Running – the side effects

Last time I discussed the prescribing of exercise, particularly running. I mentioned that Dr Margaret McCartney had written a BMJ article objecting to the “prescription” of running as though it were a drug. I believe that she is wrong and that prescribing exercise is much the same as prescribing a drug.

One similarity is that side-effects may result from either.

Running injuries

Most runners sooner or later suffer leg, knee, calf, ankle or foot pain. These are lessened by such precautions as wearing good, well cushioned running shoes, building up both distance and speed gradually, not running too frequently, taking regular rest days, plus warming up and cooling down.

All runners are at risk of such injuries as hamstring sprain, ilio-tibial band syndrome, patello-femoral pain (runner’s knee), shin splints, ankle sprain, achilles tendinopathy, plantar fasciitis. This sounds a formidable list – indeed about 50% of runners suffer an injury of one sort or another each year. However most of these are minor and quickly resolve with a short period of rest. More prolonged rest is needed for stress fractures, plantar fasciitis and shin splints. Occasionally they make the would-be runner become an ex-runner.

Older exercisers are  particularly prone to knee pain, often due to osteo-arthritis (wear and tear) of the knee(s). There is a common misconception that running damages the knee joint – but the opposite is true. Regular running should actually improve knee joint function  – the repeated impact can strengthen the knee cartilages. Injuries to the knee involving twists and ligament tears from other sports such as football, squash and skiing do cause long-term joint problems and are often to blame for osteoarthritis of the joint in later life.

Exercise addiction

Although not much discussed this is a fairly common disorder in habitual runners. It is characterised by taking excessive amounts of exercise to the detriment of physical health, spending so much time exercising that both personal and professional life are damaged, and exercising regardless of physical injury. Exercise addiction is often associated with eating disorders. Of all sporting activities, distance running is the most likely to be associated with exercise addiction – affecting between 10% and 15% of serious runners.

Running deaths

While injuries are normal for runners, death is extremely uncommon. However there has been a flurry of papers recently about this rare, though notorious event. While injuries affect 50% or more of runners each year, the risk of death is estimated as about 1.5 per 100,000 runners in marathons and half marathons. This hardly compares with the risk from taking common medications. “Our prescription drugs are the third leading cause of death after heart disease and cancer in the United States and Europe.”

Sudden death while running is nearly always due to cardiac arrest, usually ventricular fibrillation (VF). VF is the abnormal rhythm in which the heart muscle fibres lose their coordinated contraction and blood can no longer pumped round the system. Death follows rapidly unless cardiopulmonary resuscitation (CPR) is started as soon as possible followed by defibrillation – the electric shock which restores normal heart rhythm. Cardiac arrest in older runners is most commonly due to coronary heart disease and in younger runners to inherited cardiac abnormalities, mainly hypertrophic cardiomyopathy.

Although cardiac arrest  is a rarity in any sporting endeavour, it is usual for the organisers of long-distance races to be well trained in CPR and to have defibrillator(s) as part of their standard equipment.

A study of nearly 30 million marathon and half marathon runners in the US between the years 2000 and 2023 found 176 cardiac arrests – 1.12 per 100,000 in men and 0.19 per 100,000 in women. The widespread availability of defibrillators for such occasions has seen a considerable fall in the mortality from cardiac arrest – from about 71% before 2010 to 34% since 2010. In other words two thirds of those who suffer a cardiac arrest during long distance races are now successfully resuscitated. This can be attributed to better by-stander CPR and the availability of defibrillators.