How To Train Your Focus For Deep Mental Work
How to adapt your brain to engaging focused work
I frequently receive the question, “How long should I try to focus?” Research literature indicates that ultradian rhythms are crucial in this regard.
You might have heard of the 24-hour circadian rhythm, which is the rhythm that governs our body functions from blood circulation, blinking, pulse, heart rate, bowel activity, and growth hormone during the day. Our brains and bodies operate in 90-minute ultradian cycles within this 24-hour cycle.
Keep tasks requiring focus and intensity around 90 minutes, which fits into the biological ultradian cycle that we all have. While it’s possible to focus continuously for two or even three hours, it goes against what we know about biology and perhaps it’s more or less a combination of multiple ultradian cycles. The reason is that both sleep and wakefulness occur in 90-minute cycles.
When it’s time for me to work on a deep mentally demanding task, I set a 90-minute countdown timer. Unless I have something urgent to finish in a very short time or have taken an optimal amount of caffeine, I accept that the first 5–10 minutes of this 90-minute period are a transition and warm-up phase into focus. I include these 5–10 minutes within the 90 minutes.
After this warm-up, I try to focus on mental work or learning during the remaining time. I acknowledge that my attention and focus will drift and re-center during this period. A significant aspect of focusing is returning to focus when it wavers.
I visualize this process as the tip of an arrow broadening to encompass multiple things or focusing elsewhere in the room. The key is to bring the arrow back to where you want it and narrow it down. This is quite active and requires substantial metabolic energy. Your brain is the organ that consumes most of your metabolic energy. Most of your basal metabolic energy is directed towards brain function, not movement, heartbeat, or breathing.
Since focusing and maintaining focus is an activity that consumes a lot of metabolic energy, you might feel tired or exhausted after 90 minutes, or even after 45 minutes. Therefore, after a 90-minute focus session, take at least a 10-minute, ideally a 30-minute, break to do what I call deliberate rest.
During this time, engage in mundane tasks that don’t require concentration. Walk around a bit, but avoid looking at your phone, even while going to the bathroom, and certainly don’t look at it in the bathroom. Allow yourself a period where you relax, let your mind idle, and do not focus on anything. These mental idling periods are crucial for your ability to focus, much like short breaks between sets while lifting weights.
I know this is hard because we are constantly drawn to the incredibly rich sensory information bombarding us from our phone screens or other devices. However, I want to emphasize that our ability to focus depends not only on what happens during the focus cycle but also on what happens afterward. To maintain and improve your focus, you must enter a deliberate rest cycle where you avoid focusing.
The largest of these focus-free rest cycles is, of course, sleep. It makes sense that this deep, prolonged period where we do not control where our mind is, is the best restoration phase for the brain, even during intense dreams.
So, after a 90-minute or shorter focus cycle, stop what you are doing and engage in automatic, reflexive tasks that don’t require much mental energy for at least 10 minutes, ideally 30 minutes. You don’t need to walk around in circles or stare blankly at the sky during this rest period, but if you can do that, go ahead. During this rest period, avoid reading something that requires focus or narrowing your visual attention, like looking at your phone screen. Resting in this manner will make it easier for you to enter and complete the next focus cycle, allowing you to perform such focus cycles multiple times throughout the day.
How many ultradian cycles can we complete in a day? This depends on how well you sleep, eat, and train your focus capacity.
The paradox is that the more you practice focusing and improve at transitioning into and maintaining focus, the more you will need unfocused rest. My advice is to aim for three or perhaps four deeply focused 90-minute work sessions a day.
This means working deeply focused for 90 minutes, resting for 30 minutes, and then another 90 minutes, not back-to-back but perhaps one 90-minute deep work session in the morning and another in the afternoon.
When I say this, many people are surprised and ask, “Wait a minute! Who can live by working only 4.5 hours a day?” But I’m not saying to work only 4.5 hours a day. I’m talking about hard, mental work.
The deeper and more intense your focus, the fewer 90-minute deep work sessions you can manage. Think of physical activities: if you run a 100 km ultra-marathon, the recovery time needed is much longer than for someone running 10 km. The length of your rest period after intense work is directly proportional to how intense your work was.
At this stage of my life, by putting my phone away or turning it off, I can manage three intense, 90-minute work sessions a day. But unless there’s something urgent and stressful, I don’t do more. Between these three 90-minute deep work sessions, I do tasks that require less focus.
Some of you might manage five 90-minute intense work sessions a day. My advice is to try to do at least one a day, including weekends. On weekends, I read a real book away from my phone or listen to an audiobook while walking. But I really concentrate on what I want to learn.
If you’re not doing this at all, try doing one 90-minute intense work session daily for 4 weeks. Try to stay focused and resist the discomfort. Then increase the number of cycles you do daily.
I’m not suggesting you tell your teacher or Ph.D. advisor, “I can’t focus on anything for more than 90 minutes.” I’m talking about deep focus cycles. These are times when you really push yourself to focus and refocus, sharpening the tip of the arrow and directing it at what you want to concentrate on, which is really hard. They’re like the cycles when you lift weights at the gym.
The Importance of Eliminating Distractions
Focus isn’t an easy task for the brain — and it’s definitely not an easy task for us. Most of the time, our attention drifts in the middle of the task, in an attempt of our brain to have some rest.
The important thing here is to not have your phone near you so you don’t waste more time than you initially wanted or worse divert your attention. In a study published by the University of Chicago, scientists discovered that the mere presence of your phone near you reduces the cognitive capacity of your brain.
What if your phone had notifications on? Or that you pick it and check Instagram in the middle of the focus session? That could be a catastrophe for your focus.
I always advise that if there are some important notifications that you have to attend to constantly at work, you should engage in short-focus sessions of 25 minutes (Pomodoro technique). However, checking the phone every few minutes is a sure way to break the flow and reduce the willpower to learn more.
Enjoying the task at hand
Enjoyment plays a big role in focus — yet it’s not necessary for the achievement of the task. If you enjoy what you’re focusing on, like learning of a really interesting topic, it’s much easier to maintain focus perhaps in two consecutive 90-minute periods.
My advice is to make the task at hand as enjoyable as possible. Maybe make a counter of how many pages you need to write in a day and push yourself to reach that counter. After that, reward yourself for reaching it.
Another way that works for me is that I like to make great progress in one area in a day rather than small progress in multiple areas. That’s why I aim to make incredible progress in a day. The feeling of achievement motivates me to do more and consequently enhances my ability to focus.
I’m Noah. I’m a life coach who wants to inspire people to become the versions of themselves that they aspire to be through my writings.
My advice stems from the lifestyle that I lead every day. I aim to give you concrete steps to change your life to the life that you want without the extra philosophical generic advice.
