Male body fat >; 25% and female > 33% are the criteria for diagnosing obesity. Body fat percentage can be calculated by the following formula as body mass index value:
Body fat% = 1.2× body mass index? +0.23× age -5.4- 10.8× sex
The value of male sex is 1, and the value of female sex is 0.
Second, the water content
According to the water content in the body, the brain and spinal cord are the most, accounting for about 99%; Followed by lymph glands, accounting for about 94%; Water in blood accounts for about 83%; Water in muscle accounts for about 77%; Although bones are hard, they also contain 20% water. The above refers to the body of adults, and infants account for about 80% of the whole body on average.
Third, muscle rate.
The proportion of human muscles. Muscle rate = (muscle weight/body weight) × 100% (note: the standard value of female muscle rate is about 27%)
Extended data:
Body fat scale
1, human body fat scale is a weighing instrument that can measure fat, moisture and so on besides body weight. At present, there are two kinds of sensors for measuring body fat on the market: ito film and electrode sheet.
2. The principle of human body fat scale is that muscle contains more water such as blood, which can conduct electricity, but fat is not. Because the channel conductor of current in the body is muscle, the weight of muscle can be known from the difficulty of current passing, so as to judge the proportion of muscle in the weight.
Correct health concept:
A healthy body lies in the balance of body fat. Too much fat accumulation is harmful to the body, leading to various diseases. Human fat is an important part of the human body, which has important functions and functions in the human body, such as providing energy, protecting internal organs, maintaining body temperature, assisting the absorption of water-soluble vitamins, and participating in human metabolic activities.
However, too much fat will affect human health, leading to diabetes, cardiovascular and cerebrovascular diseases. In addition, obese patients often face various troubles such as fear of heat, influence on body shape and fatigue. Therefore, doctors and experts suggest keeping your body shape within a certain range.
At present, there are many methods to measure human body composition, especially human body fat, mainly including underwater weighing method, skinfold anthropometry, bioelectrical impedance analysis (BIA) and so on.
In addition, there are dual-energy X-ray absorption (DEXA), computed tomography (CT) and magnetic resonance imaging (MRI), which have developed rapidly in recent years.
However, these methods need expensive equipment and professional training, and patients are vulnerable to radiation, so they are not suitable for home use. BIA method is convenient to use, accurate in measurement results and relatively low in price, which is favored by consumers.
According to the theory of BIA (Bio-electrical Impact Analysis), BIA is a technology to design and estimate body composition according to different conduction characteristics of different body tissues. When a current with a frequency greater than 50kHz is applied to the body tissue, the current can pass through the extracellular fluid.
But part of the current will be absorbed by the cell membrane (resistance, R); Part of the current slows down because the cell membrane is temporarily charged, which is the reaction. Impedance (z) is the sum of resistance and resistance, and usually resistance accounts for more than 90%.
According to the above principle, the electronic fat scale contacts the user's leg by using the electrode pad on the scale surface, and then measures the bioimpedance based on the input user data and the measured bioimpedance.
Using the formulas obtained from a large number of our experiments, we can accurately measure body components, such as body fat percentage, body moisture percentage, body muscle percentage and bone weight.
References:
Baidu encyclopedia-body fat rate
References:
Baidu encyclopedia-body fat scale