Recreational SCUBA diving is popular with estimates of more than 3 million people in the US alone certified and more than 200,000 diving instructors worldwide. Based on 2016 data from certifying agencies and published in 2018, the average fatality rate with recreational diving is 1.8 per 100,000 divers per year (1)
There are several questions in the Ask the Expert archives related to scuba diving and asthma. One is copied below.
There are several reasons diving with compressed air could be a risk for subjects with asthma. The compressed air is cool and dry, increasing the possibility of exercise induced bronchospasm during the dive. Airway constriction could affect the distribution of exchanged air within the lung, increasing the possibility of pressure variation both in the descent and ascent. Pressure disequilibrium within the lung increases the risk of barotrauma and pneumothorax. Despite these concerns, the experience of recreational diving in subjects with asthma has not resulted in convincing evidence of a much greater risk in asthma. A systematic review of the literature in 2017 concluded that “there are indications that recreational divers with asthma may be at increased risk for diving-related injuries compared to non-asthmatic divers. However, it is of at most importance to obtain further evidence from large-scale, well-designed studies (2).” I provide a few other references for your review (3-5).
In summary, there is likely an increased risk of barotrauma with SCUBA diving with active asthma, increasing the risk from 1.8 fatalities per 100,000 divers per year. Well controlled asthma is likely not a significant risk based upon the experience of recreational divers with asthma. Reduced mid-expiratory may be an indicator of increased risk (3). The decision as to whether to dive or no-dive would be based upon degree of risk aversion preferred by the individual and regulatory/certifying agencies. I would encourage that albuterol be used before the dive, and the peak flow should equal or approximate the personal best. SCUBA diving should not be considered if asthma is not well controlled.
1. DAN Annual Diving Report 2018 Edition: A Report on 2016 Diving Fatalities, Injuries, and Incidents, Buzzacott P, Denoble PJ (Eds), Divers Alert Network, Durham (NC) 2018.
2. Are recreational SCUBA divers with asthma at increased risk? Ustrup AS, Ulrik CS, J Asthma. 2017;54(8):784. Epub 2016 Dec 1.
BACKGROUND AND OBJECTIVE Asthma has traditionally been regarded as a contraindication to self-contained underwater breathing apparatus (SCUBA) diving, although large numbers of patients with asthma dive. The aim of the review is to provide an update on current knowledge on potential disease-related hazards in SCUBA divers with asthma.
METHODS Systematic literature review based on the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines.
RESULTS Seven studies met the criteria for inclusion in the review (comprising a total of 560 subjects). Five studies reported an increased risk for developing diving-related injuries in divers with asthma, based on case reports (n = 1), case history combined with objective assessment (n = 1), and dives and/or simulated dives (n = 3). The remaining studies (n = 2) were based on self-reported diving habits in divers suffering from asthma, obtained from anonymous questionnaires in diving magazines, reported no diving-related injuries among respondents.
CONCLUSION Due to limited evidence it is difficult to draw valid conclusions, but there are indications that recreational divers with asthma may be at increased risk for diving-related injuries compared to non-asthmatic divers. However, it is of at most importance to obtain further evidence from large-scale, well-designed studies.
3. Diving: what to tell the patient with asthma and why? Krieger BP, Curr Opin Pulm Med. 2001;7(1):32.
Until a decade ago, divers with asthma were uniformly barred from diving with compressed air. This prohibition was based more on theoretical concerns for barotrauma than on actual data. Follow-up studies, although retrospective, do not support a ban on recreational or commercial diving for divers with stable asthma. These studies have noted that, despite the prohibition on diving, many divers with asthma have logged multiple dives without negative consequences. When those who have suffered diving-related barotrauma have undergone physiologic testing, measurements of small airways dysfunction (maximal mid-expiratory flow rates) have been lower than measurements for comparable divers who have never suffered diving accidents. Follow-up studies with long-term commercial divers have shown that a small percentage of individuals who have sufferred diving-related barotrauma also develop abnormal maximal mid-expiratory flow rates and even some airway hyperreactivity. These latter findings correlate with the changes that occur in chronic asthmatic patients, especially those who are not well treated. The decision as to whether an asthmatic patient should be allowed to dive rests on the individual's physiologic function, maturity, and insight into the consequences of poorly managed airway inflammation and bronchospasm.
4. Pulmonary barotrauma in divers: can prospective pulmonary function testing identify those at risk? Bove AA, Chest. 1997;112(3):576.
5. A review of asthma and scuba diving. Tetzlaff K, Muth CM, Waldhauser LK, J Asthma. 2002;39(7):557.
An increasing number of asthmatics participate in recreational scuba diving. This activity presents unique physical and physiological challenges to the respiratory system. This review addresses the susceptibility of divers with asthma to diving accidents, acute asthmatic attacks, and long-term exacerbation of their disease. Recommendations on fitness to dive with asthma and airway hyperresponsiveness are provided.
I hope this information is of help to you and your practice.
All my best.
Dennis K. Ledford, MD, FAAAAI
5/6/2013: Asthma and scuba diving
Are there any updated, formal or informal, policies regarding scuba diving in asthmatics? I cannot find any recent recommendations.
The last guidelines (actually a report of the scuba committee of the AAAAI) on scuba diving I am aware of were published in 1995. But you might find the reviews of this issue cited below helpful.
The most recent review article on scuba diving of which I am aware was published in 2007. In the last decade there have been several other informative reviews however, and I have copied abstracts of these for you below. As noted, to my knowledge, no information has been published in this regard since 2007, and I could not find any with a literature search. I hope, however, that these are of help to you.
Harefuah. 2007 Apr;146(4):286-90, 317. [Asthma and scuba diving: can asthmatic patients dive?]. [Article in Hebrew] Sade K, Wiesel O, Kivity S, Levo Y.
Department of Medicine 'T', Sourasky Medical Center, Tel Aviv University, Tel Aviv, Israel.
Self-contained underwater breathing apparatus (scuba) diving has grown in popularity, with millions of divers enjoying the sport worldwide. This activity presents unique physical and physiological challenges to the respiratory system, raising numerous concerns about individuals with asthma who choose to dive. Asthma had traditionally been a contraindication to recreational diving, although this caveat has been ignored by large numbers of such patients. Herein we review the currently available literature to provide evidence-based evaluation of the risks associated with diving that are posed to asthmatics. Although there is some indication that asthmatics may be at an increased risk of pulmonary barotrauma, the risk seems to be small. Thus, under the right circumstances, patients with asthma can safely participate in recreational diving without any apparent increased risk of an asthma-related event. Decisions on whether or not diving is hazardous must be made on an individual basis and be founded upon an informed decision shared by both patient and physician
Clin Rev Allergy Immunol. 2005 Oct;29(2):131-8. Asthma and the diver. Davies MJ, Fisher LH, Chegini S, Craig TJ.
Department of Asthma, Allergy, and Immunology, The Pennsylvania State University, Milton S. Hershey Medical Center, Hershey, PA, USA.
Self-contained underwater breathing apparatus (scuba) diving has grown in popularity, with nearly 9 million sport divers in the United States alone. Approximately 7% of the population has been diagnosed with asthma, which is similar to the percentage of divers admitting they have asthma. Numerous concerns exist regarding subjects with asthma who choose to participate in recreational diving. Among these concerns are pulmonary barotrauma, pneumomediastinum, pneumothorax, arterial gas embolism, ear barotrauma, sinus barotrauma, and dental barotrauma. Despite these concerns, a paucity of information exists linking asthma to increased risk of diving complications. However, it has long been the norm to discourage individuals with asthma from participating in recreational scuba diving. This article examines the currently available literature to allow for a more informed decision regarding the possible risks associated with diving and asthma. It examines the underlying physiological principles associated with diving, including Henry's law and Boyle's law, to provide a more intimate understanding on physiological changes occurring in the respiratory system under compressive stress. Finally, this article offers a framework for guiding the patient with asthma who is interested in scuba diving. Under the right circumstances, the patient with asthma can safely participate in recreational diving without apparent increased risk of an asthma-related event.
Curr Sports Med Rep. 2005 Oct;4(5):275-81. Controversies in the medical clearance of recreational scuba divers: updates on asthma, diabetes mellitus, coronary artery disease, and patent foramen ovale. Harrison D, Lloyd-Smith R, Khazei A, Hunte G, Lepawsky M.
Department of Family Practice, Student Health Service, University of British Columbia, M334-2211 Wesbrook Mall, Vancouver, British Columbia V6T 1Z3, Canada.
Primary care and sports medicine physicians are frequently consulted on medical clearance for prospective recreational divers. We discuss four common and controversial medical conditions--asthma, diabetes mellitus, coronary artery disease, and patent foramen ovale--as they relate to fitness to dive. For each condition we review the relevant anatomy and physiology, current recommendations, and the pertinent medical literature. Finally, we offer evidence-based recommendations regarding fitness to dive for potential divers with these conditions.
Sports Med. 2003;33(2):109-16. Asthma and recreational SCUBA diving: a systematic review. Koehle M, Lloyd-Smith R, McKenzie D, Taunton J.
Allan McGavin Sports Medicine Centre, Department of Family Practice and the School of Human Kinetics, University of British Columbia, Vancouver, British Columbia, Canada.
Asthma has traditionally been a contraindication to recreational self-contained underwater breathing apparatus (SCUBA) diving, although large numbers of patients with asthma partake in diving. The purpose of this paper is to review all the research relevant to the issue of the safety of asthma in divers. MEDLINE and MDConsult were searched for papers between 1980-2002. Keywords used for the search were 'asthma', 'SCUBA' and 'diving'. Additional references were reviewed from the bibliographies of received articles.A total of fifteen studies were identified as relevant to the area. These included three surveys of divers with asthma, four case series and eight mechanistic investigations of the effect of diving on pulmonary function. The survey data showed a high prevalence of asthma among recreational SCUBA divers, similar to the prevalence of asthma among the general population. There was some weak evidence for an increase in rates of decompression illness among divers with asthma. In healthy participants, wet hyperbaric chamber and open-water diving led to a decrease in forced vital capacity, forced expired volume over 1.0 second and mid-expiratory flow rates. In participants with asymptomatic respiratory atopy, diving caused a decrease in airway conductivity. There is some indication that asthmatics may be at increased risk of pulmonary barotrauma, but more research is necessary. Decisions regarding diving participation among asthmatics must be made on an individual basis involving the patient through informed, shared decision making.
Phil Lieberman, M.D.