In weightlifting, we have a condition called overtraining. It's when you train so frequently that your muscles don't grow. You're breaking down muscle while it's still trying to build up. Not only does growth get stunted, but you also experience other ailments such as susceptibility to disease.

I was wondering if overtraining also applies to cardiovascular exercise. Will running too often stunt the growth of your cardiovascular endurance? The lungs don't break down and rebuild like muscle, so I thought more training means better lungs and blood flow.

  • When I do cardio every day, I find my glycogen stores get depleted. After a few days of cardio, I start feeling like I was hit by a truck. If I take some days off and let carbs accumulate in my body, I can train way harder on the days I do cardio. That said, my typical cardio session can be 2 hours or more, so this may not apply to the average exerciser.
    – Barbie
    Commented Mar 28, 2011 at 17:28
  • Barbie is right - its possible to overtrain on cardio, but not in the same sense as you would lifting weights. Your muscles dont fatigue so much but nutritionally, you can push yourself to the limit. I've felt it before but only after contiguous weeks of exercise and dieting at the same time. Its not a muscle-ache its a general lack of energy.
    – Nobody
    Commented Apr 4, 2011 at 14:07

6 Answers 6


Yes, you can overtrain from doing an excessive amount of exercise even cardio. Overtraining "is a physical, behavioral, and emotional condition that occurs when the volume and intensity of an individual's exercise exceeds their recovery capacity". You can get injured and you can show signs of emotional and behavioral changes from overtraining.

Everybody is different so there is no one-size-fits-all rule, but there are general guidelines to help people avoid overtraining during cardio: See previous question, Is there a rule of thumb for setting running goals

"Too much too soon" is a common phrase to describe why people got injured. The Cool Running website describes phases of physical shape you should be in as a disclaimer before attempting their rigorous training program (shown is half-marathon training phases):

Beginner - For runners who currently run 15 to 25 miles per week and expect to run the half marathon in about 2 hours.

Intermediate - For runners who curently run 25 to 50 miles per week and expect to run the half marathon in under 1:45:00.

Advanced - For runners who currently run 40 to 60 miles per week and expect to run the half marathon in under 1:30:00.

Competitive - For runners who currently run over 60 miles per week and expect to run the half marathon in under 1:20:00.

Cardio is all about making the muscles you use more efficient. Say you run 3 miles a day, your body gets into a routine. Your muscles get trained to keep running that distance and naturally your endurance will increase and running that distance will feel "easier" on you. Your heart rate isn't as high as when you started training; you're body is managing oxygen better. As you push yourself, increasing your miles, you push your endurance to also increase with you.

Yes, more cardio training will make your lungs and heart operate more efficiently.

ASIDE: I know it wasn't asked but it is important to note that changing your regimen to a majority of cardio will change your muscle composition to slow-twitch (long and thin) muscles which are more efficient for endurance. If you want to target your fast-twitch muscles you got from weight lifting, you should be doing high-intensity interval training (HIIT) in conjunction with your strength training.

  • So you say heart rate and oxygen flow are better the more I do cardio? These are good things. Are there any downfalls to doing too much cardio?
    – JoJo
    Commented Mar 28, 2011 at 19:07
  • Yes, aerobic activity increases endurance. I wouldn't call it a downfall, rather a side effect, but too much cardio eventually changes your muscle composition. What are your goals?
    – Rhea
    Commented Mar 28, 2011 at 19:46
  • My goal is to lose fat without losing muscle size.
    – JoJo
    Commented Mar 29, 2011 at 1:55
  • 1
    You should do HIITS then. Endurance training will decrease your muscle size. To help fat loss, I'd look into your diet and create a small calorie deficit (nothing drastic) or tweaks (less carbs on off-days and substitute for protein to maintain daily calories) you want to make sure you have enough calories to get you through your work-outs.
    – Rhea
    Commented Mar 29, 2011 at 3:11

In cardiovascular training I haven't heard of an observed effect with overtraining relating to lung capacity or endurance. What seems to correlate more highly there is risk of injury: those who overtrain cardio increase their risk of becoming injured (and then they don't get to train at all).

It seems the correlation is directly related to the level of impact/intensity. In other words, it's far easier to overtrain doing sprints and intervals than it is to walk long distances. While not scientifically supported I'm sure anecdotally this is why some people do fine going on mega-events like running a marathon every week or running a mile every day, I'm not so sure it would be as positive a result if someone targetted runnin 10 100m sprints every day.

  • 2
    I can't believe this is the accepted answer. There are many ways of being overtrained from cardiovascular training. For instance, if you run or do a lot cycling, especially on competition level, your body will have a harder time to get a high heart rate if you don't have enough rest or easy training days in between the harder days. Which is a direct result of overtraining.
    – MJB
    Commented Feb 4, 2019 at 10:08

Yes you can over train your cardiovascular system. Endurance running and weight lifting are very different activities that stress your body's systems differently but they both rely on the Overload Principle. Basically all the benefit you get from your training happens during rest, when your body is recovering from the overload.

When you train endurance you may not be tearing your lung tissue like you do your muscle tissue in weight training but you still overload your cardiovascular system and your endocrine system and if you don't give them the appropriate recovery time those systems will begin to operate less efficiently and you're performances will begin to decline. This is not to mention the over training affects on other systems of your body, pulled muscles, stress fractures...

Ultimately, regardless of the type of training a well planned program that balances overload and recovery is important to gain maximum improvement and reduce injuries.


A simple way to view this is any excessive stress makes a person more susceptible to well, basically you name the ailment. (For an extensive look at this, see Robert Sapolsky's Why Zebras Don't Get Ulcers.)

In which case, you can overtrain from any activity. Even if your job involves you sitting down all day, if it's significantly psychologically taxing you, that will eventually lead to overworked aka overtrained. That is, overtraining isn't only a local phenomenon, such as muscles. It can be a central one i.e. the nervous system.

Another example would be chess players. Just because they're not moving doesn't mean their cardviovascular system isn't in overdrive. Or, if you're into video games, you've experienced your heart racing despite barely moving. In other words, just sitting down, if stressed, gets the blood flowing. Chronically doing that will have negative consequences, eventually impacting your ability run.

If work is kicking your ass for 12 hours every day, your training, whether lifting, running, or badminton, isn't going to go well. This is a major reason professional athletes don't do anything besides their sport.***

More specifically, runners are notorious for upper respiratory infections. Just Google "long distance runners upper respiratory infection" and you'll have plenty to keep you busy for a while.

But really, one should view this more broadly as, to some degree, stress is stress. For instance, a lack of sleep impacts everything. If the nervous system is worn out, nothing functions as well.

***During a division I football season it's been found the players are more likely to get hurt during academic test periods. Their muscles aren't more stressed during those periods, but their brain is.

Also, med school students are more likely to get sick during test times, because they're so stressed. Any wounds they have will heal more slowly too!


The phenomenon of overtraining in distance racing is similar to the problem in weightlifting. Your body needs time to recover, you can reach a plateau sooner if you don't rest, and you get diminishing returns if you don't plan well. That's just with regards to improving speed.

Even if you training is fine for your racing results, it can be overtraining in the sense that you are increasing the risk of death and heart disease... those hours of cardio are a real strain on your body.


when you do exercise physiologically you use one of three energies... ATP oxidative energy, ATP Glycogen and ATP lactic creatine phosphate. These energy depends with the intensity and duration of workout. if your goal is to lose fat you should intend to use ATP oxidative (aerobic)body use fat and carbs to produce energy; high intensity more time you will reach a fatigue level then your body might not lose weigh rather than gain or remain constant. if you want to gain muscle you might use the rest two ATPs energies because both characterized by anaerobic kinds. my points is human body has point of performance(endurance). in doing exercise we have to have a specific goal which can be leaded by a very professional program, this program will have based in frequency, Intensity and time... doing over-training means you train beyond your program... do not stress your body

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