A study has found that smelling chocolate scent alone may increase the amount of strength training people can perform. In particular, when people smell dark chocolate while fasting, hunger tends to decrease and the number of exercise repetitions tends to rise.

Japan's Gigazine reported on Oct. 12 that a research team at the University of Malaya in Malaysia examined the impact of chocolate scent on exercise performance in 23 healthy men who had done regular strength training for more than 2 years.

After fasting for about 10 hours, participants on different days smelled dark chocolate scent with 90 percent cacao content, milk chocolate scent and an unscented control solution. They were exposed to each scent for 30 seconds before exercise and during rest periods between sets.

They then used a leg extension machine to do 10 repetitions per set and continued until they could no longer perform the set number of repetitions.

In the results, total repetitions were 18 higher on average than the control condition when participants smelled dark chocolate scent. Milk chocolate scent also raised repetitions by an average of 9. Under the dark chocolate scent condition, the number of completed sets was also about 1 set higher on average than under the control condition.

A notable point was that there was no clear difference by condition in the subjective intensity of exercise reported by participants. That means exercise volume increased, but the exercise did not feel harder.

Dark chocolate scent also lowered hunger and appetite before exercise and increased feelings of fullness. The research team suggested that reduced hunger may have affected exercise performance.

However, milk chocolate scent increased exercise volume even though its appetite-suppressing effect was not clear. This raised the possibility that other psychological factors such as preference for the scent and expectations may also have played a role.

The research team stressed that the findings were from a small preliminary study. Because the experiment was limited to 23 young men and assessed only a single exercise, additional research is needed to generalise that chocolate scent is a way to boost strength training performance.