If a why-bother attitude keeps you from committing to an exercise routine, consider this: Exercise not only delivers a number of amazing health benefits -- it can also improve your sex life. Here’s how.

Lower Risk of ED

The biggest boost exercise can give to your sex life is to lower your risk of erectile dysfunction, says Jorge Chavarro, MD, of the Harvard School of Public Health. “Exercise that helps open the arteries to benefit your heart will also increase blood flow to the penis,” he says.

One Harvard study of more than 31,000 men found that physically active men over age 50 were less likely to be impotent than inactive men. The exercisers had better erections, and those who were most active saw the most benefit.

But even moderate levels of exercise, like a brisk 30-minute walk most days of the week, lowered the risk of ED. Other research suggests that many men with ED may even reverse their symptoms by getting fit.

Regular exercisers are also more likely than couch potatoes to have a healthy body weight -- a key benefit, given that being overweight is another risk factor for ED.

Improved Symptoms of BPH

Physically active men may also have fewer symptoms of an enlarged prostate, a common condition called benign prostatic hyperplasia (BPH). Men with BPH often have to urinate frequently, or have a weak stream. Men with more severe BPH symptoms may also have a low libido, trouble keeping an erection, and enjoy sex less.

A study published in the Journal of Urology found that active men cut their risk of urinary tract symptoms in half.

There's no one exercise that's best for men with BPH. Getting 30 minutes of solid exercise on most days is enough to see benefits. And you can even break up your activity into 10-minute segments.

Better Semen Quality

If you want to have kids, or think you might down the road, take note: A recent study in the British Journal of Sports Medicine suggests that men who worked out at a moderate to vigorous intensity at least 15 hours a week had higher sperm counts than inactive men.

If you lift a remote control more than a dumbbell, you should know that men who watched more than 20 hours of TV per week had considerably lower sperm counts than those who watched no TV.

Fit for the Bedroom

When it comes to the strictly muscular aspect of sex, fit men have the advantage. Men in prime shape will find sex easier and less painful than men who don't exercise much, says Neal Pire, a fitness consultant to pro athletes. “If you don’t exercise regularly, and especially if you never do crunches, you will feel soreness in your lower abdominals and your hip flexors after sex,” he says. If you are partial to the missionary position, you might feel soreness in your chest muscles, he adds.

Exercise can help you feel more confident and energized both in and out of the bedroom, which can improve sex. “When you feel good about yourself, and about how your partner sees you physically, you’re going to be more relaxed and less distracted,” says Pire.

Your best bet for overall enhanced sexual health is a well-rounded exercise regimen of strength, cardio, and flexibility training.