(Ivanhoe Newswire) -- Repetitive mirthful laughter – or Laughercise -- enhances your mood, decreases stress hormones, enhances immune activity, lowers bad cholesterol and systolic blood pressure, and raises good cholesterol (HDL).

Norman Cousins first suggested in the 1970s the health benefits of humor and associated laughter. His ground-breaking work documented his use of laughter in treating himself into remission from an autoimmune disease. His personal research was published in the New England Journal of Medicine, and he is considered one of the architects of mind-body medicine.

Dr. Lee S. Berk, director of the molecular research lab at Loma Linda University's Schools of Allied Health (SAHP) and Medicine, Loma Linda, CA, and Dr. Stanley Tan have picked up where Cousins left off.

Since the 1980s, they have been studying the human body's response to mirthful laughter. They established that laughter helps optimize the endocrine system, reducing stress by decreasing levels of cortisol and epinephrine. They demonstrated laughter’s positive effect on modulating components of the immune system, increasing production of antibodies and activating the body's protective cells.

Their studies have shown that repetitious "mirthful laughter," which they call Laughercise, causes a body response similar to the body response to moderate physical exercise.

"We are finally starting to realize that our everyday behaviors and emotions are modulating our bodies in many ways," Berk was quoted as saying.

Berk, Dr. Jerry Petrofsky and colleagues have completed a new study, which expands the role of laughter even further. They recruited 14 healthy volunteers to examine the effects that eustress (mirthful laughter) and distress have on modulating the key hormones that control appetite.

During the study, each subject was required to watch one 20-minute video that was either upsetting (distress) or humorous (eustress) in nature. The volunteers waited one week after watching the first video to eliminate its effect, then watched the opposite genre of video.

Researchers used the tense first 20 minutes of the movie “Saving Private Ryan” for a distressing video clip. This highly emotional video clip is known to distress viewers substantially and equally.

The volunteers were allowed to "self-select" the eustress video clips that most appealed to them to guarantee their maximum humor response. They were offered a variety of humorous options including stand-up comedians and movie comedies.

The researchers measured each subject's blood pressure and took blood samples immediately before and after they watched the respective videos. Each blood sample was examined for the levels of two hormones involved in appetite, leptin and ghrelin.

Researchers found that the volunteers who watched the distressing video showed no statistically significant change in their appetite hormone levels during the 20 minutes they spent watching the video.

In contrast, the subjects who watched the humorous video had changes in blood pressure and also changes in the leptin and ghrelin levels. The level of leptin decreased as the level of ghrelin increased, much like the acute effect of moderate physical exercise that is often associated with increased appetite.

"The ultimate reality of this research is that laughter causes a wide variety of modulation and that the body's response to repetitive laughter is similar to the effect of repetitive exercise,” Berk explained. “The value of the research is that it may provide for those who are health care providers with new insights and understandings, and thus further potential options for patients who cannot use physical activity to normalize or enhance their appetite."

For example, many elderly patients suffer from what is known as "wasting disease." They become depressed, lose their appetite and jeopardize their health. Based on Berk's current research, these patients may be able to use Laughercise as an alternative, initially less strenuous, activity to regain their appetite.

A similar loss of appetite is seen in widowers who suffer depression after the loss of a spouse. This can result in decreased immune-system function and subsequent illness. Chronic pain patients suffer from appetite loss due to the chemical changes in their body caused by intolerable discomfort.

While laughter may seem unimaginable in the face of deep depression or intense chronic pain, it may be an accessible starting point for these patients to improve and enhance their recovery to health.