Life expectancy: healthy living helps beat the odds

Children are hard-wired to feel immortal, researchers say. Growing up does not make contemplating death much easier. But when curiosity or retirement planning dictates, statisticians — and official calculators — can provide an expert view. Despite a dismal decade for advances in longevity, many will be surprised by their life expectancy — and the very real chance of living to 100.

In the century to 2011, UK life expectancy increased by nearly three years every decade. That reflects astonishing advances in safety and health. Although women still outlive men by nearly four years, the gap has been gradually closing over the past 50 years as men smoke less and cardiovascular treatments improve.

However, these improvements have been tailing off since 2011. While a boost for public finances and life insurers, this may be a worrying sign of increasing deprivation. Worse, Covid-19 turned back the clock for male life expectancy at birth. The most recent projections put it at 79 years, seven weeks less than reported in 2015-2017.

This estimate uses a conservative measure. “Period” life expectancy assumes that current levels of mortality, recently unusually high, will continue for the rest of someone’s life. An alternative measure, “cohort” life expectancy, makes allowances for future changes in mortality. That paints a more encouraging picture, although it involves a lot of guesswork.

Another relatively cheerful approach is to consider the age at which people typically die. The most common age at death (the modal) is 86.7 for a man and 89.3 for women. The median age at death (half younger, half older) is at least three years below that. That, in turn, is several years higher than the mean age of death, also known as life expectancy at birth, which is more sensitive to childhood mortality.

Individuals can influence their lifespan. One study of nearly 500,000 middle-aged adults found that quitting smoking added nearly six years to a 45-year-old’s life expectancy. Exercising added nearly a year to women’s life expectancy, and double that for men. A healthy diet had less of an impact and alcohol intake made no meaningful difference, although that was possibly because of under-reporting.

Much comes down to chance, but people can make their own luck. There is no changing the destination, but a healthy lifestyle means it will take longer to get there.