Cannabis Has No Effect on Exercise Performance, Breathlessness in COPD, Study Says

The use of inhaled vaporized cannabis neither improved nor worsened exercise performance and activity-related breathlessness for patients with advanced chronic obstructive pulmonary disease (COPD), according to a recent trial published in the Annals of the American Thoracic Society.

The researchers originally hypothesized that inhaled vaporized cannabis would alleviate exertional breathlessness and improve exercise endurance by enhancing static and dynamic airway function in those with COPD. To test this, the researchers conducted a randomized controlled trial of 16 adults with advanced COPD and compared the acute effects of 35 mg inhaled vaporized cannabis with a 35 mg of a placebo control cannabis.

“Amidst widespread changes in the regulatory landscape of recreational and medicinal use of cannabis, there has been a growing interest in understanding the therapeutic potential of its main cannabinoid constituent, delta-9 (∆9)-tetrahydrocannabinol (THC), which provides symptomatic relief of acute and chronic pain across a range of malignant and non-malignant diagnoses,” the authors stated.

The effects of the cannabis on physiological and perceptual responses during cardiopulmonary cycle endurance exercise testing were recorded, along with the effects on spirometry and impulse oscillometry (iOS) at rest, cognitive function, psychoactivity, and mood.

When compared with the control, the results revealed that the cannabis had no effect on breathlessness intensity ratings during exercise at isotime; exercise endurance time; cardiac, metabolic, gas exchange, ventilatory, breathing pattern and/or operating lung volume parameters at rest and during exercise; spirometry and iOS-derived pulmonary function test parameters at rest; and cognitive function, psychoactivity, and mood.

"We first became aware of the therapeutic potential of cannabis in managing COPD symptoms from patients themselves," Sara J. Abdallah, PhD candidate in exercise physiology and study co-author, said in a statement. "We decided to pursue this study because patients were reporting symptomatic relief of their COPD symptoms after cannabis use."

Although there were no meaningful positive or negative effects, the authors noted that the sample of patients was small and represented a relatively homogenous group of patients with stable yet advanced COPD. Additionally, the authors emphasized that a number of factors may have limited the therapeutic benefit of cannabis, such as the dose used, that it was inhaled rather than taken orally, and that it was administered once without repetition.

"Future clinical trials are warranted and should evaluate the therapeutic potential of various doses of vaporized and oral cannabis, including oils and pills, administered over longer periods of time in patients with mild to moderate COPD," concluded senior study author, Dennis Jensen, PhD.

Reference

Abdallah SJ, Smith BM, Ware MA, Moore M, Li PZ , Bourbeau J, et al; Effect of vaporized cannabis on exertional breathlessness and exercise endurance in advanced COPD: A randomized controlled trial. [published online July 27, 2018]. Ann Am Thorac Soc. doi: 10.1513/AnnalsATS.201803-198OC.