When I was 23 I focused exclusively on weights. When home for Christmas, I was excited to body my old neighborhood friends during pickup basketball. After all, I had seen some significant strength gains. At game time, I immediately gassed out and scored zero points and maybe got 2 rebounds. At half time my hip flexors seized up and I could barely walk home after. Go for a run, it won’t kill you.
Point here is I prefer to reduce HIIT volume to maximize fat loss opportunity during a cut. Fuel substrate preference works something like this in relation to VO2 max/intensity:
I’ll assume where you’re headed with the question is whether it’s technically still fasted cardio or not. So will put it in that context.
Answer is that it’s context/objective dependent.
Generally, EAAs + exo ketones will stimulate insulin response + activate mTOR. Common definitions for what “breaks” a fast. So if the objective is to maximize autophagy + mitophagy + general cellular cleanup efforts (usually need 24 hrs minimum), then technically both are a no (with the exception of pure ketone esters like Ketone-IQ).
If the goal is simply fat loss + having depleted glycogen stores - the reduction of fat oxidation from being in a completely fasted state vs. some EAAs is so minimal.
At a minimum - I prefer some degree of hydration + electrolytes in your situation.
When I was 23 I focused exclusively on weights. When home for Christmas, I was excited to body my old neighborhood friends during pickup basketball. After all, I had seen some significant strength gains. At game time, I immediately gassed out and scored zero points and maybe got 2 rebounds. At half time my hip flexors seized up and I could barely walk home after. Go for a run, it won’t kill you.
Good stuff Phys.
Curious on your personal cardio routine dependent on cut, maintenance, bulk?
For the most part the gain + maintenance phases for me are similar. Where things shift are during a fat loss phase.
Will provide example of last cycle.
Gain/maintain phase = 1-2x HIIT sessions/week, 1-2x fasted LISS/MICT sessions
Fat loss phase = HIIT goes down to 1x/2 weeks, 2-3x/week fasted LISS/MICT sessions
LISS = low-intensity stead state (Z2 + low Z3) → stairmill + incline walk + low resistance assault bike
MICT = moderate-intensity continuous training (Z3 + Z4) → stairmill + Jacob’s ladder
Point here is I prefer to reduce HIIT volume to maximize fat loss opportunity during a cut. Fuel substrate preference works something like this in relation to VO2 max/intensity:
< 60 % → fatty acids from adipose tissue + intramuscular triglycerides
60% - 75% → mix of carb + fat oxidation (**max rate for fat loss ~65%**)
> 75% → muscle glycogen + phosphocreatine
This is the idea of the crossover concept - at ~50% of VO2max we shift from lipids to glucose as our main source of fuel.
If you check out the write-up on the fat loss protocol I posted this past summer, I give more of the logic on this one if you’re interested.
Roger that, thanks for the breakdown. Have read your fat loss protocol and entire Substack at least 3x over lol.
Hoping for a Phys Mass Protocol soon👀
Great read! I can’t get to my fasted zone 2 until a bit later in the morning. Is it ok to use some essential aminos or exogenous ketones prior?
I’ll assume where you’re headed with the question is whether it’s technically still fasted cardio or not. So will put it in that context.
Answer is that it’s context/objective dependent.
Generally, EAAs + exo ketones will stimulate insulin response + activate mTOR. Common definitions for what “breaks” a fast. So if the objective is to maximize autophagy + mitophagy + general cellular cleanup efforts (usually need 24 hrs minimum), then technically both are a no (with the exception of pure ketone esters like Ketone-IQ).
If the goal is simply fat loss + having depleted glycogen stores - the reduction of fat oxidation from being in a completely fasted state vs. some EAAs is so minimal.
At a minimum - I prefer some degree of hydration + electrolytes in your situation.