Scientific Fitness Guide: Avoid These Eight Common Mistakes

In parks with morning running groups, community squares with dancing, and gym equipment areas, more and more people are embracing the philosophy that "exercise is medicine." However, along with this enthusiasm, many fitness misconceptions quietly emerge, reducing workout effectiveness and potentially creating health risks. In this article, we share insights from Dr. Wang Hongxing, Chief Physician of the Rehabilitation Medicine Department at Southeast University Affiliated Zhongda Hospital, and a performing arts therapist, to help you exercise scientifically and avoid eight common fitness mistakes.

Mistake 1: Working Out for Too Long

Many believe that longer workouts yield better results, but this is not true. The body has an "overload recovery" mechanism: moderate exercise allows muscles and cardiovascular function to repair and improve during rest. Exceeding 90 minutes in a single session can trigger a "catabolic state," breaking down muscle protein for energy, lowering immunity, and accelerating joint cartilage wear. For most fitness enthusiasts, limit sessions to 45-60 minutes, 3-5 times per week. Strength training should focus on 8-12 reps per set, 3-4 sets, while moderate-intensity cardio like jogging or swimming for 20-30 minutes is sufficient.

Mistake 2: Only Doing Cardio

Muscles are the engine of metabolism. Relying solely on cardio (like running or skipping rope) can lead to muscle loss, decreased basal metabolic rate (BMR), and slower fat loss. Muscle contributes significantly to daily calorie expenditure—each kilogram burns approximately 110 kcal per day, compared to 4-5 kcal from fat. Combine strength and cardio: during fat-loss phases, try 30 minutes of strength training plus 20 minutes of cardio; for maintenance, 2-3 strength sessions and 1-2 cardio sessions per week are sufficient.

Mistake 3: Targeting Only Belly Fat

Spot reduction is a myth. Fat metabolism occurs throughout the body. Localized high-intensity exercises strengthen the muscles but do not burn fat in that area. To slim the waist and abdomen, focus on overall fat loss through cardio and diet, and complement with core exercises to define muscle lines.

Mistake 4: Skipping Warm-Up

Skipping warm-ups is the leading cause of exercise injuries, particularly for weight-bearing joints like knees and shoulders. Without proper warm-up, muscles, tendons, and ligaments are less elastic, and joint lubrication is insufficient, increasing the risk of strains, tears, or meniscus injuries. Perform 5-10 minutes of dynamic warm-up such as high knees, arm circles, and lunges, targeting the main muscle groups.

Mistake 5: Not Stretching After Exercise

Stretching does not make muscles bigger, but skipping it can hinder recovery, increase tension, and reduce flexibility. Perform static stretches post-workout, focusing on trained muscle groups—for example, stretch quadriceps and hamstrings after leg exercises, or the posterior deltoid after shoulder workouts. During hypertrophy phases, consider using a foam roller first and stretching 30 minutes later to avoid affecting micro-tear recovery.

Mistake 6: Believing Sweating Means More Fat Burn

Sweating regulates body temperature and does not directly correlate with fat loss. Heavy sweating may result from high ambient temperatures, thick clothing, or individual sweat gland differences. Monitoring heart rate is more effective: the optimal fat-burning zone is 60%-70% of maximum heart rate (220 minus age). Also, pay attention to mild post-exercise hunger rather than dizziness or fatigue.

Mistake 7: Training the Same Muscle Group Every Day

Muscles need 48-72 hours to recover. Daily training of the same muscle group can lead to overfatigue. Muscle growth follows the principle of overload recovery: micro-tears from exercise repair and strengthen during rest. Overtraining the same muscles can cause atrophy, reduced strength, and inflammation. Use split routines: Monday – chest, shoulders, triceps; Wednesday – back, biceps; Friday – legs, glutes; weekends – rest or low-intensity cardio.

Mistake 8: Exercising on an Empty Stomach

Fasted workouts may burn more fat short-term but carry high risks. The body prioritizes glycogen for energy; high-intensity exercise in a fasted state can cause hypoglycemia. Long-term fasting exercise may break down muscle and lower basal metabolism. Healthy individuals should exercise 1-2 hours after meals. Those prone to low blood sugar or with diabetes can eat a banana or slice of whole wheat bread before workouts.

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