Here are my thoughts as someone who knows the brain fog too well, thanks to my ADHD.
Once you figure out the most convenient way for yourself to track when you have brain fog, I suggest you’ll track the following:
- sleep - if I don’t get enough high qualify sleep it is the most likely cause of my brain fog. High qualify = I have long uninterrupted sleep sequences and get enough deep and REM sleep.
My main source of sleep data is currently Dreem 2 but I have used Fitbit, Oura and Apple Watch as well. I have learned that checking the total time spend in bed/sleep probably isn’t enough.
- Track alcohol consumption (if you use it). If I drink even a little alcohol today, I will experience brain fog DAY AFTER TODAY.
Pay attention to the time of day of your brain fog. For example I have an energy and focus dip around 4-6pm. My mom has the same, so I’d say it is biological/genetic for us.
If I haven’t gotten good quality sleep or have had alcohol two days earlier or have done something that has drained my mental energy, I’ll experience major brain fog around that time, regardless of what I have eaten or done before.
I have found Endel app to predict quite well when my energy levels (and therefore focus etc) is in the rise, peaking, falling or recharging, too.