It is true that the cells of our body have a finite lifespan and that when they die, they are replaced by new cells. However, they don’t all do it at the same time.
As noted in the Science Desk Reference of the New York Public Library, we have between 50 and 75 trillion cells in the body. In addition, when the human body dies, it can take hours or even days for all the cells in our body to die.
Red blood cells have an approximate life of four months, while white blood cells live for about a year. The cells of the skin live for two to three weeks and, on the other hand, the cells of the colon die after about four days. Sperm live for about three days, while brain cells usually last a lifetime since neurons are not replaced when they die.
Also, nothing special happens in the body in a seven-year cycle, since cells are continually dying and replacing each other. For this reason, it should be clarified that the cells of our body are multifunctional and completely different from each other, so they are replaced at different rates. In other words, the human body is made up of cells of different ages.
The origin of this myth is unknown. However, some person may have added up all the lives of the cells in our body and assumed that they are renewed every seven years, a statement that is not true since This is a rough estimate. In fact, some cells renew in a matter of hours, while others do not regenerate throughout a person’s life.