Senescence literally means "the process of growing old." It's defined as the period of gradual decline that follows the development phase in an organism's life. So senescence in humans would start sometime in your 20s, at the peak of your physical strength, and continue for the rest of your life.

The word "senescence" is derived from the Latin word senex, meaning "old age." In the longevity and healthy aging fields, senescence is the decline in health and function associated with aging. There are several sub-terms that will often come up, including cellular senescence and organismal senescence.

What Is Cellular Senescence?

When cells lose the ability to divide because of DNA damage or a shortening of telomeres, they go through a transformation that results in decline or destruction. The cells either self-destruct (called apoptosis) or go into a period of decline (called senescence).

The ultimate end result is cell death, which is a normal part of a biological functioning and occurs regularly in your body.

Cancer cells are thought to be cells that no longer undergo the process of senescence and instead, continue to replicate and cause problems (and tumors). In fact, researchers are working to develop therapies that cause cancer cells to begin aging more like normal cells — in other words, scientists want to induce normal senescence in these cells as a way of fighting cancer.

Your Body and Senescence

While cellular senescence may be a good thing because cells are continually replacing themselves, your body will eventually go into a period of decline known as organismal senescence (in other words, senescence of the organism).

As I said above, this process begins when your body is fully developed and you're at peak strength, and continues for the rest of your life. In this type of senescence, the accumulated damage to your body begins to interfere with the body’s ability to function. This interference causes the effects we often associate with aging.

Longevity, Healthy Aging, and Senescence

Science has not yet found a way to interrupt the process of senescence as it relates to humans, and some researchers (although not all by any means) argue that we never will be able to stop it.

But we can slow it down. Your goal, then, is to slow the process of senescence as much as possible. You can do this by:

• Eating a Healthy Diet: This provides your body with the nutrients it needs to repair damage and fight off future damage.
• Reducing Stress: This prevents long-term damage from over-exposure to the stress hormones and the physiological state they create.
• Avoiding Exposure to Damaging Substances: This helps limit the amount of damage to your body’s tissues. Avoid over-exposure to UV lights, pollution, and toxins.
• Exercising more: This helps your body to build strong tissues that resist damage.
• Preventing Disease: See your doctor for routine checkups and keep your blood pressure, weight and other risk factors under control.