5 body indices every runner must know
1. Basal Metabolic Rate (BMR)
BMR, as the name suggests, is the rate of the body's basal metabolism (BM). So, what is basal metabolism? Basal metabolism is the minimum energy required to maintain normal life activities for a day. It is the energy metabolism rate when the body is awake and in an extremely quiet state, not affected by muscle activity, environmental temperature, food, or mental stress.
Basal metabolic rate is the speed of basal metabolic activities. Its units are generally energy/unit surface area/unit time (e.g., KJ/m2/hour) or energy/time (e.g., Kcal/day), with kcal/day being more widely used.
The most accurate way to measure basal metabolic rate is generally the 'indirect calorimetry method,' where the subject is usually required to fast overnight (about 12 hours) and then measured while resting in bed the next day. The measurement environment is also very strict, typically used in hospitals and laboratories.
Therefore, many researchers consider using the Resting Metabolic Rate (RMR) to replace BMR, which is the metabolic rate when the body is completely at rest. The process is more relaxed compared to BMR measurement, and the difference between basal metabolism and resting metabolism values is usually less than 10%.
Men: BMR = 10 * weight (KG) + 6.25 * height (CM) - 5 * age + 5
Women: BMR = 10 * weight (KG) + 6.25 * height (CM) - 5 * age - 161
2. Body Mass Index (BMI)
BMI, also known as the body mass index or weight index, is a number derived from dividing a person's weight in kilograms by the square of their height in meters. It is currently an internationally common standard for measuring the degree of fatness and health of the human body.
3. Body Fat Percentage
Body fat percentage refers to the ratio of the mass of all fat tissues in your body to your total body weight (mainly subcutaneous fat and visceral fat). Compared to BMI, body fat percentage can better indicate a person's 'fatness.' Having a high body weight does not necessarily mean being fat; having a high body fat percentage is the true indicator of being 'fat.'
Additionally, a low body fat percentage does not represent good health! It only proves that you are 'thin,' and nothing else. The normal range of body fat percentage for Asian women is generally between 13% and 30%, while for men, it is between 7% and 25%.
4. Muscle Mass
The composition of body weight can be divided into two major parts: non-fat substances and fat substances. Muscle content is the non-fat substance after removing about 4% to 6% of inorganic matter from the body weight. Muscle is beneficial; the greater the muscle mass, the higher the basal metabolic rate, making it harder to gain weight.
5. Body Water Percentage
Body water percentage is the percentage of body weight that is water. This data is closely related to muscle mass because muscles contain a large amount of water (about 70%). This indicator can reflect whether the weight loss method is correct. If the body water percentage decreases, it not only harms health but also increases body fat percentage.
(This article was originally published on Running Bar and is reprinted with the author's permission.)