By Katherine Menson, DO | University of Vermont Medical Center

Caffeine is everywhere around us: the stimulant is naturally present in a coffee, tea and chocolate and is synthetically added to sodas, energy drinks and over-the-counter supplements. However, some people may not realize that caffeine is actually considered a drug – and one that has been linked to respiratory care. In preterm infants, for example, it has long been used for the prevention of bronchopulmonary dysplasia.¹ In other lung-related applications, such as pulmonary rehabilitation, the benefit is less certain.

Its broad use, lack of toxicity at moderately consumed levels and accessibility makes caffeine one of the most readily used drugs in the world. It was first implicated during the 1980s as a possible treatment for pulmonary diseases that manifest in bronchoconstriction, based on case reports of therapeutic improvement in certain populations dating back to the 1800’s.^2,3 While these studies have permeated like folklore into management of respiratory diseases, it’s important to understand the facts as they relate to pulmonary health. Here’s what you need to know about caffeine as it relates to airway health and best practices:

What the Research Says

Scientists believe caffeine has multiple mechanisms of action; however, the suspected – but unverified – application in pulmonary disease appears to be inhibition of phosphodiesterase in smooth muscle, which in turn induces bronchodilation. One of its metabolites may sound familiar – theophylline – which is why the side effects of this medication overlap with the side effects of caffeine.⁴

Due to the historic interest in caffeine as a bronchodilator, a number of studies have been performed over the years to measure the effects of caffeine on asthma control and on pulmonary function testing. Cochrane’s most recent systemic review was performed in 2010, identifying seven randomized trials of 75 people with mild to moderate asthma in which the effects of caffeine versus placebo or decaffeinated products were measured. Caffeine at doses of <5 mg/kg were shown to provide a 5% mean difference in improvement in FEV1 two hours after consumption. Two of these studies found a much more significant improvement of 12-18% improvement in FEV1.⁵

Caffeine has been studied as an adjunct to exercise based on its stimulatory properties and benefits in coronary perfusion and bronchodilation, although some small studies have shown that this does not have a significant impact oxygen update (VO2) in moderate to heavy exercise.^6,7 Additionally, most patients in pulmonary rehabilitation have co-morbid disease, and caution should be given to interpreting any potential benefits seen in healthy adult volunteers.

Research on the impact of caffeine in COPD has been quite limited, and most studies investigating this association are confounded by tobacco use disorder. Findings have been mixed. A systematic review, for example, identified that coffee had no significant impact on the evolution of COPD; but one case control study found a higher risk of exacerbations with coffee consumption.⁸

Bottom Line

Ultimately, most major societies recommend against the use of caffeine in improving lung function. For one, the effects of caffeine are much more delayed and blunted compared to inhaled bronchodilators. Additionally, in the setting of SMART therapy for asthma, control of bronchoconstriction can be achieved with more novel approaches.

References

1. Yuan Y, Yang Y, Lei X, Dong W. Caffeine and bronchopulmonary dysplasia: Clinical benefits and the mechanisms involved. Pediatr Pulmonol. 2022 Jun;57(6):1392-1400. doi: 10.1002/ppul.25898. Epub 2022 Apr 5. PMID: 35318830.
2. Becker AB, Simons KJ, Gillespie CA, Simons FE. The bronchodilator effects and pharmacokinetics of caffeine in asthma. N Engl J Med. 1984 Mar 22;310(12):743-6. doi: 10.1056/NEJM198403223101202. PMID: 6700656.
3. Gong H Jr, Simmons MS, Tashkin DP, Hui KK, Lee EY. Bronchodilator effects of caffeine in coffee. A dose-response study of asthmatic subjects. Chest. 1986 Mar;89(3):335-42. doi: 10.1378/chest.89.3.335. PMID: 3948545.
4. Institute of Medicine (US) Committee on Military Nutrition Research. Caffeine for the Sustainment of Mental Task Performance: Formulations for Military Operations. Washington (DC): National Academies Press (US); 2001. 2, Pharmacology of Caffeine. Available from: https://www.ncbi.nlm.nih.gov/books/NBK223808/
5. Welsh EJ, Bara A, Barley E, Cates CJ. Caffeine for asthma. Cochrane Database Syst Rev. 2010 Jan 20;2010(1):CD001112. doi: 10.1002/14651858.CD001112.pub2. PMID: 20091514; PMCID: PMC7053252.
6. Chapman RF, Mickleborough TD. The effects of caffeine on ventilation and pulmonary function during exercise: an often-overlooked response. Phys Sportsmed. 2009 Dec;37(4):97-103. doi: 10.3810/psm.2009.12.1747. PMID: 20048546.
7. Bell C, Kowalchuk JM, Paterson DH, Scheuermann BW, Cunningham DA. The effects of caffeine on the kinetics of O2 uptake, CO2 production and expiratory ventilation in humans during the on-transient of moderate and heavy intensity exercise. Exp Physiol. 1999 Jul;84(4):761-74. PMID: 10481232.
8. Alfaro TM, Monteiro RA, Cunha RA, Cordeiro CR. Chronic coffee consumption and respiratory disease: A systematic review. Clin Respir J. 2018 Mar;12(3):1283-1294. doi: 10.1111/crj.12662. Epub 2017 Jul 7. PMID: 28671769.

Katie Menson, DO, sits on the AACVPR Board of Directors.