Is morning running more weight loss? This statement is unreliable

Transfer from: Yangtse Evening Post Release date: December 13, 2018 Release department: General Affairs Department

        There is a widely circulated saying that running on an empty stomach in the morning can burn more fat? There are two reasons: Reason 1: After a whole night of rest and sleep, the body's glycogen has been depleted. At this time, getting up early and running can only directly use fat to provide energy, which is greatly beneficial for fat consumption, and the weight loss effect is also better. Reason 2: After waking up in the morning, the metabolic rate is the lowest. Through exercise, it can significantly increase the metabolic rate, maintain the optimal state of metabolic rate throughout the day, increase energy consumption, and thus help reduce fat.

　　Do these two reasons seem to make sense? It seems very reasonable, is that the case? Below, the editor will explain from the perspective of energy expenditure whether morning running is really more effective in losing weight.

　　一、 Can a night's sleep deplete the body's glycogen?

　　Generally speaking, the average person has about 5 grams of blood sugar in their blood, 100 grams of liver glycogen in their liver, and 400 grams of muscle glycogen in their muscles. Sugar in the human body is composed of these three parts, all of which can provide heat for exercise. When the human body is in a quiet state, it consumes 1 calorie per kilogram of body weight per hour (1 calorie/kilogram/hour), and the energy consumption level during deep sleep is actually lower than this standard. Even if the energy consumption during deep sleep is 1 kcal/kg/hour, an adult male with a weight of 60 kg will consume 1 hour of energy for 8 hours of sleep at night × sixty × 8=480 kcal. Assuming that all the 480 calories are powered by Glycogenolysis, and 1 gram of sugar decomposition can produce 4 calories, then: the maximum amount of sugar consumed in a night's sleep=480/4=120 grams. That is to say, after a night's sleep, the remaining sugar in the body is 480-120=360 grams. Do you see it? A full night's rest and sleep will not lead to complete glycogen depletion.

　　二、The claim that running in the morning burns more fat cannot withstand scrutiny

　　Have the runners seen it clearly? After a night of sleep, up to 1/4 of the body's sugar can be consumed, and there is no scientific basis for the claim that "after a whole night of rest and sleep, the glycogen in the body has been completely depleted". This is still an ideal value calculated based on the assumption that during sleep, energy is completely supplied by sugar breakdown. In fact, the 480 calories consumed during sleep cannot be entirely supplied by sugar, with about half of sugar and half of fat, which means that one night's sleep can only consume about 60 grams of sugar. So to say that 'because sleep consumes sugar overnight, running in the morning relies entirely on fat to provide calories' is purely false. During morning running, there is still a mixture of sugar and fat for energy, and there is currently insufficient scientific evidence to prove that morning running is more beneficial for burning fat.

　　Moreover, blood sugar is a very important physiological index, which cannot be fluctuated at will. The normal blood sugar concentration is 80~120 mg/dl. Low blood sugar will lead to hypoglycemia, while high blood sugar will lead to diabetes. We remember that during the physical examination, the hospital should emphasize the fasting blood glucose test, because only the blood glucose value at this time can reflect whether the glucose metabolism in the body is normal. If it is true that after a night's sleep, the glycogen in the body is exhausted, wouldn't it be possible to have hypoglycemia in the morning? In fact, this possibility is very small, because first, the glycogen in the body will not be exhausted after a night's sleep. Second, the machine will mobilize all possible factors, The statement that 'after a whole night of rest and sleep, the glycogen in the body has been depleted' may seem reasonable, but it cannot withstand scrutiny. Feeling hungry after waking up in the morning is not equivalent to having no sugar in the body.

　　三、Low metabolic rate in the morning, accelerating metabolism through morning running?

　　Nighttime sleep is indeed the slowest time for the body's metabolism. At this time, all we need to do is maintain breathing, heartbeat, and basic metabolic activities in the body. During the day, we need to engage in various production and daily activities, and metabolism will increase. During exercise, metabolism will naturally significantly increase, so this statement is correct.

　　During exercise, the human body can not only maintain a high metabolic state and burn fat faster and more efficiently, but also maintain this high metabolic state for a period of time after exercise, which is called Excess post-exercise oxygen consumption. The so-called excessive oxygen consumption after Excess post-exercise oxygen consumption means that your heart rate may have returned to a quiet level after exercise, but you still keep breathing faster, that is, maintain a high metabolic state, which you may not be aware of. But in fact, for a long time after exercise, your breathing is slightly faster than before exercise, which is definitely a dream of fat people every day - sitting can lose weight, Because maintaining faster breathing for a long period of time after exercise means accelerating heat breakdown.

　　Of course, running in the morning will accelerate metabolism, which does not mean it is more weight loss. Running at any time can accelerate metabolism and will not cause significant differences in metabolism due to changes in exercise time. So it is correct to say that morning running accelerates metabolism, but there is no scientific basis to say that only morning running accelerates metabolism.

　　四、Morning running suggestions

　　Although running on an empty stomach in the morning may not reduce fat more than running at other times, it still has many benefits, such as helping to develop the good habit of going to bed and getting up early, and helping to develop the good habit of eating breakfast every day. Here are some reliable suggestions for morning running given by the editor.

　　1、It is not necessary to eat before running in the morning, but it is recommended to drink some water before running in the morning. After a night of sleep, the body will evaporate a portion of water in a non sweating manner, and the body may experience mild dehydration. Replenishing water is perfectly normal. If you feel hungry, you can eat a small amount of food as a cushion, but don't eat too much.

　　2、The outdoor temperature is relatively low in the morning, so pay attention to keeping warm and adding a coat is a good choice.

　　3、Now it has entered winter. Due to the "temperature inversion" phenomenon, the haze tends to gather on the ground when it cools down at night, while the surface heats up when it is exposed to the sun during the day, and the haze is carried to the high altitude. Therefore, in winter, the haze tends to be heavier in the morning, but it will be lighter in the afternoon. Therefore, it is recommended to reduce morning running in winter, and at least check the Air quality index before going out.

　　五、summarize

　　Running on an empty stomach in the morning can definitely reduce fat, but it won't be more effective than exercising at other times. Getting the body moving is the most important thing, which is the core idea expressed in this article.

(Editor in Chief: Xu Xiaohua, Yang Di)