Do you get enough sleep?
Do you find it difficult to fall asleep, or do you wake up in the middle of the night on a sleepy
Lack of sleep adversely affects health and work efficiency.
This time, I will tell you about the best sleep time for you and how to sleep comfortably on
Negative effects of lack of sleep on the body and mind
Many people know that sleep is important, but when they are busy, they spend less time
However, lack of sleep is known to have a negative effect on physical and mental health.
For example, it has been pointed out that when sleep deprivation occurs, the hormones that
control appetite are out of balance and appetite increases, leading to obesity. In addition,
people with chronic sleep deprivation have been found to be at increased risk of diabetes,
myocardial infarction, and angina.
It is also said that lack of sleep increases anxiety and depression, which can lead to mental
What is “sleep debt”?
Recently, I’ve come to hear the term “sleep debt” a lot.
Sleep debt is the accumulation of damage in your body like debt due to continued lack of
sleep. Overlapping sleep debt has been shown to reduce thinking ability and worsen work
For example, some studies have shown that even just 16 minutes of sleep deprivation can
have a negative impact on work (https://pubmed.ncbi.nlm.nih.gov/30905693/).
How do I know the “optimal sleep time” for me?
The average sleep time of Japanese people is 7 hours and 22 minutes according to the
2018 OECD international comparison.
This is by far the lowest, and Japan has the shortest sleep time in the world.
So how much is “optimal” sleep time?
Generally, in the case of the active generation, it is said to be “6 to 8 hours”, but there are
individual differences. There is also a view that even if you don’t care about your sleep time,
you should be comfortable the next day without feeling drowsy.
The important thing is to know “how long you should sleep to be comfortable the next day”.
Professor Masashi Yanagisawa, director of the International Institute for Integrative Sleep
Medicine, University of Tsukuba, said, “Decide wake-up time and bedtime on a weekly basis,
as first 6 hours a day, then 7 hours a day. We recommend changing your sleep time (from
In other words, try 6 hours of sleep daily for the first week, 7 hours of sleep for the next
week, 8 hours of sleep for the next week, and so on, to see which sleep suits you best. Once
you “experiment”, you will definitely find the optimal sleep time for you.
How does the air conditioner factor when you sleep?
By the way, during the summer, sleepless nights continue.
Many people are wondering whether it is okay to leave the air conditioner on or set a timer.
In the past, it was often said that leaving the air conditioner on all night would be too cold for
However, recently, it has been said that it’s better to leave it on all night, because the room
In fact, many of you may have experienced that even if you sleep for an hour or two with the
timer, it will become hot and you will wake up when the air conditioner turns off.
In order to sleep comfortably until morning during the tropical nights, it’s recommended to
set the air conditioner to a higher temperature of 27 to 28 degrees and leave it there. Also,
adjust it so that the air from the air conditioner does not hit your body directly.