Quick version
Workout soreness is a temporary soreness in the muscles that usually occurs 12–72 hours after physical activity, and it is especially common for it to occur after new or more intense training sessions. The underlying factor that causes workout soreness is mainly due to small microscopic damages in the muscle fibers that occur when the muscles are loaded more than they are used to. In this situation, the body starts a repair process that allows the muscles to recover and can become stronger over time.
Workout soreness is more common after eccentric training, for example when braking weights in strength training or running downhill. The discomfort usually goes away within a few days, but can sometimes be more pronounced after unusually hard or new training.
Certain blood values such as creatine kinase (CK) can be temporarily elevated during intense training because the enzyme leaks out of the muscles when they are loaded. Training soreness cannot be eliminated immediately, but light exercise, heat, massage, good nutrition and sufficient rest can help the body recover faster.
In most cases, training soreness is harmless, but very severe pain, severe swelling or long-term symptoms may be signs of a muscle injury and should then be assessed by healthcare.
What is muscle soreness?
Muscle soreness is a temporary pain or tenderness in the muscles that occurs after physical activity. It can appear 12–72 hours after exercise and is sometimes referred to as DOMS (Delayed Onset Muscle Soreness).
Some common symptoms of muscle soreness include:
- sore or stiff muscles
- reduced mobility
- a feeling of weakness in the muscle
- pain when using the muscle
It is especially common to experience muscle soreness after unusually intense exercise, new exercises, or increased load.
Why do you get muscle soreness?
So, why do you get muscle soreness? The most common explanation is that the muscles develop tiny microscopic damage in the muscle fibers when they are loaded more than they are usually used to. The body then responds with a local inflammatory process and begins to repair the tissue. This is part of the body’s normal adaptation to exercise.
The process – this is what happens when muscle soreness occurs:
- The muscle is loaded harder than usual
- Small tears occur in the muscle fibers
- The body starts repair and recovery
- The muscle adapts and gradually becomes stronger
Muscle soreness is therefore often a sign that the muscle has been exposed to an unfamiliar load – but it is not a requirement for the workout to have been effective.
Eccentric exercise often causes more muscle soreness
After so-called eccentric muscle work, meaning when the muscle lengthens while working, it is even more common to experience muscle soreness.
Examples of this include:
- running downhill
- lowering the weight in strength training
- walking up or down stairs after a leg workout
These types of movements often create greater mechanical stress on the muscle fibers and can therefore lead to more muscle soreness.
Can blood tests show muscle soreness?
Yes, in some cases certain blood tests can show signs of increased muscle strain after exercise. One common example is creatine kinase (CK), which is an enzyme found in skeletal muscles.
When muscle fibers are heavily loaded or sustain small injuries, more CK can leak into the blood. That is why CK levels are often higher than normal after intense exercise or in cases of noticeable muscle soreness.
However, it is important to remember that elevated CK is not specific to muscle soreness. It can also increase in cases of muscle injury, severe overexertion, or certain medical conditions. Very high or persistently elevated levels should be assessed by a healthcare professional.
This means that CK can be elevated with muscle soreness, but the test must always be interpreted in the right context. Other blood values such as AST and ALT can also rise after intense exercise, and CRP may sometimes become mildly elevated.
How long does muscle soreness last?
Muscle soreness is usually most noticeable after 24–72 hours and often goes away on its own within a few days. Mild muscle soreness typically lasts between one and three days, while more severe soreness can last up to five days before it subsides.
If the pain is very intense, starts immediately during exercise, or does not go away as expected, it may instead be a strain, overuse injury, or another type of muscle injury that needs attention.
Severe muscle soreness – when is it common?
Sometimes muscle soreness becomes unusually intense, which can feel painful and demanding. This can happen, for example, after:
- a new training program
- a very intense workout
- high training volume
- unfamiliar movement patterns, such as the first ski session or first leg workout after a long break
This is often referred to as severe muscle soreness or DOMS and means that the muscles have been exposed to a greater load than they are used to, which can cause more tenderness, stiffness, and temporarily reduced function.
How do you get rid of muscle soreness?
It is rarely possible to get rid of muscle soreness immediately, but there are several things you can try to relieve the discomfort and help the body recover:
- Light movement – low-intensity activity can increase blood circulation and reduce the feeling of stiffness. Good options include walking, light cycling, and gentle mobility exercises.
- Massage or foam rolling – this can help some people by reducing muscle tension and the feeling of stiffness.
- Heat – a warm shower, bath, or sauna can help the muscles relax.
- Adequate protein and energy intake – muscles need nutrients to recover and repair after exercise.
- Sleep and rest – recovery and repair work take place during rest.
Can you work out with muscle soreness?
Yes, it is usually fine to exercise even if you have muscle soreness, especially if the soreness is mild. However, it may be wise to keep the following in mind:
- lower the intensity
- train other muscle groups
- choose lighter activity or mobility work
If the muscle is very sore, swollen, or feels unusually weak, it is a better option to rest and allow the body to recover rather than heading back to the gym to lift weights or do another run.
Why do some people not get muscle soreness?
Not everyone gets muscle soreness after exercise, and that does not mean the workout was ineffective. Some explanations include:
- the body is used to the load
- training is increased gradually
- recovery is working well
- the muscles have adapted over time
With regular exercise, the body usually becomes better at tolerating the load it is exposed to during harder physical activity, which often reduces muscle soreness.
When should you pay attention?
Normal muscle soreness is harmless and goes away on its own. But sometimes muscle pain can be caused by something other than muscle soreness.
You should seek medical care if you experience any of the following symptoms:
- very severe pain
- significant swelling
- dark urine after extreme exertion
- pronounced muscle weakness
- symptoms that do not go away within a reasonable time
This is especially important if you know you have exercised unusually hard and also feel generally unwell.
Tip: If you often experience prolonged recovery, unusual muscle fatigue, or feel that your body is not responding to training as expected, it may sometimes be valuable to follow up on things such as nutritional status, iron levels, or other health markers that can help identify underlying causes that may be improved.
