Cold showers have been shown to relieve depression symptoms due to the intense impact of cold receptors in the skin, which send an overwhelming amount of electrical impulses from the peripheral nerve endings to the brain. (medicaldaily.com)
The reason: Plunging into the water activates a number of cold receptors that reside underneath the skin, kickstarting a process called «cold shock.» (health.com)
The main compound in peppermint is menthol, which comprises about 30 - 40 % of the plant's essential oil and interacts with cold receptors in the body, providing a «fresh» feel. (herbazest.com)