There is no guarantee that chronic risks will shorten your life, but they will reduce the number of years you can expect to live. Life expectancy for a man aged 22 in the UK is currently 79 years, which is an extra 57 years, 20,800 days, or 500,000 hours. That means that a young man has, on average, one million half-hours ahead of him, the same as a 26 year-old woman. Thirty minutes of your life expectancy is referred to as a microlife. Or, to put it another way, every time that young man or woman watches their favourite soap opera, it equates to one millionth of their life gone.
If you have unhealthy habits, it costs you microlives. If you smoke, each cigarette reduces your life expectancy on average by around 15 minutes, so two cigarettes loses you a microlife. With a 20-a-day habit you are losing 10 microlives, or five hours, so you could say you are accelerating towards your death at 29 hours for each day you live. Fortunately, improvements in healthcare and our environment mean that life expectancy has for decades been increasing by around three months for each year that passes: it is as if each day we all get a bonus of six hours of extra life – or 12 microlives – simply by virtue of living in the modern world. But a young adult who consistently drinks above minimal amounts will pay for it in microlives – around one for each seven units of alcohol. And for every extra 5kg you are overweight, it will cost you around one microlife a day.
There is one major difference between micromorts and microlives, however. If you survive your trip on the motorbike, then your micromort gets forgotten and you start the next day with a clean slate. But if you smoke and drink all day, and live on a fast-food diet, then your microlives will accumulate from day to day. It is like a lottery where the tickets you buy every day are kept in the running and so your chances of winning increase every day – except that this is a contest that you will be very keen not to win.