Wednesday, June 2, 2010

Why wait after eating to work out? empathetic to the parasympathetic?

SO, here's a thought.
You know how your folks say don't go for a swim till an hour after eating? ever wondered why?

Here's a thought: turns out that eating triggers our peripheral nervous system, in particular, the parasympathetic nervous system aka "rest and digest"  - so blood is going to digestion (the GI tract is pretty long. that's a lot of blood flow).

That means the energy going to the digestive system is not going to be as available for the rest of the peripheral nervous system actions (sympathetic), like moving muscles. So when we try to workout while we're digesting, something's gotta give - our bodies aren't optimized to do both things happily at once. Parasympathetic trying to say relax, lie down, digest. WHen working out, the sympathetic is going "fight or flight" - as you can imagine it's not a happy thing. Conflicting chemicals everywhere.

Now some folks say they have no problem working out right after eating. Anything is possible. But generally speaking, what i'm starting to think is "give my body a frickin' break" - rather than try to force it to split its energy across two demands - digest on the one hand; workout on the other - why not give it a chance to rest and digest before switching gears?

What i've also been experimenting with is, while i support my rest and digest, and since digestion starts in the mouth (especially with carbs), i'm also trying something learned at the Sustenance course last summer, and that's focus on tasting the food. For me, that means no working while eating. It also means not trying to talk and eat concurrently.

The idea is that chewing food, while it does help break down food for digestion and thus improve the likelihood of getting more nutrients/less getting processed into waste, also helps improve the taste experience which means usually eating less at one sitting - satiation is related to a taste experience. Part of my hypothesis as to why good quality chococalte means less is more because of flavour.

So how does this chewing and attention relate to digestion? Potentially longer time spent in pre-gut processing of food - which means less time needs for the gut, means less effort by the gut, means easier job for the gut, means getting to a workout sooner?

And you know what? Well i'll tell you - it's actually nice to take a bit of a break after the meal to chit chat or gaze out the window or sit for a minute - if i need an excuse i have the excuse of "i need a few minutes to digest my food - i'm going to sit for a minute" - but it's quite zen or delightful. I like delight.

I find generally speaking i can have breakie (some sprouts, veggies, oil and vinegar - being sure to get protein/greens/fats in) and comfortably be doing good cardio (rowing say) within 20 mins of eating. Not an hour. Perhaps because of the attention on chewing? And really less food does seem like more: when less is on the plate - even if it's spinach leaves - i'm going to linger over the leaf as it were.

So all we are saying is, give the parasympathetic nervous system a chance: provide opportunities to enjoy food. When we're trying to lose weight, chewing, tasting longer; using flavourings like balsamic or seasoning, indulge the flavour, all good. and the workout can be well energised.

1 comment:

B. Broham said...

Funny you mention it, something relating to this happened to me a couple of days ago.

I had eaten some tofu scramble (if you're not familiar, it basically involves tofu, veggies, oats and a LOT of spices like turmeric and cumin).

That morning's ETK PM swing session was a bit of a fiasco. I figured waiting 45 minutes was enough time to wait. By the 4th set I could feel the acid in my esophogus and my form went to hell. I felt so exhausted.

Though I did not refund my breakfast, which was a good thing.


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