Ammonia Inhalants: Use, Misuse, and Role in Sports Performance.

Context: Ammonia inhalants, also known as smelling salts, are preparations of ammonia designed to treat fainting but more commonly used by athletes to boost awareness and arousal during competition. Despite their widespread use, the physiological and performance-enhancing effects of ammonia inhalants remain poorly understood. The aim of the present study was to review the current literature surrounding the benefits, risks, and physiological effects of ammonia inhalants.

Evidence acquisition: An extensive literature review of articles pertaining to ammonia inhalants was performed through MEDLINE and Google Scholar. The search terms "smelling salts," "ammonia inhalants," "strength," "performance," "head injury," and "concussion" were used.

Study design: Clinical review.

Level of evidence: Level 4.

Results: The physiological response to acute ammonia inhalation includes cerebral vasodilation and heart rate elevation without change in blood pressure. The existing evidence demonstrates an ergogenic benefit to ammonia inhalant use only during repeated bouts of high-intensity exercise; in these subjects, ammonia inhalation was associated with increased power as measured by the Wingate anaerobic test. In contrast, there is no performance benefit to ammonia inhalants in a short burst of maximal effort despite elevated arousal and an associated perception of performance enhancement. Importantly, ammonia inhalants have no role in medical management of head injuries, as they have the potential to exacerbate an underlying brain injury due to the involuntary withdrawal reflex associated with ammonia inhalation. Furthermore, the signs and symptoms of a concussion or more threatening head injury may be masked by ammonia inhalation and lead to continued participation in competition, causing additional harm.

Conclusion: Ammonia inhalants have no role in medical management of head injuries and have limited benefit with regards to sports performance.

Strength of recommendation: B.