Can smells improve your athletic performance?

Under the supervision of Professor Marie-Eve Mathieu, Cournoyer compiled studies on the effect of odours on speed, endurance and precision in various physical activities.

Many studies have looked at the positive effect of physical activity on sense of smell, including the ability to recover the sense of smell after an accident or infection, and some have investigated hormonal or nervous response to the inhalation of specific odours.

But Cournoyer’s research project is the first to survey studies that examine whether certain odours promote or inhibit actions related to physical activity.

Cournoyer surveyed 19 studies with different—and even divergent—methodologies.

“We defined physical activity very broadly,” Cournoyer explained. “Since this is a new field, we couldn’t focus on one specific type of activity. What we found is that there are a wide variety of olfactory stimulation protocols in the literature.”

The number of participants in the studies ranged from 10 to 104 (most were in their 20s and physically fit); the duration of odour exposure varied from a few seconds to five minutes; and the methods of exposure included under-the-nose strips, absorbent cotton, masks, essential oil diffusers and more.

The studies were conducted in the U.S., U.K, the Philippines, Iran, South Korea, Japan, Palestine's West Bank, and Taiwan. There were no comparative studies.

Cournoyer classified the 19 studies by type of physical activity analyzed—strength, cardiovascular, precision and balance—and by odour tested—peppermint, citrus, lavender, ammonia, jasmine, woody scent and mixed essential oils.

Despite the variety of methodologies, some notable findings emerged.

For example, the five studies of strength-related activities showed that:

• ammonia increases heart rate, alertness and perception of performance;
• some odours can reduce diastolic blood pressure by 7 mmHg;
• peppermint added two push-ups at maximum effort;
• lavender can reduce attention span.

“Two extra push-ups may not seem like much, but bear in mind that we’re talking about fit young people for whom performance improvement is harder to achieve,” Cournoyer pointed out.

The five studies of cardiovascular function found, among other things, that:

• peppermint shaved 2.94 seconds off a 400-metre run and 53 seconds off a 1.5K run, increased cardiovascular capacity and lung function, and reduced feelings of fatigue;
• lemon and orange produced a sense of well-being during physical activity.

Two studies showed positive effects on precision. In one, jasmine improved bowling scores by 26.5 per cent. In the other, peppermint made dart players more consistent. One study even found that lavender improved balance.

“We were somewhat surprised by these results,” said Mathieu, Cournoyer's supervisor. “Some of the performance results are not negligible, particularly for improved cardiovascular response, although these are small studies and the results are crude.”