22.1 Lifespan, Life Expectancy, & Healthy Aging
Learning Objectives
- Explain the difference between life expectancy and lifespan.
Life Expectancy vs. Lifespan
Lifespan or maximum lifespan refer to the greatest age reached by any member of a given species (or population). For humans, the lifespan is currently between 120 and 125. Life expectancy is defined as the average number of years that members of a species (or population) live. According to the World Health Organization (WHO; 2019) global life expectancy for those born in 2019 is 72.0 years, with females reaching 74.2 years and males reaching 69.8 years. Women live longer than men around the world, and the gap between the sexes has remained the same since 1990. Overall life expectancy ranges from 61.2 years in the WHO African Region to 77.5 years in the WHO European Region. Global life expectancy increased by 5.5 years between 2000 and 2016. Improvements in child survival and access to antiretroviral medication for the treatment of HIV are considered the main reasons for this increase. However, life expectancy in low-income countries (62.7 years) is 18.1 years lower than in high-income countries (80.8 years). In high-income countries, the majority of people who die are old, while in low-income countries almost one in three deaths are in children under 5 years of age. According to the Central Intelligence Agency (2019) the United States ranks 45th in the world for life expectancy.
World Healthy Life Expectancy
A better way to appreciate the diversity of people in late adulthood is to go beyond chronological age and examine how well the person is aging. Many in late adulthood enjoy better than average health and social well-being and so are aging at an optimal level. In contrast, others experience poor health and dependence to a greater extent than would be considered typical. When looking at large populations, the WHO (2019) measures how many equivalent years of full health on average a newborn baby is expected to have. This age, called The Healthy Life Expectancy, takes into account current age-specific mortality, morbidity, and disability risks. In 2016, the global Healthy Life Expectancy was 63.3 years up from 58.5 years in 2000. The WHO African Region had the lowest Healthy Life Expectancy at 53.8 years, while the WHO Western Pacific Region had the highest at 68.9 years.
Life Expectancy in America
The overall life expectancy for a baby born in 2017 in the United States is 78.6 years, decreasing from 78.7 years in 2016 and 78.8 years in 2015 (Arias & Xu, 2019). The decrease from 2016 occurred for males, changing from 76.2 years to 76.1 years, while it did not change for females (81.1 years). Life expectancy at birth decreased by 0.1 year for the non-Hispanic white population (78.6 to 78.5). Life expectancy at birth did not change from 2016 for the non-Hispanic black population (74.9), and the Hispanic population (81.8). Before this unprecedented two-year decline, life expectancy had been