When faced with the temptation of eating something delicious, making the decision to get off the couch and go to the gym can seem impossible.
But there’s good news for couch potatoes: scientists have discovered the chemical that makes us choose exercise over overindulgence.
A team of researchers at ETH Zurich has discovered that a chemical in our brain called oxerine plays a key role in the decision to exercise.
In laboratory tests, mice with their oxerine systems blocked spent more time drinking a delicious shake and less time running on their wheel.
Researchers say the chemical should have the same effect on humans, potentially paving the way for a pill that makes us want to hit the gym.
There’s good news for couch potatoes: Researchers say they’ve found the chemical responsible for making us choose to exercise over snacking (file image)
Around the world, a large number of people do not get the amount of exercise they need to be healthy.
According to the World Health Organization, about 80 percent of adolescents and 27 percent of adults do not get enough exercise.
This, coupled with the availability of highly processed, high-calorie foods, has culminated in an “obesity epidemic.”
Professor Denis Burdakov says: ‘Despite these statistics, many people manage to resist the ever-present temptations and get enough exercise.
“We wanted to know what it is in our brain that helps us make these decisions.”
To understand how we resist the temptation to indulge, researchers placed mice in a chamber with eight corridors leading to different options.
The researchers placed the mice in a chamber with eight equidistant aisles. One aisle contained an exercise wheel (top) while the other was either empty or contained a “highly palatable food” (labeled HPF) in the form of a strawberry milkshake.
Of those options, one was an exercise wheel and the other was either empty or contained a “very tasty food” in the form of a strawberry milkshake.
Without any interference with their neurochemistry, the mice divided their time between exercising and eating either their regular food or the shake when it was introduced to them.
However, when researchers blocked the oxerine system using a drug or genetic modification, the mice were significantly less interested in exercising.
As this heat map shows, when the shake was added (right), the mice spent less time eating their regular food, but spent the same amount of time exercising.
Compared with mice whose oxerine systems were intact, the modified mice spent twice as much time at the “shake bar” and half as much time exercising.
Interestingly, when mice were placed in a chamber with either a shake or an exercise wheel, interference with their oxerine systems did not affect their behavior.
Professor Burdakov says: “This means that the main role of the orexin system is not to control how much the mice move or how much they eat, but appears central to making the decision between one or the other, when both options are available.”
In the past, many researchers have tried to explain our eating and exercise habits by looking at dopamine, a brain chemical.
When the mice’s oxerine system was inhibited, the addition of the strawberry milkshake caused the mice to spend significantly less time exercising and more time eating. This graph shows where the mice spent the most time
This chemical is central to our general motivation, but it doesn’t necessarily help explain why we choose to do one thing rather than another.
“Our brains release dopamine both when we eat and when we exercise, which doesn’t explain why we choose one over the other,” says Professor Burdakov.
By isolating oxerine as a critical factor, researchers hope to pave the way for treatments that could have a similar effect in humans.
Co-author Dr Daria Peleg-Raibstein said: “If we understand how the brain arbitrates between food consumption and physical activity, we can develop more effective strategies to address the global obesity epidemic and related metabolic disorders.”
Researchers believe oxerine could be key to “temptation-resistant voluntary exercise” and could even treat humans to help them choose exercise over eating (file image)
Researchers believe there is a strong chance that an oxerin-blocking drug could have the same effect in humans as it does in mice.
Scientists have already discovered that approximately one in 2,000 people has a restricted orexin system.
These people usually also suffer from narcolepsy, so oxerin-inhibiting drugs are also used to treat insomnia.
While the researchers behind this trial will continue to focus on the basic neurochemistry of oxerine, they say further clinical trials will now be possible.
Dr Peleg-Raibstein adds: “Now it will be a matter of verifying our results in humans.”
