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Rule 1 - Glutamine

Dr Francesca Alves, PhD


Have you ever felt cold-like symptoms the day after a big training session or endurance event? Or perhaps you’ve noticed that you get sick more often during periods of intense, prolonged training? While training for a half-Ironman last year, I certainly noticed that I was sick much more frequently throughout the year—which was extremely frustrating. The fact is, prolonged bouts of strenuous exercise (i.e., >1.5 hours in duration or moderate to high intensity 55-75% maximum O2 uptake) cause a temporary depression of various aspects of immune function (e.g., neutrophil respiratory burst, lymphocyte proliferation, monocyte antigen presentation) that can last up to 24 hours post-exercise1. It is this immune suppression that explains the increased prevalence of sickness in many athletes or exercise enthusiasts.


Now, I’m not suggesting that people should quarantine post intense and prolonged exercise—we’ve been through enough self-isolation to last a lifetime. Rather, athletes and individuals who partake in prolonged and intense exercise should be aware of training loads and optimize nutritional support to mitigate immune suppression. But how can you support your immune system?

The simplest way to support your immune system is to ensure that the immune cells have an adequate fuel source. Most cells in the human body primarily metabolize glucose as a fuel source, but under stress conditions, such as intense, prolonged exercise, immune cells (including lymphocytes, neutrophils, and macrophages) utilize glutamine at high rates similar to or greater than glucose2. Glutamine is a non-essential amino acid, meaning the body can synthesize it. However, the synthesis takes energy and resources that are limited post intense exercise. As a result, studies report reduced plasma glutamine levels in response to different stress situations, such as sustained exercise, trauma, and starvation3. That’s why you may see glutamine referred to as a ‘conditionally essential’ amino acid. Under certain conditions, such as intense, prolonged exercise, glutamine needs a dietary boost. That’s why Rule1 created the optimal glutamine supplement, ideal for post intense exercise to fuel immune cells and prevent post-workout immune suppression. Rule1 Glutamine is highly recommended to anyone that wants to push beyond a moderate level and duration of exercise—lowkey anyone that has just joined a run club and thought that running a marathon with only a few months to prepare is a good idea.

References

1 Wu, W. et al. Effects of Acute Ingestion of Caffeine Capsules on Muscle Strength and Muscle Endurance: A Systematic Review and Meta-Analysis. NutriAents 16 (2024). 


2 Cruzat, V., Macedo Rogero, M., Noel Keane, K., Curi, R. & Newsholme, P. Glutamine: Metabolism and Immune Function, Supplementation and Clinical Translation. Nutrients 10 (2018). 


3 Córdova-Martínez, A., Caballero-García, A., Bello, H. J., Pérez-Valdecantos, D. & Roche, E. Effect of Glutamine Supplementation on Muscular Damage Biomarkers in Professional Basketball Players. Nutrients 13 (2021). 


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