Essential oils may be able to increase athletic performance and lung function.
A 2016 study looked into the potential effects of Spearmint and Neroli oils on running performance and lung function. The subjects inhaled essential oil prior to a 1500m run. Their lung function was measured after the performance.
Inhalation of essential oils resulted in better lung function (increase in Forced Expiratory Volume in the first second and Forced Vital Capacity) and a significant reduction in running time. The effect of Neroli oil was greater than Spearmint.
Although this was only a small pilot study, the fact that the Neroli group did better than the Spearmint group shows the effect was not due to the simple fact of inhaling a fragrance.