Medical weight loss terminology analysis (Part 3): Physical activity level and related chronic disease definitions

31. Metabolic equivalent (MET) is the ratio of metabolic rate during exercise to metabolic rate at rest, representing a relative level of energy metabolism and activity intensity. 1 MET is defined as 3.5 ml of oxygen intake per minute per kilogram of body weight while the body is at rest in a seated position. 32. Physical activity level (PAL) is the ratio of total energy expenditure (TEE) to basal energy expenditure (BEE), used to represent the intensity of physical activity. The formula is: Physical activity level (PAL) = Total energy expenditure (TEE) / Basal energy expenditure (BEE). 33. Total energy expenditure (TEE) is the total energy consumed in 24 hours, including energy consumed through basal metabolism, physical activity, the thermic effect of food, growth and development, gestational nutritional reserves, and lactation. 34. Specific dynamic action (SDA) is the additional energy expenditure that occurs during the digestion, absorption, and metabolism of nutrients after food intake. The thermic effect of food on carbohydrates, fats, and proteins is 5%–10%, 0%–5%, and 20%–30% of their energy production, respectively. 35. Thermal equivalent of oxygen: The energy produced when food is oxidized by consuming 1 liter of oxygen. 36. Non-protein respiratory quotient (NPRQ): The volume ratio of CO₂ produced to O₂ consumed during the oxidation of carbohydrates and fats. 37. Estimated energy requirement (EER): The energy required to meet the body's total energy expenditure. This includes the energy consumed for basal metabolism, physical activity, the thermic effect of food, as well as the energy required for growth and development in childhood, nutritional reserves during pregnancy, and lactation during lactation. 38. Metabolic syndrome (MS): A complex metabolic disorder syndrome resulting from the abnormal aggregation of multiple metabolic components. It is a risk factor for diabetes and cardiovascular disease, and its clustering may be related to insulin resistance. 39. Diabetes melitus (DM) is a syndrome of metabolic disorders involving glucose, protein, fat, water, and electrolytes, caused by various pathogenic factors such as genetic factors, endocrine dysfunction, or dietary imbalances, leading to decreased pancreatic function and insulin resistance. Clinically, it is characterized by hyperglycemia and is classified into four types: type 1 diabetes, type 2 diabetes, gestational diabetes, and other special types of diabetes. 40. Hypertension is a systemic disease caused by pathogenic factors such as genetic factors, lifestyle, or dietary imbalances, characterized primarily by elevated blood pressure, accompanied by physiological or pathological changes in organs such as blood vessels, heart, brain, and kidneys. 41. Physical activity refers to all activities that increase energy expenditure relative to the body's resting state due to skeletal muscle contraction. In other words, physical activity includes all activities except sleep and absolute rest. 42. Physical activity frequency refers to the number of times exercise is performed per unit of time, usually measured in "weeks." It is typically expressed as the number of days of activity per week (days/week). Frequency reflects the level of regularity in exercise and is an important aspect of promoting exercise. Emphasizing regularity is an important prerequisite for the health benefits of activity. 43. Physical activity intensity refers to the level of energy consumption or physiological stimulation of the body per unit of time. It is usually expressed using metabolic equivalents (MET or MET), subjective exercise intensity scales (i.e., RPE scale, Berg scale, Borgs scale), percentage of maximum oxygen consumption (%VO₂max), and percentage of maximum heart rate (%HRmax). (When the body engages in strenuous exercise, the oxygen consumption and heart rate can reach their limits; the oxygen consumption at this point is called maximum oxygen consumption (VO₂max), and the corresponding heart rate is maximum heart rate (HRmax). It can be divided into three levels: light, moderate, and heavy. 44. Physical activity time refers to the duration of a single activity, usually expressed in minutes or hours. Cumulative exercise time refers to the sum of the duration of certain specific activities within a certain time frame to achieve a specific exercise goal. For example, an activity lasting 5 days a week, 3 times a day, and 10 minutes each time can be expressed as 150 minutes per week. 45. Aerobic physical activity refers to a form of exercise that primarily involves large muscle groups such as the trunk and limbs, is rhythmic, lasts for a relatively long time, can be maintained in a steady state, requires oxygen for energy supply, and primarily uses aerobic metabolism as its energy source; it is also called endurance exercise. Examples of aerobic activity include walking at a moderate speed of 4 kilometers per hour and cycling at a speed of 12 kilometers per hour. 46. Anaerobic physical activity refers to a form of exercise that primarily uses anaerobic metabolism as its energy source. It generally involves strong muscle contractions. Anaerobic activity can only be sustained for 2-3 minutes, and the energy for the muscle groups exerting force during exercise is mainly supplied by anaerobic glycolysis. For example, 100-meter sprints are almost entirely powered by anaerobic metabolism. Furthermore, anaerobic exercise can also occur at the end of aerobic exercises such as 5000-meter long-distance running, and is also a major form of exercise such as lifting heavy objects, push-ups, and resistance muscle strength training. 47. Flexibility training, also known as stretching exercises, refers to exercises that improve joint flexibility and range of motion through the extension, flexion, and rotation of the torso or limbs. Examples include dynamic stretching in Tai Chi, Qigong, and Yoga, as well as static stretching. 48. Muscle-strengthening activities refer to repetitive movements against resistance, which can maintain or improve muscle strength (how much resistance can be overcome), endurance (how many repetitions or how long resistance can be overcome), or power (how quickly resistance can be overcome). Examples include everyday activities such as lifting heavy objects, shoveling snow, carrying children, climbing stairs, and using fitness equipment such as weightlifting machines, free weights, or resistance bands. Exercising against resistance primarily relies on anaerobic energy (although aerobic energy is also involved throughout the exercise process). 49. Balance training refers to a combination of activities that improve the body's balance and coordination. Regular practice, whether walking, standing, or sitting, can improve the body's ability to resist internal or environmental forces that could cause falls. Specific forms of exercise include standing on one leg, walking from heel to toe, balance walking, and using a rocking board. 50. Bone-strengthening activities are exercises that exert impact on bones and load on muscles. These forces act on the bones, adapting them by changing their structure (shape) or mass (mineral content), thereby increasing their resistance to fractures. Jumping, hopping on one leg, skipping rope, and dancing are all beneficial bone-strengthening activities, as are muscle-strengthening activities. 51. Occupational physical activity refers to physical activities performed for work purposes, whether paid or unpaid. Examples include placing items on store shelves, delivering packages in an office, preparing or serving food in a restaurant, or moving tools in a workshop. 52. Transportation physical activity refers to physical activities performed for transportation purposes, moving from one place to another. Examples include walking or cycling, taking a car, or driving to and from the workplace, school, market, or shopping mall. 53. Household physical activity refers to activities performed at home or in the yard, including household chores such as cooking, cleaning, repairing the house, and tidying the yard or gardening. 54. Leisure-time physical activity refers to activities undertaken voluntarily without working, traveling, or doing housework, including exercise, walking, and playing games (such as hopscotch or basketball).