Marijuana users twice as likely to suffer cardiac arrest

After the election in November, people in selected states celebrated their narrow approval to legalize marijuana. However, in the midst of the euphoria — over the election or otherwise induced — a new U.S. study reveals marijuana weakens the heart muscle. Especially in young men.

I also recently reported on some of the more sobering statistics about increasing rates of driving while intoxicated and vehicular fatalities in “legal” states from use of this dangerous drug. But the biggest threat may be the woeful — and increasing — lack of public awareness of the drug’s dangers.

In the U.S., research shows marijuana damages lung health and mental health and performance, both short-term and long-term. Plus, I reported some years ago on findings from France that found marijuana harms heart health — leading to more hospitalizations from heart attack and strokes.

And the new U.S. study probed further into that very finding about heart health…

The hazards of inhaling

For this new study, researchers from St. Luke’s University Hospital Network analyzed data for more than 33,000 patients with stress cardiomyopathy — a sudden weakening of the heart muscle, causing chest pain, dizziness and shortness of breath. The condition can potentially lead to cardiac arrest.

The majority of marijuana users in the study were young males. Perhaps fewer survive to older ages for one reason or another. Of course, being younger, they actually had fewer risk factors for stress cardiomyopathy compared to the older non-users.

Yet, despite being younger and healthier, marijuana users were almost twice as likely to suffer cardiac arrest compared to non-users. They were also significantly more likely to require an implanted defibrillator to correct a dangerously abnormal heart rhythm.

I personally think the lack of oxygen has something to do with the whole sorry situation. It stands to reason if you block oxygen from getting into your lungs, due to the peculiar way in which the toxic smoke is inhaled, it can sensitize the heart and brain to insufficiency.

Indeed, smoking marijuana often involves performing what is known as a valsalva maneuver of taking and holding deep breaths and holding carbon dioxide, and combustion products like carbon monoxide, in the lungs. The maneuver blocks normal uptake of oxygen and elimination of carbon dioxide and combustion products from the lungs.

This peculiar type of breathing also alters and increases internal pressure in the chest and abdomen, interfering with return blood flow back to the heart. It therefore reduces cardiac output, contributing to the circulatory insufficiency associated with heart attacks and strokes (as observed in the French study, for example). Research links the valsalva maneuver with an increased risk of passing out and heart attacks.

First study to analyze how marijuana harms heart

Most previous research on the dangers of marijuana has focused on the toxicology of the drug. Frankly, I’ve never seen the physiologic effects on the lungs, heart and body explained from a functional hemodynamic standpoint like this. In fact, this may be the first time anyone has brought to light these physiologic mechanisms in this connection.

Of course, smoking marijuana can also cause long-term declines in lung function, including chronic bronchitis, from the damaging effects of excessive smoke.

So, it’s time to take a deep breath.

Dr. Ann Bolger of the University of California, San Francisco, stated that while some positive medical benefits are being attributed to those using the drug for legitimate medical reasons, “exposure may not be as benign as some people seem to think.”

That is quite a statement coming from San Francisco, where of course, it seems all manner of things are legal, and celebrated.


1.      “Marijuana use may be linked to temporarily weakened heart muscle,” Science Daily ( 11/13/2016