I recently found this system called Biorhythm.
It is a graphic chart based on each individual’s vital signs.
Those are unique and are inherent on birthdate.
A ‘scientific’ answer to those who don’t believe in Tarot, but do not use Fitbit.
Anyone could make a sketch on their own, but today every thinkable platform (either a PC or a smartphone, etc.) has a free variation of this simple program.
The one that I use on iOS also offers a list of popular activities with a percentage bar of how well you will be fit to complete them. Some offer a daily e-mail notification service.
And it works. For example, you can try doing exercise on the days showing you as physically diminished, only to find how hard it is.
Or try being witty when your intellect is on the offside, as well.