How to Apply the 90-Minute Technique for Productivity: Deep Work Blocks Across Multiple Jobs

The 90-minute technique for productivity isn’t just another passing trend—it’s a method grounded in the biology of your brain. It leverages ultradian cycles, natural 90- to 120-minute rhythms during which your body alternates between phases of high energy and focus and periods of fatigue. Ignoring these cycles—like we do when forcing marathon work sessions—leads to burnout, procrastination, and a sharp drop in the quality of your output. If you juggle multiple projects, clients, or responsibilities, this technique allows you to work with deep focus without burning out, alternating high-productivity blocks with strategic breaks that recharge your energy.

What Are Ultradian Cycles and Why Do They Matter?

Ultradian cycles are recurring patterns of brain and physical activity that occur multiple times a day. Each cycle lasts between 90 and 120 minutes and includes two phases: one of high alertness and cognitive capacity (ideal for complex tasks) and another of energy decline (where your brain needs recovery). These rhythms were first identified in sleep studies, but they also manifest during waking hours. For example, if you’ve ever noticed that after about an hour and a half of intense work your concentration fades, you’re experiencing the end of an ultradian cycle.

The key to the 90-minute technique for productivity lies in aligning your work blocks with these natural cycles. Instead of fighting your biology—by forcing yourself to work for 4 hours straight—you divide your day into 90-minute segments, each dedicated to a specific task or project. Between blocks, you take 20- to 30-minute breaks to reset your mind. This approach not only improves focus but also reduces accumulated stress by avoiding cognitive overload.

How to Structure Your 90-Minute Blocks: Concrete Steps

1. Plan Your Blocks the Night Before

Before ending your day, list the most important tasks you need to tackle the next day. Assign each to a 90-minute block, prioritizing those that require the most concentration. For example: if you have a report for Client A, a team meeting, and code review for Project B, distribute them like this: Block 1 (9:00-10:30 AM): Client A report (analytical task). Block 2 (11:00 AM-12:30 PM): Code review (technical task). Block 3 (2:00-3:30 PM): Meeting preparation (creative task). Use a timer to mark the start and end of each block, and treat breaks as non-negotiable appointments.

2. Eliminate Distractions During the Block

During the 90 minutes, your sole focus should be the assigned task. To do this: Close non-essential tabs and apps (email, social media, chats). Silence notifications on your phone and computer. Use headphones with white noise or instrumental music if you’re in a noisy environment. If an unrelated idea pops up, jot it down quickly (on paper or an app) and return to it during a break or another block. The rule is clear: nothing interrupts the 90 minutes, not even urgent tasks from other projects (save those for breaks).

3. Design Breaks That Actually Recharge You

Breaks aren’t wasted time—they’re a critical part of the 90-minute technique for productivity. But not just any pause will do. Avoid activities that continue to drain your mental energy, like checking email or discussing work topics. Instead, choose options that disengage your brain and activate the parasympathetic system (responsible for recovery): Get up and walk (even around the office or house). Drink water or eat a healthy snack (dehydration and hunger reduce focus). Do stretches or deep breathing (5 minutes of diaphragmatic breathing lowers cortisol). Look out a window or close your eyes (natural light and visual disconnection help reset your mind).

Adapting the Technique to Multiple Projects

Managing several projects, clients, or responsibilities (like freelancers, entrepreneurs, or remote teams) adds complexity to the 90-minute technique. The temptation is to jump from one task to another based on urgency, but this fragments your focus and reduces work quality. The solution is to group tasks by type or context and assign them to specific blocks. For example:

• Deep work: Blocks dedicated to tasks requiring high concentration (writing, coding, designing). Example: 9:00-10:30 AM (Project A), 11:00 AM-12:30 PM (Project B).
• Administrative work: Blocks for emails, invoices, or short meetings. Example: 2:00-3:30 PM (client management).
• Collaborative work: Blocks for calls, team reviews, or feedback. Example: 4:00-5:30 PM (meeting with Client C).
• Active breaks: Use the 20-30 minutes between blocks to switch contexts (e.g., after a coding block, take a walk before answering emails).

If a project is particularly demanding, assign two consecutive blocks (180 minutes) but with a longer break in between (45 minutes). For example: 9:00-10:30 AM (complex task) + 10:30-11:15 AM (break) + 11:15 AM-12:45 PM (continuation). This avoids fatigue while leveraging your morning energy peak.

Common Mistakes and How to Avoid Them

1. Ignoring Fatigue Signals

The most common mistake is forcing a 90-minute block when your body is already exhausted. Signs you should stop: Difficulty concentrating (you read the same paragraph 3 times). Irritability or frustration (small obstacles annoy you). Sleepiness or physical heaviness (yawning, drooping eyelids). If this happens, stop the block even if 90 minutes haven’t passed. A 10- to 15-minute break may be enough to reset.

2. Using Breaks to "Work on Other Things"

Another classic mistake is filling breaks with pending tasks from other projects. For example: after a writing block, you check emails or reply to messages. This doesn’t give your brain a break and turns rest periods into mini-work blocks. The solution is simple: breaks are sacred. If an urgent task arises, note it down and address it in the next block dedicated to that type of work.

3. Not Adjusting the Technique to Your Personal Rhythm

While 90 minutes is the standard, not all brains work the same way. Some people perform better with 60-minute blocks, others with 120. Test different durations for a week and observe: When do you lose focus? When do you feel most productive? Adjust the blocks to fit your needs. What matters is maintaining the structure: deep work + active break.

Practical Example: A Day with the 90-Minute Technique

Imagine Lucía, a freelance designer managing three projects simultaneously: a website for Client A, a social media campaign for Client B, and her own online course. Here’s how she structures her day using the 90-minute technique for productivity:

• 7:30-9:00 AM: Block 1 (online course: lesson design). Break: 20 minutes (breakfast + stretches).
• 9:20-10:50 AM: Block 2 (Client A website: layout). Break: 30 minutes (outdoor walk).
• 11:20 AM-12:50 PM: Block 3 (Client B campaign: graphics). Break: 20 minutes (guided meditation).
• 1:10-2:40 PM: Block 4 (administrative tasks: emails, invoices). Long break: 1 hour (lunch + 20-minute nap).
• 3:40-5:10 PM: Block 5 (meeting with Client A). Break: 20 minutes (snack + music).
• 5:30-7:00 PM: Block 6 (online course: content review).

By the end of the day, Lucía has made progress on all three projects without feeling exhausted, because she respected her ultradian cycles and alternated types of work (creative, technical, collaborative).

Productivity isn’t measured by hours worked, but by the quality of what you produce during your peak energy moments.

Tools to Apply the Technique (and How Foco Can Help)

To implement the 90-minute technique for productivity, you need two things: a system to organize your blocks and a way to visualize tasks by project. Tools like timers (Focus Keeper, Forest) or calendar apps (Google Calendar) are useful for marking blocks, but managing multiple projects requires more: a space where you can see all your tasks, filter them by project, and prioritize them based on context.

This is where an app like Foco can streamline the process. For example: In Panorama mode, you see all tasks from different projects (each with its project’s color), helping you assign 90-minute blocks based on priorities. In Focus mode, you filter tasks to show only those for a specific project, avoiding distractions from other work during the block. Additionally, the Calendar view lets you schedule your concentration blocks with specific dates and times, while voice capture speeds up adding tasks between blocks without breaking your flow. If you manage multiple projects, having everything in one place—with reminders, deadlines, and attached notes—lets you focus on what matters during the 90 minutes, without wasting time searching for scattered information.