More important than a human’s chronological age is their biological age, determined by physiological measurements of aging within the body which can predict health and longevity. It is these markers of aging that determine an individual’s expected lifespan, and researchers are learning more and more about how to measure indicators of biological age. With more accurate measurements and understanding comes an opportunity for better health management and a longer lifespan.
Two methods stand out amongst the plethora of scientific research as indicators of biological age: telomere length and arterial (particularly aortic) stiffness.
Telomere Length and DNA Testing
Throughout a human’s lifetime, cells will undergo as many as ten quadrillion (10^16) divisions—each individual cell, however, cannot divide infinitely. The Hayflick Limit describes cellular aging and why cells are not immortal, and it all comes down to telomeres, whose length is one measurement used to determine biological age.
Telomeres exist at the end of nuclear chromosomes, where DNA is tightly wound and stored. Each time that a cell divides, these telomeres shrink due to the inability of DNA polymerase to replicate the very end of each chromosome. Because telomeres do not actually contain coding sequences necessary for life, their position as chromosome endcaps helps to protect important genetic material from degradation after cell division.
When telomeres become too short and genetic material is in danger of being compromised by further cell division, telomeres will prevent further cell development. This can lead to a process called “senescence” or cell death. In other words, telomere length can be interpreted as a biological indicator of the body’s “clock” or biological aging. Supporting these concepts are a variety of data which suggest shortened telomeres are associated with cardiovascular disease, a leading cause of death, and diminished longevity.
Some epigenetic experts have used this knowledge about telomeres to investigate the possibility of increasing longevity and biological age by modifying telomere length, which has sparked an increased interest amongst the general population to test their own biological age via DNA testing provided by companies like TeloYears.
Aortic Stiffness and Pulse Wave Velocity
Other research asserts that aortic stiffness is a hallmark of aging just as important and telling as telomere length.
Determined by calculating aortic pulse wave velocity (AoPWV), aortic stiffness is a measure of the aorta’s flexibility or stiffness. The aorta stiffens due to a variety of factors - age, a sedentary lifestyle, poor diet, and is directly related to spinal flexibility. If the aorta is stiff blood will travel too quickly from the heart down the aorta and reflect back too soon, which doesn't provide enough time for the heart to complete it's full pump. This causes a crash in the wave of blood, increasing pressure in the blood vessels leading to increased risk of developing heart disease, dementia, and premature death - but fear not, aortic stiffness is reversible.
Because cardiovascular disease remains one of the deadliest disease processes in the world, measurements of arterial stiffness (and aortic stiffness, in particular) can serve as increasingly useful tools for the measurement of morbidity, mortality, and biological age. Studies have also shown that arterial stiffening is heavily associated with smoking, hypertension, aging of the brain, and lower fitness levels. Regular exercise can actually decrease aortic stiffness!
Thanks to recent advancements in PWV measurement technology and health tech, assessing aortic stiffness can be done quickly and easily at home. No DNA testing is required, and monitoring aortic stiffness from home with a non-invasive device like iHeart Internal Age can be a highly empowering tool for those who want to embrace a healthier lifestyle and increase their longevity.
Learn more about measuring aortic stiffness in 30 seconds and tracking your biological age regularly with iHeart Internal Age™.