When most people think of issues for athletes they usually think of musculoskeletal injuries such as sprained ankles, pulled muscles, or knee pain, but a recent study suggested immunity issues cause up to 50% of disruption to training or performance in athletes.
According to research, exercise improves immunity at moderate intensity but impairs immune function at high intensity (and duration) making many endurance and elite athletes more susceptible to respiratory infections. Infection, such as fever and fatigue, can weaken muscles, impair exercise, and predispose athletes to other injuries. For example, fever impairs coordination, muscle strength, and aerobic power while viral illnesses contribute to tissue wasting and muscle breakdown.
Drugs commonly used to treat the symptoms of infectious diseases have variable impacts. Antibiotics can cause diarrhoea and ongoing gut issues, antihistamines can cause sedation, and many ephedrine-containing compounds like Sudafed are prohibited during competition over certain amounts under the Australian (ASADA) and World Drug Agency Association (WADA) guidelines.
To explain this immunity phenomenon perhaps a recap of how the human immune system is set up may be helpful. There are two parts to the immune system, the Innate Immune System and the Adaptive or Acquired Immune System.
Innate Immune System
The innate immune system includes our first line of defence providing physical barriers such as the skin, mucous membranes, nasal hairs, eyelashes and functional barriers such as the gastrointestinal tract and defence mechanisms such as secretions, mucus, bile, gastric acid, saliva, tears, and sweat. This part of our system also houses our infection-fighting cells such as our natural killer cells and phagocytes which act like Pac-men against microbial invaders, and proteins such as tumour necrosis factor which program cell death and cytokines which play roles in cell-to-cell communication. The complement system is an additional cascade of proteins that “complements” other aspects of the innate immune system. The innate immune system is always ready to do battle with foreign invaders, irrespective of whether they have come into contact with the microbial invader before.
Acquired Immune System
The acquired immune system is a collection of cells called T and B lymphocytes, immunoglobulins produced by the lymphocytes, and cytokines that regulate the immune response. Through a complex pathway of intercellular interaction, immunoglobulins are produced after exposure to a new pathogen, so they can recognise the invader the second time around and have an inbuilt immunological memory and enhance the immune response accordingly.
Gut-Associated Lymphoid Tissue (GALT) is a collection of several types of lymphoid tissue that store immune cells, such as T and B lymphocytes and is our major defence mechanism against pathogens entering the digestive system. Peyer’s patch is a collective of lymphoid cells attached to the gut lining which is the initiation of the immune response when an infection is detected.
Secretory IgA is another substance produced by the acquired immune system produced in all areas where a protective mucosal layer exists such as the digestive, respiratory and urinary tracts to provide front-line defence. It forms the backbone of our immune system because it protects the immunoglobulins from being destroyed and protects the immunoglobulins from invading microbes.
This part of the immune system provides long-lasting protection against anything it has encountered before. When the two systems (innate and acquired) combine, they form an incredible defence against the constant barrage of infectious threats an athlete faces each day.
How does exercise impact on immunity?
So let’s examine how exercise can affect immunity. There is a substantial body of knowledge suggesting moderate exercise of up to 60 minutes at 60% of maximum heart rate improves immune cell counts and salivary IgA concentrations. Studies also show that 61% of new runner’s report fewer upper respiratory tract infections after starting running. However, there is always a flipside to everything and in the case of exercise, the term moderation is wise to observe. There is also evidence to suggest intense exercise and prolonged exercise greater than 60 minutes may both actually reduce immunity. While there is no doubt hard efforts increase VO2 max, it also forces most athletes to transition from nose breathing to mouth breathing, bypassing the nasal hairs and turbulent flow that protect the lungs from pathogens.
Inhaling larger volumes of colder and drier air thickens the mucous and disrupts the mucociliary elevator which is like our own inbuilt elevator designed specially to clear mucus from the respiratory tract. Hence why many athletes find they need to do a fair bit of “hoiking” to clear the phlegm during hard efforts in cooler months, especially when coupled with the ingestion of proinflammatory and mucous producing foods such as dairy, coffee and bananas.
As more foreign particles are deposited in the lower airways, the ability to clear them is diminished, and airway inflammation results. Studies show our natural killer cells and secretory IgA fall after intense or prolonged exercise. The key members of our acquired immune system are also affected by neutrophils and B cell function declining.
With repetitive hard and long sessions that most endurance athletes over the marathon, ultra-marathon, ironman, triathlon or cycling do on a regular basis, hormones such as cortisol, prolactin, adrenaline, and growth hormone are constantly elevated and these also impair cellular immunity.
While most upper respiratory infections start off as viral infections, athletes who develop symptoms that are ongoing may also have a secondary bacterial infection.
What can be done about an underperforming immune system?
Few athletes stop training because they get a few annoying sniffles. When on a mission, athletes should always seek out a solution to overcome or manage the issue.
At this point, it may be wise to seek help from a healthcare practitioner. Natural medicine has plenty to offer in regards to boosting the soldiers of the immune system. Most people are aware of the immune cell turbo boost vitamin C, and zinc provides but what about natures little wonders? Natural remedies such as garlic and horseradish, Andrographis, Echinacea, Cat’s claw and Astragalus can increase immune cell count and function, and anti-microbial herbs like Thyme, Thuja or Pelargonium which kill viruses and bacteria directly. Maintaining digestive system integrity and microbiome balance through quality probiotics will also help support GALT and sIGA in the adaptive immune system. Herbal adaptogens also assist with improving immunity integrity and resilience to future invasions. As with any treatment, these options are not going to be a magic bullet, but they can certainly reduce the severity of the infection, reduce recovery time and get you back to what you love doing. You should still always reduce your training load and convalesce to some extent.
Many studies use incorrect dosage ranges and timeframes for herbal medicines, so the evidence may be unclear and confusing to the untrained eye. However, when used in correct dosage ranges, they are viable options for athletes with few side effects and are permitted underperformance guidelines. Research shows that seeking treatment quickly can reduce the impact respiratory illness may have on athletic performance.
For more information on natural treatment options visit the Athlete Sanctuary www.athletesanctuary.com.au.