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Home » Cycling » For Active People, How Much Exercise is Too Much in Terms of Fighting Disease; Virtually Everything I Hoped Is Right… Or Not Exactly Wrong.

For Active People, How Much Exercise is Too Much in Terms of Fighting Disease; Virtually Everything I Hoped Is Right… Or Not Exactly Wrong.


I am your typical active lifestyle person.  My idea of exercise is not a five mile, 30-minute bike ride around a (very) long block.  Six minutes per mile, that’d be about ten miles in an hour.  I start having fun when the range is extended six-fold, and almost double the pace.  Doing the math, 30 miles, about an hour and a half, maybe a little more.

Now, during the COVID-19 pandemic, I’ve moderated my exercise because I know, only from what I’ve heard in the past, that intense exercise is bad – that the body suffers decreased resistance to illness after an intense workout.  My normal average, on an intense day of cycling, is north of 20-mph.  For me, an easy day on the bike is between 16 & 17-mph.  Therefore, during the pandemic, I’ve kept my pace between 16 and 18, with a moderately robust one or two days a week north of 19-mph for the average.

I think the problem we (and especially the medical and political class) run into is defining “how much” and “how fast” for our exercise.  My 16-mph average on a road bike feels like I’m crawling.  I have no trouble holding a full conversation at that pace unless we’re pushing into a 20-mph headwind.  Other cyclists, that’s their max pace.  You put an overweight rookie bike rider on a beach cruiser and tell them to maintain a 16-mph average and you’ll likely send them to their grave.  And therein lies the rub because most doctors have a tough time distinguishing between “rigorous” and vigorous exercise.  We know doctors and politicians have to include everyone in their guidance so we rightly assume they’re vastly more cautious than needed.  Well, it appears the evidence backs that assumption up, but the news is even better than expected for we active people.

What I’m seeking to do here is present real data so we, the exceptionally fit, can make our own determination of what is within intelligent, safe fitness and what is outside and “too much of a good thing”, for if we allow a politician to quantify this, you can bet your grandmother will be able to keep up with you using her walker because granny is more likely to vote.   And watch how this goes – I had to completely change the direction of this post when I followed the new, corrected science over popular incorrectly assumed science.

Fortunately, there exists plenty of data out there from reputable sources to work with – and most of it says the same thing – that too much of a good thing is bad.

Let’s look at a problem first.  What seems like a well written article will say something like this:

Additionally, studies performed on mice demonstrated that regular exercise performed two to three months prior to an infection reduced illness severity and viral load in obese and non-obese mice.

Thus, limited animal and human data cautiously suggest that exercise up to three days per week, two to three months prior, better prepares the immune system to fight a viral infection.

(Links removed, emphasis added)

It will then link to this study which says nothing of the sort (because trying to time when to exercise three days per week, two to three months prior to a flu outbreak makes no sense whatsoever).  The study they linked does say this, however, in the conclusion:

Chronic exercise resulted in reduced symptoms, virus load, and levels of inflammatory cytokine and chemokines. Acute exercise also showed some benefit, which was limited to the early phase of infection

Chronic is defined as regular exercise.  Acute as a one time event, shortly before viral infection.  In other words, the science says exactly opposite what the article that quoted it did.  This appears to happen a lot in the reporting of science. And then this:

Epidemiological evidence suggests that moderate exercise may reduce the risk or severity of infection, whereas exhaustive exercise may increase that risk or severity [1–4]. With respect to animal models of respiratory viral infection, moderate exercise tends to decrease morbidity and mortality, whereas prolonged, strenuous exercise increases mortality [5–8].

The point is, we all know moderate exercise is good – we who lead active lifestyles experience the benefits when the latest flu or bug seems to skip right over us.  I am the intensely moderate exerciser in my family and there have been years where my wife and two daughters were sick with something and it completely passed my by (or I actually had it and was asymptomatic because it’s a rare day I stop kissing my wife).  We start to understand a definition of moderate exercise, though – non-exhaustive.  Let’s continue.  The point then becomes, “what is exhaustive to you may not be exhaustive to me”.

We can go here for the money quote:

I believe that even a single exercise bout can be beneficial, but regular exercise provides a much bigger benefit.

This is what we regular exercisers know, regular exercise provides a huge health benefit.  It’s unquestionable, and certainly not limited to “three days per week, two to three months before infection”.  Regular exercise provides a much bigger benefit.  And add that to the previous quote that moderate exercise helps reduce the severity of an illness…

Also, in that same interview, a little further up, we get the gravy atop the roast beef and mashed potatoes:

It is safe to exercise during the coronavirus outbreak. One should not limit the multitude of health benefits that exercise provides us on a daily basis just because there is a new virus in our environment. However, there may be some additional precautions to reduce your risk of infection.

Interestingly, after reading that interview, I’m quite certain I had COVID and cleared it… and I exercised right through it, though I decreased intensity drastically while I had my mild symptoms.  Folks, I took it very easy because I thought that was the wise thing to do:

Typically, one can exercise moderately with mild upper respiratory tract symptoms (e.g., runny nose, sinus congestion, mild sore throat). However, I would recommend against exercising if you are experiencing any of these symptoms: severe sore throat, body aches, shortness of breath, general fatigue, chest cough, or fever. You should also seek medical care if you are experiencing those symptoms. Typically, recovery from respiratory viral infections takes 2–3 weeks, which corresponds with the time it takes your immune system to generate cytotoxic T cells necessary to clear the virus from infected cells. After this period, when symptoms are gone, it is safe to begin exercising regularly, but you may want to take it slow at first.

I experienced an unmistakable tightness in my upper lungs (COVID 19 typically presents in either upper or lower according to what I’ve read), a mild, dry chest cough (nothing uncontrollable).  I had no fever, no body aches, no shortness of breath and no sore throat.  I did nap considerably for the first two days but I think that was mostly due to the fact I could (I stayed home from the office after symptoms presented – not because I was too sick to work, but because it was the right thing to do for the others in the office).

This gets interesting, though, and this goes to the intensity and duration with which we exercise.  And this is why I had to rewrite this whole post; I know for a fact I am what would be classified as leading a “physically active lifestyle”.  What about the person who loves nothing more than to take their bike out for an aggressively fun 60-mile bike ride over three hours?  It turns out, there’s good news for us – and most politicians (and even doctors) who claim themselves “knowledgeable” based that knowledge on bad information.

In the first article I linked to, it talked about a “J-shaped curve” of fitness benefits.  The article goes on to suggest:

Both too much and too little are bad while somewhere in the middle is just right. Scientists commonly refer to this statistical phenomenon as a “J-shaped” curve.

That conclusion is likely wrong based on this study (do read the whole thing – I just provided the appropriate quote, the linked article goes into why previous assumptions were made on studies that were flawed – your jaw should drop an appropriate distance) :

Finally, studies of ultramarathon runners, who undertake the largest volume of exercise among athletes, have shown that these individuals report fewer days missed from school or work due to illness compared to the general population. For example, the mean number of sickness days reported over 12 months was 1.5 days in a study of 1,212 ultramarathon runners and 2.8 days in a study of 489 ultramarathon runners (). These studies compared their findings to data from the United States Department of Health and Human Services report in 2009, showing that the general population report on average 4.4 illness days each year. Thus, a number of studies challenge the “J-shaped curve,” indicating that athletes undertaking the largest training loads, become ill less frequently than athletes competing at, and training at, a lower level. These findings have previously been conceptualized by extending the “J-shaped curve” into an “S-shaped curve,” thereby suggesting that very elite athletes are better adapted to the demands of their training (). Given the nature of their design, very few of these reports—akin to many of the aforementioned studies showing increased infection risk among athletes following mass participation endurance events—used appropriate laboratory diagnostics to confirm an infection. However, despite their limitations, it is important to highlight that there are as many epidemiological studies showing that regular exercise reduces infections as there are studies showing exercise increases infections, and that these studies are often overlooked in the exercise immunology literature.

Emphasis added by me…

From my own personal experience, I’m well below the average of 4.4 illness days a year.  I’m typically between 0 and 2 for any given year.  That I can remember, I have never missed four days in a year for illness – in fact, if it weren’t for COVID-19 being a pandemic of outrageous proportions, I never would have taken a day off with the mild symptoms I had.  I’d have kept to myself and gone to work.  Where this gets tricky is where we fall on that “s-shaped curve”.  There’s a possibility that too much of a good thing can be bad, but not in the way that is popularly represented.

The point is, friends, there’s a lot of bad information out there.  The good information, the “evidence based” information says exercise regularly.  Moderate your exercise during times of illness to match symptoms and discontinue exercise in the presence of acute symptoms until they dissipate, then start back slow.  In other words, common sense prevails – and there are a lot of people out there who make restrictions and don’t use it.

For those who have politicians limiting outdoor activity during the pandemic, the evidence is clear – even during COVIDcation 2020 – we should be outdoors getting our daily dose provided we take precautions to avoid further contamination of others.  Regular exercise lessens the chance of being infected and then lessens the severity if one is.  Lives are in the balance and can possibly be saved by a bike ride or run.  Especially a long one for those of us who are fit enough for it.


  1. Sheree says:

    TBH Jim, I think it’s more of an issue for finely tuned elite athletes who tend to compromise their immune systems.

  2. unironedman says:

    Once we try and generalise, we all end up on the hook somewhere. For running, something like Maffetone or other methods can help work out where you are in terms of fitness. And even simple guides such as ‘jog with a colleague so that you can still hold a conversation’ also works, as each of us will find our own level. Sadly, for now, the lockdown is a pretty blunt instrument, with only one tune, and it’s not a good one!

  3. joliesattic says:

    Too much or too little is relative to the overall fitness of a person. If your norm is x number of minutes, miles or weight, then your body is already conditioned for that and will not be overwhelmed by any virus. If you are starting out aggressively because you think it the key to overcoming or combating the virus, then your system will be compromised. Your body will not be ready for the onslaught of this new element.
    I’m not self motivated like you are, but I’m having to talk myself into it. I have a treadmill (it’s raining a lot here these day), but I really don’t like it. I find it boring. So, I’m going to have to do something. I’m used to going to the gym and that’s currently off limits. I quit riding after my concussion, but I’m beginning to think that with less traffic out, I might give it a go again. Still, my body is no longer used to that routine, so I will have to take it slow.
    The key is to be smart and not over tax your body at any given point until it accepts what you’re trying to do. It knows even if you don’t. Listen to it.

    • bgddyjim says:

      Exactly right. I always loved running in the rain. Cycling, not so much, but running, oh yeah. If you love riding, I hope you can get back to it.

  4. 👊🏽 ATLETHIC & FIT 👊🏽 says:

    Gracias por darle like a mi blog espero que te siga gustando mi contenido

  5. […] practicing a bit of “wishful hoping”. How can I say this? Well, I wrote, way back when (just last year, I’m being facetious), that the leisurely walk stuff sounded […]

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