Does running eat muscle?

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13/09/2009 at 13:10
I just read this article and wondered if what it says is true. It claims that sprinting is much better than long-distance running because it encourages muscle growth, whereas long-distance running uses muscle for fuel. I'm curious - how can the depletion of muscles be avoided?
13/09/2009 at 13:15
I know from a more general 'working out' perspective that muscle will be depleted by almost any form of exercise if you fail to consume enough calories. If you do, then you should not really have to worry about loss of muscle mass but it would be correct to say that sprinting would be much more likely to encourage additional growth.
13/09/2009 at 13:21
I know the article talks about using muscle for fuel once glycogen stores are depleted, but what I was wondering is how to avoid this happening. What kinds of things should you eat/do in order to preserve glycogen stores?
13/09/2009 at 14:15

you mite find "the complete guide to sports nutrition" by anita bean helpful for topics like this.

 for carbohydrate loading which is done before exersize, you eat foods with complex carbohydrates (slow releasing) such as pasta and rice. the carbohydrates will be stored as glycogen in the muscle and other places in the body. during or before exersize you can use sports drinks or energy gells, these are loaded with simple carbohydrates which are fastly absorbed and give a fast release of energy, it will take 30 minutes to be absorbed, so this could be used during or 30 mins before training.

when your glycogen stores are depleted your body has two alternatives of energy stores. amino acids (muscle fibre) and fat. in short intense training fat will be used when glyogen is depleted. in long endurance training the muscle fibres will be broken down first. to avoid this you can take amino acid supplements before endurance training or event, the amino acids in your digestive system will be used before your muscle fibre.

hope this helps, forgive me if i get bits wrong its a long time since i read the book.

13/09/2009 at 14:34
Most people can store enough carbs to cover something like 20 miles without needed to replenish during a run; for runs/races longer than that you can top up on the move (energy gels, etc.) so I wouldn't say that many people's running 'eats' their muscle.  Well, it's not happened to me in 6 marathons!
13/09/2009 at 15:04

Your body will only start burning protein (not necessarily from muscle tissue) under extreme circumstances.  If your aerobic respiration is good enough you'll be able to burn fat once glycogen is depleted.  So if you've gone through the wall and you're still pushing hard (and how many people can do that?) then you risk burning some protein.  Take some fuel in on the run and you'll be fine.

Simply saying that distance running burns muscle without any qualification is sensationalist bullsh*t.  Not the first time a journo's gone for that.

13/09/2009 at 15:40
Well yes endurance exercise does 'eat' muscle - but it also builds it. Protein is in a constant state of flux in the body, it is constantly being used up and replace by your food.
Anyone else ever had the ammonia sweat after a hard workout? That's the output of protein being burned for fuel (for the brain primarily as when glucose in the blood drops, Body breaks down protein to fuel the brain which can only use glucose - not fat for fuel unlike muscles - crap explanation of complex process, sorry but hopefully it's semi sensible ).

It's complex and lots goes on while working out but the main thing is that unless you are a body builder obsessed with each mm round your bicep - then it's not really something to worry about if you eat a decent diet. i.e. enough carbs and enough protein to support your running.

If worried then a book like anita beans will give you more details and allay your fears. As usual it is a journo getting hold of one tiny aspect of something and managing to bullshit an entire article out of it.

13/09/2009 at 15:52
This is one of the reasons that some hydration products now have amino- acids in them.. They are designed for use during endurance exercise - SiS def do one although i can't remember the name. I would be willing to bet there will be gels with added protein soon too even if not already.

Basically - not really something to worry about - it's just one small aspect of fitness.

I am a marathon runner (slow one) who has the legs of a sprinter. So maybe i compensate by eating enough protein or maybe my mesomorphic body just insists on building muscle regardless of what i do. (rhetorical question BTW)

Read these articles with a pinch of salt. All these things and their effect on your body are quite small in isolation - but if you do feel like your losing muscle mass then read more about the physiology of exercise and find out exactly what's going on. It will be more than just a few runs eating your muscle mass.
13/09/2009 at 18:21

If you're doing a lot of endurance stuff and/or strength workouts then it's worth considering supplementation to help the recovery process. When I was doing a lot i used to take glutamine powder. 

13/09/2009 at 18:32
I take that too after every long run - supports the immune system (according to several nutritionists and sport nutrition books

13/09/2009 at 19:05
I read a similar article. Not sure how much science it was based on though, as the one I read said something along the lines of "as evidenced by the difference in physiques of marathon runners versus 100 m sprinters".  Since we all have different natural body shapes, perhaps some of the difference in physique between marathon runners and sprinters is down to what sport or running distance we choose in the first place, because our body shape determines what we might excel at. So, more muscular people may find they are better at sprinting, and that's why they take up sprinting.
That might explain why I'm not a very good long-distance runner, ha ha! 
Edited: 13/09/2009 at 19:05
14/09/2009 at 11:03
GymAddict wrote (see)
GA, can you recommend one that doesn't taste ? The last lot I bought was from my health food shop and it didn't mix well.
14/09/2009 at 11:15

Thats interesting GA/Siance, when I've finished my LSR i generally go for a Recovery drink which contains protein and carbs.

This blurb from their site says "Lucozade Sport Recovery contains 10g of protein to kick-start protein synthesis for muscle rebuilding and adaptation, along with 25g of carbohydrate to help rebuild glycogen stores used during exercise."

I think it's essential to take on fuel as quickly as possible after exercise to replace used stores and in fluid form this is quick, easy and tastes ok in orange flavoured.

14/09/2009 at 11:18
Interesting, and at the same time, very confusing, stuff.
14/09/2009 at 11:38

glutamine should be flavourless - i get mine from  and i just mix a teaspoon or so into diluting juice.  You need to stir just before drinking.

14/09/2009 at 11:39

Gaz, I take a recovery drink that contains protein and carbs too. Choklit milk! The glutamine is something I've been thinking of using again as I'm on a plan to increase my mileage.


Cheers GA

Edited: 14/09/2009 at 11:39
14/09/2009 at 11:58

I like the Mars chocolate drink Siance, but they're too yummy and moorish

Would you recommend a daily intake of Glutamine then to boost the bodies levels if doing higher mileage, or recommend for use anyway as a supplement.

14/09/2009 at 12:08
I used it when I was doing a silly amount of weight lifting, to enhance recovery. As with any supp, there's risk so they should be cycled. Depends on your training volume. If you get adequate recovery there's probably no need for it on a daily basis but save it for LSRs.
14/09/2009 at 12:13

Interesting how times have changed isn't it. 30 years ago when I was playing club rugby, doing weights and running a lot I only ever took vit pills and ate loads of steak, chicken or fish along with plenty of veggies and tried to stay healthy.

Thanks for the info,

14/09/2009 at 13:02
what happens if you do not replenish your glycocen reserves shortly after your work out? Say you run 10 miles, then do not eat until a few hours later? Thanks
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