Laughter has physiological effects on the body; it changes brain function and body chemistry. Some examples of the changes are:
- Increases heart and respiratory rates as well as oxygen consumption.
- Increases stroke volume of the heart and dilates blood vessels.
- Lowers levels of the stress hormone, cortisol.
Laughter also has the following effects on specific illnesses.
- Watching a comedy show after eating decreases the overall rise in glucose levels.
- Laughter increases pain tolerance and reduces stress and anxiety.
- Improves self-esteem and mood in cancer patients.
- Decreases inflammation in people with rheumatoid arthritis.
 Bennett MP, Lengacher C. Humor and Laughter May Influence Health IV. Humor and Immune Function. Evid Based Complement Alternat Med. 2009;6(2):159-164.
 Mora-Ripoll R. The therapeutic value of laughter in medicine. Altern Ther Health Med. 2010;16(6):56-64.
 Hayashi K, Hayashi T, Iwanaga S, et al. Laughter lowered the increase in postprandial blood glucose. Diabetes care. 2003;26(5):1651-1652.