Exercise implications on life expectancy

What is the definition of “life expectancy”?

The World health Organization defines “life expectancy” as the average number of years that a newborn could expect to live if he/she was to pass through life exposed to the sex- and age-specific death rates prevailing at the time of his/her birth for a specific year, in a given country, territory or a geographic area (https://www.who.int/data/gho/indicator-metadata-registry/imr-details/65). Life expectancy at birth reflects the overall mortality level of a population. It summarizes the mortality pattern that prevails across all age groups. 

What are the determinants of life expectancy?

Life expectancy at birth, broadly depends on two main determinants according to Adler and Newman, 2002 (https://pubmed.ncbi.nlm.nih.gov/11900187/). Firstly, chance of surviving early years and secondly, the type of behavior engaged in and the external support system that people have access to. One of the main external support systems in most developed countries is the healthcare system. Importantly, healthcare outcomes in association with behavioral, social and other factors could influence life expectancy (Braveman and Gottlieb 2014, Dahlgren and Whitehead 1991).

Review of literature led to identification of seven potential determinants of life expectancy (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9650666/) such as 1) health care expenditures 2) health financing policies 3) elements of medical care 4) health habits and population health 5) social determinants 6) social spending and 7) other external factors. 

This article has two key aspects to explore of which one is “what are the top causes of mortality? The second aspect is how does exercise or active lifestyle impact mortality, thus life expectancy?

What is the correlation of life expectancy and mortality? 

The most commonly used indicator for analyzing mortality is life expectancy at birth, i.e. the mean number of years that a person can expect to live at birth subjected to current mortality conditions throughout the rest of their lives. Life expectancy originates from demography but is an often-used summary measure of mortality also in epidemiology and public health in general. (https://ec.europa.eu/eurostat/statistics-explained/index.php?title=Mortality_and_life_expectancy_statistics) 

What are the top causes of mortality and reduced life expectancy?

The top global causes of death, in order of total number of lives lost are associated with three broad topics: cardiovascular (ischemic heart disease, stroke), respiratory (chronic obstructive pulmonary disease, lower respiratory infections) and neonatal conditions which includes birth asphyxia, birth trauma, neonatal sepsis and preterm birth complications. 

The world`s biggest killer is ischemic heart disease, responsible for 16% of the world`s total deaths. This is followed by stroke which accounts for 11% and chronic obstructive pulmonary disease which accounts for 6% of total deaths (https://www.who.int/news-room/fact-sheets/detail/the-top-10-causes-of-death). It is important to know why people die to improve how people live. Measuring annual mortality helps to assess the effectiveness of our health systems and direct resources to where they are needed the most. While there are preventable measures to reduce mortality rates, we will focus on the role of exercise or physical activity in lowering mortality. 

How does exercise or active lifestyle impact mortality, thus life expectancy?

Regular physical activity reduces many major mortality risk factors including arterial hypertension, diabetes mellitus type 2, dyslipidemia, coronary heart disease, stroke and cancer (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1402378/). The relative risk of death is approximately 20% to 35% lower in physically active and fit persons compared to that in inactive and unfit persons. Physical inactivity represents a major independent risk factor for mortality accounting for up to 10% of all deaths in the European region (https://pubmed.ncbi.nlm.nih.gov/21181084/). Hence, because a 40% lower mortality rate corresponds to an approximately 5-year higher life expectancy one would expect an approximately 3.5-4.0-year higher life expectancy in physically active persons compared to that in inactive persons. (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3395188/#:~:text=All%20studies%20reported%20a%20higher,%3A%203.9%20%C2%B1%201.8%20years)

Exercise makes your muscles work and burn calories. Exercises are activities designed to improve physical fitness, enhance health and prepare the body to meet the demands of life. Physical activities like running, swimming, walking, jogging and dancing are often used synonymously with exercise. 

How does exercise improve physical health? 

1. Helps control weight – which in turn can help manage body mass index (BMI).
2. Strengthens muscles and bones – which helps reduce mortality causes due to trauma, prevention of osteoporosis and risks of fractures.
3. Helps control sugar and manage diabetes.

Helps manage cholesterol and atherosclerosis related conditions in the body – reduces the risks of cardio-vascular events and stroke. 

How does exercise improve mental health?

1. Exercise makes you feel happier – Exercising peoples brain release chemicals such as serotonin and endorphin which helps sleeping better and feel happier. 
2. Improves learning, thinking and judgement capabilities as you age – with exercise, the brain structure and function changes due to neuroplasticity which helps delay age-related mental decline.
3. Helps fight anxiety and depression – exercise acts in a way similar to anti-depressant medication, lowering inflammation, promotes nerve cell growth and blood flow in the brain.

How much exercise is recommended?

The WHO guidelines (2020) recommend at least 150-300 minutes of moderate to vigorous exercise each week for adults aged between 18-64 years.

This may be achieved by walking either 90 minutes 3 days/week or 30 minutes for 5 days/week. it is also recommended to engage in strength training at least twice a week. 

A July 2022 study shows that exercise and a healthy diet can individually reduce overall risk of mortality, but the largest risk reduction comes from doing both. The results published in the British Journal of sports medicine, show that those who frequently exercise and ate healthy had the lowest risk of mortality. The study authors also note that high levels of physical activity do not counteract the negative health effects of a poor diet and a healthy diet does not counteract health effects of a sedentary life. 

According to the researchers, the findings highlight the importance of both – healthy diet and regular physical activity emphasizing its importance on reducing the risk of mortality from all causes.