Why Does Your Pain Disappear During a Workout?

Have you ever started a workout with a sore shoulder, cranky knee, or achy back, only to notice that somewhere around the 10-minute mark, the pain has basically disappeared? You finish your workout feeling pretty good and start wondering if maybe you were imagining the pain in the first place. Then a few hours later, or sometimes the next morning, it’s back.

If that sounds familiar, you’re not alone. This is something I hear about from patients all the time, and there are a few reasons why pain can improve once you start moving.

Pain and tissue damage aren't always the same thing

Pain is much more complicated than simply being a measurement of how much damage is happening in your body. Your brain is constantly taking in information from your tissues and combining it with other factors like movement, stress, sleep, previous experiences, expectations, and what is happening around you. All of that information plays a role in how much pain you actually feel.

Exercise can temporarily change the way your nervous system processes pain. As you warm up, your body temperature and blood flow increase, your tissues are moving more, and your nervous system is receiving a lot of new sensory information. Exercise can also produce changes in the brain and nervous system that temporarily reduce pain sensitivity.

This is one reason why something can feel stiff or uncomfortable when you first start moving, but noticeably better once you've been exercising for a while.

The important thing to understand, though, is that feeling better during a workout doesn't necessarily mean the problem is completely resolved. It also doesn't automatically mean that you should go from a modified workout to your heaviest weight and highest volume just because the pain went away.

Instead, think of that improvement as useful information.

So, should you keep working out when something hurts?

In many cases, yes. You don't necessarily need to stop exercising completely just because something is bothering you.

One of the biggest mistakes I see is treating pain like an on/off switch. If something hurts, people assume they need to stop doing everything until they are completely pain-free. That isn't always necessary, and for many common aches and pains, continuing to move while making some appropriate modifications can actually be a better approach.

The goal isn't necessarily to find a workout where you feel absolutely nothing. The goal is to find a level of activity that your body can tolerate right now and then gradually build from there.

Think about it as adjusting the volume rather than turning the music completely off.

How do you modify a workout when something hurts?

Let's say your shoulder has been bothering you and you notice pain when you're doing overhead presses. That doesn't automatically mean you need to stop working out altogether. Before throwing the exercise out completely, you can change some of the variables and see how your body responds.

Start by changing the range of motion. You may be able to perform the movement comfortably through part of the range but experience more symptoms toward the end. You can temporarily work within the range that feels better and gradually increase it as your tolerance improves.

You can also reduce the weight. A weight that you normally handle without a problem may be more than your shoulder wants to deal with while it's irritated. Dropping the weight doesn't mean you're going backward; it simply allows you to continue training while working within your current capacity.

Volume is another variable you can change. Maybe one or two sets feel completely fine, but by the fourth set your symptoms are starting to increase. You don't necessarily have to eliminate the exercise. You may simply need less of it for the time being.

You can also change the exercise itself. A different grip, stance, machine, or variation may allow you to train the same general movement or muscle without aggravating the area. If barbell squats are bothering your knee, for example, there are plenty of other ways to train your legs while you work on getting your tolerance back up.

Sometimes simply slowing an exercise down can help, too. Moving with a little more control can make it easier to figure out what your body actually tolerates instead of rushing through the movement and hoping for the best.

The point is that modifying an exercise isn't the same thing as avoiding exercise. You can often continue training while making adjustments that make sense for where your body is right now.

But how much pain is okay?

This is where things get a little less black and white.

There isn't one magic pain number that tells you whether an exercise is safe or unsafe. A small amount of discomfort during exercise doesn't automatically mean you're causing damage, just as being completely pain-free doesn't necessarily mean everything is fully recovered.

Instead, I like to look at the overall response.

If you have some mild discomfort that stays relatively stable while you're exercising, your movement still looks good, and your symptoms settle back down afterward, that's very different from pain that continues to increase with every set or causes you to dramatically change the way you're moving.

Pay attention to what happens after the workout, too. If your shoulder is mildly uncomfortable during your workout but feels normal again afterward and you're back to your usual baseline the next morning, that's generally very different from feeling great during the workout and then waking up the next day with significantly more pain and stiffness.

That next-day response can be really useful information.

Feeling better during exercise doesn't necessarily mean you're ready for full capacity

This is probably the part I want people to pay the most attention to.

Exercise can temporarily reduce your sensitivity to pain, which means you may feel better while you're moving than you did before you started. That's a good thing, but it can also make it tempting to do much more than your body is currently prepared to handle.

I've seen this happen plenty of times. Someone has been dealing with shoulder pain for a few weeks, they warm up at the gym, everything starts feeling great, and suddenly they're thinking, "Well, I guess I'm fine!" So they go right back to their normal weights and volume.

Then their shoulder is angry again later that night or the next morning.

The workout itself isn't necessarily the problem. The issue may simply be that the person did more than their current capacity could handle because the pain temporarily wasn't giving them as much information.

So how do you know when you can go back to full capacity?

I don't think you necessarily need to wait until you are completely pain-free before you start increasing your workouts. Instead, I want to see that you're tolerating your current level of activity consistently.

You should be able to perform the movement with reasonably good control without dramatically changing your technique to avoid symptoms. Your symptoms should be manageable during the workout rather than steadily increasing as you continue, and they should settle appropriately afterward.

I'd also want to see your strength and range of motion gradually improving, along with your ability to do more without consistently paying for it later.

Most importantly, don't base your decision on one good workout.

If you have one workout where everything feels fantastic, that's encouraging, but it doesn't necessarily mean you're ready to jump back to your previous training level. If you have several workouts where you've been able to gradually increase your activity and your body continues to respond well, that's much more useful information.

From there, you can start increasing your workload gradually. Maybe you add a little weight, then eventually add some reps or another set. You don't need to increase every variable at the same time. Give your body a chance to respond before you ask it to do more.

When should you stop and get it checked out?

While you don't need to panic about every ache and pain, there are definitely situations where pushing through isn't the right approach.

If you're experiencing severe or rapidly worsening pain, significant weakness or loss of function, new or worsening numbness or tingling, dizziness, chest pain, unusual shortness of breath, or another symptom that feels concerning or out of the ordinary, stop exercising and seek appropriate medical attention.

It's also worth having something evaluated if a particular movement continues to cause significant symptoms despite reasonable modifications, especially if the problem isn't improving over time.

You don't have to choose between doing everything and doing nothing

When you're dealing with pain, the answer usually isn't as simple as "push through it" or "stop everything."

Sometimes your body needs a little less load, a smaller range of motion, fewer reps, or a different exercise. Sometimes you can keep doing almost everything you were doing before, just at a slightly lower intensity while your tolerance improves.

And sometimes pain really is telling you that something needs a closer look.

The goal isn't to become afraid of every ache and pain or to wait until your body feels perfect before you start moving again. It's to learn how your body responds to different amounts of movement and load, make reasonable adjustments when you need to, and gradually build your capacity back up.

So the next time you start a workout with something bothering you and notice that the pain disappears once you get moving, don't automatically assume that you're either completely healed or doing something wrong. Pay attention to how the movement feels, how your symptoms respond during the workout, and especially how you feel later that day and the next morning.

Your body's response to the workout is often much more useful information than the pain you felt before you started.