In a medical world based on tests, medications, and clear protocols, laughter sounds like something too simple to affect health. But in recent decades, it has been researched more and more as part of the connection between body and mind, primarily through the field of psychoneuroimmunology, which examines how stress and emotions affect physiological systems in the body.
So true, laughter is not a medical treatment, but it does activate measurable responses in the body.
What happens in the body during laughter?
During laughter, there is an activation of the autonomic nervous system, followed by a gradual decrease in stress-related activity. Studies have shown a temporary decrease in cortisol hormone levels after exposure to humor and laughter, alongside changes in heart rate, breathing, and the general sensation of tension.
Medical reviews, including publications in the BMJ and journals in the field of cardiology, indicate that laughter can temporarily affect blood vessel function and cardiovascular metrics, but emphasize that the effect is short-term and does not constitute a standalone treatment.
Thus, for example, there were studies that found that laughter may cause a slight and temporary decrease in blood pressure after the laughter itself, especially in people with high stress levels. Some of the conclusions published in American Heart Association journals showed a temporary improvement in blood vessel function after exposure to humor. But it is important to be precise: There is no evidence that laughter lowers blood pressure permanently or replaces medication for hypertension.
The effect of laughter on the emotional state
Studies in psychology show that laughter and smiling are not only the result of a good mood – they can also create it. Already in the 1980s, it was demonstrated that when the smiling muscles are activated artificially (for example, by holding a pen between the teeth), people report a more positive and amusing experience. This phenomenon is called the "facial feedback hypothesis": The muscles in the face send signals to the brain, which affect our emotion from the bottom up. Later studies reinforced this finding and showed that a "real" smile (which also involves the eyes) increases positive feelings, and even activates areas in the brain related to emotion and attention.
The effect of smiling and laughter on mood is real but usually moderate, and varies between people and situations.
Large-scale reviews found that the effect exists but is relatively small, and is sometimes more prominent when there is no strong external emotional stimulus. Despite this, it has an accumulating health significance – laughter can contribute to improving the sense of well-being, reducing tension, and even affecting brain activity related to processing emotions. In simple words, even if a smile will not "solve everything," it can certainly tip the scale in favor of a better feeling in daily life.
Pain, stress, and the nervous system
Some studies examined the effect of laughter on immune system metrics, including white blood cell activity and antibody levels. Some found slight and temporary changes, mainly in contexts of stress reduction. However, in the medical literature, there is currently no proof that laughter strengthens the immune system in a way that prevents diseases or replaces the body's natural defense mechanisms.
Laughter causes the release of endorphins, substances in the brain that are related to a sense of well-being and pain reduction. This explains why there is sometimes a temporary sense of relief from tension or pain after laughter. It is a natural mechanism of the nervous system, not a medicinal effect in the classic sense. And yet, what is correct to say from a medical standpoint?
The broad consensus today is that laughter is not a medical treatment, but it is part of a combination of factors that affect stress and quality of life. Studies in the field of public health and quality of life indicate that lower stress levels, a higher sense of well-being, and active social connections are related to better health outcomes over time. Laughter is one of the components that can contribute to this indirectly.
How to integrate this correctly into the daily routine?
There is no need to "practice laughter" or use it as a therapeutic tool. But there is certainly room to allow more space for humor, social connections, and situations that reduce stress as part of a healthy lifestyle. It is not a medical metric measured in calories or blood pressure, but rather an indirect effect on the body's systems through the reduction of mental overload.
Laughter affects the body, that is clear. It creates temporary changes in metrics of stress, breathing, cardiac activity, and the sense of well-being. But this effect is limited in time and does not constitute a medical treatment. What remains is not a single measurable effect but rather the body's ability to step out for a moment from a state of continuous tension. In a world where stress has become a permanent part of the routine for many, even such short moments gain a different meaning, not as a cure but as part of a more general balance of life.
Dr. Lee Erez is a specialist in family medicine, Maccabi Healthcare Services Northern District