This is about the time of year when many of my athletes start getting sick. They assume it’s just par for the course and that several seasonal colds or flus are normal. I disagree and want to reinforce that there is so much we can do to protect and prevent ourselves from getting sick. My number #1 tip is to take a daily probiotic - in fact it’s one of the few mandatory supplements I tell my athletes to pick up. I’ll briefly explain below- it gets a bit ‘sciencey’ but important to understand.

Our immunity is often a forgotten part of our nutrition plan for optimal recovery. Intense exercise weakens our immunity because of the impact on our gut – an organ that is 70% of our immune system. A weakened gut leads to an open window for opportunistic, bad bacteria to invade and cause infection. This susceptibility can disrupt training – which can decrease sport performance – or require withdrawal from a competition.

Fortunately, good gut microbiota can help make sure your hours of investment in training are worthwhile. Some gut microbes work with our gut and immune cells to take care of disturbances to immunity that result from high levels of physical and environmental stress. A healthy immune system is maintained by the extensive, friendly interaction between gut microbiota and our mucosal immune system. When there’s an unhealthy gut environment, the mucin barrier weakens. This allows microbes to invade the epithelium and – ultimately – cause inflammation. Essentially, our immune system needs to have an appropriate balance between tolerating good gut microbiota and defending against bad bacteria.

Here’s how good gut bacteria strengthen our immunity:

Enhance the gut barrier. This is one of most important benefits. Probiotics can regulate the number of tight junction proteins between cells and can prevent or reverse the consequences of the bad bacteria.
Increase mucin production. Probiotics can strengthen the first line of defense – the mucosal layer. Probiotics, such as Lactobacillus, have been shown to influence mucin production.
Probiotics engage with immune cells. Immune cells are constantly communicating with gut bacteria.

How does this link back to exercise and immunity… I’m glad you asked!

High-intensity exercise is immunosuppressive. Immune changes at the cellular level include a reduction in white blood cell function, which creates a window of opportunity for bad bacteria.

The primary impact that weakens our intestinal wall barrier is the change in blood flow from the gut to skeletal muscle and the heart. This effect of changed blood flow is greater with higher intensity and prolonged exercise. Subsequently, the gut receives less: Blood, Oxygen, Nutrients and Removal of metabolites.

To sum it all up…

Endurance exercise hurts gut cells. In fact, GI complications are the consequence of blood moving away from the gut, which leads to abdominal cramps and diarrhea – major complaints experienced in endurance sports.

Athletes undergoing endurance training balance a fine line between enhancing health through exercise and hurting it. Exercise places physical stress on the gut, which lowers immunity. This is inevitable, but probiotics may be a simple nutritional intervention to fight the stress. Studies show that athletes who take a daily probiotic are 46% less likely to get sick. They also sleep better, have better absorption of nutrients and a heightened digestive system.

An easy formula to remember that really brings the point home (courtesy of my friends at Sound Probiotics) …

IMPAIRED IMMUNITY=POOR RECOVERY=POOR PERFORMANCE