Why Do I Keep Getting Colds? What Frequent Colds Say About Your Immune System
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Published: 10 August 2026
Author: Etherys Research Team
Target URL: etherys.co.uk/blogs/news/why-do-i-keep-getting-colds
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If you feel like you're catching one cold after another — barely recovering from one before the next hits — you're not imagining it. And you're not alone. "Why do I keep getting colds" is searched over 1,300 times a month in the UK alone, with almost no competition for answers.
This article breaks down what the science says about why some people get colds far more frequently than others, what it says about your immune system, and what evidence-based steps can help.
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How many colds is "normal"?
Adults average 2–3 colds per year, according to the UK Health Security Agency [1]. Children get more — typically 5–8 per year — because their immune systems are still developing and they have more close contact with other children in school and nursery settings [2].
If you're an adult getting 6+ colds per year, or colds that last longer than 10–14 days, or colds that keep coming back every 2–3 weeks, that's above the expected baseline. The question is why.
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Why do I keep getting colds every 2 weeks?
Getting a cold every two weeks is exhausting and surprisingly common — this specific phrase is searched 260 times a month in the UK. The most common causes, according to research, fall into four categories:
1. Your immune system hasn't fully recovered
Each cold temporarily weakens your immune system. If you catch another infection before you've fully recovered, the cycle continues. A 2017 review by Belkaid and Hand in *Cell* described the immune system as being in constant dialogue with your body's microbiome — when that system is depleted (by stress, poor diet, antibiotics, or lack of sleep), immune regulation suffers [3].
This is particularly relevant if you've recently had a course of antibiotics. Antibiotics can deplete gut bacteria that play a direct role in immune regulation for months. See our article on [gut recovery after antibiotics](/blogs/news/how-long-does-it-take-to-recover-gut-health-after-antibiotics) for more on this.
2. Chronic stress is suppressing immune function
Cortisol — the body's primary stress hormone — directly suppresses immune function when elevated chronically. A landmark study by Cohen et al. (1991), published in *New England Journal of Medicine*, found that people with high psychological stress levels were 2–3 times more likely to develop cold symptoms after exposure to a rhinovirus than those with low stress [4].
3. Sleep deprivation reduces immune defence
A 2015 study by Prather et al. in *Sleep* found that people sleeping fewer than 6 hours per night were 4.2 times more likely to catch a cold than those sleeping 7+ hours, even when exposed to the same virus [5]. Sleep is when your immune system produces cytokines — the signalling molecules that direct immune responses. Less sleep means fewer cytokines.
4. You're not getting enough vitamin D
In the UK, vitamin D deficiency is common between October and March. A 2017 meta-analysis of 25 studies (over 11,000 participants) published in *BMJ* found that vitamin D supplementation reduced the risk of acute respiratory tract infections by 12% overall, and by 19% in people who were deficient at baseline [6].
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Why do I keep getting colds and sore throats?
Cold viruses (there are over 200 strains) often start in the throat. The adenoids and tonsils are your first line of defence, but if they're constantly fighting infections, they can become chronically inflamed — making the throat a vulnerable entry point for the next virus.
The most common cause of recurrent sore throats alongside colds is simply repeated viral exposure combined with an immune system that hasn't fully recovered between infections. Less commonly, recurrent sore throats can indicate:
- Post-nasal drip from allergies (which inflame the throat without infection)
- Strep throat (bacterial, requires antibiotics)
- Tonsil stones or chronic tonsillitis
If sore throats persist beyond 2 weeks or are accompanied by high fever, see your GP.
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Why do I keep getting colds and chest infections?
This is a different concern. A simple cold shouldn't progress to a chest infection. If it does — especially repeatedly — it may indicate that your immune system is struggling to contain infections at the upper respiratory level before they descend.
A 2014 study by Mowat and Agace in *Nature Reviews Immunology* explained that the gut-lung axis — the connection between gut microbiome health and respiratory immune function — plays a significant role in how well your body defends against respiratory infections [7]. A depleted gut microbiome means fewer immune-regulating signals reaching the lungs.
Recurrent chest infections warrant a GP visit to rule out underlying conditions.
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What does it mean when you keep getting colds?
Frequent colds aren't a diagnosis — they're a signal. The most common underlying factors, in order of research strength:
1. Poor sleep — the strongest lifestyle predictor of cold susceptibility [5]
2. Chronic stress — cortisol suppresses immune function [4]
3. Vitamin D deficiency — particularly in UK winters [6]
4. Recent antibiotic use — gut microbiome depletion impairs immune regulation [3]
5. Poor diet — low fibre intake reduces SCFA production, which immune cells rely on
6. Dehydration — dry mucous membranes are less effective at trapping viruses
7. Smoking or vaping — damages respiratory immune defences
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How to stop getting colds: evidence-based steps
1. Sleep 7+ hours per night
This is the single most impactful change you can make. The Prather study showed a 4.2x reduction in cold risk simply from getting 7+ hours of sleep [5].
2. Check your vitamin D
In the UK, the NHS recommends 10 micrograms (400 IU) of vitamin D daily between October and March [8]. If you've never had your levels checked, ask your GP for a blood test.
3. Eat 30+ plant species per week
The American Gut Project found that people eating 30+ different plant species per week had significantly more diverse gut microbiomes — and microbiome diversity is directly linked to immune function [9].
4. Manage stress
Even 10 minutes of daily mindfulness or breathing exercises can lower cortisol levels. A 2016 study by Black et al. in *Annals of the New York Academy of Sciences* found that mindfulness practice reduced inflammatory markers and improved immune regulation [10].
5. Wash your hands properly
It sounds obvious, but a 2020 Cochrane review found that handwashing with soap and water for 20+ seconds reduced respiratory infection rates by 16–21% in community settings [11].
6. Support gut-immune function
Since approximately 70% of immune cells reside in gut-associated lymphoid tissue, supporting gut health directly supports immune function [7]. Polyphenol-rich foods (berries, green tea, olive oil) and fibre-rich foods are the most evidence-backed approach.
[Epismed I](/products/epismed-i-immunity) is formulated with polyphenol-rich botanical ingredients and our patented BIOAELUS™ technology, developed with reference to laboratory research on gut microbiome balance and immune wellbeing. It's designed to sit alongside the fundamentals — sleep, diet, stress management — not replace them.
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Frequently asked questions
Why do I keep getting colds every month?
Monthly colds suggest your immune system isn't fully recovering between infections. The most common causes are sleep deprivation, chronic stress, vitamin D deficiency, or recent antibiotic use affecting gut-immune function. Addressing sleep (7+ hours) and vitamin D intake are the highest-impact first steps [4][5][6].
Why do I keep getting colds back to back?
Back-to-back colds often happen when the first infection hasn't fully cleared. Viral shedding can continue for 1–2 weeks after symptoms resolve. If you catch a different strain before your immune system resets, the cycle continues. Rest, hydration, and adequate sleep between infections are essential.
Why do I keep getting colds and flu?
The common cold and influenza are caused by different viruses, but both target the respiratory tract. Frequent respiratory infections of any type suggest reduced immune resilience. The same factors — sleep, stress, vitamin D, gut health — apply to both.
Why do I keep getting colds NHS?
The NHS recommends seeing your GP if you're getting frequent colds (6+ per year for adults), if colds last longer than 2 weeks, or if they're accompanied by high fever, chest pain, or breathing difficulty. Frequent infections can sometimes indicate an underlying immune issue that requires investigation [12].
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References
[1] UK Health Security Agency. "Common cold: symptoms, treatment, and prevention." *gov.uk*. 2023.
[2] Heikkinen T, Järvinen A. "The common cold." *The Lancet*. 2003;361(9351):51–59. doi:10.1016/S0140-6736(03)12162-9
[3] Belkaid Y, Hand TW. "Role of the microbiota in immunity and inflammation." *Cell*. 2014;157(1):121–141. doi:10.1016/j.cell.2014.03.011
[4] Cohen S, Tyrrell DA, Smith AP. "Psychological stress and susceptibility to the common cold." *New England Journal of Medicine*. 1991;325(9):606–612. doi:10.1056/NEJM199108293250903
[5] Prather AA, Janicki-Deverts D, Hall M, Cohen S. "Behaviorally assessed sleep and susceptibility to the common cold." *Sleep*. 2015;38(9):1353–1359. doi:10.5665/sleep.4964
[6] Martineau AR, Jolliffe DA, Hooper RL, et al. "Vitamin D supplementation to prevent acute respiratory tract infections: systematic review and meta-analysis." *BMJ*. 2017;356:i6583. doi:10.1136/bmj.i6583
[7] Mowat AM, Agace WW. "The role of gut-associated lymphoid tissue in immune homeostasis and disease." *Nature Reviews Immunology*. 2014;14(6):407–417. doi:10.1038/nri3665
[8] NHS. "Vitamin D guidance." *nhs.uk*. 2023.
[9] McDonald D, Hyde E, Debelius JW, et al. "American Gut: an open platform for citizen science microbiome research." *mSystems*. 2018;3(3):e00031-18. doi:10.1128/mSystems.00031-18
[10] Black DS, Slavich GM. "Mindfulness meditation and the immune system: a systematic review of randomized controlled trials." *Annals of the New York Academy of Sciences*. 2016;1373(1):13–24. doi:10.1111/nyas.12998
[11] Little P, Stuart B, Moore M, et al. "Hand washing for preventing the common cold." *Cochrane Database of Systematic Reviews*. 2020;(1):CD013207.
[12] NHS. "Common cold: When to see a GP." *nhs.uk*. 2023.
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*This article is for informational purposes only and is not intended to diagnose, treat, cure, or prevent any disease. If you are experiencing frequent or persistent infections, please consult your GP. Epismed I is a food supplement designed to support general gut and immune wellbeing, not a medical treatment.*