Physical activity increases calorie consumption at rest

Until now, there have been two opposing hypotheses about how an organism manages its so-called energy economy.:

• The first one assumes that the body works like with a fixed salary: if we start moving more, the body compensates by reducing the cost of other functions, such as maintaining temperature or the immune system.
• The second model, flexible, claims that physical activity simply adds new costs, increasing overall energy consumption without saving on other processes.

A new study has confirmed exactly the second option: the more a person moves, the more calories they spend — without transferring energy from one system to another.

We followed 75 participants aged 19 to 63 years, whose activity levels varied greatly, from sedentary lifestyle to ultramarathoners. To accurately measure how many calories a person consumes per day, the oxygen and hydrogen isotope method was used: participants drank water with rare isotopes, and then the researchers analyzed their urine for two weeks.

The difference between the removal of these isotopes allows you to accurately calculate how much carbon dioxide and, consequently, energy the body has released. The activity level was recorded using a sensor attached to the belt.

The results showed that even with increased physical activity, the body does not reduce energy consumption for other processes such as breathing, heart function, thermoregulation, etc. In other words, the more movement there is, the higher the total energy consumption.

Previously, it was believed that with regular exercise, the body can save energy and thus limit the effect of training. However, a new study refutes this myth: the more you move, the more calories you burn — and this is not compensated by a decrease in the activity of other systems.

According to the head of the work, Professor Kevin Davy, the results confirm the importance of movement not only for weight control, but also for the overall metabolism.

The study also showed that more active participants spent less time in a sitting position, which further reduced their health risks.