What is the human lifespan?

The average human lifespan varies significantly by geography, healthcare access, and socioeconomic factors, but globally it currently averages around 73 years, with substantial variation—ranging from the low 50s in some developing nations to over 85 in countries like Japan, Switzerland, and Singapore. This represents a dramatic increase from historical norms; for most of human history, average life expectancy at birth hovered between 25 and 40 years, held down by high infant mortality, infectious diseases, poor nutrition, and lack of medical knowledge. Modern advances in sanitation, vaccination, antibiotics, and medical care have more than doubled our expected years.

However, lifespan should be distinguished from the maximum human lifespan, which appears to have a biological ceiling around 120-125 years, with the oldest verified person, Jeanne Calment, living to 122 years. While average lifespan continues to increase in most countries, we haven't seen significant changes in this maximum threshold, suggesting fundamental biological limits related to cellular aging, DNA damage accumulation, and telomere shortening. Factors that influence individual lifespan include genetics (accounting for about 20-30% of variation), lifestyle choices like diet and exercise, environmental exposures, stress levels, and access to healthcare. Understanding that lifespan represents both species-wide patterns and individual variation helps contextualize discussions about aging, health policy, and the ongoing scientific effort to extend not just years of life but years of healthy, active living—a concept called healthspan.