"I have no time" was due to lack of sleep—the deep connection between brain processing speed and sleep
"I couldn't get that done today either."
"I know what I need to do, but for some reason, I can't finish it."
"The day just flies by."
If you are a busy parenting entrepreneur, I think you have felt this way at least once.
But how do you feel when you hear this: "Your lack of time might be due to a lack of sleep."
Everyone has 24 hours in a day. The difference lies not in "what you do," but in "what state your brain is in when you do it." A sleep-deprived brain takes many times longer to complete the same task. Slower judgment, inability to maintain focus, increased mistakes, procrastination—these are all "time thieves" caused by lack of sleep.
Conversely, when you improve your sleep, you get the feeling that your 24 hours have "increased." This is not a metaphor; it is something proven by neuroscience.
Everyone is the manager of their own "body." The way to maximize your most important resource as a manager—brain processing speed—lies in sleep.Today, I will talk about this, incorporating specific numbers and the mechanisms of neuroscience.
◎ It wasn't that "I have no time," it was just that "my brain was slowing down"
☆ The mechanism by which lack of sleep slows down brain processing speed
There is a famous study conducted by Dr. Van Dongen and colleagues at the University of Pennsylvania (Van Dongen et al., 2003). They divided subjects into a "6-hour sleep per night group," an "8-hour sleep per night group," and a "24-hour total sleep deprivation group," and continuously measured their cognitive functions.
The results were shocking. The cognitive function of the group that slept 6 hours for two weeks dropped to the same level as someone who had stayed awake for two full days. Moreover, the subjects themselves felt, "I'm a little sleepy, but it's fine." The brain cannot perceive its own decline in function.
Converting this to processing speed—there are estimates that just by continuing to sleep 6 hours, judgment speed, attention, and work efficiency drop by up to 40%. In other words, a task that should take 8 hours ends up taking over 11 hours in a sleep-deprived state.
What is scary is the problem of "getting used to it." When lack of sleep continues, that degraded state becomes the "new normal." The feeling that "this is just how I am" or "my concentration is weak" might actually just be the accumulation of lack of sleep from several weeks ago. The fact that you feel "fine" is actually a dangerous sign.
Many of the days when you feel "I have no time" may actually just be that "your brain is slowing down, and you are taking extra time for the same things."
☆ Decline in prefrontal cortex function—judgment, focus, and switching all become dull
The area most affected by lack of sleep is the prefrontal cortex.
The prefrontal cortex is the center of human "higher-order functions." Logical thinking, decision-making, maintaining focus, emotional control, and task switching—all of these are under the jurisdiction of the prefrontal cortex. And the prefrontal cortex is one of the brain regions most sensitive to lack of sleep.
What happens when the function of the prefrontal cortex declines?
First, it starts to take longer to make judgments. The time spent wavering, thinking "which one should I choose," increases. Even small decisions consume energy. It takes an unusually long time just to write a single email reply.
Next, you become unable to maintain focus. You get distracted every 10 minutes. You end up checking your smartphone. You get curious about other things while in the middle of a task. The more you think "I have to focus," the more you enter a vicious cycle where you cannot focus.
Furthermore, switching between tasks becomes slower. You cannot smoothly transition from "finishing one job and moving to the next," and the previous job remains in your mind. When you try to multitask, both tasks end up being half-finished.
Another thing that is easy to overlook is the decline in emotional control. When the prefrontal cortex is exhausted, its inhibition of the amygdala (the center of emotion) weakens, making you prone to irritation over trivial matters. On the night before the day you ended up raising your voice at your child, did you get enough sleep? Emotional instability is also one of the "wasted time" factors caused by lack of sleep.
When these factors combine, it creates a state where "you are working hard but nothing gets finished." It is not a problem of how hard you are working. It is a problem with the foundation of your brain.
☆ How many times longer does the same job take when you are sleep-deprived?
Let's think about this concretely.
Suppose writing one article takes two hours when you are well-rested. When sleep-deprived (having had less than 6 hours of sleep for several days), the same task can take 3 to 4 hours. The reason is that factors accumulate: it takes time to start writing (procrastination), you lose focus midway and end up doing something else (decreased concentration), you keep wavering over expressions (decreased judgment), and major revisions are needed after finishing (decreased quality).
The same thing happens in meetings. A discussion that would be decided in 30 minutes when you are well-rested takes an hour when your prefrontal cortex is functioning poorly. Moreover, the conclusion reached is of lower quality.
The 1 to 2 hours of "your own time" you finally get after putting your child to sleep. If you use it with a sleep-deprived brain, time melts away while your processing speed remains low. Even for the same hour, an hour spent with a well-rested brain can result in more than double the actual output.
"Cutting back on sleep because I'm busy" -> "Processing speed drops and it takes extra time" -> "I become even busier"—this is the structure of the trap that parenting entrepreneurs fall into when they say "I have no time."What you should cut back on is not sleep, but the "lost time" that is being wasted by your sleep-deprived brain.
◎ The true identity of the "time thief" created by lack of sleep
☆ Microsleep—consciousness dropping without you noticing
When lack of sleep continues, a phenomenon called "microsleep" occurs.
Microsleep is a state where the brain falls asleep for 0.5 to 15 seconds without the person realizing it. Even though your eyes are open and you look like you are sitting and working, your brain has shut down for a moment.
When this happens during work, it creates moments where you are looking at the screen but the content is not sinking in. You re-read a sentence you thought you had already read, wondering, "Wait, what was written here?" Things you thought you were thinking about suddenly fly out of your mind. This microsleep might be one of the causes of "why things aren't progressing even though I'm concentrating."
If this happens dozens to hundreds of times a day, the loss is on a scale that cannot be ignored. Moreover, the person has the feeling that they "were working properly." This is the troublesome part of the time thief caused by lack of sleep.
On the night before a day when you feel, "Somehow, my work isn't progressing today," how many hours did you sleep? The answer might lie there.
☆ Procrastination and dopamine—time disappearing even when you have no motivation
Lack of sleep reduces the sensitivity of dopamine receptors. Dopamine is the substance that creates "wanting." When this function is impaired, it becomes easy to fall into a state of procrastination where you know you have to do something, but you just "don't feel like it."
And the time spent procrastinating is not "time spent doing nothing." Looking at social media, researching irrelevant things, going to make coffee, doing other trivial tasks—the brain is idling, consuming energy while just wasting time.
You have no motivation, yet time just melts away. This is the true nature of those days when you wonder, "Why did I spend the day lazing around?" It's not that your willpower is weak. It's just that your dopamine isn't functioning. And the root cause of that lies in the lack of sleep the previous night.
Sleep is a skill and a tool. By stopping the dismissal of procrastination as a "personality problem" and re-evaluating it as "possibly a sleep problem," you can start to see solutions.
☆ Mistakes and correction work—lack of sleep mass-produces "re-dos"
Another time thief is the correction work caused by mistakes.
According to research by Dr. Walker (Walker, 2017), in a state of sleep deprivation, not only does attention span decrease, but the ability to detect errors also drops significantly. In other words, not only do mistakes increase, but you also become less likely to notice them yourself.
There was a typo in the email you sent. The numbers in the document were wrong. You forgot to contact a client. You overlooked something your child needed for school. When the corrections, apologies, and responses to these "small mistakes" pile up, a significant amount of time is sucked away during the day.
Moreover, mistakes don't just steal time for corrections. They create a vicious cycle where the loss of trust, self-loathing, and increased stress further hinder your sleep.
When you feel like you've been making a lot of mistakes lately, the first thing you should suspect might not be your ability, but the quality of your sleep.
◎ Why sleeping well increases your time
☆ Deep sleep "updates the brain's OS"
During the "slow-wave sleep (deep sleep)" stage, which is particularly deep, the brain activates the glymphatic system to wash away waste products accumulated during the day (Xie et al., 2013). This is, so to speak, an "update to the brain's OS."
Old cache is cleared, and processing speed is restored. Operations that were prone to freezing become smooth. The same thing happens to the brain through deep sleep.
The feeling of having a clear and sharp head the morning after a good, deep sleep—that isn't just a "matter of mood," but the result of the brain being physically cleaned.
Conversely, mornings where you feel "heavy-headed" or "unable to organize your thoughts" are signs that you didn't get enough deep sleep. On nights when you drink alcohol or look at your smartphone late, deep sleep is likely to be shallow. What affects your performance the next morning is not just the amount of time you slept, but the "quality" of that sleep.
☆ REM sleep organizes memories and speeds up the next day's work
REM sleep (dreaming sleep) has an important function of organizing and integrating memories.
During REM sleep, the hippocampus organizes what you learned, experienced, and thought about during the day and moves it into long-term memory (Stickgold, 2005). This puts you in a state where you can "immediately retrieve what you learned yesterday" the next day.
What is even more interesting is the research result that the brain performs "problem solving" during REM sleep. A study by Cai et al. (2009) at the University of California, San Diego, reported that the success rate for solving difficult puzzles improved by 40% after going through REM sleep.
While you are asleep, your brain combines yesterday's information to create "new answers." The experience of "an idea suddenly popping into my head when I woke up in the morning" or "a problem I couldn't solve yesterday was suddenly solved this morning" is a result produced by REM sleep.
When memory retrieval speed increases and thought connections become smoother, work processing speed increases. Even with the same two hours, the amount of work you can do is completely different. On nights when you feel like "something is stuck," sleeping makes it easier to find answers.
☆ Being able to utilize the golden time immediately after waking up
The 30 to 60 minutes immediately after waking up the morning after a good night's sleep is golden time for the brain.
During this time, the prefrontal cortex is in full operation, making it most suitable for deep thinking, creative work, and important decision-making. Cortisol (the wake-up hormone) is secreted in appropriate amounts, making it easy for concentration and judgment to reach their peak.
If you are sleep-deprived, you will waste this golden time in a state of microsleep or grogginess. But if you have slept enough, you can do your most creative and high-quality work of the day during this time.
Time flows from the future. Designing tonight's sleep to make the most of tomorrow morning's golden time—that kind of reverse-calculation mindset is one of the most effective ways to practically "increase time."
◎ Everyone is the manager of their own "body"—time management was sleep management
☆ Why sleeping one hour more increases productivity more than cutting one hour to work
There are nights when you cut back on sleep thinking, "If I work for one more hour, I'll be done," aren't there?
However, this choice is often counterproductive.
If you cut one hour of sleep, your processing speed the next day will decrease. As a result, the next day, the same work will take extra time. Furthermore, the work done during that cut hour will also be of lower quality because it is done with an exhausted brain, increasing the possibility of corrections being needed.
A study by the McKinsey Global Institute (2016) estimates that productivity losses due to sleep deprivation amount to thousands of dollars per person annually. Looking at productivity per hour, the hour gained by ensuring sleep is overwhelmingly more valuable than the hour gained by cutting sleep.
When thinking in terms of "quality of results" rather than "time spent working hard," sleeping one hour more is a more rational management decision.
☆ The structure behind why parenting entrepreneurs feel they "have no time"
Those who run a business while raising children are prone to a structure that leads to chronic sleep deprivation.
Sleep is interrupted by a child's crying at night or poor health. After putting the child to bed, you finally get some time for yourself and end up staying up too late. Since you have to wake up at a certain time the next morning to match your child's schedule, your sleep time is gradually whittled away.
When you work in that state, your processing speed drops, and the same tasks take extra time. Part of the feeling that "I have no time because I have children" may actually be the structure of "I have no time because my brain is slow due to lack of sleep."
For parents, children are the best coaches and mentors. To have high-quality time with your children, the first priority is to get your own brain in order.Rather than interacting with your child with a sleep-deprived brain, even a short amount of time with a well-rested brain will be a richer experience for the child.
☆ The goal comes first—"What state of mind should I be in?" rather than "What should I do?"
When you read books on time management, they are filled with techniques like "prioritize," "set time limits," and "organize your To-Do list." That in itself is not wrong. However, if your brain is sleep-deprived and cannot perform, any technique will have its effectiveness halved.
The goal comes first! The method comes later!—Before deciding "how to manage time (method)," set "what state of mind to start the day in (goal)." The answer to that is to improve the quality of your sleep.
Before buying a book on time management, try increasing your sleep by one hour tonight. That alone has the potential to change your tomorrow.
◎ "Sleep habits to increase your time" starting tonight
☆ ① Treat sleep as your "top priority task"
The first thing to do is a shift in perspective.
In many people's minds, sleep is something you get in the time remaining after work is finished. But in reality, it is the opposite. Secure your sleep first, and then work in the remaining time.
Block out sleep time on your calendar. Impose a rule on yourself that you will not work after this time. Protect your bedtime tonight for the sake of the quality of tomorrow morning. This is not laziness; it is a management decision to protect your "brain resources," which is your processing speed.
A shift to a management style of "securing sleep to achieve maximum results in a short amount of time" rather than "cutting sleep to work."I believe this is the best way to manage time for parenting entrepreneurs.
☆ ② Put your smartphone away 90 minutes before bedtime
The blue light from smartphones suppresses the secretion of melatonin (the sleep hormone). Furthermore, content such as social media and news stimulates the brain and delays falling asleep.
Data shows that using your smartphone for one hour before bed delays the onset of sleep by an average of 1 to 1.5 hours. The experience of "it was late at night before I knew it because I was looking at my phone" is caused by this effect.
Place your smartphone on the charger 90 minutes before going to sleep. Just by doing that, you could potentially increase your actual sleep time by 1 to 1.5 hours. Use the time after putting your phone away as preparation time for your future self the next morning. Light stretching, reflecting on what went well today, and visualizing one goal for tomorrow—just this will change the state of your brain the next morning.
☆ 3. Decide on your goal for the next morning before you sleep
Before you go to sleep, decide on just one thing: "This is the most important task for tomorrow."
The prefrontal cortex performs best when there is a goal. Conversely, if you wake up in a vague state of "I have to do various things today," you will drain your brain's energy just by deciding what to start with.
If you give your brain one goal before you sleep, it will organize itself toward that goal during REM sleep, making it easier to tackle that work immediately after waking up. The productivity of your morning is completely different between a morning where you wake up having decided "I will do this today" and a morning where you wake up wondering "What should I start with?"
The goal comes first! The method comes later!—Your actions the next morning begin with the goal setting from the previous night. Time flows from the future. How you spend your time tomorrow is determined by how you sleep tonight.
Summary: If you want to create time, sleep first
Let's organize what I have shared today.
・Lack of sleep reduces brain processing speed by up to 40%, causing the same work to take extra time
・Due to the decline in prefrontal cortex function, judgment, concentration, switching, and emotional control all become dull
・Microsleeps, procrastination, and an increase in mistakes act as "hidden time thieves"
・Deep sleep resets the brain, and REM sleep organizes memories, increasing processing speed for the next day
・Sleeping one hour more is more productive than cutting one hour of sleep to work
・Starting tonight: Make sleep your top priority task, put your smartphone away 90 minutes before bed, and decide on your goal for the next morning
It is not that you don't have time. It might just be that your brain has slowed down.
Everyone is the manager of their own "body." As a manager, the most rational time investment is to get a good night's sleep tonight.
Sleep is a skill and a tool. If you want to increase your time, sleep first—that is the simplest answer taught by brain science.
■ Main References
・Van Dongen, H. P. A., et al. (2003). The cumulative cost of additional wakefulness. Sleep, 26(2), 117-126.
・Walker, M. (2017). Why We Sleep: Unlocking the Power of Sleep and Dreams. Scribner.
・Xie, L., et al. (2013). Sleep drives metabolite clearance from the adult brain. Science, 342(6156), 373-377.
・Stickgold, R. (2005). Sleep-dependent memory consolidation. Nature, 437(7063), 1272-1278.
・Cai, D. J., et al. (2009). REM, not incubation, improves creativity by priming associative networks. PNAS, 106(25), 10130-10134.
・McKinsey Global Institute (2016). Diminishing returns: Why sleep deprivation is costing you more than you think.