1, with the increase of age, the metabolic rate decreased.
As we grow older, we lose muscle cells. Young muscle cells will be repaired quickly after being damaged. The muscles of the elderly are not like this. One view is that stem cells in muscle cannot respond to injury or aging. If the damaged muscle cells are not repaired, they will atrophy and die. These muscle injuries will accumulate with age.
2. Decrease of growth hormone
Growth hormone is very important for gaining muscle and reducing fat. Women secrete more growth hormone than men. With the increase of age, growth hormone is decreasing, so it is not surprising to gain weight. Therefore, you should know that growth hormone is called "youth hormone", and some bodybuilders will inject (2-4iU) growth hormone at a low dose to reduce body fat for the purpose of reducing fat (this is just a problem, not recommended).
3, the decline of sex hormones
The decrease of testosterone (female level is extremely low) and estrogen level may also lead to the loss of muscle fibers, the tissue can not repair itself and reduce the metabolic rate.
4. Endocrine changes
The highest incidence of middle-aged women is hypothyroidism, referred to as "hypothyroidism". In addition to symptoms such as listlessness, alopecia, and edema in front of the tibia, thyroid hormone will directly affect the metabolic rate of the human body, leading to eating too much and getting fat. I have come into contact with several women with hypothyroidism, all of whom have backache. What's more, even if these women take medicine on time, their metabolic rate is still low (there is still a difference between oral medicine and self-secretion), and their fat-reducing efficiency is low.
Stress hormone (glucocorticoid) is too high. Someone said before, "What should I do if I exercise on an empty stomach to produce glucocorticoid?"? I will lose my muscles. " For non-professionals, glucocorticoid seems to be a bad thing.
In fact, the long-term increase of glucocorticoid is a bad thing you know (please pay attention to the words "long-term increase"). The body shape caused by the increase of glucocorticoid-slender limbs, increased trunk fat, and buffalo on the back. For example, if you have a "devil wears Prada" boss, then the chronic increase of your stress hormones will also cause your fat to be distributed to your torso, so it is not surprising that your back is thick.
5, the natural growth of weight
If you don't exercise at ordinary times and don't control your diet, you will gain weight every year with your age. A study in the New England Journal of Medicine in March, 2000 found that adults under the age of 25 gained about 0.5 to 1.5 pounds a year on average. The age is between 25 and 44 years old, and the annual weight% is 3.4% for men and 5.2% for women (quite amazing range).