If you're like most people, your New Year's resolution to get more exercise, maybe lose a few pounds, probably dissolved long ago. At least your motivation for it did. We've all seen the exercise magazines, the diet regimens and the tips for better living. We get it. Treat your body like a temple. Stay fit; stay healthy; stay happy. For some, this means watching what they eat and trying to squeeze in a few workouts a week. For others, this means strict dieting or intensive exercise. What most people overlook is getting it on.

If you take time to exercise, eat right and take care of your body, sex is one more thing you should add to your feel-good formula. But you don't have to take my word for it. Here's what the science says about jumping in the sack.

Sex Busts Stress

Whether it's yoga, a few episodes of your favorite TV show or walk with your dog, we all need some way to relax. But all you really need is a willing partner. One study recorded the sexual habits, stressful events and mood of a group of 58 women for 36 weeks. It found that sexual behavior on Monday could mean much lower stress levels on Tuesday.

Another study by researchers at Princeton University found that regular intercourse can promote growth in the hippocampus, the part of the brain responsible for regulating stress ... or at least that was true for the rats the researchers tested. Fortunately, there's some evidence that the effects extend to humans too. A study of 24 women and 22 men in Scotland measured blood pressure in stressful situations and found that those who were having regular sexual intercourse responded better. According to Laura Berman, Ph.D. and author of "It’s Not Him, It’s You!", this is because the endorphins and oxytocin that are released during sex create good feelings that can relieve anxiety.

Sex Burns Calories

OK, so it won't match a spin class, but sex can still make you sweat, and a simple 30-minute sex session can burn 85 calories. That may not sound like much, but think of it as the baseline depending on how long (or how hard!) you go. Arousal itself can increase your heart rate, which in turn increases your rate of calorie burn. Go at it a few times a week and you could actually lose a pound or two. (And at least you won't be spending the evening snacking in front of the TV!)

Another plus is that all that thrusting can be a great workout for your abs, thighs, butt and glutes. So the next time you’re feeling too lazy to go to the gym, try a few new moves in bed. Hey, it can't hurt! (Find out about the "love muscle" that can boost your sex life in For Better Orgasms, Flex This Muscle.)

Sex Helps You Sleep

Feeling ready to konk out after an orgasm? It isn't just the workout; the same chemicals that help you relax are also - no surprise - the ones that are released during sex. Another chemical that gets released during orgasm, prolactin, also helps promote sleepiness. According to Cindy Meston, director of the Sexual Psychophysiology Laboratory at the University of Texas Austin, "prolactin levels are naturally higher when we sleep, which suggests a strong relationship between the two."

But be forewarned. Some kinds of sex are more relaxing than others. If you have to be up early in the morning, consider something cozy rather than kinky. (But don't let that stop you at other times, read Why Get Kinky?)

It's Good for Your Heart (Awwww)

According to Scottish researcher Stuart Brody in his 2010 overview "The Relative Health of Different Sexual Activities", sex can be very beneficial to your cardiovascular health. Research published in the American Journal of Cardiology confirms this. According to researcher Susan A. Hall of the department of epidemiology at the New England Research Institute, "men who reported sexual activity of once a month or less had a higher risk of cardiovascular disease than men who reported having sex twice a week or more."

The study followed more than 1,000 men over the course of 16 years, on average. Men who reported sexual activity once a month had a 45 percent increased risk of cardiovascular disease compared to men who reported sexual activity two to three times a week.

Sex Keeps You Young

A long-term research study at Royal Edinburgh Hospital in Scotland showed photos of people between the ages of 30 and 101 to a panel of judges who were asked to guess their ages. On average, they found that having sex regularly can affect how young people look by a margin of four to seven years. Those who were having sexual intercourse four times a week (on average) were rated as a shocking seven to twelve years younger than their actual age. The results of the study were published in a book, "Secrets of the Superyoung.")

Not only does sex increase the production of human growth hormone, which improves muscle tone, but hormones like testosterone and estrogen (sex helps produce them) keep the body looking young. So skip the fancy wrinkle creams. As it turns out, the key to looking younger is as old as the human race!

Sex Is a Natural Pain Reliever

We all know that sex and orgasm can boost the body's feel-good hormones. As it turns out, many of those hormones are also great pain natural pain relievers.

"The endorphins that are released during an orgasm closely resemble morphine, and they effectively relieve pain," Meston said.

So the next time you have a headache, consider getting it on. And if you don't have an available partner, masturbation can also trigger the same chemicals that improve your pain threshold.

Sex isn't a replacement for the basics of a healthy lifestyle, but consider it an essential component of being - and feeling - well. The next time you can't help but skip the gym, consider snuggling up with your partner. Now that's a tradeoff you can feel good about.