This common act is more intimate than sex

The first sign of trouble in a relationship is usually a drop-off in kissing, according to Dr Krueger. — dpa

Your heart beats faster, your blood pressure rises and your cheeks flush.

A cocktail of “cuddle” and “happy” hormones floods your body, including oxytocin, serotonin and dopamine; as many as 34 facial muscles spring into action; and millions of bacteria are transferred from mouth to mouth.