Exercise. "Sexual activity is a form of physical exercise," according to Dr. Michael Cirigliano of the University of Pennsylvania School of Medicine. Making love three times a week burns around 7,500 calories in a year -- the equivalent of jogging 75 miles.
Heavy Breathing. A night of love can raise the amount of oxygen in cells, helping to keep organs and tissues functioning at their peak.
Strong Bones and Muscles. "Any kind of physical exercise is going to increase testosterone," states Dr. Karen Donahey, director of the Sex and Marital Therapy Program at Chicago's Northwestern University Medical Center. Testosterone is believed to help keep men's bones and muscles strong.
Lowered Cholesterol. Making love regularly can lower levels of the body's total cholesterol slightly, while positively changing the ratio of good-to-bad cholesterol.
Pain Relief. Sex can lower levels of "arthritic pain, whiplash pain and headache pain," according to Dr. Beverly Whipple, president-elect of the American Association of Sex Educators, Counselors and Therapists. Hormones that are released during sexual excitement and orgasm can elevate pain thresholds.
DHEA -- Without Supplements. DHEA (dehydroepiandrosterone), a popular supplemental hormone, is released naturally during lovemaking. "Just before orgasm and ejaculation," Crenshaw says, "DHEA spikes to levels three to five times higher than usual."
Prostate Protection. Researchers say prostate trouble may arise or be worsened by fluid buildup within the gland. Regular ejaculation will help wash out those fluids. Be cautious when suddenly changing frequency -- sudden changes may also trigger prostate problems.
Stress Relief. "Sex can be a very effective way of reducing stress levels," Donahey told Men's Health.
Love Will Keep Us Together. Crenshaw says affectionate touch will increase levels of oxytocin -- the "bonding hormone." Oxytocin is a desire-enhancing chemical secreted by the pituitary. Regular oxytocin release may help encourage frequent lovemaking.
Hormones -- Naturally. "Regular lovemaking can increase a woman's estrogen level, protect her heart and keep her vaginal tissues more supple," states Donahey.