What I found from crunching six months of my health data

Awadi Rathugamage
Awadi Rathugamage
November 22, 2022 · 2 min read Sources Verified
Updated: May 16, 2023
Guava's calendar (labels removed) of my symptom and lifestyle entries

I’ve always been intrigued by the idea of having a stats dashboard for my life. It’d be something like what a fighter pilot - or Iron Man - can see about how their systems are functioning; except I’d be the pilot monitoring the gauges of my health and lifestyle and making the necessary course corrections.

With these ambitions in mind, I’ve been a loyal user of Guava’s daily logging functionality. For a while, it was without much immediate gratification, but that's all changed with our rollout of correlation insights. The app’s analysis of my devoted diligence has surfaced some interesting patterns, some of which I thought were worth sharing (if only to spur the other data nerds out there).

1. Antihistamines can help with itchy skin and make me sleepy.

Okay, for this one, I probably didn’t need an app to tell me. I only take Zyrtec because it alleviates itchy skin, and drowsiness is a known side effect that I’ve anecdotally noted. Maybe I sleep better with less itching and without the anxiety of having it flare up during the night! Either way, the validation with data was nice.

Correlation cards from Guava app for sleep and itching skin vs Cetirizine 10mg tablet

2. I could skip the Zyrtec and eat dark chocolate pretzels instead.

Who knew that those crunchy little pieces of happiness had medicinal properties? Upon seeing this, I also confirmed that I have dark chocolate pretzels more on days that I take my Zyrtec, so the reduced itching is likely tied to the Zyrtec and the pretzels are a coincidence. But I think I’d rather just believe this at face value; I’m sure there’s an article somewhere that says dark chocolate is healthy. Speak with your doctor first to see if dark chocolate pretzels are right for you.

Correlation cards from Guava app for sleep and itching skin vs Cetirizine 10mg tablet

3. If I don’t get my daily steps in, it’s definitely the weather’s fault.

Living in Santa Barbara, I really have no right to complain about weather of any kind. Still, it seems I’m impeded from getting my steps in when in severe cold weather (defined of course as anything below 61°F) or high humidity (over 93%) - particularly annoying given the daily steps and sleep competition we have amongst the Guava team.

Correlation cards from Guava app for sleep and itching skin vs Cetirizine 10mg tablet

On a serious note, I am curious to see how these trends hold into next year, given that last December I was (1) down with COVID and (2) less active in general.

4. Alcohol is not the solution, certainly not if I want to improve my HRV.

Heart Rate Variability (HRV) is the difference in time between your consecutive heartbeats, and a higher number is generally considered to be better. This is one of my favorite correlations, for a couple of reasons. Firstly, it’s not something that I could gauge anecdotally (even though studies have found relationships between alcohol consumption and HRV), so I really did need the app to show me it was true. Secondly, I was amazed at how clearly my HRV distributions differed in the graph view.

Correlation cards from Guava app for sleep and itching skin vs Cetirizine 10mg tablet
Graph of polio paralysis cases in the US before and after the polio vaccine
Graph view of alcohol consumption vs HRV

There were many more correlations that the app surfaced - 51 in total - but I won’t go into all of them for the sake of brevity. Some of them are a little hard to believe and likely driven by coincidence (e.g. the dark chocolate pretzels one) so in future improvements we will try to reduce the noise in the patterns that are displayed. Also, for symptoms where I’m out of ideas on what the triggers could be, it’d be nice if the app suggested some things to log to see if a pattern exists for me. In the meantime, I’ll keep up the journaling; because when it’s an information problem, more data is usually a good solution!

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