Does running decrease metabolic rate?

Long distance running and calorie restriction can cause muscle loss, which in turn will caused a decreased metabolism since it's directly linked to your lean body mass. You ever notice how skinny long distance runners are? How about compared to sprinters? Guess which one has a higher BMR...

I usually run about 20-25 miles a week, and my metabolism is not slow--apart from exercise, I'm quite sedentary, but had to set MFP to "Moderately Active" so I don't lose weight faster than I want to. And I'm 49 years old, not some young kid with a naturally high metabolism.

Long distance running and calorie restriction can cause muscle loss, which in turn will caused a decreased metabolism since it's directly linked to your lean body mass. You ever notice how skinny long distance runners are? How about compared to sprinters? Guess which one has a higher BMR...

i actually haven't noticed...and this doesn't help me, as now i have a tiny fear of doing any running

was hoping someone with the smarts could alleviate that for me!

Well running by itself won't decrease your metabolic rate, it just burns a ton of calories (especially long distance running) which requires you to eat a lot more calories. Unless you are running more than a few hours or do not eat enough calories, you will not burn through all your glycogen (stored energy).

What are your goals?

I am casual when it comes to fitness. Otherwise my brain feels overwhelmed and I just give up! I go to a bootcamp every Sunday, and at least one other class (step or some toning class). I then do cardio and weights at the gym one other night. I also run at least once a week, if not more, for probably 20 minutes each time.

I eat just over 1200 cals.

I am hoping this will get me cut, which suprisingly it has to a degree. My only issues right now are my thighs being soft, my butt being a bit bigger than desired, and my abs being..more of a belly.

I would be more concerned with the fact that you are so active and eat so little. That is where you will have your biggest downfalls and will lead to muscle loss and metabolic adaption if you do this for an extended period of time.

I've been training for a marathon, so I've been running far more in the last several months than I have in my lifetime, and I don't think my metabolism has slowed. While I can tell I'm getting more efficient (ie, 20 minutes spent running will burn fewer calories for me today than it did 5 months ago), that would happen with any exercise I did regularly. Overall, especially toward the end of my training as my mileage ramped up, my appetite has gone through the roof. I'm not trying to lose weight, but I am. Running is an excellent calorie burner for me.

Really? Someone posted this on a friends stream, and I was like "wtf", is this true!!!?

Here are some articles discussing this:

http://woman.thenest.com/running-speed-up-metabolism-6200.html

http://www.livestrong.com/article/152412-does-running-speed-up-your-metabolism

http://healthyliving.azcentral.com/jogging-metabolism-9850.html

Long distance running and calorie restriction can cause muscle loss, which in turn will caused a decreased metabolism since it's directly linked to your lean body mass. You ever notice how skinny long distance runners are? How about compared to sprinters? Guess which one has a higher BMR...

This!!

This is interesting. I haven't researched the topic extensively. It seems to me that most runners – myself and my running friends included – don't rely upon running as our sole source of exercise. We train to run, training that includes cycling, yoga and weight lifting. Personally, I love running for the benefits I gain from it just as I love all the other workouts I do for their specific benefits. Intuitively speaking, I would imagine whatever muscle loss that could occur as a result of burning calories during a run would be rebuilt through other conditioning methods. While most elite runners I see have very little body fat, they also have tremendous muscle definition and that makes sense considering the muscle required to keep a body in motion over long distances.

I think you can file this under the category of broscience and continue your running.

Yes. Using your muscles does not cause your metabolism to decrease.

not eating enough while doing tons of cardio, or no cardio at all is what decreases your metabolism. As it's been proved dozens, if not hundreds of times on this forum with all sorts of data sets and numbers to back it up. It's why anyone eating around the 1200 calories a day while exercising are dumb as hell. Because yes, they are killing their metabolism. Straight up fact.

i eat more when i work out, straight up fact! but eating a lot is what made me fat to start with, straight up fact!! i just don't obsess over the numbers like i used to. and my body is thanking me for it.

you would be wise to look at the metabolic reset threads in general.

i just did a search,and the first one to come up was a cluster of wonky information that i didn't understand. can you just explain it in simple words to me, the less jargon the better!

I'll try. To expand on your original question, metabolic decrease as far as I have read is primarily driven by what you eat. The body has the ability to increase and decrease it's BMR quite a fair bit, just by food sources. The lady in that thread was proof of it, she tested her metabolism and it was crazy low, because she was eating too little. She increased her calories a bit, and her metabolism shot way up. This was done with little else done in her routine. So thats the point. Don't worry about exercise near as much as if you're eating right. It's also the trap that FARRR too many people get caught in. They think less is more, so starve themself trying to maximize weight loss. And while they are doing it, sure it's working, sure they feel fine. Sometimes for months. Until they get to a point where they don't feel fine. Start feeling tired all the time. No energy for anything. Feeling cold. so they are now seeing the effects of starvation kick in. And to compound that, since they are starved, soon as they try and eat normal, just watch the weight pile back on due to the body killing it's metabolism to burn less calories. this is why 90% of people who try and lose weight fail, because they try and do it like this with very low calorie diets which work short term, but utterly kill themselves long term. Though granted if someone is really fat, the drop 100lbs, gain back 20 cycle can somewhat work for them, lol.

The converse of this was a doc called why skinny people are skinny, or something like that. They took a dozen people who claim to eat whatever they want and never get fat, and fed them all 5k calories a day for a couple months. Unsurprisingly, they all gained weight as they were all eating way above their TDEE. (again proving the point that diet matters above all) However, they ALL had huge metabolism increases too. Just from food intake. the body tried to adapt to it's new fuel intake. A few of the people in the study actually had relatively low fat increases too as the body adapted very well.

Now in regards to your original question, running itself does not kill your metabolism. HOWEVER, there is some evidence that it may contribute, but only when 3 conditions are present. 1) you're eating in deficit, 2) cardio is your only exercise source and 3) you're doing crazy amounts of cardio. If you're doing all 3, then there is some evidence that running may make things worse for you than diet only. But this should be a moot point for everyone on here as it's well established that any proper weight loss template has to have a lot more than just cardio.

So the takeaway from all this is slow and steady wins the race. It's a lifestyle change when it's comes to losing fat and getting into shape. Whatever you're doing must be something you're able to do for the rest of your life. Trying to make shortcuts or do crazy diets will come back to bite your butt.

TLDR: Running by itself won't kill metabolism. You need a very low calorie deficit to do it. Running may just make a bad situation worse. But will not be the cause.