Interval Training Vs. Endurance Training

Which are Better? Short Intense Workouts Compared with Long Cardio Workouts

Healthy Female Lifting Weights with Trainer
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Which is better - high-intensity interval training or endurance exercise? High-intensity interval training (HITT) is one of the most effective ways to build fitness, lose weight and even improve sports performance. While I believe in these benefits of HITT, it's also important to remember the role longer, steady endurance exercise can play in a healthy lifestyle that includes long-term fitness.

Benefits and Drawbacks of High-Intensity Interval Training

Shorter, intense workouts have become the latest fitness craze, and the 7-minute workout is only the tip of the HIIT exercise madness.

For those who don't have the time or interest in long endurance exercise days, interval workouts became the ideal way to get the payoffs of exercise and still have a life beyond exercise. And although there is no question that HIIT is a great way to build, fitness, maintain fitness, and burn a lot of energy in a short time-frame, many people have trouble performing these high-effort intervals to the intensity required to get those benefits.

I'm a big supporter of interval training, but I'm also a realist, and unless you are a serious athlete, have a competitive spirit, or have a great trainer or coach, it's extremely difficult to motivate yourself to do all-out intervals. It's tough because they hurt. A lot. Your legs will burn, and your lungs will scream as you gasp for air. That's the point, but it's not for everyone. You need to have a base of fitness and then the motivation to push beyond your comfort zone to get the benefits.

That often takes time and practice.

While intervals are great, they also aren't the only thing. HIIT, while extremely effective at boosting fitness, and helping decrease body fat, isn't something to do every day. The intensity is so high that if done correctly, you'll need a day or two to recover fully.

Most people shouldn't do HIIT training more than 2-3 days per week.

It's also helpful to add variety to your exercise routine with some cross training and include lower steady endurance days. Combining hard interval days, low-moderate intensity endurance training days, and 2-3 days of weight training, can provide a well-rounded training program and produce well-rounded fitness.

HITT and Your Metabolism

High-intensity intervals use energy pathways that are quite different than those used during long, steady endurance exercise. Endurance training primarily involves the aerobic energy pathway to convert stored fat to energy, which requires a large amount of oxygen. Higher intensity interval exercise uses both aerobic and anaerobic metabolism (glycolysis) to help generate enough energy to fuel intense efforts. During HIIT, the body uses glycogen and lactic acid for energy.

The research into HIIT shows that using this energy system seems to have a whole list of other possible benefits, and many researchers believe that the hormonal changes that occur during HIIT make fat burning more efficient and effective after the exercise session is finished.

Benefits of Endurance Exercise

While it's true that all-out intervals are great for producing a high level of fitness in a short amount of time, for most people they are fairly difficult to do, and they may carry a higher risk of injury than slow, steady cardio.

When it comes to overall calorie burn, a long, steady cardio workout can burn as many, or more calories over the entire training period than a quick interval session. Because endurance training at about 60-70% VO2 Max primarily involves aerobic energy metabolism, you can exercise far longer — hours, in fact —without fatiguing. Exercising at this lower intensity allows the body to use oxygen to help convert fat to energy. This is why it's sometimes called the "fat-burning" zone.

To stay in the aerobic zone, you'll need to exercise at a lower level than during hard intervals, or slow down when you start gasping for air. The good news about aerobic metabolism is that the supply of fuel (body fat) is nearly endless, and you can exercise for many, many hours using this energy system. For this reason, the cumulative energy requirements used during long cardio sessions generally exceeds a 10-20 minute interval workout.

A full day of hiking, biking, cross-country skiing or paddling could easily burn 2000 calories or more, depending upon the terrain you cover. Plus, during that time, you'll reap the benefits of being outdoors in nature, and unplugging from all the daily gadgets and worries that are so common for most of us during a typical week.

Other reasons to consider including longer endurance exercise in your routine are because your sport requires it, or simply because you love it. If you want to perform well in a marathon, you have to train for a marathon. Same thing for anyone who wants to bicycle 100 miles in a day or finish an Ironman Triathlon. If you want to do well in endurance events, you have to train for endurance events. And some people simply love the feeling they get after long days of endurance exercise. For all these reasons, endurance exercise is still a wonderful way to build fitness.

Fat Loss and Body Composition

If you are mainly interested in seeing body composition changes, focusing on resistance training while eating a clean, healthy diet, may be the ultimate key to success, particularly in middle-aged and older populations. If you are looking for the simplest, most effective way to reach the right body composition for you, follow a healthy diet, do some weight lifting and choose which type of cardiovascular exercise you prefer—short, intense intervals or long, slow cardio—because either will help produce changes in body composition


Micah Zuhl, MS, Len Kravitz, Ph.D. HIIT Vs. Continuous Endurance Training: Battle Of The Aerobic Titans, IDEA Fitness Journal, Volume 9, Number 2. February 2012 []

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