This is a talk about immune function in sport and exercise.
My name is Michael Gleeson and I'm Emeritus Professor of exercise biochemistry,
but Loughborough for university.
I've also been in the past president of
the International Society of exercise and immunology.
After this lecture, you should know what causes infections, should have
a basic understanding of how the body protects itself against infections,
including the essential role of the immune system.
You should appreciate that immune function and infection
risk are both influenced by how much exercise you do.
You should understand why moderate exercise training is generally
associated with a lower than average risk of respiratory infections.
You should also understand why very prolonged exercise
in contrast and intensified training can actually
depress+ immune function and results in increased risk and incidence of infections.
Towards the end of the lecture,
we'll mention some of the other factors that can lower immunity in athletes and
other highly active people and contribute to an increased risk of infection.
Let me begin by first summarizing the main causes of
infection and the role of the immune system in protecting us against them.
Essentially, infections are caused by pathogens,
which is just a fancy word for infectious agents.
They come in four different types of bacteria,
viruses, parasites, and fungi.
They get transferred into our body via several different means.
They can be breathed in as
particles in the air.
They can be present in the food that we eat or
the water that we drink or we use for washing ourselves.
We can also pick up pathogens or germs from dirty surfaces,
pick those up on the tips of our fingers and if we touch those to the eyes, ears, nose,
or mouth, we can pass them to
those sensitive mucosal surfaces and they can gain entry into the body that way.
We can inhale the things in the air that we breathe in.
Then we can ingest them in the food and water that we drink.
We can get them via touching dirty surfaces to our mucosal linings.
We can also get them directly,
sometimes through cuts or abrasions in the skin.
Symptoms of infection arise when a microorganism gains entry to the body,
is able to multiply and cause tissue damage by killing ourselves.
This may arise due to the entry of some new infectious agent. It's got into the body.
Or it could be because we have activated a virus that's already sitting
there waiting to be active and the body something we call a latent virus.
The most common infections in athletes and in fact,
in the general population,
are those affecting the upper respiratory tract.
But the common cold is the most common infection that people can get.
Or the common infections are those that affect the gut,
the eyes, and the ears.
Most of those respiratory infections are caused by a virus.
Of cause we've all heard by now of the coronavirus,
but there are other ones as well like rhinovirus and
adenovirus that can also cause what we call the common cold.
It's caused by multiple different viruses that could bring about those symptoms.
Then there's also the slightly more severe symptoms we get.
The flu, which is caused by the influenza virus.