Pseudoephedrine, an over-the-counter remedy for nasal and sinus congestion, was recently removed from the International Olympic Committee’s list of banned substances and placed on the monitoring programme because there was no evidence of an ergogenic effect. Now, however, a team of UK researchers have looked at the drug’s effects on 1,500m running performance and found that it reduced finish times by nearly six seconds, or 2.1%.

Seven male athletes completed two 1,500m running trials on an outdoor track under two conditions, one week apart. In one trial they took pseudoephedrine capsules, in a dose of 2.5mg per kg of body weight 90 minutes before they started the race; in the other they received identical-looking inactive capsules (placebo).

Blood samples were taken before and after the runs and analysed for various measures, including lactose and glucose concentrations and percent oxygen saturation.
The most important finding was that pseudoephedrine significantly reduced time to completion, by 5.8 seconds. This contradicts the findings of most previous studies into the effects of pseudoephedrine but the researchers put forward two possible explanations:

1. They used three times the normal therapeutic dose of the drug;
2. The drug was administered 90 minutes before exercise, when it is most likely to have an ergogenic effect.

Because blood lactate and glucose concentrations and oxygen saturation were not significantly affected by pseudoephedrine ingestion, the researchers exclude a purely metabolic mechanism and suggest that the drug worked by increasing central nervous system stimulation, so reducing perceived exertion.

‘Scientific research is clearly needed,’ they conclude, ‘to investigate the effects of ingestion of different doses of pseudoephedrine and different exercise intensities and duration and possible mechanisms for its ergogenic effect.’

Med Sci Sports Exerc 2006; 38(2):329-333