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I Hate Muscle Aches After Workouts

Most of us wouldn’t even think about how the immune system regulates the soreness response in our bodies!


Dr Joel Yong

5 months ago | 6 min read

But the immune system response can make or break the speed of recovery.

Exercise always poses a problem to me. I have to get off that couch first and foremost, then I have to get dressed in the appropriate attire. If I’m living in a temperate climate that has winter seasons, there’s this really heavy feeling of inertia to get dressed up.

Finally, after I get dressed… I may then decide to go back to the couch again, and lie down until the feeling of wanting to exercise passes.

I’m sure it’s not just me — many people will have that same kind of feeling.

When we’re mentally tired after a full day of work, the inertia is actually greater.

But of course, when we do make it to the gym, we start to do our workouts… or we make it out the door to go for a run.

We come back later, all sweaty and tired. Get a shower, do our stuff, go to bed at the end of the day, and wake up the next morning…

To a whole new world of soreness, aches and pains.

Don’t worry, you’re not alone!

It’s perfectly normal to experience all that. It doesn’t kick in right away, but it kicks in after a period of time (it takes about 24–48 hours for me), and it is commonly termed as Delayed Onset Muscle Soreness, or DOMS.

DOMS is annoying. You go to the gym, for instance, lift some weights, and the next morning you feel that the muscles you worked out are sore. And then you curse the existence of pain on this planet. I have cursed exercise as the bane of my life quite a fair bit too.

But why does that happen, though?

This article may provide a little more insight into muscle soreness:

Exercise-induced muscle damage is frequently reported in healthy adolescents and adults following habitual and/or strenuous exercise, such as in military training, weight lifting, long distance running and in particular following short exercises that involve intense eccentric contractions. In contrast, exercise-induced muscle damage occurs very rarely following swimming.

Lifting weights, long-distance running, and “following short exercises that involve intense eccentric contractions” (otherwise known as high-intensity interval training, or HIIT) can contribute to exercise-induced muscle damage.

This muscle damage is more pronounced on new exercises that we aren’t really used to, as is echoed by this article:

However, unaccustomed and repeated eccentric muscle actions may result in muscle damage, inflammation, and oxidative stress. These events often are accompanied by loss of muscle strength and a set of symptoms referred as delayed-onset muscle soreness (DOMS). After the so-called eccentric exercise-induced muscle damage (EEIMD), muscle weakness and DOMS may last a few days (typically 5–7 d) and their magnitude is not exacerbated by effort repetition.

The problem of soreness exists as we end up causing these little bits of muscle damage as we work those muscles out. They then have to get repaired and become stronger.

That’s one major sore point right there for sure.

Why is there all that annoying muscular soreness?

The development of DOMS starts with microtrauma to the muscle fibres. As we work out those muscles, we tend to cause small pockets of damage to the fibres that have to be healed.

The healing of the muscle fibres, though, is dependent on macrophage activity. At the initial stages of DOMS, the damage causes the immune system to raise a pro-inflammatory signal in the form of pro-inflammatory cytokines. The muscle aches then appear as a result of that signal.

Is it then surprising to see that fevers and viral infections, which result in an even higher release of pro-inflammatory cytokine signals, will also contribute to the muscle soreness and aches that we feel during a severe bout of flu, for instance?

Nope. The same signal contributes to the same sensations. Just that in DOMS, we have the M1 macrophages that respond to the pro-inflammatory signal.

They conduct phagocytosis on the injured/dead muscle cells and clear out cellular debris. When their job is done, they hand over the next set of duties for the M2 macrophages to conduct.

The M2 macrophages produce anti-inflammatory cytokines to quell the inflammation signal, and new cells are grown in the muscle fibres to replace the dead cells that have been cleared out.

When the process is complete, the muscle fibre becomes stronger, and the soreness goes away completely as the inflammation signal is completely quelled.

How fast the soreness dissipates is therefore dependent on the speed of our immune response.

And the speed of our immune response is dependent on the balance between the M1 and M2 macrophages in our body.

The speed at which the M1 and M2 macrophages work are different from person to person. It also depends on the balance between these 2 macrophage populations.

For example, if someone has a much higher M1 than M2 macrophage population in their body, the resolution of the inflammation signal would proceed more slowly, and the soreness would stay there longer.

This article suggests that a macrophage is initially neutral, but it polarises into the M1 or M2 phenotype based on the prevailing cytokine signal. The pro-inflammatory cytokine tumour necrosis factor alpha (TNF-α), for instance, promotes M1 polarisation.

And it is also known that “increased concentrations of TNF-α are found in acute and chronic inflammatory conditions”, as reported in this article.

So when we’re facing health issues associated with chronic inflammation, one of the symptoms would be an increased frequency of muscle aches and pains all around the body — which we don’t really like.

Unfortunately, one who is experiencing chronic inflammation would have more M1 than M2 macrophages in their body.

A heart disease patient would therefore find the speed of the efferocytosis process in their bodies is reduced, and the clearance of the necrotic cells in an atherosclerotic plaque would also be reduced with insufficient M2 macrophages around.

Which also means, unfortunately, that the people who live with heart disease or Type 2 diabetes may also be prone to more aches and pains in their body because of the preferential differentiation of the macrophages into the M1 phenotype.

Excess body fats would further worsen the situation

In my own personal weight loss journey, I chronicled the experiences of what I went through when I was obese.

That journey included this:

I wasn’t really a workout fanatic when I was doing my PhD in Melbourne. I’d go for a 2 hour session of social badminton, play about 45 minutes in total, and sit there huffing and puffing, while getting entertained on the court sidelines by the foibles of other players on the court. Of course, I’d collapse like a sack of potatoes when I got home, and refuse to wake up the next day because just about everywhere had this sensation of soreness.

And that’s because the fat cells in obese people tend to promote the polarisation of macrophages into the M1 phenotype.

With a more pro-inflammatory environment, an obese person would also not like the idea of exercising that much, because the DOMS that they experience would also take a longer time for them to recover from, especially with a higher rate of M1 polarisation. It becomes a vicious cycle indeed.

One’s recovery rate from DOMS and a strenous workout is therefore dependent on the functionality of their immune system!

Is it the case, then, that an unfit person who take a longer time to recover from strenuous workouts would also be experiencing symptoms of a suboptimal immune system? Highly likely, isn’t it?

Would it not go without saying, too, then, that one’s exercise and recovery rates are dependent on their diet quality, their ability to manage stress and their sleep quality too, then?

But that’s the problem. When we become couch potatoes for too long, and don’t get into the habit of a regular exercise routine, we’d:

  1. Experience DOMS after a long workout.
  2. And if that DOMS is bad enough, we might not feel like going for another workout.
  3. And then we become more unfit, and the vicious cycle propagates.

Getting into the habit of regularly exercising is key — it’s good for the body and the immune system.

Unfortunately, most people have too many things on their mind and too many aches and pains to even think about exercising regularly now, isn’t it?

Most of us wouldn’t even think about how the immune system regulates the soreness response in our bodies!


Created by

Dr Joel Yong


Educator | Biochemical Scientist

Deconstructing the interconnectedness between health and business. Join my mailing list at or book a one-on-one consultation session with me at







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