Defend Yourself. A runner’s guide to maintaining an efficient immune system

Last updated: 19-Jul-18

By Diana Green


A runner’s greatest fear is poor health compromising or even bringing to a halt their training programme.

However well planned your training programme, you will only fully benefit from the regime and achieve your goals, by maintaining an efficient immune system to protect your health.

Runner’s health benefits

For many runners the main motivation for taking up running is the health benefits. Moderate levels of exercise have been found to have a positive effect on the immune system.

  • Lymph contains a large proportion of our immune army and the lymphatic system relies on muscular contractions to keep the lymph moving.
  • Blood is an important part of our defence system. Running strengthens the heart and improves circulation thus increasing oxygen supply to tissues and toxic waste removal. Blood provides us with a mobile fighting force of white blood cells.
  • The adrenals respond to the physical stress of running by producing cortisol which in small quantities is an anti-inflammatory and controls excess immune cell production.
  • Runners also benefit from the exposure to natural light essential for the production of vitamin D, which has been shown to play an important role in balancing the immune system.

Runner’s health risks

Excessive levels of exercise of high duration and intensity can be immunosuppressive. In response to the trauma of exercise, the immune system can become overwhelmed.

  • Extreme physical stress raises cortisol beyond healthy levels which can result in inflammation and immune suppression.
  • The body’s natural killer cells are suppressed allowing opportunist infections to take hold, most commonly in the upper respiratory tract.
  • Exercise involves the burning of fat and glucose for energy. Oxidation is the process whereby with the aid of oxygen cells it converts fat and glucose into energy creating millions of free radicals (electrically unstable molecules). The body reacts to the presence of free radicals by producing antioxidant enzymes, however an inability to cope with high levels of free radicals, due to extreme exercise, can weaken the immune system.
  • Runners can suffer from depleted immunity because their vitamin and mineral stores are used up in muscle energy metabolism and are not being replenished sufficiently from their diet.

Runner’s limitations

It’s important to understand your current state of health and physiological limitations when putting together a training programme. When the training and nutrition are matched to the runners needs there is sufficient stress to challenge the immune system but not to overwhelm it. The immune system will respond by improving its efficiency. A trained athlete in good health has a higher level of killer cell activity, a base level of monocytes (white blood cells) and antioxidant enzymes.

Runner’s warning

It’s essential to know what your personal state of optimum health feels like and understand early warning signs of your immune system under stress. The earlier you recognise symptoms, the faster you can take corrective action and avoid lengthy periods of illness.


Vitamin A is necessary for the production of the growth hormone which is responsible for maintaining an active thymus, the master gland of the immune system. Vitamin A is also a powerful anti-viral vitamin, it’s inclusion in cell walls makes them more resistant to viral attack.
Sources:  pumpkin seeds, cashew nuts, beans, fish liver oil, dairy products, eggs.

Beta carotene, the precursor for vitamin A, is also a powerful antioxidant.
Sources: dark green vegetables (kale broccoli), courgettes, carrots, corn, tomatoes, sweet potatoes, squash, mangoes, apricots, watermelon.

Vitamin E is necessary for normal antibody response and works in synergy with other nutrients to improve resistance to infection. Vitamin E’s strong antioxidant effects protect the immune system from damage during high levels of oxidative stress.
Sources: polyunsaturated vegetable oils, green veg, avocado, asparagus, nuts, seeds, whole grains.

Vitamin B Complex is a family of nutrients needed for the proper functioning of every single cell of our bodies, including the immune system. Pantothenic acid (B5) and pyridoxine (B6) are of particular importance. A B6 deficiency can lessen the activity of the phagocytic cells which feed on ‘invaders’, dead cells and unwanted matter. B5 is needed for the production of antibodies which target specific invaders.
Sources: whole grains, nuts, pulses, seeds, nuts, potatoes, brewer’s yeast, bananas (B6), mushrooms (B5).

Vitamin C plays many key roles in boosting immunity. It is strongly antiviral, blocking the synthesis of viral proteins needed for infected cells to be replicated. Phagocytic cells rely on vitamin C to be able to carry out their clearing-up function. C3 complement production is improved with vitamin C triggering B cells to manufacture more antibodies. Vitamin C can suppress the growth of or kill bacterias and assist in detoxifying bacterial toxins.
Sources: vegetables, especially: broccoli, tomatoes, peppers, parsley, fruits especially: citrus, currants, apples, strawberries, kiwi, papaya, mango.

Calcium is vital for the immune system. It is needed by phagocytic cells in order to attach themselves to and ingest foreign material. Cytotoxic T cells need calcium for production of the enzyme which destroys infected cells.
Sources: molasses, dairy products, canned fish, nuts, seeds, dark green leafy veg, parsley, tofu.

Magnesium works with calcium and is vital for antibody production.
Sources: molasses, nuts, seeds, whole grains, apricots, figs, bananas, pulses, potato skin.

Iron boosts overall resistance to infection needed for the manufacture of antibodies, white blood cells and detoxification of bacterial toxins. Bacteria however need iron for reproduction and when a bacterial infection is present white blood cells produce an iron binding protein. This avoids overburdening the immune system with additional iron intake when a bacterial infection is present.
Sources: molasses, nuts, seeds, pulses, lean red meat, green leafy veg, whole grains, parsley, prunes, raisins, dates, shellfish, egg yolk.

Selenium helps in the production of antibodies and the antioxidant enzyme glutathione peroxidase.
Sources: nuts, especially brazil nuts, whole grains, fish, garlic, chard and turnips.

Zinc is involved in almost every aspect of immunity. When zinc levels are low the number of T cells decreases and many white blood cell functions critical to the immune response are affected.
Sources: seafood – especially oysters, fish, lean red meat, green leafy veg, mushrooms, potatoes, nuts, seeds, whole grains, pulses, eggs.


Runners are usually knowledgeable about the importance of protein for maintaining muscle mass, as an energy source and  repair of tissue, but less aware of the vital role amino acids (the constituents of protein)  play in the manufacture of immune cells and antibodies to combat infection.
Sources of quality proteins: eggs, meat, fish, dairy products, tofu. Lower quality proteins: pulses, grains, nuts, seeds.


Fats can be a good source of energy for runners, however over focus on saturated fats and ignoring the importance of essential (so called because the body cannot make them) fats in the diet can upset the balance of the immune system. The omega 6 and omega 3 groups of fatty acids are converted into hormone like substances called prostaglandins which are involved in the regulation of `T-Suppressor’ cells, reducing inflammation, blood thinning and cell membrane integrity.
Sources: nuts, seeds and their oils, oily fish, green leafy vegetables.


Alcohol is a powerful immune suppressor, resulting in reduction in number and strength of lymphocytes and increase in number of circulating immunoglobulins.

Poor sleep can reduce natural killer cell activity.

Psychological stress as well as physical stress can have an impact on the immune system.

Rapid weight loss diets that fail to adequately fuel training sessions can weaken the immune system.

Refined sugars are not only nutrient free but require nutrients for their metabolism, wasting valuable vitamins and minerals.


  • Increase training intensity and/or mileage at a moderate pace allowing the immune system to adapt.
  • Eat a large and colourful variety of fruit and vegetables as part of your daily diet. Anthocyans are a powerful family of antioxidants and account for the different colours of many fruits and vegetables. Purple, red, orange, yellow and green fruit and vegetables all contain different types of anthocyans. Don’t rely on one or two super foods.
  • Carbohydrates play a role in how the immune system responds to heavy training by reducing circulating cortisol levels. Ensure adequate carbohydrate intake before, during and after strenuous prolonged exercise, in order to limit the extent and severity of exercise-induced immunosuppression.
  • Being well-hydrated reduces stress in exercise and also maintains the flow of saliva, which has antimicrobial properties, such as IgA (immunoglobulin A).
  • Garlic contains allicin which is anti-viral, anti-fungal and anti-bacterial. Eat a clove or a capsule equivalent daily.
  • Probiotics can help to reinforce beneficial gut bacteria which act as a first line of defense and promote good digestion and absorption of nutrients.
  • Have one tablespoon of ground mixed seeds (sunflower, pumpkin, linseed, hemp) a day added to cereals, soups or smoothies, providing a good source of magnesium, zinc, B vitamins and essential fats.
  • Vegetable soups are a great way to get a variety of immune boosting nutrients in one meal without the loss of vitamins and minerals that might occur with other cooking methods. Add some pulses or grains to your soup and top with ground seeds (see above) for a balanced immune supporting meal.


Tomato & Red Pepper Soup

(10 portions)
Calories 300  

Tomatoes are known for their outstanding antioxidant content vital for balancing the immune system. One of the star nutrients is lycopene, released by cooking making tomatoes perfect for soups.

20 g chilli pepper
25 g paprika
10 g turmeric
3 kg passata
100 g tomato paste
25 g sugar
1.25 kg red peppers
500 g onion
250 g wild rice (dry)
75 g sun dried tomatoes
10 g basil
15 ml olive oil

  • Cook wild rice until tender
  • Chop chilli, onion and red pepper and soften in olive oil
  • Add passata, tomato paste, sugar and spices
  • Chop sun dried tomato and add to soup
  • Simmer until pepper and onion are tender and then blend
  • Stir in cooked wild rice and season with chopped basil

Watercress & Sweet Potato Soup

(10 portions)
Calories 302  

Watercress is an exceptionally nutritious plant. Gram for gram it contains more vitamin C than oranges, more calcium than milk and more folate than bananas, all important nutrients for boosting immunity.

1 kg sweet potato
500 g white potato
600 g watercress
350 g leeks
500 g onion
40 g marigold bouillon
15 ml olive oil
5 g nutmeg
10 g allspice
2 g black pepper
150 g creamed coconut

  • Peel & chop white and sweet potato into chunks
  • Slice onion and leeks and soften in olive oil
  • Add potatoes, watercress, marigold, coconut and spices and enough water to cover
  • Simmer until potatoes are cooked and then blend

Miso & Bean Soup

(10 portions)
Calories 302  

Miso a fermented soya bean paste helps to support the beneficial gut bacteria which are needed for proper absorption of nutrients and a strong immune system.

400 g onion
30 g garlic
500 g parsnip
500 g carrot
250 g celeriac
400 g pak choi
300 g mange tout
650 g soya beans
450 g miso (white sweet)
50 ml mirin
50 ml tamari
5 g white pepper
15 ml olive oil

  • Slice onion finely and chop garlic
  • Fry in olive oil to soften
  • Cut carrots, parsnip and celeriac into thin sticks and add to onion
  • Add enough water to cover and simmer until veg are nearly tender
  • Slice pak choi and mange tout and add to soup with soya beans
  • Simmer until mange tout are just tender
  • Mix miso with a little of the soup broth and pour into soup with mirin and tamari
  • Season with ground white pepper

Golden Squash Soup

(10 portions)
Calories 302  

Winter Squash is more than just a starchy vegetable. As well as containing a range of immune supportive carotenoids research has shown that starch related components also have anti-inflammatory properties.

500 g red lentils
500 g onion
500 g carrots
800 g butternut squash
15 ml olive oil
10 g cumin seeds
10 g caraway seeds
50 g marigold bouillon
50 g coriander
150 ml lemon juice

  • Chop carrot and squash into chunks
  • Slice onion and soften in olive oil with cumin seeds and caraway seeds
  • Add carrot, squash, red lentils, marigold and enough water to cover
  • Simmer until veg are tender and lentils soft adding more water if needed
  • Blend to rough mix
  • Add lemon juice and chopped coriander

"Moderate levels of exercise have been found to have a positive effect on the immune system"

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Date Range

Global - Virtual


A virtual race which can be run at any time shown on the dates shown, on any type of terrain in any country.

Suitable for

For runners from beginners to experienced as you choose your own course and challenge based on the guidelines and options set by the virtual race organiser.

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An ultra distance race including at least two of the following activities such as running, swimming, cycling, kayaking, skiing and climbing. It may also include different climatic conditions (eg ice, snow, humidity, cold water, mud or heat).

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Experienced multi-skilled athletes who have trained for the different activities included in this event. Admission to these races may be subject to receipt of a recent medical examination certificate. Check with the race organiser regarding entry requirements and any specialist equipment required such as a wetsuit, skis or a mountain bike.



Increase of up to 2000 metres with very challenging climatic conditions (e.g. ice, snow, humidity, heat or at high altitude)

Suitable for

Very experienced long distance ultra runners (min 3 years’ experience) or are doing regular long distance running (>50 miles) with elevation and conditions shown (where possible). Admission to these races is often subject to receipt of a recent medical examination certificate. Purchase of specialist kit is often recommended for these races.



Increase of up to 2000 metres with some challenging climatic conditions (e.g. ice, snow, humidity or heat)

Suitable for

Experienced runners who have completed at least 4 ultras in last 12 months, or are doing regular long distance running (>50 miles) with elevation and conditions shown (where possible). Admission to these races may be subject to receipt of a recent medical examination certificate. Check with the race organiser regarding entry requirements.



Increase of up to 1500 metres

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Runners who have completed several ultra distances or similar events, or are doing long distance running regularly, with elevation shown.



Increase of up to 1000 metres

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Runners who have completed at least one ultra in last 6 months or are doing long distance running (>26 miles) regularly, with elevation shown.



Very little change < 500 metres

Suitable for

First ultra event. Runners completing a marathon or doing regular long distance running (>26 miles) in the last 6 months.