The term "longevity" is sometimes used as a synonym for "life expectancy" - however, the term "longevity" is sometimes meant to refer only to, especially long-lived members of a population, whereas "life expectancy" is always defined statistically as the average number of years remaining at a given age.

Life expectancy at birth has risen rapidly during the last century due to many factors, including reductions in infant mortality, rising living standards, improved lifestyles and better education, as well as advances in healthcare and medicine.


Economic development and the improvement in some environmental conditions (for example in many urban areas), improved lifestyles, advances in healthcare and medicine, including reduced infant mortality, have resulted in a continuous increase in life expectancy at birth during the last century.


Significant factors in life expectancy include gender, genetics, access to health care, hygiene, diet and nutrition, exercise, lifestyle, and crime rates. Evidence-based studies indicate that longevity is based on two major factors, genetics, and lifestyle choices.

Twin studies have estimated that approximately 20-30% of an individual's lifespan is related to genetics, the rest is due to individual behaviors and environmental factors which can be modified. In addition, it found that lifestyle plays almost no factor in health and longevity after the age of 80, and that almost everything in advanced age is due to genetic factors.
https://www.disabled-world.com/fitness/longevity/