A unit of time, specifically of change in life expectancy, = 30 minutes. The British statistician David Spiegelhalter coined the term in 2012 to roughly quantify, in popular literature, the effect of various health practices.¹ One microlife is roughly equal to 1 millionth (hence the SI prefix “micro-”) of 57 years. Fifty-seven years is taken as roughly that portion of the average human life span during which one has some control over personal health practices.
The unit is meant to be used to compare common beneficial and non-benefical activities. For example, 20 minutes of daily exercise yields 2 microlives, and a diet with daily fruits and vegetables, 4 microlives. Negative values are also used, e.g., smoking two cigarettes a day costs -1 microlife.
1. D. J. Spiegelhalter.
Using speed of aging and “microlives” to communicate the effects of lifetime habits and environment.
BMJ 2012; 345 (17 December 2012)
A minor correction: BMJ 2012;345:e8676
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Last revised: 30 May 2015.