Last updated:

25 July 2023

Sweat it out, or stay at home? Let’s see what science says about training through illness.

should you workout when you're ill

Reading time:

4 min read

I’d rather poo a hedgehog than miss a few days at the gym, and if you’re anything like me then you probably feel the same way.

But what should you do when illness strikes?

There’s a lot of confusion about this question amongst fitness enthusiasts, with some believing that training through illness will actually help you to recover faster (I’m sure you’ve heard the expression “sweat it out!” before), and others recommending you take time off instead.

When I ran a poll for my Twitter followers, the results came back 50/50.

So it’s time to get real. Let’s look at what science says about training through illness.

Expected Impact On Performance

Notice the title of this article. There’s a reason I didn’t ask CAN YOU workout when you’re ill, and instead I opted for SHOULD YOU.

You see, there’s nothing to stop you from training if you really want to. Heck, there’s probably a few people at your local gym doing it right now. Your body can’t physically stop you from going to the gym, and the physiological process of building muscle remains exactly the same as far as your muscles are concerned.

However, in the immortal words of Jeff Goldblum:

“We were so pre-occupied with whether we could, we didn’t stop to think if we should.”

Because even though the body is capable of hypertrophy, it is highly unlikely that you’ll be able to create the necessary stimulus it needs. That’s because most people see their RPE (rate of perceived exertion) drop significantly when they’re suffering from illness, so even if they manage to drag themselves to the gym they find themselves going through the motions.

Like Rambo in a field of Vietcong, your unwell body is facing off against a dangerous opponent. It’s a war you will eventually win, but placing additional stress on your immune system via training will only lengthen the time it takes to complete the battle.

Can You Sweat Out A Cold?

should you workout when sick

I will say this only once:

You can not sweat out a cold.

Honestly. I love training, and I equally love the idea of de-snotting myself, so if this was true I’d run to the gym faster than a toupee in a hurricane…

… but it’s not.

This popular belief stems from a misconception about what sweat actually is. You see, a lot of people in the fitness world still follow outdated advice from the 1970s and 1980s, when it was believed that sweat is a combination of toxins which are leaving the body during exercise. We now know that’s not the case – sweat is actually just water!

One thing which will happen, though, is the body will still release a bunch of feel-good endorphins (like dopamine) as it would in any other workout, which temporarily makes us feel Lego Movie awesome, and this is why people believe it sorted them right out, but once those endorphins fade, the illness remains.

How To Decide if You’re Too Ill To Workout

Use the neck check system.

A 1996 study published in the Journal of Athletic Training recommends looking at where your symptoms are occurring:

  • Above the neck (sneezing, headache, etc), or
  • Below the neck (chest pains, coughing, shortness of breath, tightness, vomiting, etc

If your symptoms are below the neck then you’d be very restricted in the weights room, and it’s advisable not to train until you feel better. If your symptoms are above the neck you can probably still get away with training, but will be forced to greatly reduce the intensity of your workout. (1)

Finally, it’s definitely worth considering the potential health risks you pose to your fellow gym members. I mean, nobody wants to be known as the inconsiderate cock-toboggan who wiped out half the gym with a flu epidemic, and we definitely don’t want another fucking lockdown.

Which presents us with an important final question:

Do you want to train through illness because it’ll make you feel better, or because you hate the prospect of a non-training day?

Either way, my advice is to buy some red Lucozade, climb inside a warm blanket and post memes like this until you feel better. You’ll be fine.

i hate rest day


  1. Weidner T. G., et al. Sport, exercise, and the common cold. J Athl Train (1996).

Who Is Russ Howe PTI?


Russ has been a personal trainer in the UK since 2002, and provided both training advice and full programs on this website since 2011.

His work has been featured in Men’s Fitness magazine, and the content on this website led to him being voted one of the world’s top 50 fat loss coaches by HuffPost.

Russ spends his time coaching men and women inside the legendary Powerhouse Gym, South Shields, and writing training tips for the 114,301 members of his popular free training e-mail (join it below).

Response to “Should You Workout When You’re Ill?”

  1. Fitoru mct avatar
    Fitoru mct

    I think it depends on how ill a person is. I never really thought about checking where symptoms are, that’s a fantastic piece of advice.

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