T Nation

HIIT vs. Low Intensity Cardio when glycogen depleted


#1

Obviously I like hiit, its all i've been posting about lately. But would low intensity cardio be superior to HIIT later in the week (after a few days of low carbs) when your body has less glycogen for fuel and may be more inclined to go catabolic? Or would some pre - hiit whey fix this?

Judah


#2

bump


#3

Yes and no. While the lower intensity would utilize more FFAs as a percentage as fuel, you'll still burn more calories overall with HIIT. Personally, however, I'd still rather just crank up the intensity and offset the potential LBM loss with a boatload of BCAAs pre- and post-HIIT (along with traditional post-training nutrition).


#4

Empirically, more LBM is lost with longer duration cardio than with HIIT; many here could probably vouch for this.


#5

In the absence of adequate muscle glycogen--as would be the case with a low-carb diet--I would have to say that the low- to moderate-intensity route would probably be best for you.

While I'm a strong proponent of HIIT, you will not be able to sustain adequate intensity with this method of cardio training in the absence of muscle glycogen. You simply cannot mobilize fatty acids--whether they be from intramuscular triglyceride stores or adipose tissue--quickly enough to meet the high-intensity energy needs.

In addition, in a state of glycogen depletion, your best bet is to go the aforementioned route. However, if you're carbing up, then I would recommend HIIT for your energy system work early in the week (or however frequently your carb-ups are) until you're relatively depleted. This is when you would commence the lower intensity, steady-state stuff.