The Art of Quantifying Exercise Intensity and Energy Consumption: Practical Guide to Weight Loss, from Heart Rate Monitoring to Step Count Conversion

In addition, everyday physical activities, such as housework like mopping, washing dishes, and doing laundry, as well as commuting activities like walking and cycling, are all important forms of physical activity. These activities can also help with weight loss by increasing energy expenditure. Many people are too busy with work to exercise, so housework or daily commutes are the most practical and feasible ways to engage in physical activity. Recently, many of my colleagues have joined the ranks of those who walk to and from get off work, either walking the entire way or walking a few stops before taking the bus. After a few months, they saw results, not only controlling their weight but also increasing their energy levels. Housework is often done intermittently; it is generally believed that each session of this type of activity should last 10-20 minutes for its effects to be cumulative.

Activity level is determined by activity intensity, duration, and frequency. Generally, heart rate increases with activity intensity. Heart rate (number of heartbeats per minute) can be used as an indicator of activity intensity. To improve cardiopulmonary function and achieve weight loss, physical activity must reach a certain intensity to be effective. On the other hand, to ensure exercise safety, exercise intensity must be controlled. Generally speaking, the appropriate heart rate during exercise is 60% to 80% of the maximum heart rate. That is, the pulse rate (beats/minute) during exercise should be 150 minus your age, and should not exceed 170 minus your age.

For example, a 40-year-old's ideal heart rate during exercise is around 110-130 beats per minute; a 60-year-old's ideal heart rate is around 90-110 beats per minute. You can measure your heart rate during a particular activity by immediately counting your pulse for 15 seconds after finishing the activity. Multiply this number by 4 to get your heart rate per minute (60 seconds). This calculated heart rate is already lower than your actual exercise heart rate; usually, you add 10% to the measured value to represent your actual exercise heart rate.

It's important to note that the intensity of exercise each person can tolerate varies depending on their age, health condition, and whether they are a first-time exerciser. For safety, a medical check-up should be conducted before starting any exercise program to determine your health status. Begin with low-intensity exercise and gradually increase your heart rate to enhance the fitness benefits. If persistent discomfort occurs during exercise, stop immediately and seek medical attention if necessary.

Studies have shown that during short-duration, high-intensity exercise, the primary energy source is carbohydrates (glycogen), while the mobilization and energy release of fat exhibit a delayed effect. For a period at the beginning of each exercise session, carbohydrates provide a higher proportion of energy. Fat acts like fuel in a reserve tank, only being used when the main fuel tank (glycogen) is depleted to a certain extent. Typically, only when exercise lasts longer than 20 minutes does the body primarily rely on burning body fat for energy. Therefore, to increase fat burning and reduce stored body fat, moderate-intensity, longer-duration exercise is necessary.

How long do you need to exercise each day to be effective for fitness and weight control? Generally speaking, you need 30 minutes of moderate-intensity aerobic exercise daily, 5 days a week, or 150 minutes of moderate-intensity physical activity per week, to achieve fitness results. What is moderate-intensity activity? It's activity that makes your breathing and heart rate increase, feeling exerted but not strenuous. For ease of measurement, 1000 steps at a moderate pace are often used as a benchmark. Walking 1000 steps at a moderate pace (4 km/h) takes approximately 10 minutes. The 30 minutes of moderate-intensity physical activity mentioned above is equivalent to 4000 steps at a moderate pace. Please note that one step is not the same as one meter; one step is generally equivalent to about 0.7 meters.

The time equivalent to 1,000 steps for various activities is as follows: 3 minutes of moderate-speed rope skipping; 7 minutes of aerobics, badminton, or climbing stairs; 8 minutes of cycling (12-16 km/h); 8 minutes of brisk walking (5-6 km/h); 9 minutes of mopping the floor or sweeping the yard; 9 minutes of hand washing clothes; 10 minutes of moderate-speed walking (4 km/h) or slow dancing; 11 minutes of wiping windows; 12 minutes of cooking or walking; and 13 minutes of washing dishes or ironing clothes.

The activities in the table vary in intensity, so the time required to reach 1,000 steps equivalent also varies. For example, moderate-speed rope skipping only takes 3 minutes to reach 1,000 steps equivalent, indicating high activity intensity, while cooking and food preparation take 12 minutes, indicating lower activity intensity than moderate-speed rope skipping. The above-mentioned 4,000 steps per day is the minimum requirement. Increasing activity levels appropriately will enhance the fitness benefits. The "Guidelines for Physical Activity in Chinese Adults" recommends that healthy adults achieve 6-10,000 steps equivalent daily. This refers to the total amount of various physical activities each day, including at least 4-6,000 steps equivalent of moderate-intensity aerobic exercise. For overweight and obese individuals, at least 6,000 steps per day, 5 days a week, are required for weight loss.