The smell of chocolate can make exercise easier, scientists have found

The smell of chocolate may help you train more effectively even on an empty stomach. This is the conclusion reached by scientists from the University of Malaysia. The results of the study were published in the journal Frontiers in Physiology.

The study involved 23 men aged 20–25 who performed a workout after a ten-hour fast. During exercises on a leg extension machine, before each set and between sets, participants were given dark chocolate (90% cocoa), milk chocolate (60% cocoa), or odorless water to smell.

The results showed that the aroma of dark chocolate noticeably increased endurance. On average, the men performed approximately 18 more repetitions than during a workout without an olfactory stimulus. Milk chocolate also had an effect, but a weaker one — about nine additional repetitions.

At the same time, participants did not feel that they were training harder. Their ratings on the subjective exertion scale remained the same regardless of the smell, even though they had actually performed more work. In addition, the smell of dark chocolate reduced feelings of hunger and enhanced the sensation of fullness, while milk chocolate was mainly perceived as a more pleasant aroma but had almost no effect on appetite.

The authors believe that the effect is related to the so-called cephalic phase of digestion — the body's response to the smell of food before it is actually consumed. The aroma may activate areas of the brain responsible for hunger, motivation, and the anticipation of food. According to the researchers, the smell of dark chocolate creates the impression in the body that satisfying food will soon be consumed, making the workout feel easier to endure.

The scientists emphasize that the study has limitations. It involved a small number of young men, and the mechanism of action of the smell remains a hypothesis for now. Nevertheless, the results show that simple olfactory stimulation could become an unusual way to increase the effectiveness of fasted workouts without additional calorie consumption.