Difference Between Lifespan and Life Expectancy

Lifespan vs Life Expectancy

Although the terms lifespan and life expectancy sound alike, there is an interesting difference between the two. There would be no single individual without the desire to live long, which is the same for animals, as well. Despite the fact that these terms are much common among people, their actual meanings may have missed. Therefore, it would be interesting to know what is meant by life span and life expectancy so that the difference between the two could also be understood.

What is Lifespan?

Lifespan or life span is the duration of time that one individual lives from its birth until the death. Lifespan could also mean that the duration of time from the origin until the termination of anything. Hence, this term applies to both life forms as well as abiotic forms. It is a common desire to go for the batteries with the longest lifespan. However, since it is composed of the term life, it would be proper to concentrate on the biological aspects of lifespan.

The lifespan of a blood cell is discussed based on the types of cells such as RBC, WBC, and Platelets. In addition, the lifespan of blood cells could vary from 5 – 200 days based on the function or the requirement of the body. The lifespan of the cardiac muscles in the heart is the same as the lifespan of the animal as those muscles are not replaced or regenerated.

The term lifespan can be used on cells, tissues, or organs. However, the most widely used aspect of the term is on individuals. The lifespan of dogs and cats vary with the breed, care, and the environment that they live. Additionally, it could be implied on populations, as well. Sometime the lifespan of a dead individual has also been discussed. Thus, it could be cleared out that this term has a versatile meaning as it could be used on many living and non-living entities.

What is Life Expectancy?

Life expectancy could be described as the remaining amount of time to live from a certain age, where the age could be any value. This term has been more commonly used in the human context than in the animals. Life expectancy is an expected value, and it could be calculated according to a mathematical (or a statistical) model. This term can make sense about the remaining time to live for a particular individual. Usually, the statistical models to calculate the life expectancy are based on life tables.

Life expectancy can never be definite as it is an average value of a data series. The human life expectancy values are different in one country from another as it varies with lifestyle factors and genetics. However, only about 20 – 30% of possibility had been proved to be affecting genetic factors for a low life expectancy, whereas lifestyle has about 70 – 80% of possibility to affect the life expectancy. The lowest life expectancy has been recorded from Swaziland (about 32 years) while Japan has the longest life expectancy with more than 82 years as per 2011. However, the general life expectancy of humans have been drastically increased with advances in medicine and technology despite the poor food habits.

Lifespan vs Life Expectancy

• Lifespan is the time between birth and death, but life expectancy is the time until the death from an age (or stage) of choice.

• Life expectancy is a guessed or expected number based on the statistical analyses, whereas lifespan is an observed value.

• Lifespan is more versatile than life expectancy.

• Life expectancy is mostly used for humans while lifespan can be used on anything.