via Health Chronicle:

Mark Twain once said, “Humanity has unquestionably one really effective weapon—laughter. Power, money, persuasion, supplication, persecution—these can lift at a colossal humbug—push it a little—weaken it a little, century by century, but only laughter can blow it to rags and atoms at a blast. Against the assault of laughter nothing can stand.” Twain was right, except he forgot to mention laughter’s ability to profoundly affect our health.

Laughter is the best medicine for many scientifically proven reasons:

1. Laughter is one of the best stress relievers. A good bout of laughter can keep the muscles in your entire body relaxed for up to 45 minutes. Now imagine cracking a few good jokes all day long. You’ll never have a crick in your neck or an aching back again.
2. Dr. Gulshan Sethi, a doctor of cardio-surgery at Tucson Medical Center says that laughter is like internal jogging. It tones all the internal organs and strengthens the abdominals without ever doing a single sit-up.
3. Laughter induces better social relations. The contagious nature of a smile or a good laugh help us to connect with others leading to friendships and even romantic closeness. In fact, couples who laugh together are more likely to stay married longer. People who have enduring relationships have also proven to outlive those who have few friends and are unmarried.
4. Laughter boosts our body’s immune response. Studies have found that laughing at a funny movie or finding humor in a stressful situation helps to increase the production of natural killer cells – white blood cells that attack cancer, colds, and foreign bacteria.
5. Laughter combats depression. When we laugh our bodies dump a bunch of good neuropeptides into our blood stream including oxytocin and dopamine.
6. Laughter reduces physical pain. Perceived pain levels in participants of many different studies are lowered when they laugh. Life may cause us pain here and there, but laughter helps us to deal with it better.
7. Finally, laughter is a measurable trait found to be higher in those who are more resilient. If you want to find a successful person who can take the punches of life just as easily as the accolades, you’ll find someone who laughs a lot. Laughter builds character and lessens rigidity.