With COVID-19 dominating all news channels, it seems like as opportune a time as any to become better acquainted with the brain, the immune system and what happens when we experience stress.
Current Global Stress Levels
Given current stress levels, it feels only fair to acknowledge that most of what we know about how the brain modulates the immune system comes from researching stress. The brain is the central control system for the body and its functions. Largely shielded from infection by the ever so protective blood-brain-barrier it is in a particularly privileged position although that doesn’t make it complacent about its immuno-duties for the rest of the body. The brain through fibres, neurotransmitters and hormones manages the body. Immune cells have receptors for these mediators produced by the brain and it is via these that the brain modulates immune cells. The immune system can communicate with the brain through chemical messages that float around inside the body. This means that if our immune system is weakened our whole body won’t operate as usual.
When faced with ‘stressful’ stimuli, your hypothalamus (a very small region at the base of the brain) triggers an alarm throughout your body, activating nerve and hormonal signals which then prompt your adrenal glands to release a surge of hormones most notably adrenaline and cortisol. You are probably well versed with the feelings of heightened adrenaline – increased heart rate, elevated blood pressure and boosts of energy, think of the few minutes before you are to give a presentation or compete in a sporting event. This adrenaline burst is in fact, useful and helps us perform if used efficiently. It is the elevated cortisol that we are particularly concerned with. Cortisol is the primary stress hormone and has a number of effects on the brain and the rest of the body. It increases glucose in the bloodstream so that it is available to your body for use as needed when under stress. However is also plays havoc with other systems – it alters the immune systems and disrupts the digestive systems, the reproductive system, growth processes, interrupts sleep and cognition.
Stress Does Not Discriminate
Long term elevated cortisol can cause damage to the hippocampus and impair the learning and memory that the hippocampus is involved in. Given the environment around us, perhaps the more immediate effect that we need to know about is that the stress response suppresses the immune system increasing susceptibility to colds and illnesses. Whilst I am not advocating complacency we should also remember that undue stress might paradoxically cause us more harm and bear in mind that the negative effects of stress do not discriminate.
So at a time when stress levels are high and rising and it is near impossible to escape the tumultuous world around us, how can we better protect ourselves and ensure our systems are working as best they can be?
I apologise for the repetition as I am sure my next words are two that you have all heard many times over – mindfulness meditation! I can already see the regular practitioners nodding their heads knowingly. There are so many studies to this point, I honestly do not have the word count to talk through them all but as an overview 20 randomised trials examining the effects of mindfulness meditation on the immune system found:
- Reduced markers inflammation. Inflammation is often correlated with decreased immune functioning
- Increased CD-4 cells. CD-4 cells are white blood cells that support the immune system.
- Increased telomerase activity. Telomerase work to prevent chromosome deterioration.
If that isn’t convincing enough, Professor Richard Davidson from the University of Wisconson Madison conducted a study to look at whether mindfulness meditation could alter brain and immune function. Participants were injected with the flu vaccine and were then split into two groups; a mindfulness training group and a control group. After eight weeks, those who participated in mindfulness meditation showed a greater level of antibodies available to respond to and prevent potential illness.
Mindfulness meditation isn’t just a behavioural technique, regular practice can actually lead to structural changes in the brain. Research shows that mindfulness meditation increases activity in the prefrontal cortex, right anterior insula, and the right hippocampus. These areas are acting as the command centre for the body’s immune system. Mindfulness meditation stimulates these areas which in turn helps the immune system function more effectively.
Our Second Brain
The story wouldn’t be complete if we did talk about gut microbiome. Yes that’s right, the much talked about second brain. Our gut is full of microbiota and these play a vital role developing and maintain the immune system. Stress can lead to a major imbalance in the gut microbiome and mindfulness meditation is a very effective stress reduction technique. Complement your mindfulness practice with a kombucha. To build up the gut microbiome cultures and maintain that diversity, look to fermented foods and drinks.
There are a myriad of things one can do to protect their immune system and ensure it is working efficiently, particularly in times like these when your body is calling on it more than ever. It is a horrible reality that so many people are being affected by COVID-19, not just those who are unwell but also the wider community. The healthcare system is under immense pressure, small businesses through to large co-operations across all industries are glaring at dire forecasts as the economy shifts globally. These are truly difficult times but perhaps the best we really can do is to, ‘keep calm and carry on.’