Taking ibuprofen before exercising to prevent pain may appear harmless, but combining the drug with intense physical activity and dehydration can increase the risk of serious complications.

Spanish cardiologist Aurelio Rojas has warned against treating the common painkiller like a sporting supplement.

‘Ibuprofen before training could send you to hospital,’ he said.

Ibuprofen belongs to a group of medicines known as non-steroidal anti-inflammatory drugs, or NSAIDs.

These drugs reduce pain and inflammation by blocking enzymes involved in producing prostaglandins, substances which also help protect the stomach and maintain blood flow to the kidneys.

During intense exercise, blood is redirected towards the working muscles. Sweating and insufficient fluid intake can simultaneously reduce blood volume through dehydration.

Ibuprofen can further restrict the kidneys’ ability to maintain their blood supply, creating a potentially dangerous combination.

Official medical guidance warns that taking NSAIDs while dehydrated can prevent the kidneys from protecting themselves properly and contribute to acute kidney injury.

The risk is considered particularly relevant during prolonged endurance exercise, training in hot conditions or when someone is already dehydrated.

A randomised trial involving ultramarathon runners found higher rates of acute kidney injury among those given ibuprofen than among those receiving a placebo.

NSAIDs can also irritate the stomach, increase the risk of gastrointestinal bleeding and, particularly at higher doses or with prolonged use, raise the likelihood of heart attack or stroke.

Taking ibuprofen occasionally and at the recommended dose is not inherently dangerous for every healthy person.

But using it preventively before training can mask pain that would otherwise signal an injury and provides no guarantee of improved performance.