How HIIT Can Improve Your Run Time

Want to know the quickest way to improve your running performance? Dr. Jonathan Su, the Get-Fit Guy, explains why HIIT training is so effective and the best way to incorporate it into your running program.

Dr. Jonathan Su, DPT, CSCS, TSAC-F, C-IAYT
5-minute read
Episode #577

I received a question from listener Alex from Austin, Texas recently about the best way to improve his run time. Alex shared in his email that he’ll be running his first 10K race in about 8 weeks and wanted to know if I had any suggestions that’ll help give him a performance boost.  

I was pretty excited to get this question! When I was a U.S. army physical therapist and Master Fitness Trainer, I did a lot of work helping people improve their running performance. It was my favorite part of the job and a topic I enjoyed reading research about. 

There’s evidence supporting resistance training, plyometric training, high-intensity interval training, altitude training, and even nutritional interventions such as caffeine intake as effective means of improving endurance performance. 

But if I had to choose only one of these approaches, I would choose high-intensity interval training—known as HIIT—hands down. The concept of HIIT is simple: you alternate between exerting high-level and low-level effort.

Not only is HIIT easy to implement into any endurance training program, its effectiveness is also well supported by research. Remarkably, participants in one study more than doubled their “time until exhaustion” on an endurance test after only two weeks of HIIT.

Japanese researcher Dr. Izumi Tabata was among the first to recognize the special benefits of high-intensity training. While studying the workout routines of Olympic speed skaters in the mid-1990s, he was surprised to discover that those who performed four minutes of higher-intensity exercise produced better results than those who performed an hour of lower-intensity exercise.

Keep listening to find out why HIIT is so effective. Plus, I’ll show you how to improve your run time with a simple HIIT program that you can incorporate into your training routine. 

Why HIIT is effective

As I mentioned earlier, the concept of HIIT is straightforward: you alternate between exerting high-level and low-level effort. What this looks like in practice is running near your max effort for 30 seconds or even a couple of minutes. Then, you run or walk at a much lower level of effort for the same amount of time or more before you do it again.

HIIT is higher in intensity but shorter in duration, with training sessions lasting anywhere from a few minutes up to 20 to 30 minutes at most. This is in contrast to traditional endurance training approaches where you would train at a continuous low or moderate intensity level for longer periods of time. 

Why is HIIT considered one of the most effective forms of exercise for improving physical performance even with shorter training sessions? It turns out that training at near maximal effort levels changes the body in ways that training at moderate or low intensity levels simply doesn’t. 

For example, on a physiological level, there’s greater activation of your anaerobic or “without oxygen” metabolism during HIIT. Your body switches into anaerobic metabolism when the intensity of physical activity is high because your aerobic or “with oxygen” metabolism can’t keep up with your body’s energy needs.

The problem with anaerobic metabolism is that its capacity is limited to about 2 minutes at most. After that, you run out of steam and have to lower the intensity of physical activity back down to a level where your aerobic metabolism can keep up. On a side note, aerobic metabolism is essentially limitless as long as you’re consuming enough calories.

One reason HIIT is so effective at improving endurance performance is because it changes the intensity level of physical activity where your body switches from aerobic to anaerobic metabolism. This inflection point is known as the lactate threshold and is the border between low and high intensity work.

The end result? You can maintain a faster running pace without crossing over into the highly limited anaerobic metabolism. 

Another bonus of HIIT is that the lower volume of training potentially means reduced risk of overuse injuries without sacrificing performance gains. 

HIIT program for runners

So, let’s look at how Alex, and every runner listening to me, can incorporate HIIT into their training program. According to a review that looked at 15 studies on HIIT for recreational runners, an ideal running plan that includes HIIT would have 2 to 3 HIIT sessions a week combined with low or moderate intensity continuous run sessions. 

The HIIT sessions would consist of 60 seconds or less of high intensity exercise performed at close to all-out intensities followed by the same amount of time or up to twice the amount of time of rest. Additionally, the accumulated amount of time exercising at high intensity levels should be 10 minutes or more for each HIIT session.  

A simple HIIT program for runners training for a 5K or 10K would look like this:

  • Day 1: 1 minute of running at close to all-out intensities followed by 2 minutes of walking repeated 10 to 15 times.

  • Day 2: Stretching and core exercises

  • Day 3: 20 to 45 minutes of low to moderate intensity continuous running

  • Day 4: stretching and core exercises

  • Day 5: 1 minute of running at close to all-out intensities followed by 2 minutes of walking repeated 10 to 15 times.

  • Day 6: Rest

  • Day 7: Rest

I recommend starting this program at least 4 weeks before your race. Begin at a lower repetition for the HIIT sessions on days 1 and 5 and at a lower intensity and duration for the continuous running on day 3. Gradually increase your repetitions during HIIT sessions and the intensity and duration of continuous running over time. 

Also, be sure to start each running workout with a 5 to 8 minute jog to allow your muscles to warm up. Begin slowly and gradually increase your running pace until you reach a brisk pace toward the end of the jog. 

Days 2 and 4 are stretching and core exercise days which will help you prevent injuries and improve running performance. Days 6 and 7 are rest days and are just as important as training days because your body needs rest to recover, repair, and get stronger. You can go back and listen to my episode about rest days from last November to learn more.

If you’re new to running or you’re just getting back into running after a long break, it’s ok to start with 5 repetitions and a lower intensity during HIIT sessions for a few weeks to allow your body to adjust. 

Every few weeks, you can replace the continuous running days with a full 5K or 10K at your race pace. There’s nothing better than putting in the hard work and watching your 5K or 10K time improve!

Thanks, Alex, for sending in this question! I hope you can put this knowledge to use in training for your 10K. If you have a question that you want me to answer on the show, email me at getfitguy@quickanddirtytips.com or leave me a voicemail at 510-353-3104.

All content here is for informational purposes only. This content does not replace the professional judgment of your own health provider. Please consult a licensed health professional for all individual questions and issues.

About the Author

Dr. Jonathan Su, DPT, CSCS, TSAC-F, C-IAYT

Dr. Jonathan Su is the host of the Get-Fit Guy podcast. He is a physical therapist and fitness expert whose mission is to make fitness accessible for everyone. Dr. Su is author of the bestsellers Six-Minute Fitness at 60+ and Six-Minute Core Strength.

Got a question for Dr. Su? You can email him at getfitguy@quickanddirtytips.com or leave him a message at the Get-Fit Guy voicemail line at (510) 353-3104.