I'm a big fan of Paul McKenna. It was reading and listening to his Instant Confidence and Change your Life in Seven Days books that gave me the tools to beat the bouts of depression that plagued my first 40 years. One thing he talks about regularly is ultradian rhythms, and it's something I'd been meaning to look into more for a while.
For the uninitiated, they are our body's natural cycles of energy and rest that flow through the day. Usually in 90 to 120 minute cycles. I'd often noticed that some days my daily walks were easier or harder than others, and I realised it was probably these that were causing the fluctuations. I also wondered if these explained periods of focus and distraction through the workday.
Turns out, it does. And I know because I built an app, Ultradia, to analyse my Apple Watch data and figure out when my energy peaks and troughs were.
I'm finding it really helpful to plan my exercise and periods of deep work around lighter chores and relaxation, and becoming much more productive in the process.
And yes, I've been listening to far too much Sleep Token lately, too :-)