Most facial redness during exercise or exertion can be considered normal; however, if you are concerned or worried that the redness represents something more than just the normal cooling-down process, or if it is accompanied by other symptoms including diarrhea, shortness of breath, palpitations, low blood pressure, or light-headedness, you should consider being evaluated by your primary care physician in order to rule out any medical condition. First get CBC with ESR, thyroid profile, BP, blood sugar test done first to ruleout any medical condition.