A Hot—and Cold—Shower
How it helps: Temperature fluctuations jump-start your immune system, says Donielle Wilson, a naturopathic doctor in New York City. At the end of a shower, stand under the hottest stream you can take for 30 seconds, then turn the temperature to cold for 10 seconds. Repeat three times, finishing with cold.
Good to know: A steamy shower helps keep nasal passages clear and can prevent cold-causing bugs from taking up residence in your nose.