Bring Back LOW Intensity Cardio for Fat Loss

From flickr profile: Mr.TimDC http://creativecommons.org/licenses/by-nd/4.0/

Ever since the “High Intensity Training” movement swept the fitness industry, low intensity or steady state cardio has been thrown out with a vengeance. I am pleased to see this “fad” came along because it brought sprinting, heavily lifting, and interval training to the forefront. These are all types of training I highly suggest for those who are able to handle it. The big question on my mind was how does low intensity cardio fit into a fat loss program? After all, bodybuilders both in the natural and open arena have been using it for decades to get down to the minimal body fat percentages of 2-4%. I strongly believe in looking at what professional athletes do to achieve their goals. For increased speed, look to sprinters, for more power on the football field, look to the NFL, and for maximal fat loss, look to bodybuilders. It is what they do for a living. 

Regardless of the extensive anabolics used in the open division, you cannot blame all their results just on this one component. Let’s take an open mind about this for a second. Take out any notion or negative opinion you may have about the sport and just take a non-biased look at what they do. They are the elite of building muscle and getting extremely lean. No one else is as effective at doing this. 

So what do they do to lose fat? In addition to diet, they use low intensity cardio to help burn off fat. Now most of us are not bodybuilders or anything close to one, but we can still take valuable lessons from them on how to lose fat.  So why would you do low instead of high intensity cardio? 

1. It takes little or no recovery time 
   
2. It burns calories without overtraining 
   
3. It won’t cause a major rise stress hormones
   


Low Intensity Cardio
This is roughly defined as light activity that gets you somewhere around 55%-65% of your maximum heart rate. For many people this may consist of a light hike, fast walk, easy-moderate cycling, yard work, or other light activity.

These are all great ways to get low intensity cardio in. If on a cardio machine, check you heart rate and keep it around 60%.

Light hiking

60% HR on a cardio machine

Light cycling Pic fr:Flickr:Montgomery County Planning Commision http://creativecommons.org/licenses/by-sa/4.0/

No recovery time needed
Sprints and intervals are great, but they can be overly taxing when done multiple times a week. I found this out first hand when I started sprinting a few years ago. My goal was to get my usual 4 days of intense lifting and 2-3 sprint/interval workouts in. The problem was that I had to sacrifice intensity in the weight room for a good track workout. Sprinting is an all-out activity that is very demanding on your nervous system. If this energy is used up on the track, you won’t have it for lifting weights.

Keep doing sprints or intervals, but keep them to 1-2 times a week depending on your goal. The good thing with low intensity cardio is that you don’t need much recovery time and it won’t affect your weight training workouts.

Burning calories without over training
For those who are really trying to speed up fat loss, doing a lot of sprint or HIIT (high intensity interval training) workouts while weight training multiple times a week and being on a diet can quickly cause you to burn out. Add in some long duration, low intensity cardio to help burn calories without over training. Also, this is a must for those with sedentary jobs because of the low activity level. 

Low Intensity Steady-State Cardio vs. Moderate Intensity Steady-State Cardio vs. High Intensity Interval Training and Hormones
Boy, I wish multiple studies existed with this title. Even if they do exist, the conditions under which the subjects are tested may not be what we are looking for. Common examples of these workouts are 45-60 minutes at 60% MHR (maximum heart rate), 30-60 minutes at 80% MHR, and 15-30 minutes at 80% MHR or to exhaustion in intervals for low, moderate, and HIIT workouts respectively. I’ve seen many studies testing the effects of exercise on hormones, but I have not seen studies specific to what the common exerciser actually does while comparing these intensities. 

There is evidence that high intensity workouts are more hormonally favorable for fat loss and muscle building than moderate steady state cardio. I believe this to be true. HIIT workouts being more favorable than moderate steady state cardio is supported. 

Low intensity cardio elevates stress hormones less than moderate intensity cardio. There is a positive correlation between exercise intensity and stress hormones. So won’t high intensity cardio elevate stress hormones even more? Yes, but they often drop back down soon after or the effects of cortisol is negated by an increase in anabolic hormones. 

In addition to your weight training, my suggestion is to do 1-2 days of HIIT workouts or sprints and 1-2 days of low intensity cardio at 60%MHR for 45-60 minutes. This will help you lose fat without overtraining and becoming exhausted. 


References:
1) Godfrey RJ1, Madgwick Z, Whyte GP. The exercise-induced growth hormone response in athletes. Sports Med. 2003;33(8):599-613.
2) Hackney AC1, Hosick KP, Myer A, Rubin DA, Battaglini CL. Testosterone responses to intensive interval versus steady-state endurance exercise. J Endocrinol Invest. 2012 Dec;35(11):947-50.
3) Hill EE1, Zack E, Battaglini C, Viru M, Viru A, Hackney AC. Exercise and circulating cortisol levels: the intensity threshold effect. J Endocrinol Invest. 2008 Jul;31(7):587-91.