The 90-Minute Technique: How to Harness Ultradian Rhythms for Deep Work (Even with Multiple Jobs)

The 90-minute technique for productivity isn’t just another trend—it’s a method grounded in how your brain actually functions. For decades, concentration was treated as an unlimited resource: just sit down and work until you burn out. But the science of ultradian rhythms—natural cycles of activity and rest that repeat every 90-120 minutes—proved that the human brain operates in waves. Ignoring them is like swimming against the current: you end up exhausted with fewer results than you could achieve. The key lies in syncing your work blocks with these cycles, especially if you manage multiple projects or jobs simultaneously. In this guide, we’ll break down how to apply the 90-minute technique step by step, with concrete examples for freelancers, students, entrepreneurs, and anyone juggling complex tasks without losing focus.

What Are Ultradian Rhythms (and Why They Matter for the 90-Minute Technique)

Ultradian rhythms are biological patterns that regulate functions like sleep, digestion, and—crucially—sustained attention. Every 90-120 minutes, your brain cycles through a phase of high activity (where concentration and creativity peak) followed by a natural energy dip. This rhythm was first documented in the 1960s by psychologist Nathaniel Kleitman, who observed that even during sleep, the body alternates between rapid eye movement (REM) and non-REM phases in roughly 90-minute cycles. The fascinating part? This same pattern repeats when you’re awake: after 90 minutes of intense work, your brain demands a reset. Pushing beyond this limit doesn’t just reduce efficiency—it can lead to cumulative stress and avoidable mistakes.

The Evidence Behind the 90-Minute Cycle

Real-world studies have confirmed that working in 90-minute blocks boosts productivity by up to 30% compared to continuous workdays. For example, a study of professional violinists (published in The Power of Full Engagement) found that the most successful musicians practiced in 90-minute sessions followed by short breaks, while less advanced players tended to drag out their sessions without pauses. Companies like Google and Microsoft have also adopted policies allowing employees to structure their days in 90-minute blocks. The technique isn’t magic—it’s applied biology.

The brain isn’t designed for linear concentration: it works in waves. Leveraging those 90-minute peaks is the difference between drifting and making progress.

How to Apply the 90-Minute Technique in 5 Concrete Steps

1. Identify Your Natural Cycles (Without Forcing the Clock)

While 90 minutes is the standard, your ultradian cycles may range from 80 to 110 minutes. To find yours, try this for a week:

• Work on a complex task (e.g., writing a report, coding, studying) without interruptions and note the start time.
• When your concentration dips—even slightly—check the clock. That’s your personal cycle.
• Repeat the exercise at different times of day (morning, afternoon, evening) to spot patterns. For example, morning cycles are often shorter (80-90 min), while evening cycles may stretch to 100-110 min.
• Use that duration as your work block baseline. If your cycle is 100 minutes, adjust the technique to 100 minutes of work + 20 minutes of rest.

2. Plan Tasks Based on Cycle Intensity

Not all tasks require the same level of focus. The 90-minute technique works best when you align task complexity with your ultradian phase:

• First 30 minutes: Ideal for creative or problem-solving tasks (e.g., designing a strategy, drafting an article, brainstorming). In this phase, your brain is fresh, and dopamine—linked to motivation—is high.
• Minutes 30-60: Best for analytical or repetitive tasks (e.g., reviewing data, responding to complex emails, editing a document). Concentration remains strong, but your brain settles into a steadier flow state.
• Last 30 minutes: Perfect for mechanical or low-cognitive-effort tasks (e.g., organizing files, making routine calls, checking notifications). Energy starts to dip, but you can still be productive with lighter work.

3. Design Rest Breaks That Actually Recharge (Not Just Scrolling)

The most common mistake with the 90-minute technique is using breaks to check social media or emails. These activities don’t let your brain disconnect—they still drain attention. Instead, try these science-backed alternatives:

• Physical breaks (5-10 min): Stand up, walk, stretch, or do deep breathing. Movement boosts blood flow to the brain and reduces cortisol (the stress hormone). A Stanford study found that walking increases creativity by up to 60%.
• Sensory breaks (3-5 min): Close your eyes and listen to instrumental music, look at nature (even a photo), or smell something pleasant (like coffee or mint). These stimuli activate the brain’s default mode network, linked to relaxation.
• Social breaks (10-15 min): Talk to a coworker about something unrelated to work (e.g., weekend plans, a book you’re reading). Brief social interactions release oxytocin, which counteracts stress.

4. Manage Multiple Jobs Without Overloading Your Brain

If you juggle several projects or clients, the 90-minute technique can help you avoid cognitive overload. The trick is to assign each block to one job and use breaks to switch contexts intentionally. For example:

• Block 1 (90 min): Job A (e.g., developing a feature for Client X).
• Break (20 min): Walk and listen to a podcast unrelated to work.
• Block 2 (90 min): Job B (e.g., writing a report for Client Y).
• Break (20 min): Grab coffee and chat with a colleague about a non-work topic.
• Block 3 (90 min): Job C (e.g., planning your own business strategy).

This approach has two key benefits: 1) Avoids forced context-switching, which drains up to 40% of mental energy (per a University of California study), and 2) gives each project the deep focus it deserves without mixing priorities. If a job needs more time, you can chain two 90-minute blocks with a longer break (30-40 min) in between—but never exceed 180 minutes on the same task.

5. Adjust the Technique to Your Chronotype (Morning vs. Night Person)

Your chronotype—whether you’re a morning person, night owl, or somewhere in between—affects how you should apply the 90-minute technique. For example:

• Morning people (larks): Your peak concentration cycles are typically between 6:00 AM and 12:00 PM. Use early blocks for complex tasks and save administrative work for the afternoon.
• Night owls: Your energy peaks after 6:00 PM. Schedule demanding blocks for the evening and use mornings for lighter tasks or meetings.
• Intermediate types: Your energy is steadier. Distribute 90-minute blocks throughout the day, but avoid extremes (very early or very late).

Practical Example: A Day with the 90-Minute Technique for Freelancers

Imagine you’re a freelance designer working for three different clients while also managing your own side project. Here’s how you could structure your day using the 90-minute technique:

• 7:30 - 9:00 AM: Block 1 - Client A (design wireframes for an app). High-creativity task.
• 9:00 - 9:20 AM: Break - Walk outside and listen to an audiobook chapter.
• 9:20 - 10:50 AM: Block 2 - Client B (review feedback and adjust designs). Analytical task.
• 10:50 - 11:10 AM: Break - Drink tea and stretch.
• 11:10 AM - 12:40 PM: Block 3 - Personal project (create content for your portfolio). Creative task.
• 12:40 - 1:30 PM: Long break - Lunch and a 20-minute nap (no screens).
• 1:30 - 3:00 PM: Block 4 - Client C (follow-up meeting and adjustments). Social task.
• 3:00 - 3:20 PM: Break - Chat with a colleague about a non-work topic.
• 3:20 - 4:50 PM: Block 5 - Client A (finalize wireframes and send). Mechanical task.
• 4:50 - 5:10 PM: Break - Listen to instrumental music and close your eyes.
• 5:10 - 6:40 PM: Block 6 - Personal project (research design trends). Learning task.

In this example, each block is dedicated to one job, breaks are active and varied, and the most demanding tasks are scheduled during early cycles (when energy is highest). Plus, the personal project—often postponed—gets guaranteed time.

Common Mistakes with the 90-Minute Technique (and How to Avoid Them)

• Mistake 1: Ignoring fatigue signals. If you’re distracted after 60 minutes, don’t force the remaining 30. Adjust the block to your real cycle or take a 5-minute micro-break to reset.
• **Mistake 2: Using breaks for

• . Checking emails or messages during breaks isn’t resting**—your brain stays in work mode. Keep activities separate.
• Mistake 3: Not planning blocks in advance. If you start the day without a clear task list for each block, you’ll waste time deciding what to do. Spend 10 minutes each night assigning tasks to the next day’s blocks.
• Mistake 4: Skipping breaks. It’s tempting to extend a block when you’re in

• , but this disrupts your ultradian rhythm and leaves you drained later. Trust the method: breaks are part of the work.
• Mistake 5: Applying the technique on chaotic days. If you have back-to-back meetings or emergencies, the 90-minute technique won’t work. On those days, use shorter blocks (45-60 min) or postpone deep work.

Tools to Implement the 90-Minute Technique (Without Overcomplicating It)

You don’t need complex apps to apply this method, but a few tools can help you visualize blocks and stay on track:

• Timers: Use a 90-minute hourglass (yes, they exist) or apps like Focus Keeper (iOS) or Be Focused (Android) to time your blocks. The key is to set the timer to ring once at the end—no distractions mid-block.
• Calendars: Block 90-minute work sessions and breaks in your calendar as non-negotiable appointments. In Google Calendar, create recurring events with different colors for each activity type (work, break, meetings).
• Task lists: Split your daily list into 90-minute blocks and assign one priority task per block. Avoid cramming multiple micro-tasks into one block—the technique works best with deep focus.
• Physical reminders: If you work in a fixed space, place a sticky note with the start/end times of each block where you can see it (e.g., on your monitor). This keeps you accountable.

How to Combine the 90-Minute Technique with Other Productivity Methods

The 90-minute technique isn’t exclusive—you can integrate it with other methods to amplify its benefits. Here’s how:

1. 90-Minute Technique + Time Blocking

Time blocking involves assigning specific time slots to tasks in your calendar. Combine it with the 90-minute technique for a foolproof daily structure. For example:

• Block 1 (90 min): Task A (high priority).
• Block 2 (90 min): Task B (medium priority).
• Block 3 (90 min): Task C (low priority).
• 20-minute breaks between blocks.

This combo forces you to protect your time and prevents low-priority tasks from hijacking your focus.

2. 90-Minute Technique + Eisenhower Matrix

The Eisenhower Matrix sorts tasks into four quadrants based on urgency and importance. Use the 90-minute technique to tackle each quadrant at the optimal time:

• Quadrant 1 (urgent and important): Schedule these blocks first thing in the morning, when energy is highest.
• Quadrant 2 (not urgent but important): Assign these blocks after breaks, when your brain is refreshed but not exhausted.
• Quadrants 3 and 4 (urgent but not important / neither): Delegate or eliminate these tasks. If you can’t avoid them, do them in the last blocks of the day, when concentration is lower.

3. 90-Minute Technique + Deep Work

Cal Newport’s deep work focuses on concentrating on one complex task without distractions. The 90-minute technique is the perfect complement: it gives you a time-bound framework for deep work, knowing a break is guaranteed. For example, if you’re writing a book, use a 90-minute block to write uninterrupted, then rest and repeat.

Adapting the 90-Minute Technique for Teamwork

If you collaborate with others, the 90-minute technique might clash with meetings, tight deadlines, or the need to stay available. Here’s how to adapt it:

• Sync blocks with your team: For group projects, propose shared focus blocks (e.g., 10:00-11:30 AM) where everyone commits to working silently without interruptions. Use tools like Slack or Microsoft Teams to set your status (e.g.,

• ).
• Protect individual blocks: If syncing isn’t possible, reserve at least two 90-minute blocks per day for solo work and communicate your unavailability (e.g.,

• ).
• Use breaks for collaboration: Leverage the 20-minute breaks between blocks to respond to messages, review feedback, or make quick calls. This keeps interruptions out of your focus cycles.
• Adjust block length: If your work requires frequent meetings, shorten blocks to 60 minutes and use breaks to prep or wrap up. Example: 60 min work + 15 min break + 60 min meeting.

The 90-Minute Technique in Practice: How to Start Today

Implementing this method doesn’t require a radical overhaul—just small tweaks to your routine. Here’s an action plan to start today:

• Step 1: Pick a test day. Don’t overhaul your entire week at once. Start with one day (e.g., tomorrow) and apply the 90-minute technique to 3-4 blocks.
• Step 2: Set up your environment. Before starting, eliminate distractions: close unnecessary tabs, mute notifications, and notify anyone who might interrupt (e.g.,

• ).
• Step 3: Define tasks for each block. Use a list or calendar to assign one priority task per 90-minute block. Example:
• - Block 1: Draft the report for Client X.
• - Block 2: Review code for Project Y.
• - Block 3: Plan social media content.
• Step 4: Time and rest. Use a timer for the 90 minutes and, when it rings, get up from your chair. Do something screen-free for at least 10 minutes.
• Step 5: Evaluate and adjust. At the end of the day, review what worked and what didn’t. Did you concentrate better? Did breaks recharge you? Tweak block length or task types based on your observations.

How to Use Foco to Apply the 90-Minute Technique Across Multiple Jobs

If you manage several projects or clients, tools like Foco can help you implement the 90-minute technique without losing sight of priorities. For example:

• Organize jobs by color: In Foco, each project or client has an assigned color, so you can quickly identify which job a task belongs to. When planning your 90-minute blocks, group tasks by project to avoid forced context-switching.
• Use Panorama mode for a bird’s-eye view: This mode shows tasks from all your jobs in one screen, each with its color. Perfect for planning your day: drag tasks into 90-minute blocks based on priority and complexity.
• Filter by job in Focus mode: When it’s time to execute a block for one project, switch to Focus mode to see only that job’s tasks. This removes visual distractions and keeps you locked in.
• Block time in the calendar: Use Foco’s Calendar view to assign 90-minute blocks to tasks. For example, create an event called

• from 9:00-10:30 AM and link it to the task. If you sync Foco with Google Calendar or Outlook, you’ll see these blocks alongside external meetings.
• Leverage voice capture for recurring tasks: If you have tasks that repeat in each block (e.g.,

• ), use voice capture to create them quickly. Say:

• , and Foco will generate the task with fields pre-filled. This saves time on administrative details.
• Use Burst for planning full blocks: If you need to create multiple tasks for a single 90-minute block, use Burst to dictate them all at once. For example:

• . Foco will split them into individual tasks, which you can then assign to the appropriate blocks.

The 90-minute technique is about working with your brain, not against it. Tools like Foco aren’t essential, but they can simplify logistics when juggling multiple fronts—letting you focus on what really matters: executing with quality and without burnout.