The awareness of one's own motivation to exercise is more important than heart rate.

Often, dedicated aerobics instructors or gymnastics coaches are overly focused on heart rate measurements. They rigorously monitor every movement of the trainees, demanding that each trainee reach a standard heart rate, but they completely ignore the trainees' breathing and feelings, such as comments from the trainees themselves saying things like "too difficult" or "too easy." Various experiments have proven that directly asking athletes about their level of effort is more reliable than measuring heart rate; researchers call this "exercise awareness." Furthermore, most people are more likely to reach an aerobic state when exercising alone.

People who exercise regularly and still suffer from heart disease are extremely rare. Conversely, the rate of heart disease is significantly higher for those who don't exercise, indicating that a sedentary lifestyle is far more dangerous than a lifestyle with regular exercise. Therefore, electronic cardiac devices that enhance heart function are completely unnecessary for someone who exercises regularly; conversely, they are essential for those who dislike exercise or are in poor health, because an inactive lifestyle will gradually erode your life.

There was once a man who mistakenly believed that heart rate was a necessary indicator of exercise effectiveness. He discovered that his heart rate increased in a steam room, so he always sat there, with an electrocardiogram monitor attached to his chest, asking the steam room operator to adjust the steam temperature according to his heart rate. He thought that simply sitting in the steamy room, casually flipping through some magazines, would make him very healthy. We can't help but chuckle at such an idea, because we know that achieving good health is not as simple as just increasing heart rate. Our lungs, muscles, and indeed the entire body must be active. Otherwise, as I discussed in previous chapters, trying to cure a cold with antibiotics or lose weight by simply dieting are merely treating the symptoms, not the root cause, and cannot cure the imbalance in our physiological systems. Only by starting with the whole body and engaging in systemic, holistic exercise can we achieve fundamental change.

You can interpret your physical condition from your heart rate. It can tell you whether your health is improving or declining. It can also tell you whether your exercise is excessive or insufficient. However, it is ultimately just a tool. Treat this theory as one of the common-sense principles, not the only standard. Don't ignore the information sent by other parts of your body just because of your heart rate. The formula for calculating heart rate is indeed helpful, but it is by no means as perfect as we imagine.

Does it mean there's no reward without effort?

A woman once complained, "When I take fitness classes, the instructor always tells me to exercise vigorously because he says there's no such thing as a free lunch. But you advise us to take it slow and methodical. Who's right?" I think both sides are right! It all depends on your goals. If you just want to lose fat, then take it slow and methodical. If you want to build muscle, then do every movement with force and keep going!

Generally speaking, when we lift heavy objects using only a specific muscle group, especially after repeated lifting, our muscles will feel sore. This soreness is mainly caused by lactic acid production, which indicates that you are doing anaerobic exercise. When we lift heavy weights, muscle tissue expands and compresses nearby blood vessels, reducing blood flow to the muscles and hindering oxygen supply. When muscles are oxygen-deficient, metabolic processes cannot function, leading to the production of lactic acid. Excessive lactic acid buildup causes muscle soreness, but this symptom is only temporary; the pain will disappear once blood flow is restored to the muscles.

Take sit-ups as an example. It's an exercise that uses a small amount of abdominal muscle strength to support the weight of the entire upper body. Imagine: your left hand is lifting the weight of your abdominal muscles, and your right hand is lifting the weight of your upper body. Now do you understand what I mean by "lifting a heavy object with just a little bit of muscle"? Typical weightlifting works on the same principle. It uses a portion of muscles or muscle groups to lift a weight several times their own weight. After repeating this 10 to 12 times, it will inevitably cause soreness due to muscle fatigue or lactic acid buildup.

If you think about it carefully, you'll find that the principles of many bodybuilding exercises are essentially the same as weightlifting. Sit-ups use the weight of the upper body to replace the weight of the weight plate, while push-ups use the weight of the upper body to replace the weight of barbells and dumbbells. When I talk about different exercises, I emphasize the proportion of muscles worked by each type. Sit-ups use far fewer muscles than weightlifting, so muscles quickly become fatigued and sore. Men's chests and shoulders are more developed than women's, and their upper body weight is also heavier, so men find sit-ups more difficult than women. Push-ups are the opposite; compared to weightlifting, they work more muscles, so some people can do them for several hours straight. Standing leg raises work the external dorsiflexors of the leg, which are only a part of the leg muscles. People often mistakenly believe this exercise works the entire leg muscles, but the leg muscles are much larger than the external dorsiflexors. Raising the legs only causes the external dorsiflexors to rapidly accumulate lactic acid, achieving the effect of anaerobic exercise.

The general definition of "weightlifting" is: using a small number of muscles to bear heavy weights, resulting in rapid muscle fatigue or lactic acid production. However, carrying a 1 or 2 kilogram weight or a 30-kilogram backpack without feeling soreness does not qualify as "weightlifting." A more precise definition of "weightlifting" should be:

(1) Loading weight; (2) Anaerobic exercise; (3) Lactic acid stored in muscles increases muscle mass and hardness, but does not burn any fat.

Lactic acid is the main cause of muscle soreness, a process we call "oxidation," which is essential for muscle growth. In fact, fitness experts explain this process in detail because it not only helps with muscle growth but also strengthens muscles.

Let me reiterate: anaerobic exercise is the primary cause of muscle soreness, while aerobic exercise (fat burning) should not cause any pain. Therefore, the slogan for aerobic exercise should be "painless, fat-free." Those arguments that "no pain, no gain" likely refer to anaerobic exercise for muscle growth. Because muscles are oxygen-deficient, the content of muscle protein compounds will increase. So, when your soreness persists, your mindset should be, "What am I going to do? I'm getting bigger and bigger!"

The adage "no pain, no gain" doesn't apply to those wanting to lose weight, because muscle oxidation only burns glucose, not fat! So, if you're troubled by fat legs and force yourself to do 200 leg raises every day in the hope of losing leg fat, you're making a big mistake. This will only make your legs bigger and bulkier. Instead, you should try combining aerobic exercise to reduce leg fat and using anaerobic exercise, which produces lactic acid, to give your legs a more beautiful curve.

The correct way to burn fat: slow exercise

During my daily jog, I often encounter an overweight man. Whenever I see him, he's always panting heavily, his face flushed, and he's running at top speed. Finally, one day, I couldn't help but ask him, "Why are you running so fast?" He treated me like a fool, nonchalantly replying, "Of course, I want to burn more calories and lose weight!" But he doesn't realize that this is a huge mistake. He's incredibly stubborn and doesn't understand the importance of learning new things. If you have friends like this, please share the key points of this article with them.