Fat Loss - High Intensity or Steady State?

The key to fat loss: high intensity interval training or steady state cardio? 
by Simon Jurkiw, Research and Education Manager at Maximuscle.com

Power-walking on wet cold mornings, or repeated sprints on the bike; this seems to be the choice that many competing bodybuilders will be making this year in their quest for razor sharp abdominals and striated glutes. A common question for the confused competitor is, which one will get me shredded? Well, energy balance is key and nutrition is a fundamental part of that; this article focuses on whether high intensity interval training (HIIT) or steady state cardio is a better choice to increase energy expenditure.

Historically, bodybuilders have favoured long power-walks to ensure they stay in the ‘fat-burning’ zone. The ‘fat-burning’ zone graph is prominently displayed on a majority of cardio-vascular equipment in gyms across the globe. As a result, you often see people training at a very low-intensity; the perception being a slight percentage increase in heart rate could have the disastrous consequence of taking them out of their fat burning zone.  Bodybuilders that perform steady state cardio, such as an hour walk, generally point to the increased contribution of fat as a fuel with lower intensity, longer duration exercise.

More recently, many bodybuilders have accepted that this magic fat burning zone may not actually exist and have embraced HIIT.  The main premise of HIIT is that a period of high intensity or maximal exercise is followed by active recovery and then repeated. For example: 10 bouts of 15 seconds maximal on a stationary bike, followed by 45 seconds active recovery. Advocates of high intensity interval training, point to the benefits of high calorie expenditure over a short period of time.

So, going back to the original goal – which one will get me shredded?

There is a plethora of research studies highlighting the benefits of HIIT. For a competing bodybuilder, increasing energy expenditure is a main goal. Treuth et al (1996) compared low intensity with high intensity cycling and found that the high intensity session significantly increased energy expenditure during rest, exercise and over 24 hours with similar substrate oxidation rates to low intensity exercise.

Bodybuilders are primarily concerned with burning body fat and retaining hard-earned muscle. Talanian et al (2007) found that seven HIIT sessions over a two week period,”increased whole body and skeletal muscle capacity for fatty acid oxidation during exercise in moderately active women.” Basically, more body-fat was used as a fuel. 

The Tabata Protocol has received a lot of attention recently. In very brief summary, Dr Izumi Tabata demonstrated that only 4mins of work (20 seconds sprint, 10 seconds rest x 8) had pronounced effects on performance and energy expenditure in elite athletes.

There is clear evidence that HIIT can play a role in helping a bodybuilder drop body-fat; however, I feel there are a few important factors to consider before jumping on the bike for daily HIIT sessions.

Research from Parra et al (2005) showed that HIIT sessions that did not include days for recovery did not improve performance. This suggests that the muscle fibres suffered fatigue. A typical pre-contest phase lasts 12-16 weeks; performing upwards of four HIIT sessions per week on top of normal training is going to generate a lot of fatigue very early on. Let’s not forget, assuming rest periods are short, a typical weight training session is a form of HIIT in itself.

A majority of the research on HIIT is performed on elite endurance athletes whose training, and physiological make-up, is very different to bodybuilders. An endurance athlete will be able to cope with the increased intensity more easily than a bodybuilder.

Many bodybuilders do little in the way of conditioning work year round so base fitness levels, realistically, aren’t that high. Attempting to squat, deadlift and adding in multiple HIIT all while cutting calories may result in decreases in performance and unnecessary feelings of fatigue. Although a pre-contest bodybuilder is aiming for condition, not performance, maintaining as much muscle as possible is imperative – performance is part of this. Avoiding over-training in the early stages of a diet will also aid adherence, which in turn provides results. Fatigue may be inevitable, but it needs to be managed.

Again referring to the original question of which form of cardio should be the weapon of choice, clearly an argument can be made for both. In which case, why not utilise both? HIIT could be utilised away from training larger muscle groups to increase calorie expenditure over a prolonged period in a time efficient manner. HIIT also has the advantage of making “low intensity exercise less difficult, and more easily tolerated (Hunter et al, 1998).”  Steady state training can be used to increase energy expenditure during periods of fatigue, or when training larger body-parts (which creates more stress). An example, based on a typical 4 day weights split could be:

Monday AM: Steady state cardio 
Monday PM: Back
Tuesday PM: Chest + Shoulders + HIIT
Wednesday: OFF
Thursday: AM: steady state cardio
Thursday PM: Quads/Hams/Calves
Friday PM: Arms
Saturday: HIIT
Sunday: Off

Some prefer weights in the morning, others in the evening. Individual schedules, work and family life will dictate what works best for each individual. There are infinite variations; the above just provides a framework that utilises both types of cardio.

Obviously, an assumption has been made that cardio-vascular exercise has to be added to a pre-contest regime; an argument can be made that cardiovascular exercise isn’t necessary to get in contest condition, but that’s an entirely different article!

Hunter GR, Weinsier RL, Bamman MM & Larson, DE. (1998). A role for high intensity exercise on energy balance and weight control. International Journal of Obesity, 22, 489-493
Parra, Cadefau, Rodas, Amigo & Cusso. ( 2005) Scandinavian Physiological Society, 169, pg 157-165
Tabata I, Nishimura K, Kouzaki M, Hirai Y, Ogita F, Miyachi M, Yamamoto K (1997). Effects of moderate-intensity endurance and high-intensity intermittent training on anaerobic capacity and VO2max. Medicine and Science in Sports and Exercise, 28, 1327-1330
Talanian JL, Galloway, SDR, Heigenhauser G J F, Bonen  A, & Spriet  LL (2007). Two weeks of high intensity aerobic interval training increases the capacity for fat oxidation in women. Journal of Applied Physiology, 102, 1439-1447
Treuth MS, Hunter GR, & Williams M. (1996). Effects of exercise intensity on 24h energy expenditure and substrate oxidation. Medicine & Science in Sports & Exercise. 28, 1138-1143