A method for digital thermal monitoring assessment of vascular function comprising a temporary arterial occlusion using a pneumatic cuff positioned on a subject's upper limb, monitoring skin temperature at the fingertip of the occluded limb for a period of time before, during, and after the occlusion, calculating a Zero Reactivity Curve based on variables including start temperature room temperature, and the slope of temperature decline during the occlusion, and assessing vascular function based on comparing the Zero Reactivity Curve and the observed temperature rebound after the occlusion is removed. A vascular reactivity monitoring apparatus for measuring skin surface temperature comprising an inflatable cuff for placement around a subject's limb, a digital thermal measuring device and photoplethysmography measuring device for placement on a finger of the subject's limb wearing the cuff and a second digital monitoring device and photoplethysmography measuring device for placement on a finger of the subject's contralateral limb.
