Heart HealthLaughter is linked to the healthy function of blood vessels and greatly helps with heart health. A Maryland School of Medicine study found that laughter causes the tissue that forms the inner lining of blood vessels (the endothelium) to expand in order to increase blood flow, while stress has the opposite effect, constricting blood vessels and reducing blood flow.

The endothelium regulates blood flow, adjusts coagulation and blood thickening, and secretes chemicals and other substances in response to wounds, infections or irritation. It also plays an important role in the development of cardiovascular disease. 

The endothelium is affected by atherosclerosis or hardening of the arteries, a major cause of heart disease and death.

Laughing maintains a healthy endothelium and reduces the risk of cardiovascular disease, heart attack and stroke. When you laugh, the blood flow increases and the blood pressure rises; but when you stop laughing, blood pressure drops back to its baseline. This relaxing effect helps bring down blood pressure. This generates deeper breathing, which in turn sends more oxygenated blood through the body.

We don’t know yet why laughing protects the heart, but we know that mental stress is associated with impairment of the endothelium, the protective barrier lining our blood vessels. This can cause a series of inflammatory reactions that lead to fat and cholesterol build-up in the coronary arteries and ultimately to a heart attack… The ability to laugh — either naturally or as learned behavior may have important implications in societies such as the U.S. where heart disease remains the number one killer.
Dr. Michael Miller, director of the Center for Preventive Cardiology at the University of Maryland Medical Center
Dr. Michael Miller, director of the Center for Preventive Cardiology at the University of Maryland Medical Center

Laughter reduces the risk of heart attack and stroke

Laughter helps reduce the stress hormones produced in the hypothalamus section of the brain, lowering blood pressure, reducing risk of heart attack and stroke. Significant reductions can occur in minutes and last for days.

Our findings show that the physiological effects of a single one-hour session viewing a humorous video appear to last anywhere from 12 to 24 hours in different individuals. This leads us to believe that by seeking out positive experiences that make us laugh we can do a lot with our physiology to stay well.” ─ Lee Berk, DrPH, Assoc Res Pro Loma Linda School of Medicine

Laugh to practice safe stress!Negative emotion or attitudes have been found to be related to a number of diseases. Among patients with heart disease, those with a pessimistic outlook about their ability to recover enough to eventually resume their daily routine were more than twice as likely as optimists to have died one year later, even when severity of the condition was taken into account.

Another study of patients recovering from heart attacks showed that those who scored high on tests of sadness and depression were eight times as likely as more optimistic patients to die within the next 18 months. Risk of death was tripled both among those who tended to hold in their anger and those judged to be very anxious.

Aren’t there contraindications to laughter for heart patients?

A literary review of 67 years of research on laughter published in the British Medical Journal in December 2013 reviewed what modern science knows about its beneficial and harmful effects. They found one case of death by laughter. She was 50, schizophrenic, and was referred for polymorphic ventricular tachycardia (she had a history of heart problems) after Ziprasidone therapy (an antipsychotic drug known to increase mortality in people with dementia-related psychosis). She had intense, sustained laughter one day after hearing a joke, collapsed and could not be revived. For the record, this is why pathological laughter can be dangerous. People with these symptoms just can’t control themselves and fall into excess, or distress.

More valid concerns were raised in that particular review against hearty and “intense side-splitting laughter” that can adversely impact certain people with pre-existing health conditions. The conclusion however was unavoidable and predictable: “The benefit-harm balance of laughter is probably favorable.”

I'd rather dilate than earlyThe incidence of heart attack while shoveling snow, for persons with impaired heart function, is alarmingly high,” says Dr. William Fry, professor emeritus at Stanford University, a man who has studied the health aspects of laughter for decades. “But unexpectedly and against logic, the incidence of heart attacks suffered while laughing is surprisingly low.”

We recommend you always take the safe approach and avoid extremes of any kind. Intense and forced laughter is neither helpful nor necessary. Beyond a certain point the body stops producing happy hormones and shifts into distress. It is like everything else. You can’t eat too much food even if it is healthy.

Here is how to make laughter safe and foolproof:

  • Follow your heart, but take your brain with you. If you have any kind of concerning medical condition don’t ask for trouble. Always get the advice of your doctor first before starting this or any other exercise regime. If you chose to ignore this advice, you are doing so at your own risk;
  • Enjoy everything you do. Respect your own limitations, and take it very easy. A smile is as good as a laugh if that is all that is available to you today;
  • No new pain! Avoid extremes. Stop immediately if anything becomes painful or uncomfortable, even to the slightest degree. When in doubt always ask a medical professional before engaging in laughter or any other kind of exercise regime. If you suffer from anything complicated, advanced, acute, severe, unstable or uncontrolled, then you should get written permission from your doctor before doing anything, including laughing.
  • If you laugh more, drink more water. It may not be much, but considering that many people are chronically dehydrated, sometimes even a little dehydration can be too much. If you experience some heaviness in the head or mild to moderate headaches after laughter, that could be a warning sign. Always listen to your body. Be gentle next time…and drink more water!
Ultimately laughter is about breathing, and breathing is not a contraindication to life. Research carried out in December 2013 in a Kidney Dialysis Hospital unit in Melbourne, Australia, showed that a 30-minute Laughter Yoga session every two days for 30 days had no adverse effect on patients with extreme health conditions, quite to the contrary:

Heart health in the trenches: Got a heart transplant, laughed a lot, back to normal

70-year-old Linda LeVier credits laughter with her survival: in 2007, on April Fool’s Day, she had a heart transplant. She believes laughter, especially the deep kind that starts in the belly, helped her recover with no complications and no signs of organ rejection.

“More and more research is showing that when you do it as an exercise, it has amazing physical and psychological benefits that help you with challenges in your life,” she said.

Could laughter really have been responsible for her survival and recovery?

LeVier’s cardiologist, Dr. James Heywood with Scripps Clinic in La Jolla, said it definitely didn’t hurt.

“I don’t have the scientific basis, but I do know that a person’s attitude is extremely important in terms of how they’re going to heal,” Heywood said. “I think she did very well. For as sick as she was, she had a rather uneventful recovery. No rejections. She’s been restored to normal health.”

Three years before needing the heart transplant, Linda had complications from heart surgery that left her with congestive heart failure. It was during those years that she started going to laughter groups. While her heart continued to weaken the rest of her body and spirit got stronger. She was laughing with her surgeon and the anesthesiologist on the way into the operation room!

Relevant studies

Here is a good place to start:

  1. Comparing simulated and spontaneous laughter: Simulated laughter resulted in a higher heart rate and lower heart rate variability compared to spontaneous laughter or watching non-humorous content, similar to the effects of exercise (Law, Broadbent, & Sollers, 2018).
  2. Laughter’s impact on blood vessel walls and overall health: Laughter causes relaxation of endothelium, increases blood flow, and triggers healthy physical changes in the body (Rowson, 2013).
  3. Laughter yoga on mood and heart rate variability in patients awaiting organ transplantation: Laughter yoga showed improved immediate mood and increased heart rate variability, indicating potential benefits in improving HRV and mood aspects (Dolgoff-Kaspar et al., 2012).
  4. Laughter and mental stress on arterial stiffness: Laughter decreased arterial stiffness and augmentation index, while stress had the opposite effect, highlighting laughter’s beneficial acute effects on arterial stiffness and wave reflections (Vlachopoulos et al., 2009).
  5. Effect of laughter on the cardiovascular system: Studies have identified a variety of beneficial cardiovascular effects of laughter, including improved endothelial function and reduced adrenergic activity (Miller & Fry, 2009).

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