Combining HIIT and LISS

agthorn

I like to combine high intensity intervals and lower intensity steady-state back to back. It seems like the optimal set-up; the HIIT is more effective at releasing stored lipids and the LISS is more effective at burning them. What I haven't been able to find is how far apart you can have them and still get the benefits of the combination.

NROLW and other things I've read say to do intervals, stop for at least 5 minutes, and then do whatever low-intensity cardio you like for as long as you like. So there's a minimum, but what's my window of opportunity?

tl;dr - after stored lipids are released, how long do they hang out before they go back into storage?

agthorn

Bump?

jayliospecky

*looks around* Oh, sorry, I don't know either.

There should be somebody around here knowledgeable enough to answer this question.

*waits*

piesbd

LOL! bumping b/c I am interested in the answer too!

RaeN81

I am unsure of the exact amount of time between the two, but I have been reading for training and apparently, the glycogen window (the time when it is optimum to eat post workout) is 30-90 minutes after a workout so I would imagine that it is slightly tighter than this because you would expect that the reason the glycogen window is open is because you continue to burn calories at an increased rate or use the calories more effectively for muscle recovery. Sorry I cannot be more specific than this but I am interested to see what others will post.

diabolotry

I'm not sure I understand your question.

You start burning fat after other, more easily burned, energy sources are depleted and you continue to burn said calories so long as your body requires it to function. It's either used or the body doesn't need it so it stays right where it is.

agthorn

I'm still looking. I did see a study that reported serum HGH was elevated for 90-120 minutes after a HIIT workout with 30 second sprints, but I don't know if that same time window translates to lipid availability.

I'm really interested in whether or not it would be worthwhile to add a HIIT workout at my office gym before my yoga class an hour later. So if a 60 minute window is too long, it's probably not worth it.

agthorn

I'm not sure I understand your question.

You start burning fat after other, more easily burned, energy sources are depleted and you continue to burn said calories so long as your body requires it to function. It's either used or the body doesn't need it so it stays right where it is.

A HIIT workout in and of itself will only burn about 80 calories for me. But it will also release more stored lipids into the bloodstream due to the hormonal responses. If you do low-intensity steady state cardio after a HIIT workout, those lipids in the bloodstream are immediately available to be burned. If you don't do additional cardio after a HIIT session, yes I'll still have burned those 80 calories plus whatever the post-exercise metabolic effects tack on, but the additional lipids will be taken back up into storage. I'm interested in finding out how long of a window there is before the released lipids are no longer available.