Why can repeated measurements of AIx (Augmentation Index) on the same subject vary?
AIx, like blood pressure varies through the day, and can be affected by coffee, cigarettes, heavy meals and activity. These conditions will change your heart rate and blood pressure and consequently your AIx (though may not be permanently altered). To ensure reproducible and accurate measurements, all subjects therefore should be measured under similar conditions. It is important to take SphygmoCor measurements when the subject is relaxed (either lying or sitting down) and has abstained from coffee, cigarettes, heavy meals or exercise prior to the measurement, unless these are the conditions specific to the study. All subjects have to be under similar conditions when measured, to insure reproducible and accurate measurements.
