Here’s a paragraph you don’t come across very often in scientific papers:
“The Grim Reaper, the personification of death, is a well known [sic] 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.”
Very tongue in cheek – yet this study by Stanaway and colleagues was published in BMJ, not just any old journal! The introduction concludes with a description of the study:
“We assessed whether the relation between slow walking speed and mortality results from the increased likelihood of being caught by Death. […] We hypothesized we would be able to determine the walking speed of the Grim Reaper – information of importance to public health.”
Important to public health indeed! I’d recommend reading the whole article – it’s a very amusing read. But is it legitimate? Is it possible to literally out-walk Death?
How to determine Death’s walking speed
The researchers included 1705 men aged 70 or more in their Grim Reaper walking study (actually called the Concord Health and Ageing in Men Project, CHAMP), and followed them for 5 years. They measured the walking speed at baseline, and then ascertained any deaths in the follow-up period by questionnaires and the regional death registry.
They then determined the optimal walking speed cut-off point by statistical analysis. The best estimation of the Grim Reaper’s day-to-day pace was 0.82 m/s. Men with a faster walking speed than this were 1.23 times less likely to die. None of the study participants with walking speeds equal to or greater than 1.36 m/s died, so the researchers concluded that this was likely Death’s maximum speed. In other words this is the speed you should be aiming for to outrun Death.
Frailty vs. age – measuring the risk of treatment
Research has shown that gait speed can be a reliable predictor of serious morbidity and mortality both after cardiac surgery and overall. This is exactly the sort of tool physicians seek – a relatively simple test that will help them make an informed decision and give the best possible care. This is where the Grim Reaper’s walking speed comes in. Stanaway and colleagues note that the predicted walking speed of Death corresponds very closely to the gait speed associated with the median life expectancy (0.8 m/s) using data from diverse populations.
Providing good medical care to the elderly is often challenging. Treating physicians are faced with difficult choices – for instance, there may be a great potential benefit to cardiac surgery, but with a high risk of postoperative complications and poor recovery, it can be tricky to figure out if it is worthwhile overall. To the extent that it is possible, predicting whether a patient will benefit from a procedure or not is extremely useful. Frailty is increasingly a well-established prognostic tool for health outcomes in the elderly. This definition also includes slow walking speed in addition to shrinking, weakness, exhaustion and low physical activity.
As we’ve discussed before, health care providers are faced with a real challenge in maintaining the same quality of care as the population ages. This summer, CERG will be starting a large research study on exercise training and morbidity and mortality in the elderly, called Generation 100. Now, more than ever, is the time for preventative medicine.
Written by Hanna Sofie Ellingsen at CERG.