sleep-restWhile I haven’t had any kind of significant illness for several years now, I suppose it was just a matter of time before I did get sick again.

Whether it’s from relocating to a totally different climate at a higher altitude, or being in a large population area, I managed to catch some kind of bug.

While a constantly running nose could have been just an allergy thing, the swollen lymph nodes on my neck confirmed that I had some sort of infection, probably sinus related. Antibiotics, rest, and fluids were the obvious solution offered by my doctor, but the “rest” portion was a bit frustrating.

During the last month I’ve been working on tracking performance metrics and tinkering with my workout regimen. The last thing I wanted to do was put the project on hold. Obviously, I could tell that my body was fighting off some kind of illness, but on the whole I didn’t feel all that bad.

Now, of course I did the prudent thing and stopped training for the week. And, instead of continuing to stay up later and working on articles or reading, I went to bed extra early. Big deal, that is what most people would do, wouldn’t they? Perhaps not. I know quite a few runners or gym nuts who would have a hard time missing a workout just because they have a runny nose.

When you are sick or sleep-deprived, you need to rest. The last thing your body needs is further stress brought on by an exercise workout.

The repair of muscle following the tissue damage brought on by exercise is primarily an immune response. The inflammation that leads macrophages to the site of the damage operates in much the same way as when you are sick. It is highly counter-productive to further tax your immune system with muscle regeneration when it should be seeking out harmful viruses and bacteria.

Further, particularly strenuous bouts of exercise promote the release of cortisol, as does dysregulated sleep patterns. While usually a pretty useful hormone (stimulates glucose release from the liver to stabilize blood sugar) it also suppresses your immune system, a mechanism which is for obvious reasons quite problematic. Cortisol accomplishes this by “muting” the action of white blood cells and preventing the release of substances in the body that cause inflammation.

Without inflammation, proper muscle regeneration will be seriously delayed. In general, sleeplessness correlates with changes in the immune response and the pattern of hormonal secretion of compounds like cortisol, but also of human growth hormone. Most of your growth hormone is released during deep delta wave sleep, and it’s quite essential in the process of tissue repair and growth.

Sleep-deprivation will also dull your senses and reduce your physical capabilities, increasing the chance of accidental injury during exercise.

Lack of sleep is linked causally to impairment of critical cognitive, metabolic, immunologic and restorative physiologic processes. Sleeplessness accounts for impaired perception, difficulties in keeping concentration, vision disturbances, as well as slower reactions. This is not the condition you want to be in while negotiating a tricky woodland trail.

Further, your performance in general is likely to be reduced, and it will be difficult to know the cause for your lower exercise output. Was it because you were already fatigued? Did the exertion hurt more because you’re already feeling achy? Purposeful training should involve the gathering of observations about your output and your overall state.

Significant lack of sleep will alter not only your levels of muscle glycogen, but also your subjective perception of effort. If you can’t adequately determine whether or not your performance is improving, your training will be less than effective.

Won’t my body start detraining and atrophying if I don’t exercise?

Growing muscle takes a lot of effort and energy, and your body will not shed it lightly unless under extreme duress, like starvation. In fact, during a week off you still might find that you increase your numbers on lifts or exercises once you get back to your training. The time off could have been just enough for your muscles to fully repair and prepare you for your next session. I know that this was the case for me during this recent illness.

So, the moral of the story is to be smart and just take it easy when you’re tired or under the weather. This is exercise were talking about, not battlefield or life-threatening situations. Give your body a break and let it repair itself.

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9 Responses to Sick or Tired? You Need Rest, Not a Workout

  1. Anonymous User says:

    just wait until you have children! I ended up with Shingles!

  2. Mark Cancellieri says:


    I totally agree with you on the importance of sleep, which is why I made it my first experiment on my new Experimental Living blog:

    You wouldn’t believe the difference that it has had on my energy levels, happiness, and motivation. I highly recommend trying a sleep experiment to improve sleep habits to anyone feeling run down and tired.

    During my research, I also found out about quite a few negative consequences to sleep deprivation that were surprising to me (e.g. higher risk of colon cancer!). Check out the link for more info.

  3. Nice article today. I am just returning from a week off and being sick. I used to freak out if I didn’t get a workout in, but now its not a big deal and I’m seeing bigger gains with more rest days :)

  4. David Csonka says:

    Oi Kristin, my dad had a recent bout of shingles. Not fun! And, glad you’re feeling better too Alissa!

  5. Ramon says:

    Yes, wait until you have children! I have a 4- and a 1-yr old and they are going to give you a workout! The only time I can exercise is when everyone is still in bed which is around 5 in the morning. The catch there is if the kids go to bed early the previous night, if not, its going to be a hit-or-miss kinda thing for me in the morning. Hard but I try to make the most out of it.

  6. Anonymous User says:

    We caught it early so it wasn’t so bad. Let me know that I needed rest too..(When claire was an infant)

  7. Ed says:

    I apply the old adage that if the illness is above my neck, I run, but if it is below, I don’t. So a head-cold or allergies won’t stop me, and in fact I feel better afterwards as a run tends to clear things up.

    If in my lungs though or something else entirely (stomach virus, etc) then I lay off. I won’t run with a fever either.