"I have found in my training that short and fast interval runs are more effective for weight loss," McGreer told POPSUGAR. Besides burning lots of calories during the workout, he explained that HIIT workouts also increase something called the EPOC effect (which stands for excess postexercise oxygen consumption), which is the idea that your body is pulling in more oxygen to recover from your workout, and more oxygen means more energy which means more calories burned, even when you're no longer exercising. This "afterburn effect" isn't going to burn hundreds of calories or last all day, but it does give you a little bump that can help.
Interval runs also give you the chance to get into that fat-burning high heart rate zone without being too hard on your body. "If you're doing interval training, you can get your heart rate to that sweet spot range and back off to recover, then repeat, a number of times," explained Josh Muskin, a CrossFit Level 2 coach who specialises in endurance athletes. "Interval training ensures that the total time in the sweet spot zone longer than what the athlete could sustain in one continuous session." Try this simple 30-minute interval running workout as a start.
Even though interval runs can be great for weight loss, we don't recommend you do them every day; the intensity can still lead to injury or burnout. Mix in a longer, slower-pace run or two to increase your endurance, which will help you perform better on those HIIT runs. And for weight loss especially, consider adding strength training into your routine. Building muscle boosts your metabolism, which means you'll burn more calories throughout the day and not just when you're working out.
While 30-90 minute runs and higher intensities can help you lose weight, again, it's important that you work up slowly to those longer distances and faster paces. "You really need to listen to your body," McGreer told POPSUGAR. Even seasoned runners who run daily, he explained, still suffer from overuse injuries like shin splints and knee issues. Take your time, space your runs throughout the week, and (coupled with a healthy diet) your runs will help you see results.