Exercise and its effect on our immunity
COVID-19 is here and it looks likely to stay for the foreseeable, uncertain future. Our approach within Tri Training Harder has been to switch our athletes’ focus to what they ‘can’ achieve during this unusual period whilst prioritising their health and immunity.
But why are we doing this? Coach Alan Ward writes about the impact of exercise on our immune system to explain some of our considerations.
(Updated 2-4-2020: To include ITU Recommendations please see the end of the article for a link to the entire ITU Document)
As endurance athletes, it is widely accepted that upper respiratory tract infections (URTI) have a higher incidence in those training for this type of sporting performance. As endurance athletes place a high demand on their respiratory system the logical link seems to make sense. Normal advice is for an athlete to cease training if they experience symptoms below the neck as exercise during illness comes with significant risk of more serious illness. Advice for symptoms above the neck is to reduce training intensity and volume. At the moment respiratory health is on all of our minds with the development of the global pandemic.
The general understanding at a coaching level is that there is an ‘open window’ post demanding exercise within which an athlete’s immunity is impaired. The ‘open window’ hypothesis works around the idea that after training there is a dip in our immunity, particularly after sessions that are either prolonged or high intensity. Many research papers have been written looking at this area and in 1997 the International Journal of Sports Medicine published this article, which brings together much of the early research. This review highlights that moderate sessions <60min in duration and intensity <60%VO2MAX (Tempo to SweetSpot) are associated with less physical disruptions. The review also states that athletes should heed that “mental stress, undernourishment, quick weight loss and improper hygiene have each been associated with impaired immunity”.
In 2010, further research published in Exercise Immunology Review showed changes in markers of immunity for up to 8 hours post exercise. In this study ‘A’ grade riders, similar to Cat 1 UK riders, were used in a trial in which the subjects completed a ride for 2hr at 90% of their second ventilatory threshold , a.k.a Lactate Threshold / F.T.P. After the ride blood samples were taken at 2, 4, 6, 8 and 24hours in order to observe immune variables. Many changes in these variables, including reduced white blood cell counts and function, were noted for up to 8 hours post exercise. The conclusion of this research noted that these changes could be a reason for increased incident of upper respiratory tract infections in athletes training for endurance sports. It is also worth noting the high intensity of this session 2hrs at SweetSpot is a huge effort to make. Respiratory system demand, breathing rates, will be very high as will the overall TSS of the session, 162TSS to be precise.
Who would like to see this session appear in Training Peaks?
This final review of published research from 2018 looks at more recent papers than the earlier cited 1997 paper and instead questions the certainty of the ‘open window’ hypothesis. It is, however, worth noting that in the conclusion of this paper they state that “leading an active lifestyle is likely to be beneficial, rather than detrimental, to immune function, which may have implications for health and disease in older age.” It does seem that the focus of this paper is upon activity rather than performance in comparison to the earlier papers.
Is is clearly really important that we remember the positive things that exercise brings us. It is easy to get lost in the research and it is important to remember that these studies are very specific snapshots into precise questions asked by scientists in an environment they are deliberately trying to control.
What for some is light exercise, for others is extreme training and all the various combinations in between. It can be dangerous to give out one size fits all advice. However, it seems prudent at this time to recommend a general reduction in training overall volume and intensity load.
Overall, exercise is fantastic for our mental health and also, in normal circumstances, tends to bring some excellent social and well-being aspects to our lives. The simple task of stroke, crank and stride tend to distract our minds just enough to help us put a stop to worries that tend to circle our brain with the voice only growing louder. Activity can itself be a mindfulness practice and reduce our overall stress.
However, at this time athletes need to be careful with overall load and fatigue. Fatigue, particularly chronic fatigue, have been shown to be linked with physical changes in response of your immune system. This likely means a reduction in load would be a very wise choice currently. At this point, COVID-19 has been shown to be asymptomatic for up 14 days and therefore it seems wise to be cautious because you could be infected but unaware.
With no events to aim for during this period, and a potentially serious illness imminent, all training should be set with caution and certainly well within any athlete’s capability. It is far more important at this time to leave a reserve of energy to allow us to minimise our physical and mental stress, maximise our immunity and if required fight the illness. The internet is full of lots of advice from ‘professionals’ in the fitness industry advocating high intensity, prolonged efforts and of ‘enthusiasts’ pushing to get more time in virtual worlds and races. We hope they remain healthy, but the risk is really high, too high, in our opinion. The first rule of coaching is to do no harm.
Our approach so far has been to reduce all intensity to sub threshold, very short efforts or strength related intervals that are more force focussed than intensity focussed. Now is not the time to be overreaching and aiming to progress our fitness to a new FTP or new personal best with physical effort and physical load, TSS load of sessions or weekly volume of training. But this doesn’t mean to say athletes can’t improve.
Athletes should now try to perfect what they can do. Sleep well, eat well, work on mobility, stability and excellent conditioning, so that when the time comes to work hard again you will have shifted your potential nearer to your ambitious goals. If you are one of those athletes who is normally crammed for time and rams sessions into their daily routine, lets for once actually take a lesson from the professional athletes. It is not only the years of experience, dedicated practice, honing of skills and large training volumes that allow pro athletes to go fast. It is how well they look after themselves. Being a professional athlete is literally a 24/7 job, so let’s do as they do and focus on doing all the little things really well. Now is the time to take stock and work on the areas we know are weaknesses and remove our glass ceilings. Our fitness will certainly come back, but then we will have an upgraded chassis to race on.
Our blogs over the coming weeks will help you achieve this so for now stay tuned, stay healthy and #believestriveachieve
In an updated note the ITU have issued a Coaching and Training Guideline document in the screenshot you can see the main section that is applicable to our coaches and athletes approach to training during this pandemic period.
General wellbeing not performance enhancement.
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