of cognitive decline decades later.
Why? Scientists point out that during sleep your body clears metabolic waste products and misfolded proteins that clog up your brain and contribute to cognitive decline. They do this through a special system called the glymphatic. When you don’t sleep enough or have fragmented sleep, this cleaning mechanism doesn’t work as well. It’s your brain’s detox system. Plus, your brain forms new connections with neurons, or nerve cells, during deep sleep. without this neuroplasticity, you don’t learn and remember as well.
Smart Strategies for Improving Sleep Continuity
Knowing how important sleep is, let’s look at evidence-based strategies for improving yours:
- Keep your sleep schedule consistent every night, even on weekends.
- Do something relaxing before bedtime. Make it something unrelated to technology.
- Dial back the temperature and noise and keep your sleep environment dark, cool, and quiet.
- Avoid coffee or switch to decaf after 12:00 P.M. to ensure most caffeine is out of your system Also, avoid alcohol close to bedtime
- Stay physically active and include both aerobic and strength training.
- Manage stress through relaxation techniques, such as mindfulness, deep breathing, and meditation.
Conclusion
We still have a lot to learn about the phase of existence called sleep. What we do know is fragmented sleep is harmful to our health and well-being in more ways than one. When you struggle to stay asleep, it disrupts your natural sleep patterns and makes it harder for your body to repair. It also interferes with memory consolidation. So, make it a priority to improve your sleep quality through good sleep hygiene tactics. If you’re still struggling to get a good night’s sleep, talk to your doctor. Fragmented sleep can also be a sign of more serious health issues, like sleep apnea.
References:
- “Interrupted Sleep: Causes & Helpful Tips – Sleep Foundation.” 12 Mar. 2024, https://www.sleepfoundation.org/sleep-deprivation/interrupted-sleep.
- Okuda M, Noda A, Mabuchi S, Iwamoto K, Banno M, Miyata S, Yasuma F, Ozaki N. Sleep fragmentation and working memory in healthy adults. Sleep Sci. 2021 Apr-Jun;14(Spec 2):111-117. doi: 10.5935/1984-0063.20200088. PMID: 35082979; PMCID: PMC8764943.
- “Sleep fragmentation, microglial aging, and cognitive … – Science.” 11 Dec. 2019, https://www.science.org/doi/10.1126/sciadv.aax7331.
- Stepanski EJ. The effect of sleep fragmentation on daytime function. Sleep. 2002 May 1;25(3):268-76. doi: 10.1093/sleep/25.3.268. PMID: 12003157.
- “The impact of sleep disorders on glucose metabolism: endocrine and ….” 24 Mar. 2015, https://dmsjournal.biomedcentral.com/articles/10.1186/s13098-015-0018-3.
- “The Epidemiology of Sleep and Diabetes – PMC – National Center for ….” 08 Aug. 2018, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6437687/.
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