E    Autumn blues、 Let the sunshine in．    Falling leaves, withering flowers, cold winds, faint sunshine．  71_  Spirits can be low．People who suffer from "the autumn blues" often are extremely exhausted, lack energy, need more sleep, feel increased appetite and gain weight．    "The exact cause of this condition, often called seasonal depression or seasonal affective disorder （SAD）, is not known yet," says Chen Jue, associate professor at Shanghai Mental Health Center．"But recent studies indicate that weather change is influential and strongly suggest that this condition is caused by changes in the availability of sunlight．"    One theory is that with decreased exposure to sunlight, the biological clock that regulates mood, sleep, and hormones is delayed, running more slowly in winter．  72  ．Another theory is that brain chemicals that transmit information between nerves may be altered （改变）in individuals with SAD．It is believed that exposure to light can correct these imbalances．    “ _ 73 _ Remember, spring always lives in your heart," Chen says．    Here are some tips to deed with autumn depression．    、Go outdoors and get some sunlight．Move around．Fresh air and exercise improve the respiratory（呼吸）system and blood circulation and regulate the nervous system．Thus, exercise is calming and relieves one's mood．    、Relax at work．Stretch, breathe deeply．Take a tea break．Think of your next vacation．    、_74_ Chocolate and sugar raise the spirits．    、Look at bright colors, such as red and orange．Color therapy improves mood．    、Listen to your favorite music．You can dance to it, or just lie on a cozy couch, reading a novel．    、  75  Blooming plants are cheering．    、Call friends or family when you feel lonely or depressed．Recall some happy memories．