A lot has been written about the demographic of people most likely to suffer from worse symptoms if they catch COVID-19. People with underlying health conditions are certainly at more risk; men seem to suffer more than women at all age groups; and age is definitely a factor, with younger people supposedly more able to throw off the symptoms more easily. What is becoming clear though is that our own body’s response to the virus is far more important than the virus itself. So how well prepared are you? And what does exercise have to do with it?

As I was passed on my walk by a multitude of amateur joggers in Richmond Park this weekend I couldn’t help wondering

1) how many of these new joggers are going to need intense physiotherapy help very soon; and

2) whether the competitive training that is breaking out online and on social media is doing more harm than good to our immune systems.

It all comes down to the amount of training you do, and how much stress you are under at the same time. So here’s the question: Does training hard doing more harm than good to our immune systems?

All Stress Adds Up


We may think of stress as being only psychological. So many are losing their jobs or financial security right now. Many of us have lost close relatives. It’s an unprecedented, extraordinarily psychologically stressful time.

But the body interprets and responds to psychological, physiological and physical stress in exactly the same way. So adding in more stress with a new intense workout routine while you’re locked down at home may be the worst thing to do right now.

Importantly, some recent research documented the importance of the perception of stress. Some people endure typically stressful situations far more easily than others, and this obviously will affect the impact on their individual immune system. In other words, if you are finding lockdown tough for whatever reason, you might need to take it easy when it comes to exercise.

How Bad is it?


Athletes under heavy training schedules can see both their innate and acquired immunity decrease by as much as 15-25%. It is often reported that athletes are particularly susceptible to Upper Respiratory Tract Infections, but the evidence is not conclusive. However, what is definitely true is that heavy training, along with other stresses, will add up to decrease your immunity.


Walsh, 2018


Why Does Exercise cause stress? Isn’t it good for us?


Well yes, exercise is definitely good for us. And there is a large body of work that shows consistent daily exercise has a beneficial effect on immunity. It’s about how much and how often.

If an athlete is overstressed, physically or psychologically, adaptation can start to fail, leading to the symptoms of overtraining. This is not just reserved for elite athletes; in Third Space Medicine we see it a lot in recreational athletes as well.

When we train, we train to become deliberately weaker for a short period of time, in order to get the rebound called ‘supercompensation’, which is when our muscles increase in size and our ability to accept load increases.

However, if we train too fast, or without enough recovery in between sessions, we are in danger of overtraining, which leads to a reduced ability to accept load. Taking on a heavy exercise session 6 days out of 7 doesn’t leave enough time for recovery. Prolonged heavy training sessions in particular have been shown to decrease immune function; potentially providing an ‘open window’ for opportunistic infections.

Then there’s the hormonal response.

Exercise over a certain intensity, or over a certain length of time leads to an increase in cortisol release. In its normal function, cortisol helps us adapt to challenges by converting proteins and fats into energy, releasing glycogen and counteracting inflammation.

But sustained high cortisol levels slowly break down healthy muscle and bone, slow healing, impair digestion, interfere with endocrine function, weaken the immune system and disrupt emotional wellbeing.

Another hormone called DHEA, which is the precursor to oestrogen and testosterone will be decreased during periods of stress. Insufficient DHEA also contributes to impaired immune function.

The Importance of Sleep


Sleeping enough is important at any times, but during stressful periods like now it is even more crucial. Scientists suggest that sleeping less than six hours per day for a period of four days can impact negatively on immune function.


What are the symptoms?

In early overtraining, it’s all about the sympathetic nervous system (‘fight or flight’) You might notice

  • blood pressure and heart rate are increased both resting and exercising;
  • heart rate takes longer to recover after exercise,
  • you feel irritable or anxious and your energy is lower on more days,
  • your sleep is disrupted;
  • allergies start to flare up,
  • sugar cravings are difficult to resist and
  • more importantly, you start coming down with colds, ‘flu or digestive problems more easily.


With severe overtraining, these symptoms can alter. You might experience

  • Low or normal resting and exercising heart rate and blood pressure
  • Fatigue and depression
  • Loss of motivation
  • Hypoglycaemia during exercise
  • Deep sleep but don’t feel rested when you wake.

Our recommendations to maintain immune health in athletes:

  • Monitor your stress levels carefully and don’t push it.
  • Switch up your exercise. Use the Third Space live training sessions to do body weight on one day; yoga the next; take a walk the third day and so on. Undertake easy-moderate training sessions after any high-intensity session.
  • If you are trying to increase your programme, keep the increase of volume and intensity to only 5-10% per week, and only if you feel ready and not stressed.
  • Use daily sessions and even maybe shorter, spike training sessions rather than fewer, longer sessions
  • Prioritise recovery and sleep. Aim for more than 7 hours per night. If you are having trouble sleeping, try a nootropic, CBD oil, magnesium or melatonin ( only available online from overseas)
  • Avoid crash-dieting and don’t skimp on the complex carbohydrates – we need them to provide nutrients that help with stress levels
  • Ensure adequate protein intake.
  • Consider supplementing vit C, D, zinc and a probiotic for the immune system.

If you’re concerned about your nutrition and immune system during Lockdown, make sure you’ve downloaded our pdf on Boosting Immunity

Any memberships taken out in April 2020 also receive our free collection of Immune Boosting Recipes