Not Hungry After High-Intensity work, but Super Hungry After Low-Intensity Cardio

Different people react differently to different stimuli. That's not helpful but that's reality. My reaction to high vs low intensity cardio is pretty much exactly the opposite of yours.

Different strokes for different folks. I am not hungry any longer after any of my running.. On lifting days particularly leg day, I can chew my arm off..

From someone who has been running 2 1/2 years, how you train and how you eat prior and after is how you body adapt. You learn how to eat and when to eat that suits you.

In short longer runs or the shorter ones leave me not very hungry, shorter ones tend to be higher in intensity and the longer ones slow and steady..

Role of Endorphins?

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC489033/pdf/jnnpsyc00489-0001.pdf

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4613613/pdf/npp201567a.pdf

I think it may also have to do with the type of muscles you've built. You probably have more quick twitch muscle fibers that aren't as adept to low intensity, endurance exercises that slow twitch muscle fiber are good at.

Matthewdouglas0 wrote: »

I've been trying to figure this out, and wanted to see if anyone knows the answer. Generally, when I do 30 minutes of cardio in the 140 to 160 BPM range, I am not particularly hungry afterwards, but I am in that "Eh, I could eat," mood. If I wait long enough (say over an hour), I'll generally get hungry, but not intensely hungry.

By contrast, after a low intensity walk for 30-40 minutes at probably 100 BPM, I will sometimes get so incredibly hungry after wards I can hardly control myself. I feel like I've had a massive blood sugar drop and need any carbs/sugar I can get my hands on in order to get rid of the desperate feeling.

Does anyone have any idea why low intensity exercise does this to me, but high intensity does not?

There are three domains of endurance exercise used in the scientific literature. Moderate, heavy and severe.

Moderate feels exactly as its titled...moderate and sustainable...a long time pace, it is also aerobic (almost completely).

Heavy is the range where you can sustain for around 20-60 minutes but it hurts and you will blow up usually within the hour. Think a 5k-10k RACE in running. You are now starting to depend on your anaerobic ability more as the aerobic system can not meet all your body's energy needs.

Severe is the area where you can only make it a few minutes, it hurts like hell and you can not really talk. You overwhelm oxygen delivery and delete your anaerobic storage. While it really hurts its a good place to visit once or twice a week to get strong...its also called VO2 max workout.

When you are working in the heavy and especially severe range your muscles need a lot of blood or in other words all the oxygen you can get to them. Other organs are basically pulled off line so the muscles get what they need (this also happens in the times of crisis as some mentioned above). Please note in heavy you can also fully delete yourself it just takes longer...this seems to be the zone you are in. Also know when you are deleting your anaerobic storage this is a powerful signal to your body that bad things are happening...its creates a mini crisis...hence blood flow is changed (and you come back stronger with rest).

When you are done you body needs time to recover from the shock you just put it through and to return to baseline. If you plan on going the next day you need to eat in the as soon as you can...at least a little. It helps with recovery which helps with adaption to the training. The research is not clear on what is "best" but sugar is a good place to start. This is a whole another conversation.

So to answer your question: When you are in the moderate range your organs are still ok and working ok (not great but working), its not a huge push...when you go hard you are doing more "damage" and blood flow to non necessary organs is significantly reduced so it takes long for your body catch up and send hungry signals to the brain. I did a three hundred mile bike ride in one day this summer (took 17 hours). I made sure to stay moderate for the entire ride. I needed my stomach working as I needed to take in calories all day (burned 11000 that day). If I ever went to hard and entered heavy it would have doomed my ride. Its was the same way in my ironman...stay in moderate or else its a very long(er) day.

I now only train on the bike but have been an endurance athlete for a long time. The paces that used to be severe are now moderate. EVERYONE is different so you HR is only good for you but you can easily know what zone you are in with a really simple test (which has actually been researched)...if you can sing/talk...moderate, when singing is out and talking is getting harder you entered heavy, when you cant do anything other than gasp words you are at the end of heavy or are full in severe. Finally, HR really lags behind as its the result of pace not what determines pace...its very down stream measure of your effort.

The best athletes in the world visit heavy and severe ~two times a week and do crazy volume of moderate.