How is metabolic age calculated?

The term metabolic age is often mentioned on various websites, and its calculation is offered by several devices. So what is it really about?

The basis of metabolic age is quite simple – although it is not an officially recognized quantity, it determines how your basal metabolic rate (BMR) compares to the average BMR value of the population with the same chronological age as you. So even though you and your friend are 40 years old (in chronological age), your metabolic age values ​​may be different because of the difference in your basal metabolic rate. Does it seem complicated? This issue will be explained in more detail in the following text.

What is basal metabolism?

Basal metabolism is the amount of energy you use each day to keep your body functioning normally. We can include, for example, the function of the brain, the pumping of blood through the heart pump, the activity of the respiratory muscles, the secretion of hormones and many others. Simply put, this energy would be enough for you to survive if you were lying motionless in bed.

Basal metabolic rate is affected by many factors – gender, age, body composition and even ambient temperature. As for the effect of chronological age, the basal metabolic rate does decrease as you get older, but in a different way than you might think. The decrease is not “gradual,” as the majority of the population believes  – it is more about longer development blocks. The fastest metabolism is between the ages of 1 year and 20 years. But then comes a long constant phase that lasts until the age of 60, and there are no dramatic differences between the metabolism of a 30-year-old and a 50-year-old (with the same lifestyle and body composition). Another significant drop in the rate of metabolism occurs only after the aforementioned sixty. Are you interested in this area in more detail? Read the article Does the rate of metabolism slow down with age?

In real life, however, other factors come into play, such as an age-related decrease in the rate of movement, a lower amount of muscle mass or, conversely, an increase in the amount of fat tissue. Thanks to this, the BMR will actually decrease by about 1-2% every 10 years .

How is metabolic age calculated?

There are many equations for calculating metabolic age – some include basal metabolic rate, others calculate body composition, waist circumference or blood pressure. And here a rather fundamental problem arises in the accuracy of the calculation – the BMR itself can only be measured in laboratory conditions, where it is also necessary to follow strict principles in order not to distort the results. So, if you have decided to measure your metabolic age in a fitness center, where you will be placed on a “smart” scale or, in the best case, on an InBody device that works on the principle of bioimpedance, you must take the resulting value with a grain of salt.

The issue of relevant and accurate measurement methods was also dealt with in the study by Hertel et al. from 2021 . In their research, the calculation was based on the concentration of metabolites obtained from blood samples and nuclear magnetic resonance spectroscopy , which is usually only available in hospital or laboratory facilities. Just to give an idea, the equation used to calculate metabolic age for male respondents was as follows:

From this figure, it is evident at first glance that the accuracy of the results comparable to the methods used in the studies cannot be reliably achieved in field conditions, and the resulting value is rather indicative.

So does this mean that the metabolic age figure is useless?

Although after reading the previous lines it may seem to you that comparing metabolic age with chronological age does not bring you anything fundamental, the opposite is true – at least to a certain extent. Metabolic age values ​​that you get from commonly available places will most often calculate with body weight, height, chronological age and body composition. A summary of these values ​​can help you evaluate your physical health , because excess weight and excess body fat is associated with the risk of many diseases. Although you can’t completely rely on its accuracy within a single measurement, in the long term it can show you quite well how the functioning of your metabolism is developing.

And how would it look in practice? Let’s say you are 35 years old and you repeatedly come out with a metabolic age of 25 years. From this you can take the information that your current lifestyle is appropriately set. If, on the other hand, you regularly get values ​​around 50 years old, it is appropriate to think about whether your regime might need a change. After implementing appropriate measures, you can then monitor whether the metabolic age values ​​decrease over time, and thus evaluate the appropriateness of the chosen changes.

• Did you know that obesity carries the risk of a long-term inflammatory environment in the body? You can find more interesting things in the article Obesity is not just a cosmetic problem: how do I know that I have it and that it can harm my health?

4 simple tips to lower your metabolic age value

1. More movement, more food

Movement is the best means available to support the functioning of the metabolism. A higher energy expenditure will allow you to take in more food, and your metabolism will go into overdrive. Even digesting the food itself requires a certain amount of energy, and  during strict reduction diets or starvation, the metabolism often “freezes”  – besides, such eating plans are unsustainable, unsuitable for the psyche and in many cases even dangerous.

And during which type of movement do you expend the most energy? Look mainly among aerobic activities with a lower intensity, but for a longer duration of execution. Examples are brisk walking, running, cycling, swimming, group lessons (aerobics, zumba) and others. However, make sure that you enjoy the activity and stick with it for a long time. What is the role of aerobic training for weight loss? you will find out in our next article.

2. Strength training

In addition to aerobic exercise, which is characterized by a high amount of released energy, you should also “sniff” exercise with weights 2-3 times a week. Strength training supports the growth of muscle mass, which is crucial for the speed of metabolism (the more muscles, the faster the metabolism). If you also give your body a good workout and reach for heavier weights on the barbell, you can look forward to the so-called EPOC effect, i.e. increased oxygen consumption after exercise. Up to 24 hours after training, your metabolism can run  6-15% faster .

3. Maintaining optimal weight

As already mentioned, body composition is closely related to metabolic rate. Excess weight and an increased amount of fat is a burden for the organism, and the contribution of adipose tissue to the function of metabolism is really poor. Therefore, pay attention to optimal energy intake and a balanced ratio of all macro and micro nutrients, and cover the drinking regime exclusively with pure water or unsweetened teas. Another necessary component of proper weight regulation is, of course, the aforementioned movement.

• What exactly is a healthy diet? You will learn everything in the article How to eat correctly or the principles of healthy eating
• Why is the drinking regime an essential part of a healthy lifestyle? Read the article Proper drinking regime as one of the keys to better health

4. Sleep

In the area of ​​normal metabolic function, sleep cannot be forgotten either – its quality and sufficient amount are key to the regeneration of all body systems. With sleep deprivation, not only will you not have the energy to move, but what’s worse, the ratio of hormones released in your body will change, you will have a greater appetite, and your muscles will grow less efficiently. Simply put, everything you strive for on the way to better metabolic function will come to naught due to lack of sleep.

• Are you wondering how the above mechanisms of sleep deprivation work? See the article Lack of sleep: Increases stress, appetite and slows muscle growth

What to take from it?

Metabolic age compares the value of your basal metabolic rate with the average value of the population that falls into your chronological age category. However, the exact calculation of this quantity is inconsistent and very complex, so outside of laboratories and medical facilities you will get a rather rough estimate .

However, even not completely accurate information can help you in evaluating your health, especially in the longer term. With repeated measurements , you will know if your lifestyle corresponds to the principles important for overall health , or if a change is required. You can also monitor whether the measures you have chosen are effective or not.

And how to support the normal functioning of your metabolism? Pay particular attention to maintaining a normal weight, exercise and quality sleep. The result will be not only a more favorable number on paper, but also better health.