Intuitively, we all recognize that there is a connection between how we live and how we die. It then makes sense that if we are stressed during our youth, it will have an impact on how we age and how fast that takes place. At the beginning of the 20th century, Rubner, a German physiologist came up with the idea of living beings having a fixed time for which a body can go on. His main hypothesis was that an organism could carry on an activity for a specific number of times and, after that time; wear and tear would cause it to fail. For example, the heart can beat only so many times before it will fail.
Using studies he conducted about the heartbeats, breaths and various parameters in animals, he calculated lifetime number of heartbeats, metabolic rate and other parameters. For example, an elephant with 35 beats per minute lives a lot longer than say a rat with 400 beats a minute (the rat uses up its allocation of heartbeats faster). He theorized that this was the real explanation why some species live longer than others. It was obvious that similar thinking could be applied to individuals within the same species to explain the difference in life span.
Subsequent studies and research have demonstrated the fallacies in Rubner’s hypothesis and it is not considered credible anymore. Modern theory is that it is the long-term exposure to various stress-response hormones that can accelerate aging.
One particular case is interesting and worth examining separately. This has to do with the release of glucocorticoids during stress. The brain controls the release of the glucocorticoids by secreting corticotrophin releasing factor (CRF), which, in turn, signals the pituitary to release the glucocorticoids. How does the brain decide when there are enough glucocorticoids in the blood?
The brain controls the release of CRF (and, in turn, the glucocorticoids) using a negative feedback loop. The portion of the brain that senses the levels of glucocorticoids is the hypothalamus. It turns out that older people have a damaged hypothalamus. This will account for the higher levels of glucocorticoids even ‘ during normal times.
It is like a leaky water tank and the feedback system is faulty. What could have caused the failure of the feedback system? The answer is not definite but the most likely culprit is the glucocorticoids during earlier chronic stress! This means that a lifetime of being exposed to gluco-corticoids will lead to hippocampal damage which will lead to more glucocorticoids being released in the bloodstream— a frightening cascade!