It might sound like the worst start to your day — you get into the shower, and it's ice cold. But while you might not enjoy it, a cold shower could actually be good for your health. Spending time in cold water is not a new idea — the Ancient Greeks used cold water as a form of therapy as early as 3,500 BC. And things like cold water swims and ice baths have become quite popular around the world. Experts believe there are a few reasons cold showers could be good for us. Corey Simon, a doctor at Duke School of Medicine in the US, told CNN that having one or two cold showers a week helps him be more mentally present. He believes the reason for this is that he has to mentally prepare himself for something stressful: the cold water. But once he's in it, he feels like he's in control of that stressor. In fact, a 2022 study found that participants who showered for a minute in 10- to 14-degree water every day for two weeks had lower stress levels than a control group. Cold showers could also be good for our immune system. In a study done in the Netherlands in 2016, people who spent 30 to 90 seconds in a cold shower took 29% fewer sick days from work. Cold water has also been found to improve circulation, and can reduce muscle pain after a workout. Research suggests that taking a cold shower often could increase your metabolism too. But experts say it's important to speak to your doctor before taking cold showers often, because it could be dangerous — especially for those with certain conditions, like heart or circulatory problems.