14 ways sex can be good for your health

Yes, we know -- Valentine's Day isn't about getting lucky – it's about being lucky in love.

Still, we couldn't resist collecting the many stories and studies we see every month heralding the benefits of healthy sex and presenting them here. Consider it 4you's little act of amour for the upcoming holiday.

How much of this is hard science vs. wishful thinking? While much of the research was quite rigorous, some of the studies were very small (and yet, as is often the case, resulted in big headlines).

The bottom line: Healthy people who have healthy sex probably will find it makes them feel better physically and emotionally. So why not go for the glow?

1. Sex is good for your heart: February is American Heart Month, so we'll start with the cardiovascular benefits. Sex boosts your heart rate the same way exercise does. It's like climbing a couple of flights of stairs, doctors say, or spending several minutes on a treadmill. That can be bad, of course, if you're heart is in bad shape – and people at risk need to be careful. But according to the American Heart Association, having sex is linked with less than 1 percent of all heart attacks and less than 5 percent of incidences of chest pain. For healthy adults, the more pulse-racing time spent in the sack, the better. In a 2001 study at Queens University in Belfast, researchers found that having sex three or more times a week reduced men's risk of heart attack or stroke by half.

2. Sex relieves stress and depression: One thing researchers tend to agree on is that sex makes your brain happy, at least temporarily, and that helps you relax. The rush of endorphins you always hear so much about can cause a state of euphoria and, maybe, a longer-lasting sense of well-being. Sex also lowers your blood pressure, which tends to go up when times get tough.

3. Sex can help you lose weight: It burns calories. For some more than others. Enough said.

4. Sex may keep you from getting sick: Scientists have linked regular sex (once or twice a week) with higher levels of an antibody that can protect you from getting a cold.

5. Sex can improve self-esteem: We recognize there all kinds of pitfalls (not to mention punch lines) for this claim. But best-case scenario, sex makes you feel loved, and feeling loved makes you happier with yourself (those endorphins again).

6. Sex helps you sleep: You thought you were just plum worn out. But researchers say the oxytocin released during sex makes both men and women sleepy. (There's some debate about whether it also makes you want to cuddle.)

7. For women, sex strengthens the pelvic floor muscles: The muscles you use doing Kegel exercises to improve bladder control can get a similar workout during sex.

8. For men, sex reduces prostate cancer risk: The Journal of the American Medical Association has reported that high ejaculation frequency is related to a decreased risk of prostate cancer.

9. Sex makes you more appealing: While having sex, a woman's body produces more estrogen, which could mean shinier hair and softer skin. And some experts say all that sweating – followed by a nice long shower, of course – will make your skin glow. Indirectly, your desire to please your partner can cause you to take more care with your appearance, your manners and your mood. You work out. You brush your teeth. You put on Chapstick. You clip your toenails. You're prettier and nicer!

10. Sex can help relieve pain: Again, it might be only temporary, but some researchers posit that the rush of feel-good hormones can help with headaches, joint pain and some symptoms of PMS.

11. Sex helps you stay aware of your general wellness: Often, symptoms such as lack of libido and pelvic pain are signs of bigger health issues. So if you notice a problem, see your doctor. And be warned: Having sex with multiple partners can increase the risk of some kinds of infection, cancers and, of course, STDs. One group of researchers even found that men who have extramarital affairs are a bit more likely to risk sudden cardiac death. (Possibly because the partner was much younger, or there had been excessive food and alcohol consumption.)

12. Sex can make you look and feel younger: Couples who have sex at least three times a week look more than 10 years younger than the average adult who makes love twice a week, says neuropsychologist Dr. David Weeks, who made a 10-year study of the subject. Besides keeping themselves in good shape (see Nos. 3, 5 and 9) for their partners, Weeks told the BBC back in 1999, "Sex is the most intense kind of pleasure and that triggers certain chemicals. In women it produces a human growth hormone which helps the process." And most sexperts agree that if you don't use it, you lose it – in this case, elasticity, lubrication, muscle tone and desire.

13. Sex can improve your sense of smell: Whether this is a good thing or not may be up for discussion, but a study in mice shows that prolactin -- a hormone known to surge after a man or woman has an orgasm -- can double the number of new nerve cells in a mouse's olfactory bulb, the part of the brain that handles smell, according to a research team at the University of Calgary.

14. Sex can get your day off to a fabulous start: Forget the energy drink! Skip the morning workout! A quickie will get your blood pumping. And it will keep you and your partner feeling good – and good about each other – all day long.