The Negative Effects of Caffeine on Pulse Wave Velocity
The Validity of iHeart Experimental Tests
When iHeart testing throughout the day, the effects of recent lifestyle choices will have an influence on Internal Age readings. It can sometimes seem as though inconsistencies or inaccuracies are occurring, but these readings actually contain a lot of useful information.
iHeart users are encouraged to take a reading each morning to establish a baseline Internal Age. This should be performed under the same conditions each day for consistency; typically immediately after waking up. Additional tests taken throughout the day are informally referred to as Experimental Tests. These impromptu readings should always be preceded by a 2-minute rest period, but may still exhibit significant fluctuations as they are reflective of the tester’s immediate past. Recent exercise, stress, food choices, medications, and myriad other factors will have an effect on Internal Age results, which can therefore be used to assess the positive or negative effect those recent choices are having on the body.
While it may not be effective to include experimental readings when considering Internal Age trends, the variance in results from these tests can be used to help discern the impact of lifestyle choices.
Caffeine’s Stiffening Effect on the Aorta
One common item that causes an increase in Internal Age is consumption of caffeine. Studies have repeatedly proven that caffeine increases blood pressure and has a stiffening effect on the aorta, therefore increasing Aortic Pulse Wave Velocity (PWV)—a measurement system for blood pressure effects and aortic stiffness, and the primary determinant of iHeart’s Internal Age ‘scoring’ system. One 2005 study published in the American Journal of Clinical Nutrition concludes:
"Chronic coffee consumption exerts a detrimental effect on aortic stiffness and wave reflections, which may increase the risk of cardiovascular disease."
More recently, a 2012 study in the International Journal of Nutrition, Pharmacology, Neurological Diseases found:
"Acute administration of caffeine produced rise in blood pressure [and] arterial stiffness ... in health subjects as indicated by pulse wave velocity and b/a ratio."
The Safe Number
Despite caffeine unanimously increasing blood pressure and having a stiffening effect on the aorta, each person reacts differently and therefore a ‘safe number’ of cups per day cannot be provided. As with many things we suggest here at iHeart, the secret really is moderation. Listen to your body and ask yourself how important it is that you have another cup of coffee. Are you blindly embracing a habit or do you really need the boost today?
By that token, iHeart can be used as a mindfulness tool to help you to monitor the effects of your choices and bring awareness to decision processes such as this one. iHeart measures an entirely personal health metric (Aortic PWV) that will respond differently to various stimuli for each person, and will allow you to find your own ‘safe number’ of cups of coffee per day before health risks become unmanageable.