I’ve been collecting data about myself on a daily basis for the past 3 years. Half a year ago, I switched from using 42goals (which I only remembered to fill out once every few days) to a Google form emailed to me daily (which I fill out consistently because I check email often). Now for the moment of truth – a correlation matrix!
The data consists of “mood variables” (anxiety, tiredness, and “zoneout” – how distracted / spacey I’m feeling), “action variables” (exercise and meditation) and sleep variables (hours of sleep, sleep start/end time, insomnia). There are 5 binary variables (meditation, exercise, evening/morning insomnia, headache) and the rest are ordinal or continuous. Almost all the variables have 6 months of data, except that I started tracking anxiety 5 months ago and zoneout 2 months ago.
The matrix shows correlations between mood and action variables for day X, sleep variables for the night after day X, and mood variables for day X+1 (marked by ‘next’):
The most surprising thing about this data is how many things are uncorrelated that I would expect to be correlated:
- evening insomnia and tiredness the next day (or the same day)
- anxiety and sleep variables the following night
- exercise and sleep variables the following night
- tiredness and hours of sleep the following night
- average hours of sleep (over the past week) is only weakly correlated with tiredness the next day (-0.15)
- hours of sleep (average or otherwise) and anxiety or zoneout the next day (so my mood is less affected by sleep than I have expected)
- action variables and mood variables the next day
- meditation and feeling zoned out
Some things that were correlated after all:
- hours of sleep and tiredness the next day (-0.3) – unsurprising but lower than expected
- tiredness and zoneout (0.33)
- tiredness and insomnia the following morning (0.29) (weird)
- anxiety and zoneout were anticorrelated (-0.25) on adjacent days (weird)
- exercise and anxiety (-0.18)
- meditation and anxiety (-0.15)
- meditating and exercising (0.17) – both depend on how agenty / busy I am that day
- meditation and insomnia (0.24), probably because I usually try to meditate if I’m having insomnia to make it easier to fall asleep
- headache and evening insomnia (0.14)
Some falsified hypotheses:
- Exercise and meditation affect mood variables the following day
- My tiredness level depends on the average amount of sleep the preceding week
- Anxiety affects sleep the following night
- Exercise helps me sleep the following night
- I sleep more when I’m more tired
- Sleep deprivation affects my mood
The overall conclusion is that my sleep is weird and also matters less than I thought for my well-being (at least in terms of quantity).
Addendum: For those who would like to try this kind of self-tracking, here is a Google Drive folder with the survey form and the iPython notebook. You need to download the spreadsheet of form responses as a CSV file before running the notebook code. You can use the Send button in the form to email it to yourself, and then bounce it back every day using Google Inbox, FollowUpThen.com, or a similar service.