Adventure travelers with asthma should be especially wary of asthma exacerbations, according to a study in the Archives of Internal Medicine. Researchers interviewed 203 people with asthma who visited 56 countries on adventure vacations. Of this group, 147 people engaged in high-altitude trekking. A total of 88 people experienced asthma attacks during their trips. These attacks were rated as the worst ever by 32 people and as life-threatening by 11 people. Researchers identified 2 risk factors for asthma attacks during travel: use of inhaled bronchodilators 3 or more times per week before travel was linked to a more than 3-fold risk for an attack, and participation in intense physical exertion during treks raised the risk 2-fold. The study authors concluded that asthma therapies should be intensified before embarking on adventure trips in order to achieve adequate control. They also suggested that asthmatics should be discouraged from intense trekking.