Best cardio choices to lean up WHILE keeping muscle (Part 1)


- Long steady-state cardio with calorie restriction can cause muscle loss AND fat gain

- HIIT heart rate training is usually superior to steady state cardio and doesn't take nearly as long

- Spiking the heart rate above 90% of its max has big hormonal effects that impact fat loss

- Long distance running can be detrimental to gains and also cause long term injuries


What the hell is cardio?

Cardiovascular exercise is defined as keeping the heart rate sustained at approximately 120bpm or above for 30 straight minutes (NSCA definition).  The heart rate changes with age and fitness but generally 120 beats per minute is the lower threshold I've found.

With this definition it is certainly possible to get a cardiovascular workout while building muscle at the same time with weight training.  We do this by monitoring the heart rate during exercise.  This is easy, as you can find your pulse on your wrist or jugular, with your pointer and middle finger.  Obviously if you have technology like a fitbit or pulse monitor watch this is automatic.

Cardiovascular exercise, in theory, should cause the body to turn on the "aerobic machine" meaning that fat is used as a fuel source over time instead of the other macros.

So I just need to hop on the treadmill or elliptical for 30 minutes and I'm good?

Unfortunately not.  While many fitness competitors prefer the steady state cardio method, I have seen many instances where a low body fat can be achieved with little to no steady-state cardio. 

What I mean by "steady state" cardio is prolonged cardio with a sustained heart rate.

I personally never put my clients on a treadmill.  First of all, it makes no sense to me why anyone in a state like Colorado would prefer to walk indoors unless its freezing out.  Secondly, maybe its my attention span but I want to shoot myself about five minutes into the session.  Its just so BORING!  and boring workouts don't keep people engaged long term.

Steady state cardio also has a catabolic effect on muscle which is exactly what we don't want to do.  Not to mention that most people's running stride, including my own, is pitiful and so over the long run ankle, foot, knee and back problems tend to come in.

Enter high intensity interval weight training:  The king of physique training

Bret Contreras ( has a laundry list of bikini competitors that usually do less than 20 minutes of steady state cardio a week.  In fact, they don't workout all that long in general, yet they are world-class competitors many times!

Many strength coaches including CT over at also advocate high intensity cardio performed in under 20 minutes, usually less than 10.  In fact, that is where I first got this idea years ago.  And it worked great for me!

Without getting into too much detail it has to do with heart rate and hormones.  Here's a great example:

Person A does 30 minutes of steady state cardio, using a 120bpm as a baseline.  The key is to stay around and slightly above this for all 30 minutes.  This person will break a good sweat for sure.  Due to the slight increase in heart rate there will be a higher percentage of fat being used with regards to carbohydrate (our go to energy source in most cases).

Person B does 10 minutes of high intensity training.  We'll use a jump rope.  1 minute of steady state followed by 30 seconds of sprinting in place with the rope.  We repeat this for 10 minutes.  The heart rate spikes to about 85% of their max heart rate at the end of each sprint, and then slowly returns to normal during the steady state minute.  10 minutes in we stop.

Who burned more calories?  More importantly than that...who burned more fat?  After all, calories don't mean sh*t here, we're only concerned with losing bodyfat.

The person on the treadmill burns a higher percentage of fat compared to other (carb and protein).  Very good!  However...

Person B burns less fat in percentage to carbohydrate, in fact they burn more calories total than the treadmill runner...but the percentage is lower.  So what gives?

Actually, even though the percentage of fat being burned is lower in person B, they still end up burning more TOTAL FAT.  

Check the graph below...

courtesy of 

courtesy of 

This graph shows two things.  First, we can see that the grey (treadmill workout) fails to burn as many calories per minute and overall.  This is listed as the "After Burn Effect".  The after burn effect is the key to why HIIT workouts are more effective overall.  they are shorter in duration and actually cause increased metabolism over the next 24-48 hours.  This is not only more efficient it also causes you to burn fat while you sleep!

In the next part I'll actually link a video where I explain this whole thing in detail, but for now, experiment with spiking the heart rate to 165 - 185 with interval training, let your heart rate drop back to 120 and then resume the HIIT won't be dissapointed!

Ben Hetzel

Strength and Conditioning Specialist

Benjamin Hetzel