The 90-Minute Technique: How to Work in High-Concentration Blocks to Manage Multiple Projects Without Burnout

The 90-minute technique for productivity isn’t just another passing trend—it’s a method grounded in the biology of our brains. Our bodies operate in ultradian cycles: 90- to 120-minute periods during which we alternate between phases of high energy and natural fatigue. Ignoring these rhythms—like we do when forcing marathon workdays—leads to exhaustion, procrastination, and, paradoxically, fewer results. The key lies in aligning our work sessions with these cycles, especially when juggling multiple projects, clients, or responsibilities. In this article, we’ll break down how to apply the 90-minute technique step by step, with concrete examples for freelancers, remote teams, and professionals who need to maintain clarity without sacrificing their well-being.

Why 90 Minutes (and Not More): The Science Behind the Method

In the 1980s, researcher Nathaniel Kleitman discovered that humans experience cycles of brain activity that repeat every 90-120 minutes. These cycles, called ultradian rhythms, regulate everything from sleep to our ability to concentrate. During the first 90 minutes of a cycle, our brain is in its optimal phase for complex tasks: the prefrontal cortex—responsible for decision-making and creativity—functions at peak efficiency. After that time, energy declines, attention scatters, and the body craves rest. Forcing concentration beyond this limit isn’t just inefficient; it’s counterproductive. Studies in work environments show that people who work in 90-minute blocks with structured breaks complete 40% more tasks than those who work in continuous 4-5 hour stretches.

The Myth of Multitasking and the 90-Minute Technique

One of the biggest enemies of productivity is multitasking, especially when managing multiple projects at once. Switching contexts—for example, moving from drafting a report for one client to answering emails from another—consumes up to 23% of our mental energy, according to neuroscience research. The 90-minute technique solves this problem by assigning each block to a single project or type of task. Instead of jumping between responsibilities, you dedicate a full cycle to one thing, reducing cognitive fatigue and improving work quality. For instance, a freelance designer could use a 90-minute block to work on a client’s logo without distractions, then switch to another project in the next cycle.

How to Apply the 90-Minute Technique: Concrete Steps

1. Plan Your Blocks the Night Before

Planning is the cornerstone of the 90-minute technique. Before ending your workday, review your active projects and assign each one a block in your calendar for the next day. Prioritize tasks that require the most concentration—like writing, designing, or analyzing data—for the first cycles, when your energy is at its peak. Use a simple rule: one block = one project or type of task. For example:

• Block 1 (9:00-10:30 AM): Draft proposal for Client A (creative task).
• Block 2 (10:45 AM-12:15 PM): Review code for internal project (analytical task).
• Block 3 (12:30-2:00 PM): Client meetings (communication tasks).
• 15-20 minute breaks between blocks: Walk, stretch, or do something unrelated to work.

2. Eliminate Distractions During the Block

A 90-minute block only works if you protect it from interruptions. Before starting, close unnecessary tabs, silence notifications, and let your team know you’ll be unavailable. Tools like airplane mode on your phone or browser extensions that block social media can be helpful. If you work in a shared space, use headphones with instrumental music or white noise to create a psychological barrier. The idea isn’t to isolate yourself completely but to minimize context switches that break your workflow.

3. Use a Visible Timer

The 90-minute technique requires discipline, and a timer is your best ally. Set an alarm for 90 minutes and another for your break. Seeing the time remaining helps you maintain your pace and prevents you from diving too deep into one task while neglecting others. Some people prefer physical timers, like kitchen timers, because the act of turning the dial at the end reinforces commitment. If you use apps, choose one that displays the time in full screen without additional distractions.

4. Adjust the Duration Based on Your Energy

While 90 minutes is the standard, not all days are the same. If you notice your concentration waning earlier, shorten the block to 60 or 75 minutes. What matters is respecting your body’s natural cycle. For example, after an exhausting meeting, a 60-minute block might be more realistic than a 90-minute one. Flexibility is key: the 90-minute technique isn’t a dogma but a tool you can adapt to your needs.

Real-World Examples: How Professionals Apply the Technique

Case 1: Freelancer with Multiple Clients

María, a graphic designer, manages projects for five different clients. Before, she jumped from one task to another as emails came in, leaving her exhausted by the end of the day. Now, she uses the 90-minute technique like this:

• Morning (high energy): 2 blocks for creative design (Clients A and B).
• Afternoon (medium energy): 1 block to review feedback (Client C) and another to plan the week (administrative tasks).
• Breaks: 20 minutes between blocks to walk or have a screen-free coffee.

Result: María delivers her projects with higher quality and without the feeling of always running. She’s also reduced her workday by 20% without affecting her productivity.

Case 2: Remote Team with Frequent Meetings

A software development team distributed across three time zones adopted the 90-minute technique to sync their work. Their strategy:

• Asynchronous blocks: Each member chooses two 90-minute blocks per day for deep work (e.g., coding, documenting).
• Synchronous blocks: 1 daily block for meetings and coordination, always at the same time for everyone.
• Golden rule: No meetings outside of synchronous blocks unless it’s an emergency.

The team reported 30% fewer unnecessary meetings and an improvement in code quality, as developers could focus without interruptions.

Common Mistakes and How to Avoid Them

• Mistake 1: Not taking real breaks. Using the 15 minutes between blocks to check social media or emails isn’t a break. Your brain needs to disconnect: get up, hydrate, or do something that doesn’t involve a screen.
• Mistake 2: Overloading blocks. Assigning more than one complex task to a single block dilutes its effectiveness. If a task requires more than 90 minutes, break it into parts and distribute it across multiple blocks.
• Mistake 3: Ignoring energy cycles. Not all blocks are equal. Schedule the most demanding tasks for when your energy is at its highest (usually in the morning).
• Mistake 4: Not reviewing the plan at the end of the day. The 90-minute technique requires constant adjustments. Spend 5 minutes at the end of your day evaluating what worked and what didn’t, and adjust the next day’s plan accordingly.

Productivity isn’t measured by hours worked, but by the clarity with which you make progress on what matters.

Tools to Implement the 90-Minute Technique

While the 90-minute technique doesn’t require specific tools, some can make it easier to apply:

• Timers: Apps like Focus Keeper (based on Pomodoro but adjustable to 90 minutes) or Be Focused for iOS. For those who prefer analog, a kitchen timer works just as well.
• Calendars: Block your 90-minute sessions in Google Calendar or Outlook as non-negotiable events. Use different colors for each project or task type.
• Task managers: Tools like Foco let you organize your blocks by project, assign colors, and see at a glance which tasks correspond to each cycle. For example, you can create a workspace called "Design Client A" (in blue) and another "Code Review" (in green), and use the Panorama mode to view all your day’s tasks, each with its color. When you enter the Focus mode for a specific project, the dashboard filters only the tasks for that block, helping you concentrate without distractions. You can also group tasks by due date and assign durations, making it easier to plan your 90-minute blocks precisely. If you use voice capture, dictating a task like "Review wireframes for Client B, 90 minutes, tomorrow at 9:00 AM" will automatically create a block in your calendar with the correct duration.
• Distraction blockers: Extensions like StayFocusd (for Chrome) or Freedom (multi-platform) help you stay focused during your 90-minute blocks.

Conclusion: The 90-Minute Technique as a Lifestyle

The 90-minute technique for productivity isn’t just a method—it’s a work philosophy that prioritizes quality over quantity. By aligning your sessions with your body’s natural rhythms, you not only increase efficiency but also reduce stress and avoid burnout. The secret lies in consistency: start with a couple of blocks per day, adjust as needed, and, above all, be compassionate with yourself. Productivity isn’t about doing more in less time; it’s about doing the right thing at the right moment.

If you manage multiple projects at once, this technique can be your ally for staying in control without losing clarity. Tools like Foco can help you organize your 90-minute blocks by project, assign priorities, and visualize your day at a glance, but the real change begins with the decision to work with your energy, not against it.