Immune Function & High-Intensity Exercise


When it comes to training there is a delicate balance between over-reaching and overtraining.  While short periods of high-intensity training can be beneficial, it is detrimental to train at that intensity all the time.  More is not always better.

One of the risks of overtraining is that you are more likely to get sick.  There appears to be a U-shaped relationship between training volume (in particular, intensity) and immune function (as shown in figure 1).  In other words, moderate intensity exercise has immune-boosting effects while high intensity exercise can compromise immune function.  This isn’t to say that you shouldn’t do high intensity exercise.  However, you may want to consider taking some extra measures to improve recovery and prevent an infection so that you can get the most from your training efforts.

What is recommended?

  • Periodization.  Regardless of your training goal, you should be including some easy days or rest days into your workout plan.  There should also be weeks when you back off from training really hard.  This allows your body to repair and build on the work that you’ve done and get ready for the next phase of hard training.  Periodization can actually be quite complex so if you’re not an exercise specialist, you may want to consider consulting one (I recommend those with a CSEP or CSCS certification).
  • Adequate sleep.  This will vary from person to person but you may need to catch some extra shut eye during periods when you are training hard
  • Post-workout carbohydrates.  After intense training, it is recommended to eat ~60g of fast-absorbing carbohydrate.  This will go into your muscles and help with repair and recovery.  This is especially important if your main goal is performance.   On the other hand, if your goal is aesthetic or you’re looking to lean down in the off-season, you may not want to eat carbs after your workouts – this will force your body to use fat and convert it to glucose instead. The downside is that your recovery and performance will suffer a little bit so be sure to take advantage of some of the other strategies if you are eating low carb.
  • Supplement with Quercetin (kware-se-tin) – this flavonoid is found in many plants and has been shown to have a positive effect on the human immune system.  Take advantage of its anti-viral and anti-inflammatory properties try including some of these foods into your diet: black or green tea, apples, sweet potatoes, kale, red onion, broccoli, black plums, and berries.  Quercetin is also available as an herbal supplement which may be useful if you are undergoing a period of high-intensity training.
  • Greens powder.  Even if you eat lots of fruits and vegetables, the quality of our soil just isn’t the same as it once was, therefore if you can swing it I recommend taking a daily greens powder to help you get all of the vitamins, minerals, and phytochemicals that help your cells function at their best.
  • Parasympathetic system activation.  Your nervous system has two complementary systems: the sympathetic nervous system is in charge of the fight or flight response and the parasympathetic nervous system is in charge of relaxation.  Most people overtax their sympathetic system to start with and intense training is another stressor on your body, therefore it is important to find ways to calm down and restore the balance.   When the parasympathetic system is in charge, your body is better able to digest food better, fight infections, and repair and build those muscles you’ve been working so hard.  Some things that work for me are listening to ocean sounds, progressive muscle relaxation, yoga, and mindfulness meditation.  Find what works for you.

Remember, training is when you break down your body.   You can’t just keep beating it down without giving it the materials and the downtime to recover and get tougher!   Train smarter, not just more 😉

~Live Inspired~!




Jones HP. Immune cells listen to what stress is saying: Neuroendocrine receptors orchestrate immune function. Psychoneuroimmunology 2012;934, 77-87.

Walsh NP, Gleeson M, Pyne DB, Nieman DC, Dhabhar FS, Shephard RJ, Oliver SJ, Bermon S, Kajeniene A. Position statement. Part two: Maintaining immune function. Exerc Immunol Rev 2011;17:64-103.


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