Has anyone ever told you that for every breath you take, you have one less breath on this Earth? While this may come up once in a while in the poetry of angst-ridden teens, it does ring true. It is an awfully depressing way to look at life, but it is one that when used right, can empower you to make the most of what you have.
Never mind the philosophy though, let’s get into the science, which I’m assuming you’re here for. Why do we have one less breath on this Earth for every breath we take? Can’t life just go on… indefinitely?
Now, your natural reaction to this question would be no. However, why? Why not?
This is because of… aging! Aging is a process that occurs within your body as a direct result of your genetics, lifestyle, and general physics. I’ll explain these 3 tenets in this article.
First, there’s genetics. Your genome is the collection of all your DNA. If you haven’t already learned from the 6 or so songs about DNA out there, it makes up who you are, and can code for anything from your hair color to variations in your tastebuds. There are some longevity genes out there, and having certain mutations within those genes can correlate in a positive or negative way with your longevity [1].
Stanford Medicine News Center. (2015, January 22). Telomeres on Chromosome [Illustration]. Stanford Medicine News Center. https://med.stanford.edu/news/all-news/2015/01/telomere-extension-turns-back-aging-clock-in-cultured-cells.html
Also, there’s epigenetics. Your epigenome is what controls how much certain genes are expressed, based on chemical tags altered by your environment and choices. Some genes can be expressed more with age, and some less, which influences your appearance, and health. Another thing it can influence is your lifespan, as certain genes perform more positive things for us, but are expressed less with age, and vice versa. This is being studied to create a clock to measure your internal organ age for now [2].
Another key part of aging is your lifestyle. Making positive choices can affect the amounts in which genes are expressed, by changing the chemical tags within your epigenome. For example, meditation can actually promote positive epigenetic change, which has been found to lead to less inflammation and reactive oxygen species (these are a hindrance toward longevity) [3]. Going on a bit of a tangent, reactive oxygen species are really unstable molecules, due to their lack of a pair for one of their electrons. If you imagine most molecules as mainly stable humans at a dinner party, these are the crazy aunts who are dancing on the table. However, most of the time, molecules strive to become more stable. In their quest, these molecules steal other electrons to pair with from other molecules, making others free radicals too! This can actually cause damage to your biomolecules. Also, another part of lifestyle, exercise has been found to reduce rates of premature death, and reduce hallmarks of aging [4].
Lastly, there’s physics. The second law of thermodynamics states that the total entropy of a given system cannot decrease over time, and that it can only increase. Entropy is the total indispensable energy of a system, and what this law is saying is that we can only lose potential over time. This applies to aging, as we lose the expression of positive genes, energy, mobility, and more over time [5]. Entropy represents a lot of youth in a way.
I titled this article “aging and the brain,” and I am darn well going to fulfill that. You may be wondering why the brain has not been mentioned once (except for in a reference to meditation), and that’s because I wanted to establish what aging was before we talked about the interaction.
There are so many neurodegenerative diseases (diseases involving the loss of neurons) that are associated with aging, like different types of dementia, Parkinson’s, and more. Clearly, the brain is implicated in aging. But how?
There is a whole phenomenon called brain aging. This is composed of several hallmarks, including neurodegeneration, dysregulation of calcium, mitochondrial dysfunction, and more [6].
Neurodegeneration, as was mentioned earlier, basically means the death of neurons. This can be associated with some aforementioned diseases, but it also happens in perfectly healthy aged brains as well.
Dysregulation of calcium is prevalent in aging brains, even though calcium is one of the most highly regulated ions in the brain. Maintaining homeostasis of different molecules in the brain is important, and this phenomenon disrupts that, causing changes in function [7].
Mitochondrial dysfunction is caused by the buildup of reactive oxygen species. These are molecules generated during cellular respiration and different processes the mitochondria runs, and they are highly unstable and reactive, causing damage to different biomolecules (DNA, RNA, proteins).
Shutterstock. (n.d.). Human Brain [Illustration]. https://medicalxpress.com/news/2018-11-neuroscientist-hidden-region-human-brain.html
Overall, brain aging is a fascinating phenomenon, and is an interesting explanation for why we have one less breath for every breath we take. These diseases are important to study and learn about, and I’d highly recommend reading more!
Citations
University of Haifa. (2017, August 22). Genetic mutation encourages longevity in men. ScienceDaily. Retrieved November 26, 2020 from www.sciencedaily.com/releases/2017/08/170822103432.htm
Horvath, S. (2013). DNA methylation age of human tissues and cell types. Genome Biology, 14(10), R115. https://doi.org/10.1186/gb-2013-14-10-r115
Venditti, S., Verdone, L., Reale, A., Vetriani, V., Caserta, M., & Zampieri, M. (2020). Molecules of Silence: Effects of Meditation on Gene Expression and Epigenetics. Frontiers in Psychology, 11. https://doi.org/10.3389/fpsyg.2020.01767
Garatachea, N., Pareja-Galeano, H., Sanchis-Gomar, F., Santos-Lozano, A., Fiuza-Luces, C., Morán, M., Emanuele, E., Joyner, M. J., & Lucia, A. (2015). Exercise Attenuates the Major Hallmarks of Aging. Rejuvenation Research, 18(1), 57–89. https://doi.org/10.1089/rej.2014.1623
Hayflick, L. (2007). Entropy Explains Aging, Genetic Determinism Explains Longevity, and Undefined Terminology Explains Misunderstanding Both. PLoS Genetics, 3(12), e220. https://doi.org/10.1371/journal.pgen.0030220
Peters, R. (2006). Ageing and the brain. Postgraduate Medical Journal, 82(964), 84–88. https://doi.org/10.1136/pgmj.2005.036665
Kumar, A. (2009). Susceptibility to calcium dysregulation during brain aging. Frontiers in Aging Neuroscience, 1. https://doi.org/10.3389/neuro.24.002.2009
Written by Nina Khera