Another way to lower cortisol levels is by forest bathing, surrounding yourself with trees,4422 which may also elevate natural killer cell activity, as shown in a series of randomized controlled trials I document in see.nf/forestbathing. It turns out, as I explain in my follow-up video see.nf/treefragrance, trees produce aromatic volatile compounds called phytoncides,4423 like pinene, that you breathe into your lungs in the forest.4424 They enter your bloodstream4425 and boost natural killer cell activity.
