It has been scientifically proven that while all commonly accepted vital signs like Blood Pressure, Average Heart Rate, Respiration Rate, EKG, and various electrographic based Stress Tests are normal, a decrease in heart beat-to-beat variability may represent the very first sign of distress. More sudden cardiac deaths happen in the early morning hours when the beat-to-beat variability is narrow. The widest variability normally is in the evening, and it is probably the best time to exercise for most people. Some cardiovascular medications have a negative effect on beat-to-beat variability. For example, antiarrhythmic and antihypertensive drugs may dangerously decrease heart rate variability making patient susceptible to sudden death.
The stress and distress evaluation, based on beat-to-beat variability can be a useful daily method for general health and medications effects assessments. Measurements of beat-to-beat intervals, helps one to find the best time to exercise, the best time to take medications or decide on the benefit or harmful effect of cardiovascular medications, chemotherapy, antibiotics, realize the time when one must see a physician promptly or just when to avoid strenuous activity.
This particular method is not evaluated by FDA and is not a substitute for professional cardiovascular evaluation.