The Ideal Length of Time for Focused Work (90 minutes)

In the quest for productivity, one question often arises: how long should one focus on a task without interruption? The answer, according to neurobiology, might surprise you.

Understanding Ultradian Cycles

Before we delve into the specifics, it's important to understand the concept of 'ultradian cycles.' Most of us are familiar with circadian rhythms, the 24-hour biological cycles that govern our sleep-wake patterns. Ultradian cycles, on the other hand, are shorter cycles that occur within the span of a day.

Our brain and body operate on these 90-minute ultradian cycles throughout the day. These cycles influence various physiological processes, including our ability to focus and concentrate.

The 90-Minute Rule for Focused Work

According to the research literature, the ideal duration for a bout of focused work aligns with these ultradian cycles - approximately 90 minutes. This doesn't mean that you need to strictly adhere to 90 minutes, but it provides a reliable guideline.

Attempting to push beyond this, say into two or three hours of continuous focus, is not in line with our underlying biology. It's not impossible, but it's not optimal either.

Making the Most of Your Focus Time

When you sit down for a focused work session, it's important to acknowledge that the first few minutes are often a transition period. Think of it as a warm-up for your focus. This time should be included in the 90-minute work session.

During this period, you'll likely find your focus flickering or shifting. This is normal. The key is to actively redirect your focus back to the task at hand. This process of refocusing requires metabolic energy, which is why it's important to nourish your brain with a healthy diet and adequate rest.

Applying the 90-Minute Rule

The 90-minute rule can be applied to various activities, from mental work like studying or writing, to physical activities like exercise or skill learning. Even in conversations or therapy sessions, you might find that your attention starts to wane after about 90 minutes.

One practical way to implement this is by setting a timer for 90 minutes at the start of your work session. This helps you stay mindful of your focus levels and gives you a clear endpoint to work towards.


Understanding the neurobiology behind focus can help us work more effectively and sustainably. By aligning our work sessions with our natural ultradian cycles, we can optimize our focus and productivity. Remember, it's not about working longer, but working smarter. For more help with focus work, try an NSDR track for focus.

FAQs About the 90-Minute Rule

1. Can I work longer than 90 minutes if I'm in the zone?

Yes, occasionally, if you find yourself in a state of flow and feel highly productive, you can extend your work session slightly. However, it's essential to take regular breaks to avoid burnout.

2. What can I do during my break after a 90-minute session?

During your break, it's best to engage in activities that allow your mind to rest and recharge. Simple activities like stretching, going for a short walk, or practicing mindfulness can be beneficial.

3. Is the 90-minute rule applicable to creative tasks?

Yes, the 90-minute rule can apply to creative tasks as well. Our brains need time to process information and generate new ideas, making it crucial to respect our natural cycles for optimal productivity.

4. Can I use the 90-minute rule for household chores?

While the 90-minute rule is more applicable to focused mental or physical work, it's still helpful to apply it to tasks like cleaning or organizing. Breaking these chores into smaller 90-minute sessions can prevent exhaustion.

5. What if my job requires continuous attention for extended periods?

For jobs that demand constant vigilance, such as medical professionals or emergency responders, try incorporating short breaks whenever possible. Even a brief pause can help refresh your mind and enhance overall performance.