Anything that can go wrong will go wrong


The Grim Reaper, the personification of death, is a well known mythological and literary figure. Reported characteristics include a black cloak with cowl, a scythe, and cachexia. High quality scientific research linking the Grim Reaper to mortality has been scarce, despite extensive anecdotes.

Walking speed is a commonly used objective measure of physical capability in older people, predicting survival in several cohort studies. A recent meta-analysis found that being in the lowest fourth of walking speed compared with the highest was associated with a threefold increased risk of mortality. Moreover, the association between slow walking speed and mortality seems consistent across several ethnic groups and shows a dose-response relation. Although the association between walking speed and mortality has been well documented, the plausible biological relation between the two remains unclear.

We assessed whether the relation between slow walking speed and mortality results from the increased likelihood of being caught by Death. By assessing this relation using receiver operating characteristics curve analysis, we hypothesised we would be able to determine the walking speed of the Grim Reaper—information of importance to public health. […]

[1705] men have been followed for a mean of 59.3 months. Walking speed at baseline was not available in 77 men, mostly through inability to complete the test. A total of 266 deaths occurred during follow-up. […]

Based on receiver operating characteristics analysis and estimation of the Youden index, a walking speed of 0.82 m/s (2 miles (about 3 km) per hour) was most predictive of mortality. Therefore, we predict that this is the likely speed at which the Grim Reaper prefers to ambulate under working conditions. Older men who walked at speeds greater than 0.82 m/s were 1.23 times less likely to encounter Death. In addition, no men walking at speeds of 1.36 m/s (3 miles (about 5 km) per hour) or above were caught by Death (n=22, 1.4%). This supports our hypothesis that faster speeds are protective against mortality because fast walkers can maintain a safe distance from the Grim Reaper. Interestingly, the predicted walking speed of Death estimated in the present study is virtually identical to the gait speed (0.80 m/s) associated with median life expectancy at most ages and for both sexes in a recent meta-analysis of gait speed and mortality using data from diverse populations. This indicates that the preferred walking speed of the Grim Reaper while collecting souls is relatively constant irrespective of people’s geographical location, sex, or ethnic background.

{ British Medical Journal | PDF }