Backed by ubiquitous technologies that have altered the boundaries of our work lives, we are now equipped to work from anywhere, any time. 24/7. Always on. Fuelled to power through the moments in which our bodies crave rest.
Of course, it’s not hard to imagine the damage that this approach might inflict on a human body over the long run. Sleep deprivation first kills our physical and cognitive performance, and then it kills us.
But what if we reimagined work and rest? What if we listened to what decades of research tell us about routines and human performance and then applied it to our day-to-day lives? What if we thought, worked and rested in cycles?
Think in Cycles
Let’s begin by looking at the biology.
For some time now, we have known that the average human being passes through five 90-minute cycles of sleep each night. We know this because electroencephalography (EEG) allows scientists to monitor the electrical activity in the brain during a night’s sleep, and consistently marks out a 90-minute cycle by virtue of differences in delta wave patterns and REM sleep.
While our sleep cycles become more disrupted and mixed in their stages as we get older, the typical adult can expect to take 90 minutes to complete a full cycle.
Here’s where it gets interesting. In 1963, Nathaniel Kleitman famously called this 90-minute sleep cycle the basic rest-activity cycle (BRAC). But Kleitman’s model made one important distinction: the cycle also applied while we were awake.
Kleitman’s central observation was that our brainwaves followed a consistent, repetitive pattern of 90-minute cycles throughout the 24-hour day. (In chronobiology, this is known as an ultradian rhythm.)
For the first 45 minutes, brainwaves move faster, which corresponds with greater alertness during the day. As the cycle moves into the last 20 minutes or so, brainwaves begin to slow down, and the body starts to feel more tired. Kleitman saw this as the period in which the body readied itself for the next 90-minute cycle.
While the literature has since debated the difference in these patterns between awake and sleep state, ultradian cycles are a widely accepted reality of nature.
The lesson: we need to think in cycles. We need to recognise the cyclical nature of our energy and design our work and rest patterns accordingly.
Let us call this cycle thinking from here on.
Work in Cycles
If there is some truth in ultradian cycles, then it’s only logical that designing our work and practice according to these cycles could produce better performance.
Work in 90-Minute Cycles
Look no further than perhaps the most famous study of practice ever done for evidence of the potential benefits. In 1993, Karl Anders Erikson and his colleagues famously studied the techniques and time required for violinists to reach expertise. The most proficient violinists were found to practice most typically in three blocks of 90 minutes.
Coincidence? Perhaps. We can’t, of course, deem this causative, but we can say that 90-minute batches of deep work may play to two key strengths. First, they are aligned with our ultradian cycles. And second, they provide compelling structure to commit to practice.
Work in 25-Minute Cycles
An alternative is to shorten these cycles and focus on batches of high-level alertness and intense focus. The Pomodoro Technique, developed by Francesco Cirillo in the 1980s, recommends cycles of 25 minutes, with short breaks between. After 4 cycles, we take a longer break.
The obvious benefit here is we cut the cycle short before our alertness starts to slump. The technique also provides a nearer-term incentive of a break – something that is evidentially helpful in countering procrastination.
Sleep in Cycles
While structuring our workdays in line with our chronobiology has its merits, let’s not forget that ultradian cycles apply over 24 hours. There are therefore some strong arguments to incorporate cycle thinking into our rest routines.
Sleep in 90-Minute Cycles
In his book Sleep, Nick Littlehales makes a compelling case to think about our sleep differently. Instead of thinking about how many hours sleep we are getting, Littlehales suggests we should think about how many cycles of sleep we are getting.
Littlehales even argues that we should structure the timing of our sleep in 90-minute increments to avoid waking up in the middle of a cycle in our groggiest state. In other words, if our scheduled wake-up time is 7am, we should count back 5 cycles (or more or less cycles if our bodies need them). 5 cycles equate to 7.5 hours, and so we would need to get to sleep at 11:30pm in this case. We might therefore get into bed at around 11pm to allow some time to get to sleep.
Rather than interrupting a natural cycle with a necessary alarm, we can design our routines to build in completed sleep cycles. Getting the right start to a day by waking at the end of a cycle inevitably can have a positive impact on our performance on that day.
Nap in 25-Minute Cycles
Remember those violinists? Interestingly, the most proficient violinists had another important routine in common. On average, they napped for 24 minutes each day.
25 minutes of napping allows our body to enter light sleep, which has a range of important performance-enhancing functions, such as increasing our brain’s capacity to form new synaptic pathways and consolidating memories.
Instead of shaming the nappers, we should wise up to the benefits of incorporating a nap cycle into our routines.
Experiment with Cycles
With all that said, there is an important caveat. 90-minute and 25-minute cycles aren’t a one-size-fits-all solution. They are merely average times that have been arrived at by studying performance and brain activity. In other words, different people have different cycles.
The key to effectively working and resting in cycles, then, is to experiment.
Test different work and rest time cycles. See if they elevate your performance. Tweak and adjust the times and frequencies to finetune towards your sweet spot.
The ultimate lesson here is to think, work and rest in cycles. Not just because there is wide-ranging evidence of ultradian rhythms, but because it may just elevate your performance, productivity and well-being.
How you achieve that end varies from person to person, but cycle thinking is a platform from which we can extract these benefits.
Cycle thinking recognises an unavoidable reality of the universe: that every living thing functions in cycles. That life itself is one giant cycle made up of thousands of short cycles. And that we can design a day-to-day routine that recognises and capitalises on that reality.
What are you waiting for? Think in cycles.