Asthma and related respiratory problems are increasingly common in the general population and even more prevalent among athletes, as recent issues of Peak Performance have made clear (see PP193, February 2004 and PP195, April 2004). And the scientific journals are currently overflowing with articles about the signs, symptoms, causes and effects of these problematic and sometimes dangerous conditions.

Amateur athletes can take comfort from the latest evidence that they are at far less risk of respiratory problems than their élite counterparts. In a study carried out in the South of France, 95 amateur endurance-trained male athletes responded to a questionnaire about respiratory disorders and underwent resting spirometry – the standard diagnostic test for asthma⁽¹⁾.

The subjects, including long-distance runners, endurance trekkers, cyclists and triathletes, were all competing at regional level and training for a mean 10 hours per week, having been involved with their chosen sport for a mean of 8.5 years.

Four of these athletes (4.2% of the total) reported active diagnosed asthma and a further one had a previous diagnosis of exercise-induced bronchoconstriction (EIB), bringing the total affected by respiratory problems to 5.3% – much lower than the prevalence observed in élite endurance athletes and in the same range as the general population in France.

The researchers acknowledge that their results might have been skewed by the non-inclusion in their study of female athletes, who are thought to be at higher risk of asthma and EIB than men.

The balmy Mediterranean climate might also have been a factor, since it is cold dry air that particularly predisposes to asthma. The researchers conclude that: ‘training 10h per week in a temperate climate does not put athletes at high risk for asthma or EIB’.

The prevalence of asthma among élite would-be Olympians is three times greater than the French researchers observed, according to the findings of an Italian study⁽²⁾. The researchers in this case aimed to assess the prevalence of asthma and atopy (allergy) in athletes who were trying for a position on the Italian Olympic team for the 2000 Games in Sydney.

A total of 1,060 athletes (male and female) were divided into three groups of sport activities:

1. Anaerobic – speed and power sports;
2. Aerobic-anaerobic – football, basketball, tennis, handball;
3. Aerobic – long-distance running, swimming, cycling, rowing.

Asthma and atopy were diagnosed by means of self-administered questionnaires, followed up by spirometry in athletes who reported wheezing or asthma and in an equal number of randomly selected controls.

Athletes reporting wheezing or asthma represented 15% of the total sample, although only a minority of these had moderate or severe disease, and the prevalence of atopy was 18%.

The study also showed a significantly higher prevalence of asthma and related respiratory problems among aerobic athletes (particularly swimmers) than those in the other two groups – with more than 20% affected by wheezing or asthma compared with just over 10% in the other two groups.

Worryingly, a significant impairment of lung function was found even in athletes suffering from mild and rarely troublesome asthma. ‘Future research,’ conclude the researchers, ‘needs to assess whether or not this impairment can decrease the athletic performance in spite of a constant training and a presumably high threshold for symptoms.’

More worrying still is the prevalence of exercise-induced respiratory problems among élite ice hockey players. US researchers examined resting lung function and asthma-like symptoms in relation to hyper-responsiveness of the airways in 43 élite women ice hockey players who participated at National Team level between 1999 and 2001.

Asthma-like symptoms were present in 17 of these athletes (a staggering 39.5%), although only nine (21%) had lung function test results consistent with EIB.

The fact that the asthma-like symptoms correlated with low baseline lung function but not necessarily with airway reactivity suggests the existence of more than one causative factor.

The researchers point to a growing body of evidence suggesting that the high prevalence of airway dysfunction in ice rink athletes is linked to chronic exposure to airborne ultrafine and fine particulate matter (PM1) emitted from internal combustion fossil fuelled ice resurfacing machines.

‘We propose,’ they conclude, ‘that EIB in ice rink athletes is a unique respiratory syndrome that is heterogeneous in nature, affecting the asthmatic and nonasthmatic skating athlete, with the likely trigger being high deposition of PM1 in the peripheral airways resulting from chronic high exercising ventilation exposure. The precise mechanism of this syndrome is yet to be elucidated.’

1. Int J Sports Med 2004;25:130-132
2. Int J Sports Med 2003;24:139-144
3. Med Sci Sports Exerc, vol 36, no 3, pp405-410