Physical Effects Boosts immune system by increasing white blood cells Speeds up metabolism by activating the sympathetic nervous system which increases heart rate. Homeostasis burns calories by bringing the core body temp back up. Reduces pain by causing blood vessels to constrict which reduces swelling and inflammation Improves recovery by reducing fatigue post exercise Stresses the body in a positive way Mental Effects Increases mood by releasing neurotransmitters norepinephrine and endorphins (runners high) Improves will power to do difficult things Rules Of My Challenge 13 Weeks Jump in the ocean at least once per week A week runs from Mon morning to Sun evening Can be any time of the day Full head must go under water Can be in the water for as long or as little as you like Methods To Try Cold Exposure Ocean swim challenge like I did. Shower hot and then cold at the end. Gradually build up to 2-3 minutes. Straight up cold shower Bath tub filled with water and bags of ice Studies The Effect of Cold Showering on Health and Work: A Randomized Controlled Trial https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5025014/ Effects of Cold Water Immersion and Contrast Water Therapy for Recovery From Team Sport: A Systematic Review and Meta-analysis https://journals.lww.com/nsca-jscr/Fulltext/2017/05000/Effects_of_Cold_Water_Immersion_and_Contrast_Water.32.aspx Adapted cold shower as a potential treatment for depression https://www.sciencedirect.com/science/article/abs/pii/S030698770700566X