Pain during exercise: how much is okay? The traffic light guide

Hurt doesn't always mean harm. Learn the pain-monitoring 'traffic light' that physiotherapists use, so you know when to keep going, when to ease back, and when to get checked.

6 min read · last reviewed October 1, 2026

If you live with back pain, knee osteoarthritis or a sore shoulder, you might feel stuck. Exercise is supposed to help, but it hurts. Does that mean you're doing damage? Should you stop?

For most people with ongoing muscle and joint pain, the answer is reassuring: some pain during exercise is normal, and it usually isn't a sign of harm. This guide shares a simple tool that physiotherapists use to help you know how much is okay.

Hurt doesn't always mean harm

Pain is your body's alarm system. When you have had pain for a while, that alarm often becomes extra sensitive. It can ring when you move, even when your tissues are not being damaged.

That's why guidelines for osteoarthritis tell people that joint pain may increase when they start exercising, and that regular exercise is still good for their joints in the long run. Over weeks, as you get stronger and your body gets used to moving, the alarm usually quiets down.

Research backs this up. Reviews that compared exercise that was allowed to be a bit painful with exercise that was kept pain-free found that painful exercise was not worse. A 2025 review concluded that pain during exercise may not need to be avoided for people with long-lasting muscle and joint pain to improve.

That doesn't mean "no pain, no gain." You don't have to push through severe pain. It means you can work with some discomfort, and use it as a guide.

The pain traffic light

This approach is based on the pain-monitoring model, first tested by Swedish researchers in people with knee pain around the kneecap, and later in people with Achilles tendon pain. In those studies, people were allowed to keep exercising with pain up to 5 out of 10, as long as it settled by the next morning. In the Achilles study, people who kept up their sport using this guide recovered just as well as people who took a break from sport.

First, rate your pain on a scale from 0 (no pain) to 10 (the worst pain you can imagine). Then use the traffic light:

Green light: 0 to 2 out of 10

Go ahead. Little or no pain. You can keep going, and you may be ready to make the exercise a little harder over time.

Amber light: 3 to 5 out of 10

Usually okay. Keep going with care. This level of discomfort is generally acceptable, as long as:

• It settles within 24 hours, or by the next morning, back to your usual level
• Your pain and stiffness aren't building up from one week to the next

If both of those are true, you can carry on at the same level. If the exercise felt easy and pain stayed low, you might progress.

Red light: more than 5 out of 10

Ease back. Pain is too high. Also treat it as a red light if:

• Pain is still worse than usual more than 24 hours after exercise
• Your pain or stiffness is getting worse week by week
• The pain is sharp, stabbing or sudden, or comes with swelling, a "pop," or giving way

What to do: make the exercise easier. You could do fewer repetitions, use less weight, move through a smaller range, slow down, or rest longer between sets. Then build back up gradually. If the red light keeps happening, or pain doesn't settle, check in with your physiotherapist or doctor.

Something you can do today: After your next exercise session, write down your pain score during exercise and again the next morning. This simple log tells you a lot.

Tips for using the traffic light

• Your score is personal. A 4 for one person may feel different for another. What matters is how your pain changes.
• Check the next morning. The 24-hour check is one of the most useful parts of the guide.
• Expect ups and downs. A flare doesn't mean damage. Ease back for a day or two, then build up again.
• Change one thing at a time. If you increase weight, don't also increase repetitions and how often you exercise in the same week.
• Muscle soreness is different. Achy, tired muscles a day or two after a new or harder workout (often called delayed onset muscle soreness) is normal. It usually peaks around day 1 to 2 and fades within a few days.

When the traffic light doesn't apply

This guide is for ongoing muscle and joint pain, such as back pain, osteoarthritis and tendon pain. It is not for:

• Chest pain, pressure or discomfort. Stop and call 9-1-1.
• Severe shortness of breath, fainting, or a racing or irregular heartbeat with dizziness. Stop and call 9-1-1.
• A new injury, such as a sprain, fall or a sudden "pop." Get it checked.
• The first days or weeks after surgery or a fracture. Follow your surgeon's or physiotherapist's advice.
• Hot, red, swollen joints, or pain with fever. Get checked the same day.
• New numbness, tingling or weakness. Call your care team.

Talk with your physiotherapist

A physiotherapist can help you find the right starting level, set your own traffic light zones, and plan how to progress. Programmes such as GLA:D for hip and knee osteoarthritis teach people how to use pain as a guide during exercise.

Something you can do this week: Share your pain log with your physiotherapist or doctor, and ask them whether the traffic light approach fits you.

Questions to ask your care team

• How much pain is okay for me during and after exercise?
• What should I do if my pain flares after exercise?
• How should I adjust my exercises on a bad day?
• How will I know when I'm ready to make my exercises harder?
• Which symptoms mean I should stop and call you?

This article is general information, not medical advice. Talk with your health care team about your own situation. In an emergency, call 9-1-1 or your local emergency number.

In an emergency, call 9-1-1 or your local emergency number.

General information, not medical advice. It does not replace your own care team. If you think you or someone else is having a medical emergency, call 9-1-1 or your local emergency number. If you are in crisis or thinking about suicide, call or text 9-8-8 (Canada and the US).

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