Working Out While Sick: Should You Be Exercising Or Resting?

QUESTION: I was just wondering what your thoughts are on working out when you’re sick? Especially when it comes to weight training and cardio? What do you recommend to others and what do you do yourself in cases like this?

ANSWER: Let’s start out with the first and most obvious part of what’s truly being asked here, which is essentially whether I think this person (or any other person) should work out while sick.

And my simple honest answer is that I don’t know. Why?

Because It Depends

On what exactly? All sorts of stuff. For starters, it depends on what you mean by “sick.” Do you have a mild cold? A fever? A sinus infection? The flu? Food poisoning? Ebola? 100 other things?

From there it depends on the specific form of exercise we’re talking about. Even if we know it’s weight training or cardio, there are still a ton of possibilities for what might be taking place during those workouts.

For example, is the weight training some kind of low rep strength focused session where you’re going for singles, doubles or triples on exercises like squats or deadlifts? Will it be a more traditional intelligently designed muscle building workout? Will it be one of those 3 hour long stereotypical bodybuilding workouts? Will it be some kind of women’s “toning” workout involving pretty pink dumbbells? With there be lots of supersets with little to no rest? Something metabolic oriented? High volume or low volume? High intensity or low intensity? Is it “arm day” or “lower body day?” And so on.

If it’s cardio, is it going to be a comfortable walk around the block, 30 minutes on a bike, an hour+ on a treadmill, hill sprints, sled drags, marathon training or 100 other things with varying amounts of duration and intensity?

See what I mean? This is why “it depends” is the only legitimate answer to this question.

But having said that, I still completely understand that your natural reflex is to punch me in the balls whenever I answer a question with “it depends.” So, here’s my attempt to provide a more specific answer by telling you what I personally do when I’m sick.

Weight Training

Let’s start with weight training. Here’s a breakdown of how I approach a weight training session (which in this context refers to weight training designed for the purpose of building muscle… for example any of the workouts included in Superior Muscle Growth) in the 3 most common scenarios…

  • Scenario #1: A Cold
    If it’s a cold – be it a mild cold or even a really bad cold – with typical cold symptoms… I’ll almost always go ahead with my workout exactly as planned.
  • Scenario #2: More Than A Cold
    If it’s something more significant than a cold – with symptoms worse than that of a typical cold – I’ll almost always stay home.
  • Scenario #3: Not Sure
    If it’s somewhere in between and/or I just can’t decide what to do… I’ll show up and see what happens. I’ll basically treat each little part of the workout as a step for me to evaluate before moving on to the next step. So if step 1 (some pre-workout warm up stuff, mobility work, foam rolling, etc.) goes fine, I’ll move on to step 2 (warm up sets for my first exercise). If that goes well, I’ll move on to step 3 (actual work sets for that first exercise). And so on. If a step doesn’t go well, then I just adjust the rest of the workout as needed based on how I feel right there in that moment (or, if it’s REALLY bad, just go home… which by the way is something that has never actually happened).
    So maybe I’ll turn it into an impromptu deload day, or maybe lower the volume a bit in certain spots, or maybe lower the intensity a bit in certain spots, or maybe do something some degree easier than I was planning on doing, or maybe drop some of the less important stuff at the end of the workout, etc. Basically, as long as I’m feeling okay enough, I keep on training at 100%. If that changes, I make whatever adjustments I feel I need to make.

What To Expect

Now let’s take it one step further. Let’s say scenario #1 (or a good version of #3) occurs, and you find yourself at the gym attempting to work out… while sick. How should you expect it to go?

Once again, it depends. But here’s what I can tell you from my own experience.

The good news is that strength levels are virtually the same. At least for me. In fact, I’ve set PRs while sick on more than one occasion. I don’t know if it’s because I go in expecting things to go worse and so maybe there’s less “pressure” to perform well, or maybe that I’m expecting things to be harder which causes some other gear to kick in to compensate? Or maybe it’s just the fact that my strength levels are exactly as good as they would have been if I didn’t happen to be sick?

Whatever it is, I’m almost always impressed at how well the workout goes in terms of strength. I rarely (if ever) notice any meaningful drop-off there.

Endurance on the hand… not so much. If there is any noticeable decline in performance happening, it’s mostly in the endurance category. So I’m a little more out of breath. A little more fatigued. Work capacity is slightly reduced. And the simple fact that it is literally harder to breathe because I’m all stuffy and whatnot certainly plays a big role here, too.

And beyond strength and endurance performance… it’s just annoying to lift while sick. Even if things are going well, there’s still just random points in the workout where my only thought is “ughhhhh.” So things like mental intensity, focus and motivation will likely be lacking a bit, too.


I think I can best sum up this section of this article by saying “lolz.”

Why? Because if you’re a regular reader of mine, you know that I’m not exactly a huge fan of doing cardio. So the idea that I’m going to have lots of personal experience to draw on here is… well… funny.

The truth is, sick or not sick, I’m pretty much just as likely to be doing cardio. In fact, on the rare occasions when I was regularly doing cardio over the last decade or so, I would have gladly taken being even the slightest bit sick as the perfect opportunity/excuse to skip doing cardio that day.

So yeah, I’m probably not the best person to field this part of the question because it’s just not something I have much experience with. However, I do have two relevant thoughts.

  1. First, based solely on the drop-off in endurance I notice during weight training (combined with the fact that it’s just harder to breathe when you’re sick), I’d imagine anything more than “light” cardio would suck quite a bit under these conditions.
  2. Second, I think it’s much less of a big deal to miss a cardio workout than it is to miss a weight training workout. Meaning, you’re more likely to be (slightly) set back by missing the weight training workout (primarily as a result of neural adaptations rather than any actual loss of muscle mass) than you would be from missing a cardio workout. In fact, since the main reason that most people do cardio is to burn calories/lose fat, that missed workout could very easily be made up for by making a minor adjustment to your calorie intake that day. Weight training doesn’t have a back-up plan like that.

Consider Other People, Too

One final thing worth mentioning if you’re going to go into a public gym while sick for any type of training: please go out of your way to avoid getting other people sick.

Wash your hands, cover your mouth/nose when you sneeze or cough, etc. Basically, all of the things you should have learned to do by the time you were 5, please do them in the gym as an adult.

Thanks bro.

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