Even a little running improves prognosis
Is running associated with a lower risk of all-cause, cardiovascular and cancer mortality, and is the more the better? A systematic review and meta-analysis (Br J Sports Med. 2019;0:1–9)
A little running has big health benefits, and lots of running may not do much more, researchers say.
Running has been long thought to improve cardiovascular health and longevity but there was uncertainty as to what training intensity and frequency is needed to achieve the desired effect. Some research even suggested J-shaped effect, with competitive long-distance runners having higher risk of medical complications including atrial fibrillation. A paper recently published in the British Journal of Sports Medicine by Professor Pedisic from Victoria University in Melbourne attempts to address some of these questions. Pedisic with colleagues analysed 14 studies with more than 200,000 participants and follow-up 5.5 to 35 years.
The meta-analysis confirmed benefits of regular exercise as expected but surprisingly showed that the amount and frequency of exercise can be much less than normally recommended by public health authorities.
The scientists found that running reduced all-cause mortality by 27%, cardiovascular mortality by 30% and cancer mortality by 23%. These impressive benefits can be obtained by as little as 50 minutes running weekly which is much less than in most guidelines. There was no additional benefit with increased frequency, speed or duration of running with the longest studied running time of 4.5 hours per week. The researchers were not able to quantify health benefits of less than 50 minutes of weekly running because that was the lowest amount of exercise in the analysed studies.
For comparison, the World Health Organization recommends at least 150 minutes of moderate exercise per week or 75 minutes of vigorous exercise per week. Pedisic stressed that the findings of their meta-analysis don’t necessarily mean that more running doesn’t provide more benefit; they were simply not able to prove that. Similarly, they haven’t found any evidence that very high intensity running leads to any harm; mainly due to difficulty of recruiting a sufficient number of high-volume runners to reach statistically significant conclusions. The study also didn’t look into differences between running and other forms of physical activity. The crucial difference will be however between doing nothing and getting up from the couch for some - even quite short - exercise.