This is a commonly reported side effect with minoxidil, although with a lot of other side effects it's not "officially" listed (though it should be!)
Usually people will say more cardio and drink more water, which you covered anyway.
With me I stopped having side effects with minoxidil when I used less, stopped applying it to damp hair and waited around an hour to apply it after I woke up and never put it on just before going to sleep (an hour before bed most of the time).
