The iHeart Physiological Age System www.iheartalive.com uses a fingertip pulse sensor to measure Aortic Pulse Wave Velocity (AoPWV). The Aorta, pictured in red below, is the body's largest blood vessel, located just in front of the spinal column, coursing through the chest and abdomen.
When the heart beats a pulse wave travels down the walls of the Aorta. Towards the bottom of the Aorta this 'primary' pulse wave reflects back towards the heart. The speed with both the primary and reflected waves travel depends on Aortic Stiffness and Blood Pressure. The speed with which these waves travel is known as AoPWV.
With aging there is an stiffness throughout the body that affects the Aorta as well. With increased Aortic Stiffness there is higher AoPWV and the reflected wave returns to the heart earlier and earlier.
In the diagram below the reflected wave is circled in red. In a young person the reflected wave appears late in the cardiac cycle. In a young person the reflected wave returns just as the heart is ending its contraction phase. In a young person the reflected wave induces flow of blood into the arteries that feed the heart muscle. In an older person the reflected wave returns when the heart is still contracting. This forces the heart to work harder, it creates high peak pressures that damage the fragile blood vessels of the brain and when the heart contraction ends there is less force to induce flow of blood into the arteries feeding the heart.
The pulse shapes shown above are characteristic of younger and older pulses. iHeart uses a very high resolution and high sampling speed pulse sensor to perform pulse analysis, precisely locate the reflected and determine AoPWV. AoPWV determined by iHeart corresponds closely to AoPWV determined using the 'gold standard' Carotid-Femoral method recommended in the scientific literature.
Once AoPWV is obtained using iHeart, the reading is compared to average AoPWV values from the entire human age spectrum in order to calculate a corresponding Physiological Age.
AoPWV is affected by changes in Aortic Stiffness but is also affected by changes in Blood Pressure (BP). In the same way that BP readings in a doctors office should always be taken after resting for several minutes, iHeart AoPWV readings should always be taken in a condition of rest. An iHeart reading taken just after standing up will show a lower AoPWV reading because blood pressure drops upon standing.
It is normal for iHeart Physiological Age to vary up to 10 years at different times of the day and from day to day. This is related to short term changes in blood pressure. Immediately after an exercise session your Physiological Age may be increased above your usual because Blood Pressure rises with exercise. A few minutes to an hour or so after exercise Physiological Age may be lower than your usual because Blood Pressure drops for a few hours after exercise before returning to baseline.
If you are emotionally stressed, have had a restless night or there are other factors that would affect your blood pressure your Physiological Age will change.
Watching your trend over a few weeks is the best way to see if you have had benefit from attention to exercise, diet or stress management.
iHeart is a simple way to follow changes in the shape of your arterial pulse as a result of AoPWV effects. It does not take long for someone to get familiar with their unique personal rhythms as displayed by iHeart.
So........
Come on, get younger with iHeart!
https://www.indiegogo.com/projects/iheart-physiological-age-system
No comments:
Post a Comment