Lifespan ≠ Healthspan — Human Longevity
83 Years. That’s the average lifespan of a Canadian. That may seem like a long time to be alive; but how many of those years do we actually spend as a healthy person?
What is your healthspan? That might seem like an unfamiliar word. But arguably, it’s even more important than lifespan — so let’s take a look at what it is.
Healthspan is the percentage of your life that you spend in “good condition.” In your “optimal health.”
But once again, what does that really mean?
Essentially, your lifespan is the amount of time you spend, well, alive; and healthspan is the amount of your lifespan that you spend healthy.
Unfortunately for us, as we age our bodies become weaker, and we fall ill more easily. We don’t spend out entire life being healthy, and that’s why our healthspan is not equal to our lifespan.
Human longevity — As we know it
Since the beginning of time, humans have been obsessed with the idea of living forever. This lead to some serious innovation like modern medicine.
There are so many factors that contribute to why we age, and why that age comes with health consequences. But to understand how to extend our lifespan, we first need to understand how to increase our healthspan.
The equation then becomes: higher healthspan ⇢ higher lifespan.
Let’s get down to the factors that decrease your healthspan:
- Senescent cells
- Lack of NAD+
- Lack of stem cells
How do these impact our healthspan?
Senescent cells
Senescent cells were once normal cells. They fulfilled their function and divided as normal cells do. Senescent cells idle in our systems as we age. They send out signals so that they immune system can come clean them up, but as we age — the signals get weaker and the immune system stops responding. These signals encourage the other cells to become senescent.
Senescent cells don’t contribute any value to your body and have many negative repercussions such as damaging and inflaming surrounding cells + tissue.
So what caused them to become senescent?
These cells are caused by our telomeres being run down. Telomeres are the cap at the end of our DNA strands that gets run down every time a cell divides. This is useful as the telomeres protect vital DNA. They are quite similar to the plastic cap at the end of your shoelace.
Senescent cells can be destroyed by senolytics — drugs that works to eliminate these cells from the body. A company called Senolytics Therapeutics is developing an innovative range of senolytics, as they vary depending on the targeted location (heart vs. liver). You can learn more about their company here.
By eliminating senescent cells, we can slow down aging and prevent diseases.
Lack of NAD+
NAD+ (short for Nicotinamide Adenine Dinucleotide) regulates bioenergy and helps turn nutrients into energy. It works by binding onto other enzymes to cause reactions, just like a mosquito has to prick you to suck your blood, and afterwards (the reaction) you’ve got a bump on your arm.
However, unlike mosquitos, NAD+ is really good for your body. But… it comes with a catch. It declines with age.
Fortunately for us, multiple companies are coming out with NAD+ vitamins, face creams.
NAD+ becoming accessible is huge for increasing our healthspan as two of the most important benefits of this product are DNA repair, and eliminating stress-induced apoptosis(cell death).
Lack of stem cells
I’m sure that someone somewhere has mentioned stem cells before. I’m just here to reinforce that they are the most adaptable of all the cell variations.
Why are stem cells so special?
They are unspecialized cells. That means that they can become virtually any type of cell.
There are two types of stem cells
- Embryonic stem cells
- Adult stem cells
While embryonic stem cells have the ability to specialize and become any other type of cell, adult stem cells can only become certain types of cells.
Stem cells decrease with age, and therefore your body becomes weaker — as it doesn’t have the means to repair itself using its own cells.
Many researchers are looking into 3D bio-printing to help create stem cells, as they can heal almost any issues that the body has, and will increase human healthspan as we age.
The ethics of longevity
At the end, all it really comes down to, is 3 main questions…
- Is it theoretically and technologically possible?
- How will it affect the availability of resources for the population?
- Should we pursue the goal of life extension?
Questions 1 & 2 are hard to answer because we don’t have enough data to support a definite answer.
Question 3 however can be left completely up to your opinion. Cultural beliefs and spiritual beliefs are some of the most common factors that clash with increasing the human lifespan.
John Harris a bioethicist at the University of Manchester summed up the biggest portion of the dilemma quite nicely.
“People would either have to stop thinking that saving lives is important, or they’ll have to stop thinking that there is something wrong with deliberately bringing about death at a certain point.” — John Harris on LiveScience
Key takeaways
- Humans have been working on ways to increase our healthspan, and are hoping that in turn it increases out lifespan.
- Senescent cells cause inflammation but can be treated with senolytics.
- NAD+ is responsible for DNA repair, turning nutrients into energy, and eliminating apoptosis due to stress. NAD+ levels decrease as we age but we can take tablets as supplements.
- Stem cells are unspecialized cells that can become any other type of cell but the amount our body has decreases with age. Scientists are working on being able to 3D bio-print stem cells.
- The ethics of humans living longer is being debated.
Got questions? Send me an email: haileyvallabh003@gmail.com
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