Physical activity strategies for a healthy weight: setting exercise goals, quantifying energy expenditure, and developing habits

It is widely recommended that healthy adults engage in at least 150 minutes of moderate-intensity physical activity (MET) or 75 minutes of vigorous-intensity physical activity (VIM), or a combination of both, per week. That is, based on an estimate of 4.0 MET for moderate-intensity activity and 8.0 MET for VIM, the average weekly amount of moderate- and VIM should reach 600 MET-min. A healthy adult weighing 60 kg would burn approximately 600 kcal per week from moderate-intensity physical activity, averaging about 120 kcal per day (based on a 5-day week). To obtain sufficient health benefits, it is now recommended to achieve 300 minutes of moderate-intensity physical activity (MET), or 150 minutes of vigorous-intensity physical activity (VIM), or a combination of both, per week. In other words, to maintain a healthy weight, approximately 1200 kcal should be burned per week from moderate- and VIM, averaging about 240 kcal per day. To achieve the above recommendations, at the lowest intensity of moderate-intensity physical activity (MET=3.0, such as walking at a speed of 4 km/h), 4080 minutes of physical activity are needed daily. If it's brisk walking (5.6 km/h) or cycling (1216 km/h), with an intensity of MET=4.0, then 3060 minutes of physical activity are needed daily. Based on the pathways of energy expenditure in adults, the daily energy expenditure of a typical healthy adult should account for more than 15% of their total energy intake through physical activity. When an adult's energy intake is 1600-2400 kcal, 15% is 240-360 kcal. This energy expenditure will be used for all daily activities. Generally, essential daily activities are mostly low-intensity self-care activities, daily housework, or office work, averaging about 80 kcal per day. If one actively engages in the above-mentioned moderate-intensity or higher physical activities, the total daily energy expenditure through physical activity can reach 200-320 kcal. If we estimate based on walking at a speed of 4 km/h for 10 minutes (approximately 1000 steps for a healthy adult, consuming about 30 kcal), then we should complete about 6000 steps of activity per day. Based on the Metabolic Equivalents (METs) database for various activities, we estimate the energy expenditure of common forms of physical activity. Walking (3 km/h, slow pace) is 2.0 MET; walking at 4 km/h is 3.0 MET; walking at 5.6 km/h is 4.0 MET. Cycling at speeds below 12 km/h is 3.0 MET, and at speeds between 12 and 16 km/h is 4.0 MET. Household activities such as washing dishes are 2.3 MET, walking while cooking is 2.5 MET, and sweeping and mopping are 3.3-3.5 MET. Among recreational sports, Tai Chi is 3.5 MET, badminton is 4.5 MET, jogging is 7.0 MET, and swimming or moderate-speed rope skipping is 8.0-10.0 MET. Reasonably arrange daily physical activity: (1) Set appropriate goals and achieve them gradually: Due to differences in individual health, physique, ability and other conditions, increasing physical activity to maintain a healthy weight can start from a lower level of activity or be maintained at a level suitable for the individual. Choosing a lower level of physical activity also has the effect of protecting and promoting health; while choosing a higher level of activity, under the premise of moderation, can obtain more health promotion benefits. Setting daily activity goals according to the weight loss plan does not mean that the daily physical activity volume and content should be rigidly uniform or all-encompassing. It can be divided into a week as a period of time, and the content of aerobic exercise, sports and entertainment activities, muscle and joint function exercises and physical activities in daily life and work can be coordinated; according to individual physical conditions, the weekly exercise volume can also be set within an appropriate range. Regardless of the level of the weekly activity volume goal set, it should at least include an appropriate amount of moderate-intensity aerobic exercise. That is to say, when the activity volume goal is low, aerobic exercise is the main content; and only at a higher goal level is it possible to engage in more diverse activities. (2) Pay attention to cultivating interest and skills and gradually form exercise habits: When carrying out physical activities, personal interests, sports skills and daily life habits should be considered. First, it's essential to recognize that physical activity is a means to promote health and maintain weight, and like a balanced diet, it's a necessary component of a healthy lifestyle, not a waste of time. Second, it's crucial to comprehensively consider various timeframes during work, commuting, housework, and leisure time, identifying feasible opportunities to increase physical activity beyond daily self-care and household chores. Simultaneously, maintain personal physical activity habits or cultivate practical exercise skills. Most importantly, integrate physical activity into your daily work, life rhythm, and environment as much as possible. This helps maintain exercise habits and allows you to experience the health benefits of exercise. Based on energy expenditure calculations, for a 60kg adult: 20 minutes of moderate-speed walking burns 60kcal, 20 minutes of brisk walking burns 80kcal, and 30 minutes of jogging burns 210kcal. If the daily goal is 180kcal, it can be achieved through 45 minutes of brisk walking; if the daily goal is 300kcal, it can be achieved through 30 minutes of brisk walking combined with 60 minutes of folk dancing and 10 minutes of indoor cleaning. Through diverse activity combinations, daily energy expenditure can be effectively increased, promoting weight control.