I've read that regular aerobic exercise actually helps keep hunger in check. I've noticed this myself -- for several hours after a (modest) workout, I am satisfied by small, light meals. Anybody know the physiological basis for this effect? Something to do with neurotransmitters?
There are three reasons I can think of:
1) Your inner organs tend to smoosh around when exercising. It takes a while before your stomach settles down. (I'm thinking specifically of running. How hungry are people after riding a roller coaster?)
2) If you dehydrate, your body suppresses hunger until water needs are met.
3) In high school health class (see, you should have stayed awake!), the three major "blood users" in the body are the brain, motor muscles, and digestive tract. You only have enough blood for 2 of the 3. Assuming that the brain wins out :) , that means exercising and digesting fight it out for the remaining resources.
Two reasons why you might be hungrier after swimming (vs running):
1) Swimming doesn't jostle your inner organs as much as running. So your stomach will be ready sooner. :p
2) Swimming lowers your skin temperature more (once you stop exercising). I've read (sorry don't remember where) that being cold causes the body to want to build up fat reserves.
All the more reason to jump in a hot tub after practice. :D
I think I'm getting closer to the answer. After a number of internet searches, I stumbled into the following article:
psychology.about.com/.../aa081000a.htm
It identifies serotonin, a neurotransmitter, as one mechanism by which exercise may moderate appetite levels. Another article I read mentions endorphins (which are also neurotransmitters, and which are released during prolonged exercise).
Now, I'm going to have a sandwich.
I might temporarily have suppressed apetite right after a swim, but I am voracious about 30 minutes later. It's very similar to the hunger I get after skiing.
Usually after about an hour of swimming, all I can think about is a huge cup of coffee and fried eggs and bacon. Swim to eat, eat to swim.
okay, here's a twist...
exercise like jogging, running, floor/step aerobics do decrease or supress my appetite, BUT swimming makes me voracious / ravenous! Anyone else experience this?
when at rest ,the body in association with the mind decides that it's a good idea to eat.
this is a survival tactic that the body/mind automatically goes into when given time to rest.
when swimming/exercising the body/mind is adrenalising,using reserves from the blood/fat etc this now being mode 2 stops the body from returning to want to stockup..for a while....
now where did i put that pizza...:D
I did some additional web-surfing on this subject, and it does appear to be the neurotransmitter serotonin that is involved here. Serotonin is secreted at a higher level during extended periods of moderate to heavy exercise. Along with its likely effects on mood (e.g., runner's high), it tends to suppress one's appetite for heavy, fatty foods, and incline one's tastes toward carbs. (This is consistent with Shaky's dissertation above.)
Personally, I find that I eat less overall on the days when I swim, even during the dangerous late evening hours spent in front of the tube. I think the above mechanism might explain why I would prefer lighter meals after workouts. In addition, in my case I think there is an additional psychological component -- I just don't want to mess up the progress I've made (in weight control) by pigging out after a good hard workout.
What Shaky says is so true!!!
As for swimming making people hungry, there are two factors.
First is, that swimming generally burns more calories then running.
Second is that it does lower the body temperature slightly, and the body does respond by wanting to store some fat.
You can offset some of that by swimming in warmer pools if you can, sit in a jacuzzi for a while after a swim, or taking a long hot shower. (long enough for your body to warm up.)
