Don't be irritated, upset or depressed. Or too stressed-out for too long, or seethe with anger. If these moods become habits of mind, they will affect your health, add wrinkles to your face and make you age prematurely.

Maintain a good mood and even spirits for good health is common traditional advice to Chinese women for beauty and health - the same goes for men.

Life has ups and downs, and being happy or sad doesn't undermine your health.

Sudden and sharp mood changes or prolonged bad or blue moods, however, can disorder the flow of internal energy and damage the organs.

Control your mood, says traditional Chinese medicine, though it's often not easy. Life is stressful and complicated.

Western medicine, too, knows that long-term stress and exposure to cortisol, the "stress hormone" can cause cardiac, immune, nervous, metabolic, cognitive and other problems.

TCM identifies seven emotions or feelings: happiness, anger, worry, thought, sorrow, fear and shock.

They are, of course, not so simply detectable as facial expressions.

TCM believes our psychology is closely related to certain organs and energy flows.

The energy in wu zang (the five internal organs) supports the changes of mood, according to "Huang Di Nei Jing"("Medical Classic of Yellow Emperor"), the fundamental classic of TCM.

Energy in the heart supports happiness; liver energy is used for anger; spleen energy for worry and thought; lung energy for sorrow; kidney energy for fear and shock.

Therefore, being stuck in a certain mood for too long will consume a lot of energy in the related organ and can damage it. Since the organs are not isolated but interrelated, damage in one organ may cause disorder in another. For example, when the liver is hurt (say, from too much anger), the stomach and spleen are usually the first to experience related disordered energy.

Sudden, dramatic changes in mood can also damage health, since energy flows change direction and status with our strong emotions.

The Yellow Emperor's classic describes the changes of energy that result from different moods. When people get angry, the energy in the liver will flow upward to the head, making the face flush.

Extreme sudden anger can cause fainting and broken blood vessels; some people spit blood. Hypertension patients can have cerebral accidents or strokes.

"Pricking blood therapy" is a widely used emergency TCM treatment for cerebral infarction (stroke); practitioners prick the tip of patients' fingers and squeeze out blood to relieve the accumulated energy and blood in the head. Make sure you call emergency services at the same time.

Happiness and good spirits benefit the health in most cases, as they can relieve nervousness by slowing down the energy flow. Yet, prolonged euphoria, being giddy with joy for a long period, is not healthy as it draws too much energy from the heart. It can cause difficulty in concentration, even blackouts in extreme cases.