Does Cardio REALLY Kill Gains?

1For most of you guys out there, CARDIO sounds like a 4-letter word. When I first started training, I was told not to do cardio because I’d lose gains. I looked over at the treadmill with a big grin on my face and waved goodbye.

Years later, I finally was told the truth: steady-state cardio offers some serious advantages for lifters. Once I started incorporating it into my routine, I actually improved my performance in the weight room. True story.


To understand the value of steady-state cardio for lifters, we first need to understand what fuels our body. Adenosine Triphosphate (ATP) is the currency our muscles use to pay for the work we do. ATP is the most basic form of energy and without it we’d be downright screwed.

We have 3 main energy systems we rely on to produce ATP:

  1. ATP-PCr system: This system kicks ass, but can only do so for six to ten seconds at a time. It’s the fastest at producing energy, but requires more time to recover.
  2. Glycolytic: This system is the intermediate one. It can hit hard and fast like the ATP-PCr system, but can’t sustain that for more than about 120 seconds of true work.
  3. Aerobic: This bad boy is awesome when it gets going. It takes longer to get up and running, but it’s incredibly efficient and you can count on it for hours at a time.5

High intensity forms of cardio such as sprints, and other HIIT-type training, work the ATP-PCr and glycolytic energy systems. This form of exercise is quick, dirty and straight to the point. You burn through a ton of ATP and glycogen in a short amount of time and you need longer to recover.

Aerobic cardio, on the other hand, can seemingly go on forever. Once you’re in the aerobic system, you can crank out ATP for hours on end thanks to its superior ATP production.


The most obvious point of cardio is that is easily improves body composition. In terms of physical development, the combination of resistance training and aerobic training is unmatched. This is likely due to the fact that resistance training increases metabolic rate, while aerobic training decreases hunger levels. Improved body composition also leads to increased leptin and insulin sensitivity, as well as increased testosterone and lower estrogen levels.


One of the most long-standing arguments in the lifting world against aerobic training is that it wastes away muscle tissue. Lifters who have put in countless hours of work are worried they’ll see all of their hard work for their gains disappear. Poof!

This concern is a given and one that does seem to be a reality. But when done correctly, aerobic training won’t be responsible for destroying your gains in the weight room. In fact, it might be just what you need to move beyond the progress plateau.4

If you’re still concerned, the perfect options for you would be cycling, swimming, rowing or even some time on the (dreaded) elliptical. The higher impact the cardio, the more muscle loss that’s likely to occur.