Alternative Medicine Kills, page-11

Obviously love is not measurable and never will be, but you can get a reasonable idea via its effect in the body. Cardiac coherence would be one way. Then looking for synchronization of cardiac coherence in the patient. Or a quietening of the default networks on fMRI. The most important thing of all is how it changes the patient's health - these things are easy to measure.

If you want to know your coherence, download https://play.google.com/store/apps/details?id=it.softarea.heartrate&hl=en

Then post up your scores.