A step too far?

There is little doubt that long-distance running improves our fitness, but new science is starting to suggest that there may be downsides to such punishing physical exertion.

During long runs the blood flow is redirected from organs to muscles. Among the consequences are damage to the small intestine and reduced kidney function. Routinely running long distances is now also believed to increase the risk of certain long-term health problems, notably cardiovascular ones. Middle-aged male athletes have been found to have more calcium deposits in their hearts than non-athletes, along with twice as many artery plaques to boot. After a run such as a marathon the immune system also becomes suppressed for a few hours.

Studies of female athletes suggest that they are less susceptible to such cardiovascular consequences, possibly due to the protective effects of oestrogen or lower testosterone levels.

All this doesn’t mean that a good run is not a healthy thing to do. But overdoing it may not bring all the benefits one may expect. Studies have indicated that running some 10 km a week is ideal, while athletes running more than 40 km a week gained no extra benefits while increasing the risks of certain conditions.

So the message from this piece of science seems to be yes, go for a run it’s a healthy thing to do, but don’t overdo it and give your body the chance to recover in between.