Day 8: Head outdoors for a sprint hill workout.
You’ve been doing two-a-days for the past week, now it’s time to shake up your workout a little. “Find a hill — hopefully one that’s 200 yards or so — and create an entire sprint cardio session around it,” says Kaiser. Here’s how: Sprint up the hill, pushing hard the entire way, walk back down, and repeat for 10 minutes. “It will feel super intense, but since you only need to push yourself for 200 yards at a time, you can handle it,” says Kaiser. To cool down? Go for a long walk or hike after your sprints, studies find that hiking leads to happiness, as that burst of fresh air can help keep negative thoughts at bay.