Student Athletes and Immune Health

Strengthening their Resiliency and Inner Defense

By Jill Lane

Illness is the second most common reason (after injury) athletes miss training and competition. A student athlete’s ability to be and stay well is of utmost importance now more than ever. In this article we’ll cover what science has to say about healthy immune function in athletes, while helping them build their inner defense system and resiliency.


Our immune system has ‘game’ as long as we provide the best possible playing field for it to execute its game plan on. To tell you the truth, we can be doing a cruddy job of taking care of ourselves and our immune system will still go to bat for us, but not for very long.

This is not a complete overview (more like a crash course), but it’s enough to understand what’s going on and ‘who’ is doing ‘what’ from an immune standpoint.

We have 2 basic ‘sides’ to our immune system: innate and adaptive. Innate (natural) immunity is so named because it is present at birth and does not have to be learned through exposure to a germ/invader. It thus provides an immediate response to foreign invaders. The innate immune system includes physical barriers such as the skin, gastrointestinal tract and the respiratory tract as well as a variety of specific immune cells, it is looking for things that are ‘non-self’ so it can protect us.

Adaptive (also called acquired) immunity, is just that. It’s what’s acquired after you’re born. Once you’ve been exposed to a germ/invader for the first time (think common cold or chicken pox), your body creates a defense against it. That defense gives your body the capability to ‘remember’ chicken pox or that specific strain of the germ (acquires a memory) so that if exposed again, your chance of falling to infection/illness because of that invader is reduced or even eliminated.


Figure 1. Key factors that can lower immunity in the athlete. From Walsh NP. Recommendations to maintain immune health in athletes, European Journal of Sport Science. 2020;18:6:820-831. DOI: 10.1080/17461391.2018.1449895.

Cells involved in immunity (all with different functions) are:

  • Monocytes (which develop into macrophages)
  • Neutrophils
  • Eosinophils
  • Basophils
  • T Cells (mature in thymus gland)
  •  B Cells (mature in bone marrow)
  • Natural Killer Cells (also called NK or K cells)

There are also dendritic cells and the complement system – that’s a big army!

A few worth giving MVP acknowledgement to are:

  • NK Cells – The big dogs. These are our cancer fighters. NK cells are also critical for the control of certain infections, particularly viral infections.
  • T Cells – Remember/recognize germs (by their surface antigens) from the past and attack them if exposed again, help with identity, produce cytokines (inflammatory markers) to alert rest of system or they take out an invader all together.
  • B Cells – Produce antibodies which attach to outside (antigen) part of invader and call attention from other parts of the immune system.
  • Phagocytes/Macrophages – Engulf (surround and dissolve) foreign invaders (think Pac-Man).


The goal with athletic performance and overall health (which includes a healthy immune system) is to, through repetition of productive habits, build strength, adaptation, and resiliency. Let’s take a roll call of habits or conditions which could be affecting an athlete’s immune system negatively:

  • Lack of quality sleep / chronic sleep disruption
  • Under-fueling (not eating enough in relation to training and growth requirements)
  • Under-recovery (not sleeping/eating/resting enough in relation to training and adaptation needs)
  • Chronic stress (emotional, physical, or environmental)
  • Nutrient deficiencies
  • Exposure to ‘bugs’ or toxins (through travel, home, or the gym)
  • Food sensitivities (an immune system stressor by itself)
  • Over-training (training too much—quantity or intensity wise)

Below, see it spelled out visually (according to a 2018 European Journal of Sport Science paper by one of my favorite researchers on athlete immune health).


Now that we understand a bit more about immune health and what takes it out of the game, let’s talk about how we can support it.

1. Get enough sleep – the sleep science is clear (see Sleep Stats), not getting enough quality sleep (for the whole family) is a problem for all areas of health including the immune system. A lab experiment bears this out: When students at the University of Chicago were limited to only 4 hours of sleep a night for 6 nights and then given a flu vaccine, their immune systems made only half the normal number of antibodies. Reducing blue light exposure before bed by putting down the digital devices and or wearing blue light blocking glasses (my pro-athletes do this so your student is NOT too cool for these), keeping room as dark and cool as comfortably possible and trying to stick to similar wake and bedtimes can help with sleep.


  • Most adults need 7-9 hours’ sleep nightly (National Sleep Foundation 2015)
  • Most youth need 8-10 hours of sleep (National Sleep Foundation 2015)
  • Reduction in sleep time impacts the immune system and increases risk of Upper Respiratory Tract Infections (think common cold) (Cohen et al 2009)
  • Lack of sleep is an independent risk factor for increase in injury risk in youth athletes (Rosen et al 2017) Polo-Kantola 2007)
  •  Sleep extension (adding 2 hours for 2-3wks) improves almost every metric in sport performance – reaction time, swimming speed, agility, free throws, 3-point accuracy, 40 speed… (Mah et al 2011)

2. Eat enough of the right kids of foods throughout the day – see my last article (“Sports Nutrition: Supporting Performance, Growth + Wellness in Student Athletes,” Winter 2020) about the importance of eating enough food throughout the day. Amino acids from protein, omega-3 fatty acids from cold water fish, fiber from carbohydrates, and phytonutrients and polyphenols from veggies and fruits all contribute to healthy immune function and inflammatory responses. This is a step you and your student athlete can’t skip: REMEBER the goal is not to be perfect (cheeseburgers will happen); it is to be consistent.

3. Stay Hydrated – training in extreme temperatures affects immune health so staying optimally hydrated regardless of time of year is important for performance, as well as brain and immune health.

4. Train and recover responsibly – more is often not better when it comes to training. Know your athlete’s goals and make sure the training being done matches those goals while also addressing the body’s primary recovery tools (sleep and healthy food). Excessive soreness and fatigue can be signs it is time to dial it back a bit so the body can adapt and recover.

5. Get good with personal hygiene – most of us are pros at this now! I encourage athletes to wash hands up to elbows, paying special attention to the palms and between fingers. Replace toothbrushes every 3 months and especially after sickness and wash all gear regularly.

6. Manage stress – easier said than done, but it cannot be ignored! Chronic stress can have a negative impact on immunity, according to a 2004 review of 293 studies with a total of 18,941 participants. The review suggests that while short-term exposure to stressors can rev up your immune defense, prolonged stress may wear down the immune system and increase your vulnerability to illness. Many athletes have been stressed by the loss of a season, sport, or position in addition to over exposure to the unrelentless, unrealistic expectations displayed on social media. Be open to these discussions. Consider a counselor if you notice swings in mood and behavior.

7. Consider supplementation – what’s that saying…if you fail to plan you plan to fail? A handful of vitamins have been shown to support healthy immune function. Talk to your integrative healthcare practitioner about the following. Know that quality matters, not all supplements are created equal. Look for a professional brand with good in-house and 3rd party quality control testing.


Vitamin D3: If you or your student athlete have not had your levels checked, now is the time (aim for levels above 50ng/dL). A sub-optimal level of Vitamin D3 is problematic for many areas of health, immune health being just one. Vitamin D is found in foods like salmon and fortified dairy products and other beverages. I, however, concur with the Gatorade Sports Science Institute which says, “regular consumption of vitamin D-containing foods alone is not likely to maintain sufficient vitamin D status.” Consider, at a minimum, using a professional grade, NSF Certified for Sport® multi vitamin that contains around 2000IU per serving.

Probiotic: Because immune health is either strengthened or diminished by your state of digestive health, keeping digestive function in tip-top shape is important. Look for a probiotic product that is dairy-free and shelf-stable containing 5 or more identified strains. Probiotics are found in fermented foods like yogurt, sauerkraut, and kombucha.

Zinc: A chelated version of the mineral zinc is optimal. You could be getting between 15-30mg in your daily multivitamin. Zinc is found in the diet through nuts, seeds, animal protein, and beans. Zinc lozenges have mixed reviews but may also prove helpful at first sign of sickness.

Contact me for a list of the references used to support this article.

Jill Lane, mom of 3, founder of Fueling Champions® has been teaching nutrition and exercise science to pro-athletes, sports families, student athletes, coaches and health care practitioners for 20 years. Some of her current and past clients include coaches and players from the NFL, NBA, and MLB. As a former All-American, Olympic Development Team Member and Division I Scholarship Collegiate athlete herself, Jill has a clear understanding of what competitive athletes require to achieve and sustain their personal best.

Her mission to support the next generation of student athlete leaders (as well as those who lead them on a daily basis) comes full circle in Fueling Champions®.

Join us at + Instagram @TeamFuelingChampions



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