Why do men wake up in the morning?

Male morning erection may be due to male sex hormone secretion in the morning is relatively strong, so it will cause the morning show the situation. There may be because men in the evening when the urine is less, so the bladder will be more full, full bladder urine will stimulate the posterior urethra, thus causing penis excitement, causing penis erection. Male morning erection is normal, do not need special treatment, there is no harm to the body.