High-Intensity Intervals vs. Endurance Training

Are short, high-intensity workouts better than longer cardio?

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High-intensity interval training or endurance exercise? It's a choice that many people are faced with when deciding on the best workout program for their age, fitness level, and fitness goals. High-intensity interval training (HIIT) is certainly one of the most effective ways to increase fitness, lose weight, and improve overall sports performance.

It's all about packing in a lot of effort over a shorter period for time for optimal benefit. While the benefits of HIIT are inarguable, it's important to remember that endurance—referred to as steady-state cardio training—is equally important. While endurance training takes more time, it offers just as much in the way of health benefits with fewer risks.

Benefits of HIT

The seven-minute workout is only the tip of the HIIT exercise craze. For those who haven't the time or interest in endurance training, HIIT offers the payoff of a quality exercise program without consuming endless hours of your life.

HIIT affects your metabolism in different ways than steady-state cardio. With endurance training, the primary aim is to convert stored fat into energy, a process that requires a lot of oxygen (referred to as aerobic metabolism). HIIT, by contrast, uses both aerobic and anaerobic metabolism to generate energy for workouts.

  • During moderate-intensity portions of the workout, aerobic metabolism will convert fat, protein, and carbohydrates to energy in the presence of oxygen.
  • During high-intensity portions of the workout, anaerobic metabolism will convert glucose and a stored form of glucose called glycogen into energy. In the absence of oxygen, lactic acid will begin to accumulate in the muscles, causing the characteristic burn that comes with heavy exercise.

This dual metabolic process is believed to spur hormonal changes that burn fat more efficiently and continue to do so well after the exercise is finished. It also helps regulate the insulin response so that glucose levels in the blood are better controlled.

Drawbacks of HIIT

The main challenge of a HIIT program is obvious: you only get out as much as you put in. And that is where many people fall short. Over time, people will often pay more attention to the clock and less to the quality of their high-intensity routines. Others are simply unable to perform the intervals to the intensity needed to achieve quality results.

Even if you are able to cope, it's often difficult to motivate yourself when faced with extreme physical stresses at every workout. HIIT is tough because it hurts. Your legs will burn, your heart will pound, and your lungs will scream for air as you literally get soaked in sweat.

And that's the point of HIIT if you want to get results. HIIT is not about reaching a plateau and maintaining there. It's about pushing yourself out of your comfort zone so that, even if you sweat a little less, you are still pushing hard. Without a personal trainer or regular class to keep up motivation levels, many people simply give up.

In the end, HIIT isn't something you should do every day. The intensity is so high that, if done correctly, it will require at least a day or two of recovery.

Limit your HIIT workouts to no more than two or three days per week, giving yourself at least 24 hours to recover. Anything more can increase your risk of injury and overtraining.

The Importance of Endurance Training

While it is true that HIIT is great at producing a high level of fitness in a short period of time, it isn't necessarily more effective in burning calories than endurance training. In truth, a long, steady-state cardio workout can burn just as many, if not more, calories over a training session than a quick HIIT session.

Because endurance training is performed 60% to 70% of your maximum oxygen intake (known as your VO2 max), you can exercise longer—hours, in fact—without fatigue.

Because you are never deprived of oxygen, you can reach an endurance zone that allows you to stay active longer. By contrast, glucose and glycogen are rapidly consumed during anaerobic workouts, causing you to "hit the wall" more rapidly.

Add to that the fact that your heart is being stressed at a level considered beneficial to your heart health. Instead of pushing yourself to 95% of your maximum heart rate (MHR) and then stopping at the point of exhaustion, you can push yourself to 60% to 70% of your MHR, which over time can reduce both your resting heart rate (RHR) and blood pressure—both signs of improved cardiovascular health.

With endurance training, a full day of hiking, biking, cross-country skiing, or paddling can easily burn 2000 calories or more. Plus, you will reap the benefits of being outdoors. This, along with shorter recovery times, can make exercise more enjoyable and reduce the risk of burnout.

A Word From Verywell

Whatever your fitness goals, HIIT and endurance training can both get you there. Ultimately, they are two roads to the same destination: one harder and shorter, the other longer and less stressful.

While age, fitness level, and personal choice will play a role in your decision, you don't have to choose one over the other. You can incorporate both into your training schedule, along with some circuit training and strength training. The more diverse your training routine is, the less likely you will become bored or overtaxed.

4 Sources
Verywell Fit uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. American Council on Exercise. High-intensity interval training: why it works. March 2017.

  2. American Council on Exercise. 8 reasons HIIT workouts are so effective. September 2014.

  3. Boyle MA, Long S. Personal Nutrition. Wadsworth Cengage Learning. 2013.

  4. US Department of Agriculture. Physical activities calorie burn.

Additional Reading

By Elizabeth Quinn, MS
Elizabeth Quinn is an exercise physiologist, sports medicine writer, and fitness consultant for corporate wellness and rehabilitation clinics.