iHeart Internal Age

Why would you want to know your iHeart “Internal Age”? 

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You know your approach to lifestyle. You know your lab results. You may even have a fitness tracker.

But do you really know what’s happening to your biological health? 

Internal age, or biological age, is representative of the wear and tear on the body. It is what determines our health and ultimately our lifespan. We all age biologically at different rates according to our genes, what we eat, how much we exercise, stress, sleep and what environmental toxins we are exposed to. Chronological age is how old the calendar says you are, not how old we really are. It's a superficial number.

Example conditions that work against your biological age are hypertension, inflammation, insulin resistance and autoimmune disease. Lifestyle can either encourage or prevent these conditions.

How does it work?

In this animation you can see how Aortic Pulse Wave Velocity (AoPWV) changes in individuals of different age ranges. As we age, the aorta stiffens AoPWV increases and the heart has no time to relax before the reflected wave of blood returns.

The iHeart calculates your biological age based on a principle called “aortic pulse wave velocity,'' (the gold standard of aortic stiffness testing) to assess aortic stiffness which is a proven indicator of risk for developing disease.

Aortic stiffness is stiffening in the aorta, the largest artery in the body running from the chest to the pelvis. As unhealthy choices are perpetuated over time, the aorta will stiffen and lose elasticity; a vital part of its ability to deliver blood and oxygen to the organs efficiently.

Aortic Pulse Wave Velocity is the speed at which reflected pressure waves travel along the walls of the aorta. The difference between their arrival time at the fingertip and the arrival of the heart’s initial pulse is measured in metres-per-second. The faster this reflected wave travels along the aorta, with speed directly affected by stiffness, the more at risk a person is for cardiovascular effects.

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In the example, the pulse wave was measured at 9.07 meters/second. 

Increased Aortic Pulse Wave Velocity as a result of aortic stiffening has been shown to be strongly associated with the narrowing of the inside of arteries due to the buildup of plaque. The optimal cutoff value of PWV to detect patients with high 10-year cardiovascular mortality risk was 13 meters/second. (1)

Researchers at the University of Pittsburgh Schools of the Health Sciences have been studying 356 older adults (average age, 78) over the last 15 years and have concluded that maintaining healthy levels of arterial stiffness can reduce an individual's risk for dementia.

(1) Aortic Pulse Wave Velocity as a Marker of Cardiovascular Risk in Hypertensive Patients

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is NOT a medical device. It is intended for wellness education only. It is not intended to be used for any medical diagnosis or management of medical conditions.

BioImpedance Analysis

Why would you want to have a BioImpedance Analysis done?


BioImpedance Analysis (BIA) is a detailed look at your body composition. Some of the key measures you obtain:

  • Body Fat Percentage

  • Free Fat Mass Index

  • Bone Mineral Content

  • Intra & Extra Cellular Water

  • Phase Angle

Why are these measures important?

Body fat percentage:

BMI (body mass index) is the prevalent means to determine appropriate weight. It is a simple means to gauge health risk with just weight, height, a look-up table and no equipment other than a weight scale and tape measure. It is “practical” to implement.

The health concern is really about the amount of body fat one has. BIA technology can assess a person’s body fat where as BMI does not. Is it true that as BMI goes up, body fat goes up? For the general population (not athletes) yes. But one can also have a normal BMI and have high body fat that would go undetected. A recent study by researchers from the University of Florida (UF) in Gainesville discovered that people with a normal BMI but high body fat are more prone to prediabetes or diabetes, when compared with people deemed overweight according to their BMI but have a lower body fat percentage. BMI does not take into consideration individual differences in muscle and bone mass that become more important to seniors.

Another study over 40% of the women with normal BMI ranges had excess fat. These individuals who are normally rated as “low risk” based on BMI are actually at very high risk for developing metabolic disorders.

We now know that in addition to storing fuel for energy, body fat functions as an endocrine organ issuing signals important to body functions such as lipids/cholesterol and insulin sensitivity. When fat cells are overfilled, they become dysfunctional and rather than providing appropriate signaling (adiponectin) they produce signals of inflammation.

This is the result of adiponectin testing from Boston Heart (a lab we use). You can see adiponectin levels have dropped. They should be greater than 13. The person associated with these results had a BMI of 37 (obese) with a body fat of 47.6% of weight. In this case we can see the individual “does not have a normal BMI”. So the high body fat percentage and low adiponectin would be initiative.

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The National Institute of Health has stated that a high percentage of body fat can put one at risk for hypertension, high cholesterol, diabetes, and heart disease. A healthy body fat percentage can lower your risk of developing the above conditions and has other positive benefits such as increasing energy levels and improving flexibility and function.

Free Fat Mass Index:

We have measures and ranges for other important health aspects such as bone density. But what about muscle?

Muscle serves important roles in our daily functional movement providing us with physical endurance, strength and power. It also play a metabolic role with the storage of glucose. The loss of muscle as we age reduces storage capacity for glucose. Now couple that with maintaining the same levels of carbohydrates as when were were younger and we have an overflow of glucose that can only be stored in adipose tissue.

So How much muscle should one have? How much is healthy?  Free Fat Mass Index (FFMI) represents weight less body fat. Assuming bone density and total body water are within norms, FFMI gives impression of muscle mass. There is an age related level of muscle loss called sarcopenia. After age 30, you begin to lose as much as 3% to 5% per decade. Most men will lose about 30% of their muscle mass during their lifetimes. This is controllable with favorable Lifestyle practices.

Below is a scale which can aid in evaluation the appropriateness of one’s amount of muscle mass. Further below is a BIA report. The subject in the report has a FFMI of 21.5 which places between average and distinctly muscular.

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The subjects BIA results are on the top half of the report with a comparison to NHANES-III sample group on the bottom half.

The subjects BIA results are on the top half of the report with a comparison to NHANES-III sample group on the bottom half.

Bone Mineral Content:

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Bone Mineral Content (BMC) is a measurement of bone mineral found in the measured area. BMC is measured in grams (g). You may be familiar with Bone Mineral Density (BMD) which looks at bone mineral (BMC), but within a defined volume and so reveals the mineral concentration or bone mineral density in a given area/volume. The BIA provides bone mineral content for a whole body and so can not evaluate segments of the body such as hip or spinal disk bone concentrations at risk for fracture.

Dual Energy X-Ray Absorptiometry (DEXA)

Dual Energy X-Ray Absorptiometry (DEXA)

The Gold Standard for determining bone health is a measure of Bone Mineral Density measured with Dual Energy X-Ray Absorptiometry (DEXA). The typical cost of a BMD test without insurance is $150-$200. 

A person’s BMC using BioImpedance is compared to a reference population and gives a good impression of bone mineral content relative to a person of similar age, weight, height, sex and race. This is important relative to bone loss as a consequence of aging, nutritional imbalances (vitamin D, calcium, magnesium, potassium for example), lack of weight bearing activity and medications that may cause bone loss. As an example, heparin, warfarin, cyclosporine, glucocorticoids, medroxyprogesterone acetate, cancer drugs, and thyroid hormone can cause bone loss. BIA Bone Mineral Content measurement can trend the potential effect of the medication.

Intra-Cellular Water and Extra-Cellular Water:

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This is the amount of water inside the cells and the amount of water outside the cells.

A healthy fluid distribution has been estimated at a 3:2 ratio of ICW:ECW. If your body water falls out of balance, this can signal changes in your health and body composition. Whether these changes are positive or negative depend on which type of water becomes unbalanced. A favorable balance is key to moving nutrients in and waste out of the cell.

Increases in intra-cellular fluid suggest improved nutrition status, mitochondrial function, and increased cellular health.

Increases in extra-cellular fluid can suggest mineral imbalance, increased concentrations of toxins in extra-celluar space, and reduced cellular health.

One study found 0.57 to to be the cut-off ECW/ICW ratio for maximum discrimination of all cause mortality by survival analysis. (ECW/ICW ratio greater than 0.57 had higher all-cause mortality, CVD, systolic blood pressure (BP), pulse pressure, number of anti-hypertensive pills and left ventricular mass index (LVMI). LVMI is a surrogate marker of left ventricular hypertrophy and a predictor of cardiac morbidity and mortality in adults with hypertension. (1)

In the BIA chart above, the total body water (TBW) was 115.1, the extra-cellular fluid was 50.5 and the intra-cellular fluid was 64.6. The ECW/ICW ratio (50.5/64.6) is 0.78.

Phase Angle:


Phase Angle (PA) represents the relative contributions of fluid and cell membranes in the body. It has been referenced as a maker of nutritional health in several studies when monitoring chronic health conditions. Phase Angle is a single value that varies from 4.5 to 9.0 among different individuals.

A lower value phase angle is consistent with an inability of cells to store energy and an indication of breakdown in the ability of the cell to control the permeability of its outer membranes. A high phase angle is consistent with large quantities of intact cell membranes and effective control of what goes in and out of the cell. Better cell membrane health means a more efficient metabolism, a better response to and control of our hormones, and better nerve signaling. As with water compartmentalization, a low phase angle equates to accelerated aging, inflammation, poor water balance, and excessive weight.

The following image shows contributors and detractors of cell membrane health. You might recognize contributors such as CoQ10, Beta-Carotine, vitamin E and detractors such as Trans Fats, Heavy Metals and High Blood Sugar.