David Spiegelhalter, from the University of Cambridge, has coined the concept of a “microlife,” defined as 30 minutes of life expectancy – as a practical substitution for the statistical concept of the hazard ratio. He computed that a million half hours — or 57 years — roughly corresponds to a lifetime of adult exposure to any given hazard. Further, he noted that at current mortality rates in the UK, a 35-year-old can expect to live another 55 years or 481,000 hours or very nearly a million microlives. Spiegelhalter has calculated that people may lose 30 minutes of life expectancy for every two cigarettes they smoke, for being 11 pounds overweight, and for eating an extra portion of red meat daily. Dr Spiegelhalter submits that this approach “allows a general, non-academic audience to make rough but fair comparisons between the sizes of chronic risks, and is based on a metaphor of ‘speed of ageing.'”
