The core physiological principles of exercise for weight loss: negative energy balance, energy substrate conversion, and precise application of target heart rate.

Exercise is widely recognized as the healthiest and most effective way to lose weight. Its basic principle is to promote fat burning through exercise while ensuring the body receives the necessary basic energy. According to the energy balance theory, the fundamental principle of exercise for weight loss is that energy expenditure exceeds energy intake during exercise, creating an energy deficit. Energy intake should meet basic needs, while expenditure is primarily accelerated through exercise.

Energy primarily comes from food. Energy expenditure is related to metabolism, physical activity, and growth and development. Insufficient intake can affect growth and development, while excessive dieting is extremely detrimental to health. The body's energy intake includes three types of substances: carbohydrates, fats, and proteins. Glycogen stores are not large; if sugar intake exceeds needs, it will be converted into fat.

Protein is an important structural building block, and excess protein will be converted into fat for energy storage. During exercise-based weight loss, food intake must meet the body's needs and not exceed them. If food intake is not controlled during weight loss, the amount of stored fat will offset the amount burned through exercise, resulting in little effect. Strict control of food intake is essential to produce noticeable results.

Scientific exercise refers to using training methods to make the body's fat the primary energy source. The principles of a reasonable diet are: a variety of foods, controlled total intake, and a balanced combination. Heart rate is the most commonly used and simple indicator reflecting exercise intensity and the body's functional state. Target heart rate, or goal heart rate, refers to the desired heart rate level during exercise.

Exercising at too low an intensity is ineffective, while exercising at too high an intensity may cause injury. There are two methods for determining target heart rate: The maximum heart rate method. A person's maximum heart rate is 220 minus their age. The lower limit of the target heart rate = maximum heart rate × 50%; the upper limit = maximum heart rate × 60%. The heart rate reserve method. Heart rate reserve is a person's maximum heart rate minus their resting heart rate.

The lower limit of the target heart rate = (maximum heart rate - resting heart rate) × 20% + resting heart rate; the upper limit = (maximum heart rate - resting heart rate) × 40% + resting heart rate. Calculating using the heart rate reserve method takes into account the individual's resting heart rate, making it more targeted. Studies have shown that the target heart rate for obese patients exercising to lose weight is generally between 20% and 40% of their resting heart rate plus their heart rate reserve.

Determining your target heart rate plays a crucial role in weight loss through exercise. If the goal is weight loss, a specific exercise intensity is needed to ensure sustained fat burning. Knowing your target heart rate allows you to target your workouts effectively, maximizing results. Furthermore, considering the exerciser's workload is an important safety measure.

Obese individuals have lower exercise capacity than those of normal weight, and engaging in the same intensity exercise could significantly increase their risks. The purpose of determining exercise intensity is to ensure both safe and effective weight loss. Exercise safety is the prerequisite, while effectiveness is the goal. Within a certain range, a person's heart rate is directly proportional to exercise intensity. A target heart rate can be determined using an exercise stress test combined with an electrocardiogram (ECG).

Taking an exercise stress test as an example: first, the resting heart rate and electrocardiogram (ECG) are measured. Then, the ECG is recorded while exercising at different speeds on a treadmill. Based on the data, the safe exercise heart rate range and the maximum heart rate range for fat oxidation intensity are determined. The test must be conducted by qualified personnel.

Those with a positive electrocardiogram do not need to undergo further testing. Obese patients can walk at speeds of 4 km/h and 6 km/h.