What is life expectancy?
Life expectancy is the average number of years a person can expect to live, based on their age, sex, health and lifestyle. It is a statistic for a group of similar people, not a fixed date for any one person.
What affects how long you live?
Researchers have studied this for decades. While your genes set part of the stage, your everyday choices play a surprisingly large role. The factors with the strongest, most consistent evidence are smoking, physical activity, diet, body weight and chronic disease.
- Smoking is the single biggest lifestyle factor, and quitting at any age helps.
- Physical activity protects your heart, brain and muscles as you age.
- Diet rich in vegetables, fruit, whole grains and healthy fats lowers disease risk.
- Healthy weight reduces strain on your heart and lowers the risk of diabetes.
- Strong relationships are as protective for longevity as many physical habits.
How many years can you add?
This is the empowering part. These are rough estimates from longevity research of how much each healthy habit can add to your total lifespan.
| Healthy change | Potential years gained |
|---|---|
| Quitting smoking (especially before 40) | Up to 10 years |
| Regular physical activity | 3 to 5 years |
| A whole-food, mostly plant-based diet | 3 to 4 years |
| Reaching a healthy weight | 2 to 3 years |
| Strong social connections | Several years |
| Good sleep and low chronic stress | 1 to 3 years |
| Limiting alcohol | 1 to 2 years |
Lifespan versus healthspan
Living longer is only half the goal. The other half is your healthspan, the number of years you spend in good health, active and free from serious disease. The same habits that extend your life also add healthy, independent years.

