Endurance or Intensity: The Optimal Way to Burn Fat

| Fitness

As a fitness professional for close to 15 years, I have prescribed many fat-burning programs for individuals of varying fitness levels. I have also encountered of alternate fat-loss strategies that at times have impressed me, but other times have left me shaking my head! It is not within my scope of practice to discuss nutritional-based strategies, however I will address a fitness-based approach that has varying opinions in its effectiveness.

So, which is better for burning fat: High Intensity Interval Training (HIIT), or Endurance Training (ET)?

Allow me to start off by saying that neither one is better. Rather, the question that should be asked is “which one is better for me?” A popular belief amongst some fitness professionals is that HIIT is a superior method for burning fat and ET is a waste of your time. Although the total time needed to achieve results from ET is generally longer, it is important to understand how scientific research plays a role in understanding these training methods. Longstanding research has shown that ET is effective for improving one’s cardiovascular health and body composition, but more recent research has also shown that HIIT is effective as well. In terms of physiological adaptations to cardiovascular exercise, research shows that HIIT yields seemingly better results than ET, but there is more to know about the research before accepting the results at face value.

The claim that HIIT is better than ET for burning fat is, in principle, supported by research papers that have compared interval training versus continuous cardio. What is rarely mentioned are the demographic that are used in attaining the results in these particular studies. Healthy, seemingly fit men and women in their early twenties are the prime candidates for these studies, so how does this affect you? Do you fit in the demographic that matches the research criteria? If you don’t fit the criteria, then which one is better for you?

HIIT is an effective training method for those wanting to improve muscle oxidization and exercise performance [2, 3], but utilizing fat as a fuel source using this method is more prevalent in trained individuals than untrained individuals [3]. Hence, if you are a fit individual who regularly exercises, HIIT may be a viable training method for fat burning. On the other hand, if you consider yourself to be unfit or live a sedentary lifestyle, ET may be better suited to your low/moderate intensity training capability. Although results show that short duration HIIT results are comparable to high volume ET [1], untrained individuals are at higher risk of injury, or perhaps burn-out due to the associated training intensities. Before engaging in a HIIT or ET program, here are some suggestions that may help you make better decisions regarding your individual training needs:

  • Seek out a certified fitness professional and request a fitness assessment to identify your fitness level and exercise limitations
  • Determine your fitness goals, and make sure they are specific, measurable, attainable, realistic, and time-bound
  • If you are new to an exercise routine, start slow, and increase your intensity as your fitness level progresses
  • Using both HIIT and ET methods during a program cycle may be optimal for your training needs rather than relying on one method alone
  • Seek the advice of a nutritionist for your caloric and nutritional needs. Exercise alone will not optimize your results!

1 Burgomaster, K.A. et al. (2008) Similar metabolic adaptations during exercise after low volume sprint intervals and traditional endurance training in humans. J. Physiol. 586.1:151-160

2 McKay, B.R. et al. (2009) Effect of short-term high-intensity interval training vs. continuous training on O2 uptake kinetics, muscle deoxygenation, and exercise performance. J. Appl. Physiol. 107:128-138

3 Talanian, J.L. et al. (2007) Two weeks of high-intensity aerobic interval training increases the capacity for fat oxidation during exercise in women. J. Appl. Physiol. 102:1439-1447