Initial period (1st to 10th day after menstruation) - Beneficial weight loss characteristics: During this period, estrogen secretion is strong, lasting about 14 days. It's a period of depression and stress. Fitness program: You should choose soft unarmed exercise, such as simplified Taijiquan, yoga and so on. If you're still upset before bare-handed exercise starts, jogging, slow skating, and slow swimming are all helpful. Initial stage is also a good time to lose weight and build a healthy body. It should be noted that the intensity of the above activities should not be large and the time should not be long. It is necessary to avoid taking part in sports requiring skills and responsiveness, such as tennis and squash, which may make you angry and emotional fluctuations due to mistakes and failures. Mid-term (11-19 days) - Best time to lose weight: Women usually ovulate on the 14th day after menstruation, when estrogen secretion reaches its peak, it begins to decrease, and progesterone secretion begins to rise. When the secretion of estrogen and androgen is strong, it will accelerate the absorption and consumption of carbohydrate, fat and protein in the body, so the best time to do aerobic exercise is 4-5 days before ovulation. These two hormones cause water retention in the body, and without aerobic exercise, edema and weight gain may occur. Fitness program: Running, swimming and cycling should be carried out as long as possible. These exercises are particularly energy-intensive and are the best choice for people who want to lose weight. You can also take part in other advanced aerobic exercises, such as rhythmic gymnastics and dance classes. Later stage (20-28 days) - suitable for strength training features: Progesterone secretion peaks at week 3 and begins to decline at week 4, when you are about to return to the initial physiological state. Aerobic exercise can be done for a longer period of time in the 20th to 24th days, but the time, frequency and intensity of exercise will gradually decrease in the 24th to 28th days. Fitness program: In addition to the mid-term mentioned exercise, we should also do some extra strength training, and try to avoid participating in sports that require skills and reaction ability. Also remember that exercise is the best way to eliminate premenstrual discomfort. You might as well choose activities like swimming and yoga that are entertaining and less competitive. If you prefer a gym, take the time (at least 20 minutes) every day to show off on the dancing machine, rowing machine and treadmill.