Why do I still feel tired even though I'm getting enough sleep? There's a problem with the quality of your sleep!
Most people don't know what happens during their sleep. Why? Because they are sound asleep! Have you ever heard for the first time from a friend you traveled with that you have sleep apnea or talk a lot in your sleep? To improve your sleep performance, the first step is to understand the quality of your sleep.
Many people tend to think, "I fall asleep as soon as I get into bed," "I wake up feeling well-rested in the morning," or "I sleep well, so I'm fine!" Is that really true? We undergo regular health check-ups to minimize health damage resulting from lifestyle diseases. Knowing our current health status is crucial to avoid potential future illnesses and maintain our current good condition. If you decide to go on a diet, you can't determine specific approaches or goals without knowing your current weight.
Studies of people with chronic insomnia frequently report that individuals who claim to have slept only two hours actually slept five hours when their brainwaves were measured. Similarly, those who claim it takes them two hours to fall asleep often fell asleep in 20 minutes according to brainwave measurements. This is because people "misperceive" their sleep duration based on their own feelings, as they cannot objectively confirm it.
Recently, the importance of sleep and how performance sleep can improve life efficiency has gradually become recognized. So, how can we understand the quality of our daily sleep and what should we pay attention to? Traditionally, sleep examinations involved hospital stays where a polygrafi exam was performed, with sensors attached all over the body to monitor brainwaves, respiration, eye movements, oxygen saturation, body movement, and blood pressure overnight. Nowadays, high-precision measurements can also be taken using free smartphone apps, so it's worth trying them to easily understand your own data and tendencies. Please search for "sleep" in the app store and download one. All you have to do is launch the app before going to bed and place your phone next to your pillow (this is the most common type).
However, the impact of electromagnetic waves emitted from electronic devices during sleep has recently become a concern. It might reduce sleep performance, so it's advisable to be careful. To mitigate this, setting your device to "airplane mode" during measurement can cut off electromagnetic waves and calls, allowing you to sleep soundly until morning. The sleep tracking and alarm functions of the app can still be used.
Sleep Quality Checkpoints
The graph shows an ideal sleep pattern for one night, with three checkpoints.
1. Time to fall asleep
Ideally, the time it takes to fall asleep is 16 minutes! Many people might say, "I fall asleep as soon as I get into bed." If you fall asleep very quickly (roughly within 8 minutes), it could be a sign of extreme fatigue or accumulated sleep debt, leading to a state similar to collapsing into sleep. While there's no need to force yourself to wait when you're sleepy, remember that taking about 16 minutes to slowly calm your breathing and pulse before falling asleep is a gentle way to sleep without putting a strain on your body. If it takes more than 30 minutes to fall asleep, it could meet the diagnostic criteria for "insomnia."
Using your phone before bed can disrupt melatonin secretion, leading to difficulty falling asleep and reduced sleep quality.
2. Balance of NREM and REM = Deep and Shallow Sleep
As seen in the graph above, it is ideal to enter the deepest sleep about 40 minutes after falling asleep, then cycle between shallower and deeper sleep. Deep sleep and shallow sleep each have different roles, and their balance is crucial. As women often hear, "the golden hours of sleep from 10 PM to 2 AM create beauty!" This is because a large amount of growth hormone, which plays a role in tissue repair and recovery, is secreted during the initial deep sleep phase. However, if your sleep is shallow even during these hours, the secretion of growth hormone will be reduced. Furthermore, shallow sleep is essential for organizing information and consolidating memories, so it cannot be neglected. A ratio of 2:1 for deep sleep to shallow sleep is considered ideal.
3. State of Sleep Depth
Sleep depth refers to how deep your sleep is. While sleep cycles between deep and shallow stages, some people remain "deeply asleep" throughout. While deeper sleep might seem to indicate better sleep performance than shallow sleep, the body prepares to wake up during the shallowing process. If you look at the graphs of people who find it hard to wake up in the morning or lack energy in the forenoon, most show a deep sleep state in the latter half of their sleep. This means they are being woken by a blaring alarm clock before their bodies are ready to wake up. People who are "not morning persons," "can't wake up in the morning due to low pressure or low blood sugar," or "are anemic and struggle in the morning" likely have low levels of hormones like cortisol and melatonin, which are typically secreted in the morning.
Just being aware of and checking your current sleep status as described above can be a catalyst for changes in your daily habits. Re-evaluating the quality of your sleep while you are unconscious is certainly a trigger for improving the quality of your performance while you are awake.
