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3 things to do every day to support your immune system

Updated: Nov 3, 2023

1. Get a good night’s sleep

Sleep is an important immune modulator (1). Lack of sleep is known to compromise our ability to respond to infection with even just a single nights of poor sleep resulting in a decrease in natural killer cells (2) which are our first line defence against viruses.

Research suggests that 7-9 hours is optimal but this will vary for each individual. Signs you are not getting enough sleep include needing an alarm clock to wake up, reaching for coffee first thing to get you going and feeling tired and sleepy throughout the day.

Tips to improve sleep include:

  • Avoiding screens at least an hour before bedime, try reading a book instead

  • Take a bath with Epsom salts

  • Keep your bedroom dark and cool (16-18degC)

  • Exposing yourself to natural sunlight first thing in the morning to help establish your circadian rhythm

  • Have regular meal times to support circadian rhythm and try to eat dinner at least 3 hours before bedtime

  • Avoid caffeine after midday, try chicory coffee and herbal teas instead.

  • Avoid sugary, sweet treats in the evening as this may cause your blood sugar to drop during the night causing an adrenaline spike

  • Create a bedtime routine that could include meditation, gratitude journal or breathing exercises

  • Treat your bedroom as a sanctuary – try to create a relaxing, calming environment with no TVs or computers

2. Move

Studies have demonstrated that moderate aerobic exercise such as walking, jogging, cycling may reduce the risk of catching common viruses such as cold or flu by more than half (1).

Not only has exercise been shown to increase white blood cells and natural killer cells (2) (our main defence against viruses), one of the big benefits of exercise on the immune system is its impact on the lympatic system. Lymph is a fluid that is transported around the body through the lymphatic system and its job is to transport immune cells around the body looking for infection. It also carries away waste products which are transported to the liver for elimination. Unlike the cardiovascular system which as a pump (the hear) to pump blood around the body, the lymphatic system relies on movement to get it moving. When the flow of lymph fluid is disrupted its ability to do its job is reduced.

Whilst even a single bout of exercise has been found to have beneficial effects, regular exercise improves immune regulation and and over time, improves immunosurveillance against pathogens (3). For those unaccustomed to regular exercise, start slowly and build up to a regular routine. A 5 minute walk around the block, can gradually build into a half hour daily walk over a couple of weeks.

3. Relax

The nervous system has two branches – sympathetic (fight or flight) and parasympathetic (rest and digest). Both branches are essential for survival however for optimum health there needs to be a balance between the two. When we are under persistent, ongoing stress, the sympathetic branch dominates and levels of the stress hormone cortisol rise. Elevated cortisol dramatically reduces immunity and decreases the number of circulating immune cells effectively inhibiting our immune defence and increasing susceptibility to illness. Specifically, chronic stress is associated with increased risk of viral infections such as the common cold (1) and increased susceptibility and severity in respiratory illnesses (2).

Stress comes in many forms from the big obvious ones such as social isolation, stressful jobs, financial worries to the smaller ones such as writing emails, reading the news and a bad nights sleep. There is not much we can do to avoid these things however the important thing is to switch out of ‘fight or flight’.

Heart rate variability, HRV, is used to measure stress in individuals. HRV monitors give an indication of the balance between the sympathetic and parasympathetic sides of the nervous system which relate to activation and regulation of stress. Research has shown that Low HRV is associated with higher levels of stress whilst higher HRV is associated with lower rates of stress. One study which demonstrated that chronic stress has a suppressive effect on the immune system also found HRV to be a useful tool in predicting immune function (3).

Stress reduction is different for everyone but below are some of the ways shown to reduce stress:

  • Engage in a hobby such as knitting, sewing, drawing, colouring, baking

  • Watch a funny film

  • Go for a walk in nature

  • Play music – either an instrument yourself of listen to music

  • Gardening

  • Singing

  • Dancing

  • Reading

  • Yoga

  • Taking a bath

  • Write a journal

  • Express gratitude


1. Ibarra-Coronado, E G, et al. The bidirectional relationshop between sleep and immunity against infections. Journal of Immunology Research. 2015, Vol. 2015, 678164.

2. Irwin, M, et al. Partial night sleep deprivation reduces natural killer and cellular immune responses in humans. The FASEB Journal . 1996.

3. Barrett, B. Meditation or exercise for preventing acute respiratory infection: A randomised controlled trial. Annals of Family Medicine. pp. 337-346, 2012, Vol. 10, 4.

4. Neiman, D.C. Immune response to a 30-minute walk. Medicine and Science in Sports and Exercise. pp. 57-62, 2005, Vol. 37, 1.

5. Neiman, D C and Wentz, L M. The compelling link between physical activity and the body's defence system. J Sport Health Sci. 201-217, 2019, Vol. 8, 3.

6. Klein, T.W. Stress and infections. J Fla Med Assoc. 409-11, 1993, Vol. 80, 6.

7. Marshall, G.D. The adverse effects of psycological stress on immunoregulatory balance: applications to human inflammatory diseases. Immunol Allergy Clin North Am. 133-140, 2011, Vol. 31, 1.

8. Luo, H, et al. Stress determined through Heart Rate Variability predicts immune function. Neuroimmunomodulation. 2019.

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