Overtrained and Underdefended?

As the cold and flu bugs start to do the rounds we all want our immune defences to be working well.  If you take your sport seriously and are training hard you may find that you are more susceptible to these winter bugs, but is that really the case or just perception?  Research suggests that intense training can have an impact on immune function in a number of different ways, and dietary factors may have an impact too.

If you’re a serious athlete then it may be the case that you do suffer from more infections, particularly respiratory infections, than everyone else.  While moderate exercise has been found to boost immune function, intense training over a prolonged period can suppress a number of aspects of immune function.  Research has found that the hormones and other chemicals produced during hard training, such as adrenaline and cortisol, are responsible for this effect.  There are three possible mechanisms of action that in isolation, or together, can impact your ability to ward off the bugs.

In particular it seems to be the innate immune system that is affected – these are the immune cells that are non-specific, they’ll attack any bacteria or other invader in the body.  The number of these cells may be reduced, particularly where there is overtraining.  If there are less of them patrolling your body then it is possible you will experience more infections.

Another aspect of the immune system that seems to be affected is the mucosa – the lining of your gut, nose and other body surfaces that serves as an important physical barrier and line of defence against infection.  The particular types of immune cells that form part of this barrier can again be reduced when overtraining occurs.

A third piece of the jigsaw relates to the systemic inflammation that can occur when training has been intense.  Inflammation is an important part of the recovery process because it signals to your body where it needs repair.  But when intense training results in ongoing chronic inflammation this can in fact result in suppressed immune function.

It’s important to note that most of this research has been undertaken with athletes who find they have overtrained  – the kind of moderate exercise that most people do can in fact improve immune function.  But everyone is different, and while some people can exercise intensely for long periods of time without suffering from overtraining syndrome, others will get there more quickly.  The good news is that keeping your eye on a few dietary factors can help give your immune system the support it needs.

The first thing to look at is protein intake – when your body is launching an immune defence it needs plenty of protein to build and fuel the immune system cells.  Take a look at your diet and make sure you are getting at least 20g of protein in every meal, and are including protein in every snack too.

Your immune cells need vitamins and minerals to function effectively, for example vitamin A which you can get from orange vegetables like squash and pumpkin, zinc which you can get from nuts and seeds, and B vitamins which you can get from wholegrains and a range of nuts, seeds and vegetables.  Make sure you’re eating a varied diet with lots of different colours, proteins and grains.

Be wary of sugary snacks too – when you’re training hard you want all your food to count, and making sure you eat healthy snacks like the ones you’ll find in a Nutribox could help.  Many of them contain the nuts, seeds and dried fruits that can help provide the vitamins and minerals your immune system needs to function well.

If you’re interested in trying a Nutribox click here  

photo source – canstopendurance.com – it says it all!

  • Ann White
  • 06 Nov 2013

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