[youtube=http://www.youtube.com/watch?v=R-BJVK1HvKg] Look younger A long-term study of 3,500 people between the ages of 30 and 101 found that regular sex may shave between four and seven years off your physical appearance. Researchers at the Royal Edinburgh Hospital in Scotland presented photos of the subjects to an impartial panel of judges, who were asked to guess their ages. The people who were judged to be the youngest were also those who had the most sex. What’s the connection between youthfulness and getting it on? In addition to boosting self-esteem and confidence, sex increases the production of human growth hormone, which is known to improve muscle tone.

Get happy It goes without saying that sex can make you happy and contented, but a paper in the Archives of Sexual Behavior takes this idea one step further. Based on a study of 300 women that correlated condom use with depression, researchers concluded that women who never used condoms were the least depressed, while those women who always used condoms were the most depressed. One reason? The vagina may absorb the mood-boosting hormones and prostaglandins found in semen. It’s an interesting theory, but certainly no reason to advocate unprotected sex. Clearly, an unwanted pregnancy or STD would not increase anyone’s happiness.

Slim down On average, sex burns about five calories per minute, depending upon your weight. Even engaging your partner in a hot kiss boosts your heart rate, which in turn increases your body’s caloric burn. Next time you’re too busy to work out, try getting busy instead.

Fight the sniffles Sex may help fight off colds. In a study at Wilkes University in Pennsylvania, researchers found that college students who had sex once or twice per week had higher levels of immunoglobulin A, an antibody that boosts the immune system.

Keep the pressure down Want to stress less? Sex could be just the thing to keep you calm. In a study by researchers at the University of Paisley in Scotland, 46 men women were asked to give speeches to an audience who, unbeknownst to the speakers, was told to act bored and disinterested. Afterwards, the participants’ blood pressure was taken—those who reported having sex within the last two weeks had the lowest readings.

Have a heart A recent study published in the Journal of the American College of Cardiology found that erectile dysfunction (ED) is often an early indicator of poor cardiovascular health. Researchers followed more than 2,300 men for an average of four years and found that men with ED had a 58 percent greater risk of coronary heart disease. Another study showed that men who reported having three or more orgasms per week experienced 50 percent fewer heart attacks and strokes as compared with those who had less frequent orgasms. Sex may help the heart because orgasm triggers the release of the hormone DHEA, which helps with circulation and arterial dilation.

Live longer For reasons that are still unclear, regular sex may even add years to your life. A study published in the British Medical Journal found that men who had sex less than once per month were twice as likely to die in the next 10 years than those who had sex once per week. And guys aren’t the only ones to benefit: Researchers at Duke University found that women who claimed to enjoy their sex lives lived seven to eight years longer than women who were indifferent to sex.

So forget about an apple a day. To feel healthier, look younger, and live longer, an orgasm or two a week may be an effective - and certainly enjoyable - remedy.

(By Ian Kerner on CNN Health)