The next biological rhythm you need to master

Ever hit an afternoon slump and grabbed a coffee to power through? Or forced yourself to focus even when your brain was begging for a break? What if working with your body’s natural energy cycles — rather than against them— could make you more productive and less exhausted?

Most biorhythm conversations today focus on the circadian cycle, which regulates sleep and wakefulness over 24 hours. But there is an equally significant yet often overlooked shorter and recurring rhythm that influences your sleep, digestion, blinking, energy levels, alertness and performance — the ultradian rhythm.  

What are ultradian rhythms

First proposed by physiologist and sleep researcher Nathaniel Kleitman, the performance ultradian rhythm, also known as the Basic Rest-Activity Cycle (BRAC), alternates between 90-120 minutes of increased alertness and 20-30 minutes of recovery. When we work with these natural fluctuations, we optimise our task performance and efficiency. But when we ignore them and push through with stimulants (coffee, smoking, prolonged screen exposure) or sheer willpower — it leads to burnout, cognitive fatigue and physiological stress.  

That said, the impact of ultradian rhythms extends far beyond work performance. The gut’s ultradian cycle influences digestion and nutrient absorption. Hormones like cortisol and serotonin fluctuate in sync with these rhythms, affecting mood and nervous system regulation. Even sleep follows an ultradian structure, supporting memory consolidation and cellular repair. 

Tuning into your rhythm 

Tuning into your personal ultradian rhythm is key to optimising your energy and focus. Identifying your natural peaks and dips throughout the day helps you structure tasks accordingly. A crucial point to remember: your ultradian cycles are dynamic, influenced by sleep quality, stress levels and lifestyle habits on a day-to-day basis.

Starting point

Start by observing when you first feel fully alert after waking up — this marks the beginning of your first peak performance phase. Schedule high-focus tasks during these 90-120 minute work blocks and follow them with 20-30 minute recovery breaks. These structured breaks enhance long-term performance and well-being. But the real secret lies in what you do during these breaks.

Right kind of breaks

Not all breaks are created equal. Instead of passive scrolling or consuming digital content, choose offline activities that regulate your nervous system, such as breathing exercises, movement or exposure to natural light — to help enhance recovery.

Reset tool

One of the most powerful ways to reset during these breaks is play. Both structured and unstructured play, not only relieve stress but also improve focus, creativity and stress resilience. My book, Relax Play Thrive, integrates this science-backed approach, offering 111 engaging activities designed to align with natural biological rhythms, making stress regulation both effective and effortless. So, instead of pushing through fatigue, thinking you’ll take a break later, take that 20-30 minute structured break now.

Mastering your ultradian rhythms is not just about working smarter — it is about learning to work strategically with your body’s natural energy cycles. Your body operates with precision; the key lies in understanding its signals and adapting your lifestyle accordingly.

Why ultradian rhythms matter

Productivity and focus: Knowing that mental focus peaks in 90-minute cycles can help optimise work and break periods.

Well-being: Respecting natural energy dips by resting or taking breaks can prevent burnout.

Sleep Quality: Understanding ultradian rhythms can help explain why waking up at the end of a sleep cycle feels more refreshing than during deep sleep.