A healthy sex life makes people less argumentative at work, and parents who are regularly intimate tend to set a healthy example by behaving with more affection in front of their children.

Psychologists and health experts believe sex not only puts a smile on your face, but can also boost the immune system and provide stress relief.

Patricia Birch, a psycho-sexual and relationship therapist for the NHS, believes a good love life is vital for a healthy heart and mind.

She said: "If our sex lives are good we feel better about ourselves both mentally and physically -- it's as simple as that. Sex releases as many endorphins as exercise, so it's ideal for de-stressing yourself and increasing the intimacy, trust and love in a relationship. If you enjoy a night of passion this Valentine's Day, you'll have done a lot of good for your body and mind. You'll have reduced stress, burnt calories and tickled your brain with euphoric chemicals."

Endorphins, Cortisone, Estrogen

Statistics show that half an hour of sex can burn around 53 calories. That is the equivalent of running three minutes up and down the stairs, six minutes of tennis or seven minutes on an exercise bike.

Sex can also relieve arthritis and headaches because it releases endorphins, the body's own pain reliever, and cortisone, a chemical with an anti-inflammatory effect.

Post-menopausal females who are sexually active have a lower risk of osteoporosis because they produce more estrogen. Many women also cite sex as an effective way to lessen migraine pain.

And, predictably, intercourse is also a sound cure for insomnia as the body experiences intense relaxation after orgasm.

Less Argumentative, More Connected

During sex, the brain releases the chemicals dopamine and norepinephrine which create a feeling of euphoria, like being in love.

According to experts, making love also produces neurotransmitters -- chemicals which bond people emotionally to their partners.

Thus a healthy sex life makes people less argumentative at work, and parents who are regularly intimate tend to set a healthy example by behaving with more affection in front of their children.

Patricia said: "I'm constantly encouraging people to share hugs in the living room or kitchen because it's hard to keep that honeymoon bliss feeling going. Sex can keep you in that fun, playful phase. It keeps you connected."