Is it really worth tracking your sleep?

When my heart rate monitor arrives in the post, I can’t deny I’m intrigued. This small wearable device – which will be affixed to my chest for three days and three nights – promises to give me a complete ‘lifestyle assessment’, including estimates of my stress levels, fitness and sleep.

I stick the Firstbeat device to my skin with two electrodes (one on my right side just under the collarbone, one on my left side on the ribs) and go about my day. It’s a little obtrusive, but not uncomfortable, and is easily concealed under a baggy top.

I’ve chosen a three-day period that I hope might represent a good snapshot of my life. The first day, a Thursday, ends up being a fairly standard weekday, with typical amounts of work, exercise and sleep. The second day is more stressful workwise, so I drown my sorrows with some Friday drinks. The third day, a Saturday, is spent relaxing at home, but in the interests of shedding my hangover I also fit in a longish run.

After posting back my device, I receive an email from the company containing my Lifestyle Assessment. The results are a goldmine to anyone interested in the so-called ‘quantified self’. Using data about my heart rate variability (the variation in the time interval between consecutive heartbeats), the report is able to estimate everything from my calories burned to the restorative quality of my sleep.