Why does exercise hurt if it's good for you?

I understand that pain can act as a early signal to prevent more severe injury.

Why, then, does exercise hurt if it’s good for you?

That depends on your definition of “pain”.

One reason you hurt is if you overdid it - the pain is a signal to lay off.

The way exercise is good for you, broadly speaking, is because old lazy tissue etc. is stressed, and enhanced or replaced with stronger tissue, etc.

So in general, you have to do enough to cause a stress reaction, but no so much as that you over do it for your current fitness level that you are persuaded to not continue when you are not healed and happy when it is time for your next workout.

Others will probably be along with more specifics shortly.

not_alice is right.

To clarify: sudden, sharp pain during a workout is a signal to stop while “exertion” pain is simply your body working near it’s limit.

You will have some discomfort while you get back in shape but once there, you can maintain fitness without undue stress.

There is really no need for brutal, “to your limit” workouts if you are not competing in a sport or working to maximize your fitness.

What was said above.

To add, as I was told:

Building muscle actually involves the destruction of muscle. Like a broken bone heals stronger (at the break) than it was before; building muscle requires a little breakdown of muscle first. Your body will put more back.

This is not to say you are shredding muscle but at the cellular level there is some destruction and rebuilding. If you are shredding muscle (or worse, connective tissue) then that is your sudden, sharp pain and you need to stop and heal till the damage is repaired (hope it can be repaired, permanent damage is possible).

This is also why you should rest between workouts. Or at least do not work the same muscle every day. The workout causes some damage and your body needs to put it back together. So, for instance: Weights, Cardio, Weights, Cardio…etc. (lots of variations on that…point is don’t work the same thing every day).

ETA: The “burn”, if that is what the OP means, is lactic acid buildup in the muscles and causes them to ache. More in shape you are the longer that takes to affect you but happens to everyone. Rest removes it.

To reiterate:

Beginners may have a hard time distinguishing pain from discomfort. A seasoned veteran can easily tell the difference. Anyone who knows what she’s doing will avoid pain at all cost but strive for discomfort while exercising. That is, if progress instead of pure maintenance is the goal.

Is there any way to tell noobs how to distinguish between the two or is this one of those, “You gotta learn the hard way,” things to understand?

Discomfort comes on gradually and is bilateral, injury is usually a single site on the body, has an abrupt onset and hinders form.

Example: (Discomfort)You’re running hard, your legs start to ache and burn, your lungs are on fire and your breathing is labored-you’re going into oxygen debt and lactic acid is building up.

(Pain/Injury)You’re running hard, you feel a searing pain in your hamstring, you leg buckles with each step and you run with a severe limp- you just pulled a muscle (or injured the sciatic nerve).


That seems obvious and an injury that happens abruptly. Not sure you can see that coming.

I took him (her?) to mean a fine line between pushing yourself through pain for good effect and pushing yourself too far and suffering an overuse injury (ala “Tennis Elbow”) and being able to know when to stop before that happens.

Overuse injuries are seldom felt beforehand, they sneak up on you.

The main thing to remember is to take it slow on increasing exercise load.

Also, tendons and ligaments lag behind muscle in gaining strength.

ETA: Pushing hard through pain over a period of time is a good way to generate an overuse injury.

Also things like running on the same side of a crowned road.

So you are not going to foresee an abrupt injury and overuse injuries creep up on you.

What did Toxylon mean about “distinguishing pain from discomfort”?

A beginner will probably mistake the burn of lactic acid for an injury or may think a minor strain is just “the burn” and not stop.

Also, a rank beginner will be sore (very, very sore) after the first few workouts and may think they’re injured rather than the dues we all pay for our laziness. :smiley:

You’re doing the wrong exercises. Many exercises do not hurt, particularly if you are doing low-impact, aerobic exercise. The best exercises for overall health involve raising your heart rate for about 15-20 minutes, and do not cause pain, such as a brisk 15 minute walk. What many of the above posters are talking about is weighlifting or anaerobic exercises to increase mass.

It’s better to be safe than sorry, that means: as a beginner it’s better to start slowly and increase than overdo it and get injuries. Start with 15 min. of walking every day instead of 30 min. jogging. Better for multiple reasons.
Then, after a couple of weeks, you slowly increase time, then after more weeks, you increase speed. Always in slow steps. No need for pain, just a bit tiredness.

‘Exercise’ is painful (but that does depend on your definition) or uncomfortable if you are accustomed to be mostly sedentary because humans evolved in an environment where they would get tons of low-level activity, and often more strenuous exercise as well. It’s good for you because as a species we’re meant to have a baseline level of decent fitness, enough to survive in a sometimes challenging environment, built and maintained since toddlerhood. When that’s the case, moderate activity and even more intense exercise within usual bounds isn’t going to cause much soreness, etc. Most Americans these days get almost no activity, of course it doesn’t feel great to push your body past what it is habituated to.

Is there actually evidence that anything beyond light exercise (brisk walking, light resistance training, that kind of thing) *is *good for you? Intuitively, it would seem that when you get sufficiently out of breath or otherwise fatigued that it is uncomfortable to continue, that is evolution’s way of telling you to stop.

No doubt statistics show that people who exercise vigorously live longer, but compared to whom, total couch potatoes or people who incorporate walking and some light exercise into their lifestyles? (And there are probably plenty of confounding factors, such as exercise freaks having healthy diets, avoiding smoking, etc.)

Anyway, that’s my excuse. I exercise every weekday pretty much without fail, but only to the point that I’m mildly fatigued or out of breath. I tried the “run three miles a day” thing - I could do it, but I never enjoyed it. I don’t believe our ancestors routinely ran that sort of distance non-stop. More likely it was run a bit, walk a bit to catch breath, repeat until destination/quarry reached.

Are you kidding me? Our ancestors chased down antelopes until the antelope was out of breath. Then they killed it.

When I first started running, there was a lot of lactic acid soreness which was easily distinguishable from pain. Afterwards, there wasn’t any pain unless I got blisters or rolled my ankle or something. Exhaustion is also completely different from pain. I’d say if exercise actually hurts you then you’re doing it wrong, or else injured.

In fact, we’re built to exercise, especially run. So, far from painful, you should actually enjoy it, or else again I’d say you’re doing it wrong. Remember playing outside as a kid? That was pretty much all exercise, but it was fun as hell. If your particular exercise routine is a painful chore, pick something else, please. There is lot’s of fun out there to be had. If you ride your bike, or swim, or hike, or climb or something, most people don’t even call it exercise, just a “hobby”.

Stop all those grueling chores now and have some fun. Or else whatever good you’re hoping to get out of your exercise routine isn’t going to happen.

Then pick a different sport that you have fun doing. Even limiting all official sports to those who are good for your health (no golf, no contact boxing, no motor racing), there are scores of sports you probably have never even heard of. Some contemplative like Tai Chi or Yoga, some team sports like indoor rollerskate hockey or Korfball, some individual sports like archery …

Sure, it’s a bit frustrating learning new moves and a new technique at first. But if the sport itself is fun for you, you will notice less than forcing yourself to do a sport you can do, but don’t like.

In general, not just exercise, things that are good for you are not always pain-free. Things that are bad for you often feel really good.

No, what was said above most certainly applies to aerobic exercises.

I should’ve been more clear. It’s not the difference between discomfort and pain I’m getting at (I understand that), but why there’s discomfort at all in non-harmful exercise.

The “destruction of muscle to rebuild” thing makes a bit of sense, but the body is continually replacing cells everywhere and that isn’t uncomfortable. It isn’t uncomfortable when you grow more skin or get more hair. Why is it different for muscle?

What is the evolutionary benefit of causing discomfort when the body is strengthening?

Can you give some examples?