If you want proof of the extent to which stress can affect the aging process, you simply have to take a look at a U.S. president before he takes office and when he leaves.  Knowing this makes researchers even more determined to find ways to deal with stress.

Organs such as the heart, liver, and kidney are critical components of the human body. And similar to the critical components of man made products like automobiles, buildings, and so on - wear and tear on them has a cumulative effect. When we’re stressed out, our heart rate increases, our blood pressure goes up, and our adrenal glands flood our bloodstream with hormones. If this series of events happens occasionally, no real harm is done to the body. But if the stress is never ending, real damage begins to happen to the components inside of our bodies.

Think of the starter switch of a car. Every starter switch in a car has a more or less pre-determined life span range. On a normal day of driving our car we start it by triggering the starter switch three to six times a day. When we go to work, when we come home, and maybe during a few errands that we run throughout the day. This is normal use and our starter switch will last for years under normal use. Now imagine how long that switch would last if you were to turn your car on, but instead of releasing the ignition switch when your car starts, you continue to turn your starter switch. You’ll be lucky if the starter switch lasts a day.

Well, habitual stress in our bodies has a related effect. Biologists have theorized that, similar to that starter switch, each cell in the human body has a programmed and pre-determined life span. And when that life span has expired, the cell chromosomes will no longer work and the cell will die. When the body is under prolonged stress. it is persistently activating the “fight-or-flight” responses in the body. Said differently, the starter switch has been turned on and left on. The theory is that it is this constant stress that ages the body. But how? The answer is the telomere.

The region of repetitive DNA at the end of chromosomes is called a telomere. It protects the end of the chromosome from destruction. The telomere is also involved in the replication of cells. Each time a cell divides, the telomere is shortened. Eventually the length of the telomere becomes so short that it can no longer divide. At this point the cell dies. Recent studies have shown that chronic stress tends to accelerate the shortening and shriveling of the telomere, directly causing the body to age faster. The greater the level of chronic stress, the faster the body’s cells die and the faster the body gets wrinkles, weakened muscles, frailer bones, poorer eyesight, and other typical signs of aging.

Scientist can now actually measure a cell’s age by looking at its chromosomes. This means that they can measure, at a cellular level, the damage that stress is having on the cell’s chromosomes. Though more studies are needed to confirm this, one theory is that it is the high levels of stress hormones in the body, particularly cortisol, that is doing damage to the telomeres.

For a long time there has been an association between chronic stress and increased risk of major chronic diseases such as high blood pressure, heart disease, and diabetes. There now appears to be a direct link, as well, between chronic stress and premature aging in otherwise healthy people.