With the crisp autumn air, many people have once again set goals to lose weight and reduce body fat. How can you exercise scientifically to lose fat more effectively while maintaining good health?

Phrases like "exercise works better in summer" and "winter has higher fat-burning efficiency" are passed around. When, throughout the year, is exercise most efficient for weight loss?

Weather does have a certain effect on exercise outcomes. In summer, body temperature tends to be higher, and the overall activity of the nervous system, endocrine system, musculoskeletal system, etc., is relatively strong; energy metabolism is also higher, which is conducive to burning fat. Higher body temperature also helps reduce the risk of injury during exercise, because for every 1°C rise in body temperature, muscles and ligaments soften by 10%–20%, becoming more elastic and less prone to strains.

Warming up before exercise also uses this principle: with a proper warm-up, the body's temperature rises slightly, the cardiovascular and musculoskeletal systems are fully activated, exercise efficiency is higher at this time, and the risk of injury is lower.

In summer, exercising for fat loss also has certain advantages. This is mainly because when the human body encounters hot or cold weather, it consumes extra energy to regulate body temperature, which is “beneficial” for fat loss.

In winter, cold also stimulates appetite, and people are more likely to actively consume food to provide the body with more energy to maintain temperature. In cold weather, muscles and ligaments are relatively stiff, increasing the risk of injury. So, overall, summer is more suitable for exercising to lose fat.

Which type of exercise should you choose if you want to lose fat quickly?

The main factor affecting the exercise effect is exercise intensity. During low-intensity exercise, the body primarily uses fat as an energy source, with a small contribution from carbohydrates. As exercise intensity increases, the proportion of energy supplied by carbohydrates rises, while the proportion supplied by fat drops rapidly.

For example, during high-intensity activities like a 100-meter sprint, the body primarily uses carbohydrates for energy with almost no fat contribution, whereas during long-distance runs like a marathon, fat is the main energy source.

Therefore, if you want to burn fat more efficiently during exercise, low-intensity activities are the first choice. For example, brisk walking is a very good way to reduce fat. However, this type of exercise burns fat relatively slowly; the rate of fat-fueled energy production is low. If you want to lose 5 kilograms in a short time (such as one month), you need a sufficiently long daily exercise duration, such as 1–1.5 hours.

High-intensity exercise can also effectively burn fat. Because the body cannot maintain high-intensity exercise for long, high-intensity exercise usually takes the form of interval training, such as the variable-speed runs athletes do on the field. This type of exercise primarily consumes glycogen; fat is not well consumed during it. However, this kind of exercise can boost our basal metabolic rate, and after the metabolic rate increases, the body can burn fat even at rest. Compared with low-intensity exercise, high-intensity interval training sessions are relatively short, roughly 0.5 hours, which is one of its advantages.

In addition, resistance strength training is also a very good form of exercise, commonly referred to as "lifting weights." By working against resistance, this type of training can enhance the muscle metabolic level and increase the rate at which the body burns fat when not exercising.

Relatively speaking, high-intensity interval training and resistance strength training are best guided by professionals and require relatively good physical fitness to support them.

What are the benefits of appropriately increasing muscle mass for maintaining health?

Muscles can be said to be the cornerstone of bodily health. In middle age, muscles are lost at a certain rate each year. If you don't exercise at all and don't keep your muscles reasonably active, by old age your body's muscle mass will be only about 50% of what it was when you were young, and the burden on the remaining muscles is imaginable. Without a certain amount of muscle, people cannot maintain normal physical ability or independence in daily life; normal glucose and lipid metabolism is also hard to sustain, and the cardiovascular system will not be well protected, leading to more health problems.

Nowadays, people are paying more attention to sarcopenia in the elderly. Sarcopenia mostly arises from muscle loss following a lack of exercise in older adults. Regarding muscle preservation, there is a common misconception that every problem can be solved by eating. In fact, people's protein intake today is far higher than it was decades ago, yet the incidence of sarcopenia continues to rise each year, which indicates that the solution does not mainly rely on diet. On one hand, elderly people’s digestive function is weakened, making it difficult for their bodies to handle high-protein foods; on the other hand, diet cannot fundamentally resolve the problem of sarcopenia. Muscle growth and metabolism depend on physical stimulation—appropriate exercise is an excellent stimulus that can increase the activity of protein-synthesizing enzymes, promote muscle fiber hypertrophy, and improve muscle strength.

Muscle is the tissue in the body where most sugars and fats ultimately complete oxidative metabolism, so muscle is very important for maintaining health. Ensuring a normal amount of muscle in the body is beneficial for maintaining basic health and improving quality of life.