For many people, there’s a big difference between their actual age and the age they feel, which is known as your “subjective” age. We begin to develop a difference between our subjective age and our actual age sometime during our 20s or 30s, and the gap tend to widen with as we get older. By the age of 50, most people in good health feel younger than their actual age—typically, about 15 percent younger. (For example, the majority of reasonably healthy 70-year-olds will tell you they feel about 55.)

Your actual age is based on your date of birth. Your subjective age—the age you feel—is based on how you think people your age should feel. So, if you feel better than you expected to feel at your age, your subjective age is likely to be younger than your actual age. If you feel worse than expected, you’ll probably feel older.

Your subjective age may vary from time to time, depending on what’s going on in your life. For example, if you’re sick or experiencing a lot of stress, you may feel a bit older than you did when everything was going well. But, generally—for most people—the subjective age remains fairly stable.

How old you feel can have a significant impact on your physical and mental health. Studies show that—all other things being equal at the start—adults who later on feel younger than their actual age tend to have more energy, sleep better, and have fewer risk factors for disease than those who feel older. Feeling younger than you actually are is also associated with a lower risk of depression, brain atrophy (shrinkage) and death.

There are many things you can do to make yourself feel younger—keeping yourself health being the most obvious. Our online program—AGELESS—will introduce you to a wide variety of things that make people feel younger. You’ll receive information, insights and assignments that can help you achieve this goal—up to 10 years younger in 10 weeks.