section_path: Physiological effects
section_name: Physiological effects
paragraph_text: Physiological effects
  
  Humour is often used to make light of difficult or stressful situations and to brighten up a social atmosphere in general. It is regarded by many as an enjoyable and positive experience, so it would be reasonable to assume that it might have some positive physiological effects on the body.
  
  A study designed to test the positive physiological effects of humour, the relationship between being exposed to humour and pain tolerance in particular, was conducted in 1994 by Karen Zwyer, Barbara Velker, and Willibald Ruch. To test the effects of humour on pain tolerance the test subjects were first exposed to a short humorous video clip and then exposed to the cold pressor test. To identify the aspects of humour which might contribute to an increase in pain tolerance the study separated its fifty-six female participants into three groups, cheerfulness, exhilaration and humour production. The subjects were further separated into two groups, high Trait-Cheerfulness and high Trait-Seriousness according to the State-Trait-Cheerfulness-Inventory. The instructions for the three groups were as follows: the cheerfulness group were told to get excited about the movie without laughing or smiling, the exhilaration group was told to laugh and smile excessively, exaggerating their natural reactions, the humour production group was told to make humorous comments about the video clip as they watched. To ensure that the participants actually found the movie humorous and that it produced the desired effects the participants took a survey on the topic which resulted in a mean score of 3.64 out of 5. The results of the Cold Press Test showed that the participants in all three groups experienced a higher pain threshold and a higher pain tolerance than previous to the film. The results did not show a significant difference between the three groups.
  
  There are also potential relationships between humour and having a healthy immune system. SIgA is a type of antibody that protects the body from infections. In a method similar to the previous experiment, the participants were shown a short humorous video clip and then tested for the effects. The participants showed a significant increase in SIgA levels.
  
  There have been claims that laughter can be a supplement for cardiovascular exercise and might increase muscle tone. However an early study by Paskind J. showed that laughter can lead to a decrease in skeletal muscle tone because the short intense muscle contractions caused by laughter are followed by longer periods of muscle relaxation. The cardiovascular benefits of laughter also seem to be just a figment of imagination as a study that was designed to test oxygen saturation levels produced by laughter, showed that even though laughter creates sporadic episodes of deep breathing, oxygen saturation levels are not affected.
  
  As humour is often used to ease tension, it might make sense that the same would be true for anxiety. A study by Yovetich N, Dale A, Hudak M. was designed to test the effects humour might have on relieving anxiety. The study subject were told that they would be given to an electric shock after a certain period of time. One group was exposed to humorous content, while the other was not. The anxiety levels were measured through self-report measures as well as the heart rate. Subjects which rated high on sense of humour reported less anxiety in both groups, while subjects which rated lower on sense of humour reported less anxiety in the group which was exposed to the humorous material. However, there was not a significant difference in the heart rate between the subjects.