A recent study published in the Journal of the American Medical Association contends that smoking marijuana two to three times a month does not reduce lung function as much as doctors previously thought.

Marijuana smoke, which has similar components to cigarette smoke, failed to show the same decrease in lung function that was seen in cigarette smokers.

Study researchers analyzed data from more than 5,000 men and women ranging from 18 to 30 years of age, from four U.S. cities.

The pulmonary function, height, smoking behavior, and waist circumference of each study participant were measured.

“There are well known effects of tobacco on pulmonary function and we thought, going into this, that we would find similar types of effects for marijuana,” said Dr. Mark J. Pletcher, lead study author from the University of California, San Francisco.

The participant’s lung function was measured with spirometry testing, which shows how much air a person can forcibly exhale, as a way for doctor’s to quantify how well a patient’s lungs are functioning.

“People who smoke marijuana inhale very deeply, which may strengthen the muscles used for inhalation — basically making them good at the test. So even though it’s a very statistically significant result, it probably doesn’t have any physiologic meaning in terms of function,” Pletcher explained.