Wednesday 18 March 2020

COVID-19 and Exercise

Cropped photo of coronavirus by Fusion Medical Animation on Unsplash

The main news headline everywhere across the world is about the coronavirus (SARS-CoV-2) infection COVID-19. Many might not realise it but the way you exercise can affect your susceptibility of getting infections and dealing with them.

Table of contents

The central nervous system and exercise

Your central nervous system (CNS) plays a vital role in everything we do. One aspect of it is the neuromuscular system, which is made up of all your muscles and the nerves that serve them. At its most basic all movement starts with an electrical impulse from the brain that goes through your CNS to the neurons of the neuromuscular system that stimulate your muscles into movement.

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CNS fatigue

Your CNS is not an infallible working machine. It tires out and gets fatigued especially with intensive exercise.

Just as muscles get larger through muscular hypertrophy (bodytraining), which involves taxing and fatiguing them, so too does your CNS become stronger via intensive training. However for them to become stronger they initially become weaker thanks to the exercise.

It is with ample rest and recovery along with a good diet that helps it come back stronger than before, the same with muscular hypertrophy.

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CNS overtraining

CNS overtraining is where you constantly keep pushing your body with workouts that are intensive or too often with little time to recover. This places an undue amount of stress on it. Unlike muscular overtaining, which affects certain muscles, CNS overtraining affects your whole body. The result? General fatigue, the feeling of being weaker and slower, and more importantly a weakened immune-system.

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CNS fatigue and illnesses

There is a correlation between intensive training and susceptibility to illnesses such as the cold or flu. Anecdotally I can testify to this whenever I embark on a period of hypertrophy or strength training. Scientifically research proves this to be the case. Indeed the first instance provided next is the most important to consider as COVID-19 is a respiratory infection:

  • "Athletes are susceptible to upper respiratory tract infection (URTI) during intense training and after major competition; high rates of URTI have also been associated with the overtraining syndrome (staleness)."[1]
  • "Overtraining and long-term exercise are associated with an impairment of immune function."[2]
  • "Studies from several exercise laboratories have shown that after a single exhausting exercise session there is temporary immune depression, with marked changes in numbers and functional capacities of lymphocytes. These changes, which last for up to several hours, are seen in athletes and untrained individuals."[3]

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How does this impact with COVID-19?

In regards to the current COVID-19 pandemic a fatigued CNS or worse, one that is affected by overtraining, leaves you with a weakened immune-system. This means that your body will not be in its best shape to help fight the virus. Indeed if you add muscle hypertrophy to the mix, your body is also busy trying to rebuild your muscles leading to a more weakened state ill-prepared for viral infection.

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So, what should you do and what should you avoid?

There is no need to cut out exercise altogether. Rather, low-to-moderate intensity exercise could still be performed without impacting or fatiguing your central nervous system. Thus the forms of exercise to avoid are those that do impact heavily. These include but are not limited to:

  • CrossFit
  • Maximum strength
  • Hypertrophy (bodybuilding)
  • Endurance, whether it be via weight-lifting or marathon training etc.
  • High-intensity circuit training

Along with this a good diet of meat and vegetables will help provide your body with the vitamins and nutrients it needs to help your body recover from a workout and fight an infection.

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If you are still intending to exercise even if only at home bear in mind the kind of workout you are performing. Avoid strenuous taxing workouts to ensure your nervous and immune systems are in tip-top shape to fight a possible infection of COVID-19.

If you are currently going to a personal trainer and they intend to have you perform intensive exercises or proscribe you intensive exercises to perform by yourself during a period of isolation or lockdown, demand a light-to-moderate program instead.

Your health is what is most important. Also keep washing those hands!

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  1. Mucosal (Secretory) Immune System Responses to Exercise of Varying Intensity and During Overtraining. Laurel Traeger Mackinnon, Sue Hooper. Department of Human Movement Studies, The University of Queensland, Brisbane, Queensland, Australia 4072.
  2. Plasma amino acid concentrations in the overtraining syndrome: possible effects on the immune system. Parry-Billings M, Budgett R, Koutedakis Y, Blomstrand E, Brooks S, Williams C, Calder PC, Pilling S, Baigrie R, Newsholme EA. Medicine and Science in Sports and Exercise, 01 Dec 1992, 24(12):1353-1358.
  3. Overtraining Increases the Susceptibility to Infection. L. Fitzgerald. Department of Medicine, St. George's Hospital Medical School, London, UK.

Lyle Richardson,
Gym Pal - Your Friend In Fitness


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