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Winter infections can be a significant nuisance during the colder seasons. Even if we’re not seriously ill, they can leave us incapacitated for a few days, causing us to lose valuable training time and waste additional days regaining our fitness levels. Also, if you’ve ever undergone a few weeks of intense preparation for a BJJ competition, you’ve likely experienced the phenomenon of suddenly falling ill without warning.

In this article, I will explain the reasons behind this and provide you with a scientifically proven supplement protocol to help prevent and possibly shorten the duration of common infections. Enjoy!

Why Do We Get Sick in Winter and During Periods of Heightened Stress (e.g. Training Camps)?

We tend to get sick in winter because cold, dry air weakens the mucosal barrier (the inner layer of cells in the respiratory tract and mouth), making it easier for viruses to enter. Reduced sunlight lowers vitamin D levels, impairing immune function, and spending more time indoors increases exposure to germs in close quarters. Common culprits include rhinoviruses, coronaviruses, and influenza viruses, which spread more easily in cold, dry conditions.

Stress—whether physical, mental, or emotional—further impacts the immune system’s ability to prevent and combat infections. Combat sports athletes, particularly during high-stress periods like winter and training camps, face several additional risks:

1. Suppression of the Immune System
   • Stress Hormones: Chronic stress elevates cortisol levels. While cortisol is anti-inflammatory in short bursts, prolonged elevation suppresses the immune response, reducing the production of infection-fighting white blood cells (lymphocytes).
2. Physical Stress from Training
   • Open Window for Infection: Intense exercise temporarily weakens the immune system during the “open window” period, which lasts up to 72 hours post-exercise, creating an opportunity for pathogens to invade.
   • Reduced Mucosal Immunity: Heavy training decreases the production of salivary immunoglobulin A (IgA), a key protein that binds to microbes and serves as a first line of defense against respiratory infections.
3. Nutritional Deficiencies– often experience nutritional gaps due to increased metabolic demands, leading to deficiencies in critical nutrients like vitamin D, zinc, and magnesium, all essential for immune function.
4. Increased Exposure to Pathogens
   • Training Environments: Combat sports involve close physical contact, making it easier to spread infections like the common cold, flu, and skin infections (e.g., staph or ringworm).
   • Travel and Crowded Areas: Preparation camps often involve travel and exposure to new environments, increasing infection risks similar to those during winter.
5. Sleep Deprivation
   • Intense schedules and travel can disrupt sleep, which is critical for immune regulation. Sleep deprivation reduces the effectiveness of some white blood cells.
6. Psychological Stress
   • Competition Pressure: Anxiety about performance increases stress hormone levels, exacerbating immune suppression.
   • Social Stressors: Balancing training, competition, and personal life can lead to chronic psychological stress, further impairing immunity.
7. Cold Weather Effects
   • Environmental Factors: Cold, dry air dries out mucous membranes, making them less effective at trapping pathogens.
   • Reduced Sunlight: Less exposure to sunlight in winter decreases vitamin D synthesis, weakening the immune system.

How Can We Protect and Treat Ourselves?

Unfortunately, there are limited medical options to combat viruses directly. The first thing you can do is to try to address as many factors from the list above as possible.
Secondly, try to boost your immunity with supplements. But which ones?
I’ve done a deep dive into scientific studies for you. Unfortunately, there isn’t much convincing evidence for many substances, but the following seem to have the most potential:

1. Vitamin C
   • Prevention: 200–1,000 mg per day may slightly reduce the duration and severity of colds, especially in physically active individuals.
     My recommendation: 1,000–2,000 mg per day during preparation camp or cold season
2. Zinc
   • Prevention: 15–30 mg of elemental zinc per day supports immune function and reduces infection rates.
     Treatment: Higher doses may shorten illness duration but pose risks of adverse effects. Stick to 15–30 mg per day.
3. Echinacea – Results are mixed, but some evidence suggests benefits.
   • Prevention: 240–4,000 mg per day (depending on preparation) may reduce the incidence of colds.
   • Example: 2,400 mg daily of standardized echinacea extract reduced cold frequency in some studies.
   • Treatment: 3,000–4,000 mg per day during symptoms may reduce duration.
4. Gut Health/Probiotics
   • Probiotics may reduce the incidence of upper respiratory infections by modulating the immune system, though evidence is not conclusive.
     My recommendation: Two portions of fermented foods daily (e.g., sauerkraut, kimchi, yogurt, kefir).
5. Vitamin D
   • Deficiency increases the risk of respiratory infections. Supplementation in deficient individuals may help reduce the risk.
     My recommendation: 2,000 IU of vitamin D3 daily during darker months.

Other Supplements with Limited or Contradictory Evidence

• Ashwagandha (Withania somnifera): May reduce cortisol levels and stress, improving overall immune function.
• Elderberry: Some studies suggest it may reduce the duration and severity of cold and flu symptoms, but more research is needed.
• Siberian Ginseng: May improve resistance to colds and reduce fatigue due to its immune-modulating effects.
• Quercetin: Some evidence suggests it inhibits rhinovirus replication and could reduce illness duration.
• NAC (aka ACC)

Disclaimer: This is not medical advice and is for informational purposes only. Always consult your healthcare provider and conduct your own research 🙂

Summary

Prioritize sleep, manage stress, maintain proper nutrition, and minimize exposure to pathogens where feasible. Add Vitamins C and Zinc to your supplement protocol. And remember…

Train smart- stay healthy!

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Resources

Linde K, Barrett B, Wölkart K, Bauer R, Melchart D. Echinacea for preventing and treating the common cold. Cochrane Database Syst Rev. 2006 Jan 25;(1):CD000530. doi: 10.1002/14651858.CD000530.pub2

Shah SA, Sander S, White CM, Rinaldi M, Coleman CI. Evaluation of echinacea for the prevention and treatment of the common cold: a meta-analysis. Lancet Infect Dis. 2007 Jul;7(7):473-80. doi: 10.1016/S1473-3099(07)70160-3. Erratum in: Lancet Infect Dis. 2007 Sep;7(9):580.

Science M, Johnstone J, Roth DE, Guyatt G, Loeb M. Zinc for the treatment of the common cold: a systematic review and meta-analysis of randomized controlled trials. CMAJ. 2012 Jul 10;184(10):E551-61. doi: 10.1503/cmaj.111990

Singh M, Das RR. Zinc for the common cold. Cochrane Database Syst Rev. 2013 Jun 18;(6):CD001364. doi: 10.1002/14651858.CD001364.pub4. Update in: Cochrane Database Syst Rev. 2015 Apr 30;(4):CD001364. doi: 10.1002/14651858.CD001364.pub5.

Hemilä H, Chalker E. Vitamin C reduces the severity of common colds: a meta-analysis. BMC Public Health. 2023 Dec 11;23(1):2468. doi: 10.1186/s12889-023-17229-8

Ran L, Zhao W, Wang H, Zhao Y, Bu H. Vitamin C as a Supplementary Therapy in Relieving Symptoms of the Common Cold: A Meta-Analysis of 10 Randomized Controlled Trials. Biomed Res Int. 2020 Oct 9;2020:8573742. doi: 10.1155/2020/8573742.

Sartini M, Del Puente F, Oliva M, Carbone A, Bobbio N, Schinca E, Giribone L, Cristina ML. Preventive Vitamin D Supplementation and Risk for COVID-19 Infection: A Systematic Review and Meta-Analysis. Nutrients. 2024 Feb 28;16(5):679. doi: 10.3390/nu16050679.

Li Y, Yao J, Han C, Yang J, Chaudhry MT, Wang S, Liu H, Yin Y. Quercetin, Inflammation and Immunity. Nutrients. 2016 Mar 15;8(3):167. doi: 10.3390/nu8030167.