Please choose the correct ending to complete the given sentence: Sports and Fitness: [header] How to control breathing while running [title] Determine the intensity of your run. [step] Since you won't always be running at the same speed, you should implement breathing techniques that suit the intensity of your workout. Think about whether you're going on a quick jog or training for a marathon.

Ending1: Your breathing might be slower and more natural for an easy session, whereas you'll have to take a more structured approach for harder runs to make sure you don't get exhausted too quickly. [substeps] It will be especially important to keep your breathing under control during tougher runs. Ending2: [substeps] If you're running a mile, pace yourself by working your way up to faster. If you're sprinting, keep your pace as low as possible and for normal intervals. Ending3: These are a step-by-step design and keep you running in a safe and consistent manner. [substeps] Running shorter or longer sets of steps is a great way to burn calories and keep the necessary amounts of fluid in your body circulating. Ending4: [substeps] Have a breathing partner guide you through the steps. This person can tell you if you need to change directions or zoom back in if you're losing ground.

Answer format: ending1/ending2/ending3/ending4