Young woman boxing and training

First things first—what the heck is HIIT? It stands for High Intensity Interval Training. And it features a series of short, hard efforts (followed by an adequate period of recovery) that push the body to the upper end of its physical limitations; it essentially involves switching back and forth between high and low intensity exercise.

During the past several years, HIIT workouts have become increasingly popular in the fitness community because they can produce some significant results with a minimal investment of time. The investment of effort is, however, a completely different story. The short, physical efforts need to be performed at maximum intensity. When done correctly, research has proven that HIIT can be just as (or even more) effective at increasing aerobic fitness than continuous, moderate-intensity exercise or CMT.

 While you might think that the benefits of HIIT come from its high-intensity training efforts, the key component of this workout is actually its recovery intervals. The recovery window is when your cardiovascular and nervous systems (which have both been pushed to their limit) adapt to the stress, learning how to return to a normal, resting state as quickly and efficiently as possible.

Ready to HIIT it? Here’s how:

Pick any physical activity that you can safely and effectively perform at 85 to 100% of your maximum heart rate (calculated by subtracting your age from 220) for a full 30 seconds. Then allow your body to recover (return to its resting heart rate). Repeat for a total of eight interval repetitions. Each workout should take about 15 to 20 minutes. HIIT or ‘burst’ training can be done anywhere—with or without equipment—once or twice a week.

If you are a competitive, endurance athlete, HIIT won’t serve as a complete replacement for all the training you need to do. But it can often serve as the stimulus some athletes need to break out of a training plateau. Or to maintain fitness when a reduced training load has been recommended. With a little creativity, even injured athletes can find a way to do some high intensity intervals, such as deep water running efforts in a pool.  

The Benefits of HIIT Extend Beyond Fitness.

And they include hormonal balancing effects like reducing ghrelin. Known as the ‘hunger hormone,’ ghrelin is produced in the stomach and is thought to be the only hormone capable of stimulating the appetite and causing food cravings. It is also released in direct response to stress, which explains why some women tend to eat when they worried, anxious, or upset. It also enhances the actions of leptin, known as the ‘starvation hormone’ because it’s what makes the body feel satiated and full. By notifying your brain that you have eaten enough food, leptin is key to maintaining a sufficient and balanced energy level.  

HIIT is very effective for inflammatory fat loss.

A study published in American Journal of Physical Medicine and Rehabilitation cited 62 overweight subjects who performed HIIT with strength training two to three times per week over nine months and saw significant improvement in both waist circumference measurements and overall body fat. In contrast, longer exercise sessions (exceeding 60 minutes) stimulate the over production of stress hormones, like cortisol. High levels of cortisol contribute to the storage of abdominal or inflammatory fat.

HIIT stimulates the release of powerful, anti-aging hormones.

HIIT has been shown to stimulate the production of human growth hormone (HGH).  HGH slows down aging by increasing exercise capacity, bone density, and muscle mass while decreasing body fat. Long, slow distance training has been shown to damage cellular mitochondria, accelerating the aging process.      

HIIT can control and prevent high blood pressure.

A study published by the American Journal of Cardiovascular Disease showed women at high risk for hypertension saw greater improvements to blood pressure after just 16 weeks of HIIT, compared to the group that performed 16 weeks of CMT training. Improvements to insulin sensitivity, stiff arteries, and cardiorespiratory fitness were superior among the HIIT group. 

HIIT can boost your metabolism.

HIIT increases post exercise oxygen consumption (EPOC). So after you complete a workout, your oxygen and calorie consumption can remain elevated for up to 48 hours. This higher metabolic output continues to fuel your muscles as they recover, repair, and re-build.  

Have you tried implementing any HIIT workouts into your training or recovery regimen? What has your experience been? Have you had any measurable results? Let’s talk about it in the comments section below.