Avoiding common misconceptions about exercise for weight loss: Distinguishing between fitness and weight loss.

Section 4: Avoiding Common Misconceptions about Exercise for Weight Loss

In today's world where various weight loss methods are difficult to verify, more and more people believe that a balanced diet combined with appropriate exercise is the scientific and effective way to lose weight. However, experts recently pointed out that not all exercise helps with weight loss, and inappropriate exercise may actually make you gain weight.

1. The most effective way to lose weight is through exercise.

From the perspective of the body's internal energy supply, fat is only one of several energy pathways, but it's also the last one. Other substances provide energy first, and fat breakdown is only used last to provide energy to maintain bodily functions. Generally, fat-based energy supply only begins after 20 minutes of continuous exercise. Therefore, from a weight loss perspective, at least 20 minutes of exercise is necessary for the body to start burning fat. Running is a good exercise method; anyone can do it with a treadmill, and the intensity is relatively easy to control. Skipping rope is also very effective. Other options include aerobics, a fitness program introduced from abroad in recent years. It involves jumping and stretching to rhythmic music. In foreign countries, it's often performed by two instructors on stage, with dozens or even nearly a hundred participants watching from below. Aerobics is one of the most popular and effective fitness and weight loss methods abroad. In recent years, many fitness clubs and beauty centers have opened in major and medium-sized cities across my country. They offer on-site instruction from aerobics instructors, as well as learning through audio tapes. There are also more and more fitness instruction programs on television, making it possible to lose weight at home by doing aerobics.

Many people believe that if they have a thick waist and abdomen, they should do more sit-ups and abdominal exercises to lose weight. However, while sit-ups, abdominal exercises, and push-ups increase the strength of the muscles they work out, gradually giving them defined lines and improving their appearance, they don't usually burn fat during these exercises, so they don't contribute to weight loss. Unless these exercises are sustained for a considerable period, causing the body to utilize fat, they won't be effective for weight loss. Nevertheless, these are indeed very good exercises because they can make muscles fuller and more defined, helping both women and men achieve a better physique and a stronger body during the weight loss process.

2. Distinguish between fitness and weight loss.

The intensity of running differs depending on whether the purpose is physical exercise or weight loss/fitness. In the first 5 minutes of running, the heart adjusts to the body's demands, with a significantly increased heart rate and more intense, though uneven, pumping-this is the "cardiac adaptation period." After 5 minutes, the heart has adapted, pumping blood more evenly and adjusting according to the intensity of the exercise. Within the first 20 minutes of running, the primary energy source is glycogen, which breaks down into carbon dioxide and water under aerobic conditions, releasing a large amount of energy. After 20 minutes, most glycogen is depleted, and the main energy source shifts to fat. Fat is first broken down into glycerol and fatty acids. Glycerol is directly oxidized to provide energy, while fatty acids are converted into acetyl-CoA, which, after metabolism, is partially converted into glucose for energy. Since fat requires more oxygen for energy, when the running intensity reaches a hypoxic level, energy cannot be obtained through fat oxidation.

If your goal is to improve your physical fitness, you should run for at least 5 minutes; otherwise, it won't help improve your cardiovascular function. The longer you run (more than 5 minutes), the better the cardiovascular training will be. Speed ​​is secondary and can be adjusted according to your own physical condition.

Running for weight loss and fitness should last at least 20 minutes at a slow pace to maintain even breathing. A slow, long run of 20 minutes or more not only depletes glycogen stores but also utilizes fat. Because jogging is not very strenuous and doesn't cause excessive oxygen deficiency, it helps burn fat, thus achieving weight loss. During the first month of running, weight may increase slightly due to increased appetite, but it will drop rapidly in the second month. If you stop running, gradually reduce the amount and duration of exercise each day to avoid "rebound weight gain."

3. Three types of exercise that are not conducive to weight loss

Not long ago, experts compiled a list of three types of exercise that are not conducive to weight loss:

High-intensity exercise: Increased exercise intensity leads to a corresponding increase in the body's need for oxygen, nutrients, and metabolic byproducts. This necessitates the heart to increase its contraction force and frequency, and thus, its output of blood. During high-intensity exercise, the heart's output may not meet the body's oxygen requirements, resulting in an anaerobic metabolic state. Anaerobic exercise does not primarily utilize fat for energy release; instead, it relies mainly on the breakdown of stored glycogen. In an oxygen-deficient environment, fat cannot be utilized and may produce incompletely oxidized acidic substances, such as ketones, reducing exercise endurance. After short periods of high-intensity exercise, blood sugar levels drop. This drop in blood sugar is a major cause of hunger, often leading to increased appetite, which is extremely detrimental to weight loss.

Short-duration exercise: During aerobic exercise, the body initially uses stored glycogen for energy. After about 20 minutes, the energy supply shifts from glycogen to fat. Only after about an hour of exercise does the body primarily rely on fat for energy. For example, popular aerobics workouts for weight loss and body shaping typically last only about an hour. This means that exercise stops just as fat breakdown begins, resulting in minimal weight loss.

Explosive power training: Human muscles are composed of many muscle fibers, mainly divided into two categories: white muscle fibers and red muscle fibers. During exercise, such as explosive power training, the white muscle fibers are mainly trained. White muscle fibers have a larger cross-section, so the muscle group is more likely to develop and become bulky. Using this method to lose weight will make you "bulkier" the more you train.

In short, to achieve overall weight loss, one should engage in low-to-moderate intensity, long-duration (over 1 hour) aerobic exercise that raises the heart rate to 120-160 beats per minute. Examples include aerobics, jogging, and long-distance swimming.