More than just annual birthday parties, wrinkles, and gray hairs, aging has two main components: primary aging, which is the natural process of senescence; and secondary aging, due to age-related diseases such as cancer, Alzheimer's, Parkinson's, osteoporosis, osteoarthritis, and macular degeneration.
Outside of gender (see next question) only 25% of lifespan variability is due to genetics; the rest depends on behavior and the environment.1 Habits such as smoking, excess drinking, and prolonged unprotected sun exposure reduce longevity; but researchers have implicated problems at the cellular and molecular levels as well. Oxidative stress, telomere shortening, build-up of DNA damage, mitochondrial deterioration, and insulin-receptor signaling all contribute to aging. Restricting calories increases the lifespans of mice and worms, but as for us, researchers are unsure.
While gender is a huge factor – over 90% of centenarians are women – lifestyle choices also play a role in passing the 100-year mark. Overall, centenarians ...
