Running in the heat can help to improve your cardiovascular fitness, as your body has to work harder to cool down and maintain a safe body temperature. It can also help to improve your endurance, as your body adapts to the heat and becomes more efficient at using oxygen and energy to keep you going. However, it's important to take proper precautions when running in the heat, such as staying hydrated, wearing lightweight and breathable clothing, and avoiding to run during the hottest parts of the day. So, if you're up for the challenge, running in the heat can be a great way to push yourself and improve your fitness levels.