Aging Biomarkers – Chronological v Biological Age

Chronological age can be defined as the time measured from an individual’s birth to a particular date. Biological age is more complex, since it positions an individual within its own lifespan and probability of survival, meaning that a 67 year old man with a biological age of 60 is more likely to live longer than a 67 year old man with a biological age of 70. These concepts are related and in some cases the values can be equal but they are not the same thing.

Chronological age is simply a number representing the length of someone’s life to a particular point; therefore it is difficult to associate biomarkers to it since any biomarker with any influence in the capacity for survival would immediately be more related to biological age. A strict chronological age biomarker should be a biological feature that changes over an individual lifespan but doesn’t directly affect the probability for survival.

There are several biomarkers currently being used that don’t influence survival greatly and are related to older individuals, these could be easily called “chronological age biomarkers”. Reduction of the coronal pulp cavity (using radiography) is a very common method used in forensic science, however, in adults most signs of aging like wrinkles and silver hair are features that can manifest at different points in someone’s life and won’t be useful to accurately determine someone’s biological age.

When looking for aging biomarkers that will reveal the biological age of an individual, these can be split between functional (macro) and physiological (micro) biomarkers.

Aging Biomarkers Infographic

Biological Biomarkers

After many decades of research, the scientific community now agrees on 9 hallmarks of aging that relate to physiological processes acting at the cellular level. These are: accumulation of genetic errors due to genomic instability, telomere attrition or degradation, epigenetic alterations, damage of the internal mechanism in charge of quality control for protein synthesis, deregulated nutrient sensing, mitochondrial dysfunction, loss of the capacity to grow and change stem cell exhaustion and altered intercellular communication.

All of the physiological biomarkers considered above provide data about the capacity of the organism to sustain operation of its own processes over time and also about its capacity to withstand different forms of stress.

These nine hallmarks of aging are robust candidates to be considered for any system dedicated to the determination of biological age; however, obtaining accurate measurements of any of them requires a lot of specialized equipment and capable staff, since they cannot be evaluated easily. Some of them like stem cell exhaustion or mitochondrial dysfunction can only be measured by taking a biopsy and performing a longitudinal study in vitro under laboratory conditions, something that most laboratories don’t provide as part of their usual services.

Functional Biomarkers

Fortunately, functional biomarkers are easier to measure and are considered equally valid to measure biological age. These cover both cognitive and physical performance and include visual acuity (Snellen chart), auditory acuity (pure tone audiometry), decision reaction time, grip strength (dynamometers), body mass index (height and weight measurement), blood pressure (systolic and diastolic pressure), lung capacity (spirometer) and memory.

Functional age is a specialized form of biological age, is task-oriented, and can provide valuable information in regards to an individual’s capacity to perform a particular task or its vulnerability within a certain set of conditions.

All biomarkers mentioned in this article have shown correlation with the process of aging in the past, however, a system designed to provide an accurate value for someone´s biological age will have to integrate a large number of these variables at the same time and incorporate an elegant method to accumulate, process and interpret data from a considerable amount of sources.

Sofa exercises mean you don’t have to be sedentary while watching TV

If you’ve got a desk job and enjoy films and TV dramas then you’re at a big risk of not moving around enough every day. Research shows that being a weekend warrior (1-2 big gym sessions a week) is not as good for your longevity as regular movement every day.

If you’re watching live TV with commercial breaks then that is the ideal time to get up and move around – maybe a few quick walks up and down the stairs or through your apartment.

And if there aren’t any breaks that’s not an excuse either! I’ve found a few useful sofa workouts that can be done at the same time as watching TV.

With these it’s possible to perform a good mix of abs, legs and upper body exercises. Here are 4 of my favourites:

  • Seated scissors
  • Couch crunches
  • Chest squeeze
  • Sofa dips

sofa exercises
I’m not suggesting these routines count towards your (minimum!) 150 minutes of moderate exercise per week – but they will make sure you keep moving around even when not moving about.

See these websites for full work out details:
DAREBEE – excellent selection of workouts including cardio sofa and sofa abs
Holmes Place – 6 exercises you can do from the sofa, including the most chilled side plank ever!
BuzzFeed – 12 station circuit with animated GIFs demos
ChicagoTribune – 5 exercises you can do without upsetting your inner couch potato

Review of longevity technology in Passengers (movie)

This isn’t a film review, but a review of longevity technology in the 2016 movie. For those not familiar with the plot the film is about a totally automated interstellar craft with 5,000 “passengers” – humans in suspended animation on their way to a newly colonised planet. During the 120 year journey a fault results in one of the passengers being awakened 90 years early and raises the moral dilemma of would you wake someone else up to keep you company even if you knew they would die with you before arriving. It’s a Hollywood blockbuster so this interesting and realistic should-I, shouldn’t-I question is crammed into a disaster movie set on a nuclear fusion powered spaceship, though there is a great scene  where they lose gravity while someone is in a swimming pool and so suddenly finds herself swimming in a giant bubble with no up or down.
For full synopsis and trailer check out IMDB.

Longevity Technology References

My main criticism is that by the time human technology has advanced so far that interstellar colonisation is routine then aging would be a long distant memory. Even it hadn’t been possible to prevent death entirely it would certainly have been slowed enough that a 90 year inconvenience would be survivable. But given the entire plot and dilemma revolves around their inevitable death I understand the movie has to overlook this! And as a side thought, even when people do live forever they may still go into suspended animation for long journeys – perhaps to minimise boredom or save resources.

The interesting medical technology in the film revolves around the Autodoc – a diagnosis and treatment chamber along the lines of the reconstruction chamber in The Fifth Element but with a sleeker design. With a quick body length scan it was able to diagnose over 600 faults in one character and predict their time of death. For less critical patients (though in this case, already dead – don’t ask, it’s a fun sci-fi!) Autodoc is equipped with a range of robotic surgical instruments and injection devices. It’s control panel flashed up a couple of times listing available procedures with included stem cells treatments but it was too fast to read any more so will have to wait for the DVD 😉

Autodoc from Passengers film

With the Tricorder XPRIZE to be announced in a few months (which will automatically diagnose a set of 12 diseases ) I’m looking forward to an Autodoc being developed early in the 2030s – version 1 might not be able to fix everything but the majority of today’s illnesses really could be diagnosed and treated that quickly in the not too distant future.