You've heard about the health benefits of laughter, but what really happens when you laugh that makes it so beneficial? Doctors and scientists have a few ideas.

Exercise Your Heart and Abs–It turns out that laughing is a lot like exercising. A good laugh can increase your heart rate, exercises your diaphragm, and even contracts your stomach muscles.

Burn Calories–With the similarities between laughter and exercise, it shouldn't come as a surprise that laughing helps you burn calories. In fact, one study found that 50 calories are burned in 10 to 15 minutes of laughter.

Reduce Stress–There's actually a physical reason that laughter reduces stress. In addition to being a great emotional release, laughter reduces the number of stress hormones (such as cortisol and epinephrine) in your body and helps boost good hormones like endorphins.

Increase Blood Flow–Scientists have found that blood vessels function healthily when people watch comedies, which means they expand and contract more easily and help blood flow normally. This is in stark contrast to the tightened blood vessels that were found in people after watching a drama. In short, laughter improves blood flow, which helps prevent heart attack and heart disease.

Improve Cholesterol Levels–Recently, researchers have found that people with Type 2 Diabetes who watched funny videos for at least 30 minutes each day had better cholesterol levels after just two months.

Strengthen Your Immune System–There's also evidence that laughter helps boost immune cells and antibodies, making your system better prepared to fight viruses. So, a little laughter not only makes you feel better in the short-term, but also can help you remain healthier in the long-term.

In addition to all of these physical reactions and benefits, laughing is beneficial for your mental health, too. It's a great anti-depressant…not to mention a great way to interact with friends and family while you strengthen your social relationships.

"Laughter Is An Instant Vacation" video copyright 2009, Simple Truths, LLC. Visit www.SimpleTruths.com for more inspirational movies and gifts of inspiration.