Metabolic equivalent, perceived exertion, and talk test to control exercise intensity

(II) Determining Exercise Intensity using Metabolic Equivalents (METs)

Metabolic equivalents (MEEs) are based on resting energy expenditure and express the relative energy metabolism level during various activities. Energy expenditure is generally expressed as oxygen uptake. The body's oxygen consumption is directly proportional to the energy expenditure during physical activity. The absolute value of resting oxygen consumption is approximately 250 ml/min, and the relative value is approximately 3.5 ml/min/kg. This value at rest is defined as 1 MET. Alternatively, the maximum oxygen uptake can be estimated using indirect measurement methods and then converted into a MET value.

Because this indicator allows for comparison of exercise intensity across different activities, it is widely used in exercise prescription development. The most common method is to look up the average METs value for the relevant activity to determine the intensity or metabolic level of a specific activity. However, when using it as a reference, it is important to be aware of potential racial differences.

(III) Determining Exercise Intensity by Self-Perceived Force (RPE)

In 1970, G. Brog first proposed using a rating of perceived exertion (RPE) of 6–20 to evaluate exertion intensity. Subsequent studies have shown that subjective evaluation of exertion is highly correlated with exercise load, percentage of maximum heart rate reserve, minute ventilation, oxygen uptake, and even blood lactate levels. Brog proposed that RPE × 10 is approximately equal to heart rate. RPE levels 11–16 are equivalent to a heart rate of 110–160 beats per minute, a value within the typical training intensity range. For normal individuals, RPE 11–16 is also close to 50%–75% of maximum METs (Mean Adjustments for Extreme Exercise) within the absolute exercise intensity range. Studies have shown that RPE is not affected by factors such as age, sex, and race, and can be applied to various populations.

(iv) Determining exercise intensity through "talk test"

The "talk test" is also a way to prevent excessive exercise intensity. If the exercise intensity is moderate, the exerciser can still talk with their companion. In short, both the "slightly tiring" and "talk test" are effective in controlling the amount of exercise appropriately.

Generally speaking, the intensity of aerobic exercise must reach at least 75% of your maximum heart rate. The intensity at which you feel "a little tired" during exercise actually meets the requirements for aerobic exercise intensity. In other words, aerobic exercise is the kind of exercise that makes you feel "a little tired," at which point a normal person's exercise heart rate is approximately between 70% and 75% of their maximum heart rate.

V. Control the duration and frequency of exercise

The duration of a weight loss exercise session should generally be 30 to 60 minutes per session, with the time spent reaching a certain heart rate being at least 5 minutes.

Exercise frequency should be arranged based on achieving the physiological indicators required for fitness activities. Reasonable arrangement of exercise frequency:

(1) 4 to 6 times/week, 1 time/day, persist in long-term exercise, and the interval should not exceed 7 days.

(2) If you have a long-term exercise foundation and good physical condition, you can increase the exercise frequency appropriately, 5-6 days/week, 1-2 times/day. The two exercise sessions a day should be arranged in the morning and evening respectively.

(3) People who are just starting to participate in sports or who have a sports foundation but have stopped exercising for more than 2 consecutive months should follow the three-three system to arrange the frequency of exercise, that is, exercise at least 3 days a week (1 time/day), and after the third week of continuous exercise, they can start the normal number of exercise sessions and the exercise program of the physiological standards of fitness exercise.

(4) Once you start exercising for weight loss, stick to the plan and don't interrupt it. Exercising once a day can quickly improve your physical function and fitness, achieving the effect of weight loss and fitness; exercising every 2-3 days can slowly improve your physical function and fitness, which can also play a certain role in weight loss; exercising every 4-5 days can maintain your physical function and fitness without declining, but it will not improve your physical function and fitness, and will not achieve the effect of weight loss and fitness; not exercising for 7 consecutive days will cause your physical function and fitness to decline. During continuous exercise, if you stop exercising for 4-5 consecutive days, your physical function and fitness will begin to decline; if you stop exercising for 7-8 consecutive days, your physical function and fitness will decline to the level of two weeks ago, which means that the exercise effect of two weeks will be lost.

VI. Emphasize tidying activities

Cool-down activities are 5-10 minutes of low-intensity exercise performed immediately after the main exercise. For example, after running, you can transition to a brisk walk and do some stretching. Cool-down activities have the following benefits: they help blood return from the muscles to the heart more quickly, help eliminate muscle soreness as soon as possible, and help lower body temperature gradually.