Methods and apparatus for diagnosing cardiovascular health in a patient by monitoring changes in skin redness levels, which is associated with perfusion and ability of circulatory system to adapt to physical exertion. Color detectors including colorimeters and spectrophotometers may be used to monitor and quantify skin color. Wet run solutions such as acetylcholine solutions may be applied to the skin area being monitored. Skin redness can be monitored during the course of exercise or a stress test, as well as during recovery. Wearable color detector devices can be worn by patients during exercise.
