Is there a link between immunity and the exposure to plants?

At this time of the year, when the heat is at its peak and seasonal allergy symptoms wreak havoc, many people tend to take refuge indoors. However, it seems that these people may derive surprising health benefits from spending more time outdoors: a series of studies suggests that people improve their immune function when they leave their concrete environment for a few hours in order to enjoy forests, parks and other areas where trees are plentiful.

At this time of the year, when the heat is at its peak and seasonal allergy symptoms wreak havoc, many people tend to take refuge indoors. However, it seems that these people may derive surprising health benefits from spending more time outdoors: a series of studies suggests that people improve their immune function when they leave their concrete environment for a few hours in order to enjoy forests, parks and other areas where trees are plentiful.

Naturally, decreased stress levels partly explain these results. But scientists believe that phytoncides – airborne chemicals that plants emit to protect them from rotting and insects – may also benefit humans.

A study conducted in Japan found that people who walked in the woods had lower concentrations of cortisol (a stress-related hormone), a lower pulse rate, and lower blood pressure than people who walked in the city. Other studies have also suggested that spending time in forested areas raises levels of white blood cells.

Exposure to plants and trees may therefore have beneficial effects on our health, although it is not yet known what specific mechanisms are involved. If you live in an urban area, this is yet another good reason to leave the concrete and asphalt behind and go take a stroll in the countryside!