High-Intensity Interval Training (known as HIIT) has swept through the fitness world and pulled in nearly every kind of athlete on the way. Everyone from bodybuilders to runners to dancers has found value in HIIT. Research keeps coming out that supports the far-reaching impacts of this approach to fitness. But for those who haven’t yet given HIIT a try, all this hype can make it feel a little intimidating. Make no mistake, HIIT will get the blood pumping and the heart racing. But it’s very easy to get the hang of and can be adapted to just about any form of cardio or body weight focus.
What is HIIT?
Fans of HIIT often have their own specific version or versions that they prefer to use, but beginners can rest assured that at its core, HIIT is easy to use. At its most basic, HIIT is nothing more than short bursts of intense exercise with rest periods in between. The periods of exercise can be as short as 10 seconds or as long as five minutes. Rest periods are either the same length as or shorter than the periods of activity. And, for maximum benefit, there should be between three and six periods of intense activity with a rest period between each one.
Things get slightly more complicated from there. Longer intervals (anywhere from 3-5 minutes), should aim to get the heart rate just below its maximum threshold. In these cases, the rest periods should be roughly the same length of time as the activity intervals. Short exercise intervals (anything under three minutes) should be broken up by rest periods that are shorter than the periods of activity. Shorter activity intervals also require more of an all-out approach where the athlete goes as hard as they can from start to finish.
Why Should I Use HIIT?
The short answer is: because it is wildly effective. A more in-depth answer can be found in the multitude of studies that have been carried out in the last ten years or so. Each one reveals some new benefit to HIIT and the results are surprisingly wide-ranging.
Improve Active and Resting Heart Rates
One of the most obvious benefits of HIIT is the way it affects a person’s heart. The exact numbers change depending on a person’s starting fitness level. But multiple studies have shown that HIIT can improve a person’s max heart rate, resting heart rate, and the amount of blood moved every time their heartbeats. A person’s max heart rate can improve as much as 46% in and their resting heart rate lowered in just 24 weeks. The amount of blood pumped, called the Stroke Volume, can increase by 10% in only 8 weeks. A higher stroke volume results in a lower resting heart rate and can be a sign of a healthy heart.
Increases Growth Hormone Levels
Growth hormones aren’t the first thing that most people think of when they’re training. But that doesn’t make the hormones any less important! Increased growth hormone levels also protect muscles when the body needs energy. This forces the body to burn more fat rather than the muscle.
A study published in the American Journal of Physiology-Regulatory, Integrative and Comparative Physiology in November 2018 showcased the time-saving benefits of HIIT. The study found that 20 minutes of HIIT produced the same results as 30 minutes of moderate-intensity jogging. While ten minutes might not sound like much of a trade-0ff, three sessions of HIIT a week saves up to half an hour. That, combined with the rest of HIIT’s benefits, makes an excellent case for the use of the training method.
Increases Mitochondrial Function
At this point, most people know the function of the mitochondria. Their importance in fitness is less well-understood, unfortunately. Mitochondrial Function refers to how well cells transform fuel (fat) into energy. Some studies also suggest that HIIT increases the number of mitochondria a person has but that point is still under debate. Long periods of low-intensity increase mitochondrial count, however. HIIT then strengthens the mitochondria to make them more efficient fat burners.
Lowers Insulin Resistance
Rates of diabetes and pre-diabetes are globally on the rise. There is currently no cure for these issues, but there are treatments and preventative measures. One such measure is to lower a person’s insulin resistance. This allows their body to more efficiently absorb and process sugar. Multiple studies have proven that HIIT is an effective way to lower a person’s insulin resistance. Not only does this decrease their risk of diabetes but it also aids in weight loss and weight maintenance.
Improves Cognitive Function
The link between mental health and fitness is well-known. HIIT’s effects, however, are still relatively new to most people. The results are surprisingly far-reaching. Studies have shown that HIIT improves general cognitive function and encourages the production of Brain-Derived Neuropathic Factors (BDNFs). BDNFs are necessary for mood regulation, memory, and learning. The brain also uses BDNFs to heal aged and damaged cells.
HIIT Workouts for Runners
HIIT is limited only by a person’s fitness level and creativity. It can be tailored to fit nearly any fitness goal and level. A few running-specific variations are listed below.
On the Track
HIIT on the track is a little different from other forms of HIIT. Instead of setting a time limit and going as hard as possible until it ends, runners should go as hard as they can on the straight-aways. A timer should be running so that they can see how long it took them. Walk the curves as a rest period before sprinting down the next straight-away. Repeat this circuit 4-6 times. The goal is to reduce the amount of time it takes to make it down a straight-away. Once the runner has reached an optimal time, they can apply a new HIIT variation to their track time.
On the Trails
Always ease into trail runs, with or without the use of HIIT. They have a higher injury risk than track runs. Once a runner is comfortable on the trail, however, HIIT can add a needed boost to their run. Mix five 30-second sprints into a 20-minute run. Once that is no longer a challenge, the runner can aim for a 40-minute run broken up by ten 30-second sprints.
Find a hill with a comfortable incline. Set a timer for 30 seconds and sprint as hard as possible up the hill. Rest periods are however long it takes to walk back down the hill. Repeat three times with the goal in mind of four 1-minute sprints with a downhill jog serving as a rest period.
How Much is Enough?
New HIIT users often make the mistake of pushing themselves too hard. This only leads to injury. Newcomers and anyone training for a competition or marathon should only incorporate HIIT twice a week. Anyone using HIIT as their main training method can increase their use to three or four times a week with at least one rest day in between.
- Runner’s World, The Ultimate Guide
- Self, High Intensity Interval Training
- Men’s Health, What is HIIT?
- Wikipedia, High-Intensity Interval Training
- Shape, 8 Benefits of High-Intensity Interval Training
- WebMD, High-Intensity Interval Training
- NIDDK, Insulin Resistance & Prediabetes
- Wikipedia, Stroke Volume