Discovering Chronotypes and Optimal Sleep Habits

As an advocate of good sleep hygiene, one of the talks I was most looking forward to at Biohacker Summit 2018, was Hannu Kinnunen’s Finding your Chronotype and Optimal Bedtime.

Hannu dived into ways of measuring performance by time of day, starting with a look at keystroke time, as measured by search engines. The slowest time was between 4-5am which would go against our natural Chronotypes and circadian rhythms, while the fastest times were seen during normal office hours.

The concept of finding your chronotype was based on levels of peak performance with early chronotypes hitting their optimal productivity during early morning, compared to later chronotypes who may hit this peak in the evening. The majority of people fell somewhere in between.

Hannu is the lead scientist from Oura Health, a company who have developed the Oura ring; a smart ring which tracks sleep cycles, heart rate and body temperature. With so much data at their fingertips, Hannu’s team is able to correlate the amount of sleep with optimal performance, finding that consistency was key, rather than a few hours one night and nine hours the next.¬†He also explained how our brains come to expect things and recognise¬†patterns.

There were a few practical takeaways, such as students studying for exams achieved higher grades when revising at the same time of day as their exams. This extended to athletes too, where training at the same time as their competitions led to better performance.

It was shown that if you were looking to get a few extra hours of sleep, it is better to go to bed earlier than your normal bedtime, rather than counting on a lie in. Similarly, going to bed too late isn’t optimal as the heart rate starts to increase, making high-quality sleep difficult.

Further Reading

Interested in learning more about heart rate whilst sleeping? Oura have produced some interesting graphs, showing the impacts of going to bed too late or after a big heavy meal.