I've been using a garmin for a while and it looks like my HRV gets worse as my propensity for a headache / migraine increases. It would be interesting to see if

I've been using a garmin for a while and it looks like my HRV gets worse as my propensity for a headache / migraine increases. It would be interesting to see if there is any correlation with brain activity and the other bio information it gathers so I can perhaps create an early warning system - not sure what it will do though, perhaps I'll just start my anti-migraine ritual sooner and maybe abort more than currently.