Etiquette aside, some evidence suggests that a hot shower before exercising can increase your body temperature, encouraging blood flow and loosening any tense muscles, which should theoretically result in an easier workout. Unfortunately, though, since your body temperature will be higher to begin with, the chances of you burning out earlier in your workout are also higher. On the flip side, studies indicate that taking a quick cold shower, particularly before some cardio, can help the body withstand prolonged exercise at higher intensity levels, since the cold temperature lowers your heart rate, leaving both your muscles and heart with more room to keep on pumping during a workout before they inevitably overheat. For more on this “heated” topic, checkout my interview on the DSC Blog.