Science

Most people would typically think than smelling a scent (unless it's a powerful poison or medicament) won't change much in a person's health... but apparently, a variation in the scent environment has effect on the human brain, especially if the person is already old and their senses are degrading. It has also been observed that viral infections damaging a person's olfactory nerves result in changes to the brain - with less input, the neural networks involved with scent tend to atrophy. Coinidentally, some neural networks involved with scent recognition are also involved with memory.

Prios studies already support the idea that training one's sense of smell helps older people avoid cognitive deterioration. This study brings highly significant statistical results and adds one bit - wakefulness is not required to benefit. Apparently, the stimulation a person receives from feeling different scents bypasses sleep (or maybe, even improves the quality of sleep).