This question popped up last week and I though maybe more people are thinking the same.
The short answer is no. So you can stop reading now if you’d like
The notion that we need steady state cardio* for fat loss comes from the old idea that we have various heart rate training zones. When your heart rate is seriously high, you’re burning glycogen (or sugar), when it’s more moderate, we’re burning fat as a fuel source.
(*Steady state cardio is what we traditionally think of as “cardio” – running, biking, etc. for about 20 plus minutes.)
The above idea is a gross oversimplification of what goes on in the body, but it’s helpful for our discussion here.
When we’re in a moderate state of exercise, i.e. we can breathe relatively comfortably and speak 5-9 word sentences, we are predominantly burning fat. So it stands to reason that we need this for fat loss.
BUT, when we drop out of the steady state, we don’t continue to burn any more calories to recover.
When we go into an intense exercise state, like a tough CrossFit workout, we are burning glycogen as a fuel source. Afterwards, our body is still “working out” as it tries to recover from the Metcon, and this is where you continue to burn fat.
Again, this is an oversimplification of very complicated processes in the body.
Some of the members train with heart rate monitors and they’re regularly in excess of 170-180bpm for up to 20 minutes, far more cardio than they would get on the bike or rower!
So if fat loss is the primary goal of your training in CrossFit, what extra should you be doing? Sleep, active stress reduction, and nutrition. 30 minutes extra sleep will do way more for your waistline than another run (and a whole heap of more benefits too!) Dialling in your nutrition by inputting EVERYTHING into MyFitnessPal and making weekly adjustments will speed up your progress. For one, you’ll notice all the times we go off plan, and how much a cumulative impact they have.
Is there a time when you do need extra cardio? Yes. Primarily you need this as a competitive CrossFitter if you need to increase your recoverability. You’re at this stage when your sleep, stress reduction, and nutrition are all pretty dialled in and the increase in training volume is the best thing for your progress.
I really fleshed out that short answer, didn’t I?
Have a great week making the small, vital steps towards your goals! And if we can help with anything, let us know!
Thanks!
Colm