So, the dreaded lurgy has caught up with you!
Do you hit the gym to “sweat it out” or stay home?
Read on to help you decide what to do next time a cold or flu hits you.
A quick overview of the immune system:
This is the hard working part of the body that fights all the daily bacteria, viruses, fungi, parasites etc we are exposed to.
Using barriers such as mucous linings (in the nose), chemicals (stomach acid) and specialist cells as a first line of defense, the innate immune system can fight off many “attackers”.
When bugs get past this first line of defense, the adaptive immune system kicks in.
This is composed of highly specialized cells and processes and helps us fight infections by preventing pathogens from colonizing and by destroying microorganisms like viruses and bacteria.
We have specialized white blood cells (T and B cells) which have a kind of memory.
It’s this memory that makes them so effective. Once they “recognize” a specific pathogen, they mobilise more effectively to fight it.
This is what we mean when we talk about “building immunity.”
It also explains why kids get sick more often than adults – their adaptive immune system is less mature than ours as they’ve had less exposure than we have.
This is also the basic premise of vaccination. The vaccination introduces a tiny dose of a pathogen into the body so the immune system knows what to do when confronted with a bigger dose.
How good is the human body!!
Back to the question: Should you exercise when sick?
First of all, let’s clarify that there is a difference between a workout and moving your body.
A workout routine that gets you sweaty and short of breath, triggers a stress response in your body which a healthy body can deal with to make you fitter and stronger over time.
When you’re sick, a big workout might be more than your system can handle.
Before you head for the couch when the sniffles hit, read on:
Unless you’re super unfit, a light workout might actually help.
By light workout, I mean a walk or bike ride outside, tai chi or a bit of gardening.
These non-cardio workouts can actually strengthen your immune system.
Remember – my light workout might be different to your light workout so let your perceived rate of exertion be your guide.
Your what? I hear you say.
Perceived rate of exertion is how you rate your level of effort on a scale of 1 – 10.
1 being super easy, 10 being Wow! I can only manage this for about 30 seconds.
How exercise affects the immune system
It is believed that exercise may play a role in both our innate and our adaptive immune response.
- One prolonged vigorous exercise session leaves us more susceptible to infection. (eg running a marathon may temporarily depress the adaptive immune system for up to 72 hours.)
- On the other hand one brief vigorous exercise session doesn’t cause the same immune-suppressing effect.
- And: just one moderate intensity exercise session can actually boost immunity in healthy people.
Think about the “fit” people you know. How often do they get sick?
As a general rule, daily exercise of at least 30 mins a day can boost your immunity which is why fitness is linked with health.
On the other hand, if you know any athletes that train really hard, you might have noticed that they can get sick after a grueling competition or race. This is due to the effect I talked about above – one long, intense session can suppress the immune system for a while.
So, to summarise:
- Consistent, moderate exercise and resistance training can strengthen the immune system over time. i.e. train hard while you’re healthy.
- single high intensity sessions can interfere with immune function.
So take it easy when you’re feeling sick. Note – I didn’t say take to your bed straight away!
The key thing to take away from this: is to learn to listen to your body.
I like to use the 10 minute rule.
Start exercising, if, after 10 minutes you’re still feeling yuck, scale it back (or stop). Chances are you’ll actually be feeling ok within that time period.