How does training and competing affect our immune system?

Ugh, doing Juneau -1 (4x18 SS) today wiped me out and was by no means moderate. Felt like I needed a nap after.

Moderate in my opinion means under threshold (keep an eye on heart rate too) and also an interval duration that we are used to.

I get ill for 3-4 days after almost every important single day race. I used to get frustrated by it, but now I tell myself it means that I put it all out there.

Coronavirus patient under quarantine: 'I feel fine… been doing my workouts’

For those that don’t read the article. That title is a bit misleading, he stated he had a 102 fever and knew something was wrong. He said he was listening to experts and have them make the decisions but is doing better now and has 7 days left of his quarantine.

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Debunking the Myth of Exercise-Induced Immune Suppression: Redefining the Impact of Exercise on Immunological Health Across the Lifespan

I’m just gonna copy the abstract here too, because I think it’s important (bolding is me). The podcast has in the past been supportive of the “open window” hypothesis, which doesn’t seem to be accepted anymore:

Epidemiological evidence indicates that regular physical activity and/or frequent structured exercise reduces the incidence of many chronic diseases in older age, including communicable diseases such as viral and bacterial infections, as well as non-communicable diseases such as cancer and chronic inflammatory disorders. Despite the apparent health benefits achieved by leading an active lifestyle, which imply that regular physical activity and frequent exercise enhance immune competency and regulation, the effect of a single bout of exercise on immune function remains a controversial topic. Indeed, to this day, it is perceived by many that a vigorous bout of exercise can temporarily suppress immune function. In the first part of this review, we deconstruct the key pillars which lay the foundation to this theory—referred to as the “open window” hypothesis—and highlight that: (i) limited reliable evidence exists to support the claim that vigorous exercise heightens risk of opportunistic infections; (ii) purported changes to mucosal immunity, namely salivary IgA levels, after exercise do not signpost a period of immune suppression; and (iii) the dramatic reductions to lymphocyte numbers and function 1–2 h after exercise reflects a transient and time-dependent redistribution of immune cells to peripheral tissues, resulting in a heightened state of immune surveillance and immune regulation, as opposed to immune suppression. In the second part of this review, we provide evidence that frequent exercise enhances—rather than suppresses—immune competency, and highlight key findings from human vaccination studies which show heightened responses to bacterial and viral antigens following bouts of exercise. Finally, in the third part of this review, we highlight that regular physical activity and frequent exercise might limit or delay aging of the immune system, providing further evidence that exercise is beneficial for immunological health. In summary, the over-arching aim of this review is to rebalance opinion over the perceived relationships between exercise and immune function. We emphasize that it is a misconception to label any form of acute exercise as immunosuppressive, and, instead, exercise most likely improves immune competency across the lifespan.

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From the women’s running article we could extrapolate that either would be better than a long continuous ride like Long Fellow:

“Nieman and colleagues have been surprised by one of their consistent findings. While long, hard runs seem to lower immunity, the same is not true of long, intermittent runs. “

And any session has less negative impact if you are fuelling your rides:

“By measuring glycogen in immune cells, Neiman has discovered that a three-hour run (with no carb intake) depletes those cells just as it depletes your leg muscles, and the immune cells become noticeably dysfunctional. You could say they bonk. When runners consume carbs during the same run, their immune cells “look and perform much better,” says Nieman.“

Hi, I will have a crack the paper linked by @Peter

  • Athletes often think they are sick when they are not

Indeed, of 37 episodes of URTI reported by athletes in this study, only 11 of these (30%) had a positive laboratory diagnosis.

  • The study of disease transmission and exercise are not conclusive

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

  • Vigorous and prolonged exercise doesn’t increase your chances of getting sick

  • Studies based on salivary Iga levels are unreliable

  • Most adults have sub-optimal oral hygiene

  • Post exercise our immune system is in a heightened state of surveillance, not weakened

I got about it a third of the way through. I guess exercise is not detrimental as the graph indicates, and if you think you are sick after exercise or a race; 1. You probably aren’t sick, 2. If you are sick, you were probably sick before you started training


This is the Highlights ‘translated’ by me :slight_smile:


Exercise is good for the immune system and metabolic health.

Exercise reduces the risk of illness

Illness risk is increased in athletes during periods of intensified training and competition.

Fuel your workouts for immune support.

Habitual exercise improves [immune regulation, delaying the onset of age-related dysfunction.

The illness risk increase is contended by the paper @peter linked, in that they’re observations were correct but their conclusion wasn’t.


Darkgerbil, the highlights are:
• Acute exercise is an immune system adjuvant that improves defense activity and metabolic health.

• Data support a clear inverse relationship between moderate exercise training and illness [risk].

• Exercise training has an anti-inflammatory influence mediated through multiple pathways.

• Illness risk is increased in athletes during periods of intensified training and competition. [Edit: the classic studies are marathoners, who do an exhausting race and have higher rates of illness after a race.]

• Increased carbohydrate and [polyphenol] intake is an effective nutritional strategy for immune support. [Edit: eat carbs and blueberries]

• Habitual exercise improves [immune regulation], delaying the onset of age-related dysfunction.

[My own reading of this is that you should exercise at your normal intensity – not at a ramped up rate – and nor should you do a single, marathon-equivalent workout.


Ha: I read the other responses after typing my own. [Note to self: read the whole thread first.] It’s interesting to see the three slightly different takes on the papers. I guess that I’d emphasise the effect of ramping-up, marathon-type efforts.

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Thanks guys, I appreciate your summaries! :grinning:

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The pubmed debunking paper is interesting, I don’t have time to get through the rest of it today but so far I think the practical advice to ‘exercisers’ is similar except on very hard efforts.

So I guess we either train as usual, or train as usual but leave out massive efforts.

I’ve got to say that the Debunking paper reads quite convincing so far, but for me my marathon race is cancelled anyway, so there’s no need to put in 3h hard runs either way. Depending on whether allowed outside or I’m confined to home I’ll continue with either LV Olympic Tri plan or a MV Sweet Spot plan.


Seems to match my own conclusion after a year of medical research overload:

Brisk walking is arguably one of the best forms of exercise for your general health.

You won’t get fast but you’ll be fit!

I wonder where 10 mile TTs fit in the spectrum of hard training efforts vs immune system?

Our season starts in only two weeks time so I’ve been pondering this one…

I have 2 wks of SS2 left, which I’m going to postpone and switch to Zone 2 rides 2hr x 4/week until things improve. Washington State has closed restaraunts, hair places, gyms, bars, etc. I was just at the hardware, and folks there weren’t careful about the 6 foot limit.

I doubt this will be a concern soon, surely all events will be cancelled.

Funnily enough we just announced that all our club events are cancelled until further notice, so you were absolutely right!

If you’re in the UK British Cycling has cancelled all events, sportives and training…as has British Triathlon and England Athletics.

Wellll, I couldn’t resist. Did Mills today.