IT'S THE season for road races and mini-marathons, but any of amateur runners who attempt to ward off pain by taking over the counter painkillers may be ill-advised.
The drugs may cause serious side-effects in these circumstances, says research published in the 'British Medical Journal'.
Many competitors try to prevent pain interfering with their performance by taking painkillers that are readily available in pharmacies and supermarkets.
In a bid to find out what impact these common drugs might have, the authors quizzed participants in the 2010 Bonn Marathon/Half-Marathon about their use of medication, and any symptoms they had during and/or after the race.
Of those who took painkillers before the race, one in five said they also used painkillers during training to curb or ward off pain; one-in-10 said they had pain symptoms before the start of the race. This compares with 1pc of those who didn't touch painkillers.
Withdrawal from competition because of stomach problems was significantly more common among those taking painkillers.
And while withdrawal as a result of muscle cramps was rare, it was significantly more common in those who had taken these drugs.
Runners who popped painkillers were five times as likely to experience symptoms as those who didn't take these drugs; the overall difference in risk was 13pc.
Symptoms included stomach cramps, cardiovascular problems, gastrointestinal bleeds, blood in the urine and joint and muscle pain.
The rate of symptoms rose in parallel with increasing dose.
One-in-10 of those runners taking diclofenac took over 100mg; 43pc of those who took ibuprofen, the second most popular choice, took doses of 800mg or more -- which is twice the recommended dose.