Speaking of age, we used to talk about our chronological age. Then scientists started talking about our biological age; in other words, about biomarkers that better predict functional capacity of our bodies than chronological age. Now they say that, because cells in our bodies regenerate differently, each of our organs is of a different age. Hence, it is totally impossible to say how old we are. See below to what extent our organs age differently.
A complete regeneration of our skin cells occurs within 14 days. New skin cells are formed in deep layers of dermis. Gradually they get closer to the surface and replace old cells. Our old cells die and slough off.
Skeletal muscles tissues are renewed every 15-16 years. How quickly cells in our muscles are regenerated depends on our age. The older we become, the slower is the process of regeneration.
All cells in skeletal tissues become renewed within 7-10 years. Usually, in our skeleton both new and old cells work together. Unbalanced diet might significantly worsen the regeneration process and influence the quality of new cells and, consequently, lead to health complications. Every day, our skeletal tissue generates thousands of millions of new cells.
A total regeneration of blood cells occurs during 120 or 150 days. If your body is healthy, your blood daily generates as many new cells as it loses. Roughly, every day your blood produces 500 billions of new cells performing different functions.
For long time, scientists thought that cells of heart tissues do not renew themselves at all. Yet new researches have shown that heart cells get fully regenerated once in twenty years.
Our crystalline lens and brain cells that absorb visual information are not renewed. The age of these cells are equal to our biological age. What is regenerated is cornea cells. Good news is that it takes cornea as little as 7 or 10 days to renew itself.
Hippocampus, that is, a part of the brain responsible for learning and memory regenerate their cells regularly. And so do the olfactory bulbs. What is important is that the more you physically exercise and the more you use, as Hercule Poirot says, your gray cells, the more often new neurons are built in these areas.