Chemical discovered that makes people choose exercise over snacks

The discovery may free people from the refusal to do physical exercise

Surely each of us has been overcome by laziness, and instead of physical activity we preferred to eat something tasty and do more peaceful things at home. If the choice of pleasures often outweighs physical exercise, then this can lead to not entirely favorable consequences for the body. But now scientists seem to have figured out why this might be happening.

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Scientists have discovered a chemical that makes us choose exercise over fun. A team of researchers from ETH Zurich has found that a chemical in our brain called orexin plays a crucial role in the decision to exercise.

In lab studies, mice with the orexin system blocked spent more time drinking a tasty milkshake and less time running on a wheel.

The researchers say the chemical should have the same effect in humans, potentially opening the door to a pill that makes us want to hit the gym.

In today's world, physical inactivity is as much (if not worse) a pandemic that is affecting more and more people.

According to the WHO, about 80% of teenagers and 27% of adults do not spend enough time on physical activity. Combined with the availability of high-calorie, highly processed foods, this has led to an obesity epidemic.

Professor Denis Burdakov says: “Despite these statistics, many people manage to resist the ever-present temptations and get enough physical exercise. We wanted to find out what exactly in our brain helps us make these decisions.”

To understand how we resist the temptation to indulge, the researchers placed mice in a chamber with eight corridors leading to different time-filling options.

Among these options, one was an exercise wheel, and another was either empty or contained a «very tasty treat» in the form of a strawberry milkshake.

Without any interference with the mice's neurochemistry, the animals divided their time between exercising and eating either regular food or the milkshake when offered.

However, when the researchers blocked the orexin system with a drug or genetic modification, the mice were significantly less interested in exercising.

Compared to mice whose orexin system was intact, the modified mice spent twice as much time in the milk bar and half as much time exercising.

Interestingly, when the mice were placed in a chamber with a milkshake or a running wheel, interfering with their orexin system had no effect on their behavior.

Burdakov notes, “This means that the primary role of the orexin system is not to control how much mice move or how much they eat, but rather to decide between one option and another when both are available.”

Dopamine was previously thought to be responsible for the choice of entertainment or exercise. Yes, this chemical is crucial to our overall motivation, but it doesn’t necessarily help explain why we choose one activity over another.

By isolating orexin as a critical factor, the researchers hope to pave the way for treatments that could have a similar effect in humans.

Study co-author Dr. Daria Peleg-Reibstein said: «If we understand how the brain chooses between food intake and physical activity, we may be able to develop more effective strategies to combat the global obesity epidemic and related metabolic disorders.»

The researchers believe there is a good chance that an orexin-blocking drug would have the same effect in people as it did in mice.

Scientists have already found that about one in 2,000 people have a defective orexin system.

People with orexin deficiency often develop narcolepsy, which is why orexin-inhibiting drugs are also used to treat insomnia.

While the scientists behind the study will continue to study the underlying neurochemistry of orexin, they say that further clinical trials will now be possible.