Why am I catching colds and other infections more often as I get older?
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Key Takeaways
Illnesses become more common with age because the immune system gradually weakens (a process called immunosenescence), chronic diseases and medications add extra strain, and the airways, gut, and skin lose some of their natural protective barriers. The result is slower pathogen clearance, milder early warning symptoms, and longer recovery times—especially if vaccines are out-of-date or sleep, diet, and physical activity decline.
Does aging itself weaken my immune system enough to explain more infections?
Yes. From around age 50, the thymus shrinks, antibody quality declines, and inflammatory signals become chronically high, making it harder to fight new germs. "Think of immunosenescence as both a thinner shield and a slower sword," notes Sina Hartung, MMSC-BMI.
- Lower birth of naïve T-cells after age 60Thymic involution cuts production of new T-cells by roughly 3% each year, so your immune army has fewer fresh recruits.
- Antibodies lose precisionB-cells still make antibodies, but the average binding strength drops 20–30%, slowing virus clearance.
- Chronic low-grade inflammation (inflamm-aging) competes for resourcesBaseline CRP levels rise from <1 mg/L in young adults to 2–3 mg/L in many seniors, distracting immune cells from new threats.
- Mucosal barriers thin over decadesNasal cilia beat up to 40% slower in people over 70, allowing more viral particles to settle.
- Recovery from common viral infections becomes noticeably slower after mid-lifeMayo Clinic notes that diminished coordination between aging innate and adaptive immunity means colds and flu often linger longer in adults over 60 compared with younger adults. (Mayo)
- Risk of serious infection starts to rise steeply from about age 50GSK reports that the gradual immune decline accelerates by the fifth decade, making infections both more frequent and more severe in later life. (GSK)
Sources
- Mayo: https://mcpress.mayoclinic.org/healthy-aging/aging-and-the-immune-system/
- NIH: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1931833/
- NJH: https://www.nationaljewish.org/education/health-information/health-lifestyle-tips/how-aging-affects-your-immune-system
- NIH: https://pmc.ncbi.nlm.nih.gov/articles/PMC3061194/
- GSK: https://www.gsk.com/en-gb/behind-the-science-magazine/age-related-decline-immunity-infectious-disease
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When should frequent infections in older adults raise a red flag?
More sniffles can be normal, but certain patterns signal something more serious. "An infection every month is not unusual, but confusion, fever that won’t break, or weight loss should prompt urgent care," warns the team at Eureka Health.
- Fever over 38.3 °C (101 °F) lasting more than 48 hoursPersistent high temperature suggests pneumonia or sepsis, not a simple cold.
- Unintentional weight loss over 5 % in 6 monthsMay point to hidden cancers or uncontrolled diabetes undermining immunity.
- Shortness of breath at restCould indicate heart failure, pulmonary embolism, or severe respiratory infection.
- New confusion or falls during illnessDelirium is often the only early sign of serious infection in adults over 70.
- Two or more antibiotic courses in 3 monthsRecurrent infections might reflect an undiagnosed immune deficiency or resistant organism.
- Anorexia or sudden functional decline may herald infectionGuidelines note that new loss of appetite, reduced mobility, or even a slight rise in respiratory rate can be an early clue to serious infection in older adults, sometimes appearing before fever or cough. (AAFP)
- Immune cell aging explains higher pneumonia and COVID-19 rates in seniorsAn NIH-supported analysis of 768,762 adults found 63 age-related changes in white blood cell DNA that weaken immune responses, increasing susceptibility to respiratory infections in older adults. (NHLBI)
How do lifestyle and chronic conditions make older adults sicker more often?
Conditions such as diabetes, COPD, or kidney disease impair defenses, while habits like poor sleep and low protein intake slow recovery. "Every decade after 40, muscle mass drops about 8%, and with it goes a stockpile of amino acids your immune cells need," says Sina Hartung, MMSC-BMI.
- Type 2 diabetes triples risk of pneumoniaElevated glucose paralyzes neutrophils and fuels bacterial growth.
- Polypharmacy suppresses immune alertnessProton-pump inhibitors, corticosteroids, and some biologics each raise infection odds by 20-50%.
- Poor sleep cuts natural killer cell activityAdults sleeping under 6 hours for one week had a 4-fold higher chance of catching a rhinovirus in a landmark study.
- Low-protein diets delay antibody productionLess than 0.8 g/kg/day protein intake correlates with longer flu recovery in seniors.
- Four-plus diseases in seniors projected to nearly double by 2035Modeling of England’s over-65 population indicates the proportion living with four or more chronic conditions will rise from 9.8 % in 2015 to 17 % by 2035, adding layers of immune strain. (MarketWatch)
- Age-related T cell decline blunts infection defensesNational Jewish Health notes older adults generate fewer naïve T cells and existing T cells divide less effectively, weakening responses to new pathogens and lengthening recovery times. (NJH)
Sources
- MarketWatch: https://www.marketwatch.com/story/prepare-for-a-sick-old-age-twice-as-many-older-people-will-suffer-from-four-or-more-diseases-by-2035-2018-01-25
- NCBI: https://www.ncbi.nlm.nih.gov/books/NBK51842/
- NJH: https://www.nationaljewish.org/education/health-information/health-lifestyle-tips/how-aging-affects-your-immune-system
What concrete steps can I take today to reduce infections?
Small, consistent habits rebuild defenses. The team at Eureka Health emphasizes: "Vaccinate, ventilate, and validate your sleep—those three V’s prevent most winter sick days."
- Stay current on influenza, COVID-19, shingles, and pneumococcal shotsCDC data show a 50–85 % drop in hospitalizations among vaccinated adults over 65.
- Aim for 7–8 hours of sleep nightlyEach extra hour under 6 hours correlates with a 12% higher cold risk.
- Walk briskly 150 minutes weeklyModerate exercise boosts antibody response to vaccines by up to 40%.
- Add 25 g of high-biologic-value protein per mealSupports lymphocyte proliferation; Greek yogurt or legumes are practical options.
- Practice diligent hand and surface hygieneProper 20-second handwashing cuts gastrointestinal infections in care-home studies by 30%.
- Verify and optimize your vitamin D levelsDr. Michael Turner notes that daily Vitamin D/K supplementation of 4,000–10,000 IU, tailored to blood levels, is a core part of his winter infection-prevention protocol because adequate vitamin D supports immune cell function. (TurnerMD)
- Schedule meaningful social interaction each dayThe Washington Post reports that loneliness dampens immune responses and advises joining classes, book clubs, or simply phoning a friend to bolster social connection and lower infection risk. (WaPo)
Sources
- NIH: https://medlineplus.gov/ency/article/004008.htm
- WaPo: https://www.washingtonpost.com/wellness/2024/12/16/immune-system-aging-strong-boost/
- Healthline: https://www.healthline.com/health/flu/boost-immune-system-over-65
- TurnerMD: https://michaelturnermd.com/wp-content/uploads/2025/01/Stop-Getting-Sick.pdf
Which lab tests and medications are worth reviewing if I’m always sick?
A targeted work-up catches hidden problems and avoids unnecessary drugs. "Start with basics: CBC, CMP, HbA1c, and vaccine titers often reveal the culprit," advises Sina Hartung, MMSC-BMI.
- Complete blood count (CBC) with differentialLow lymphocytes (<1.0 × 10^9/L) suggest immune deficiency or medication side effect.
- Serum immunoglobulin levelsIgG under 600 mg/dL doubles bacterial infection risk and may need replacement therapy.
- HbA1c check if >45 yearsAn A1c above 7 % is strongly linked to skin and urinary infections.
- Medication reconciliation with pharmacistStopping or switching one immunosuppressive drug can cut infection frequency by half.
- Consider vitamin D level (25-OH D)Levels below 20 ng/mL correlate with more respiratory infections; supplementation may help under supervision.
- Update age-appropriate vaccines to prevent avoidable infectionsHealthline lists an annual flu shot, a pneumococcal vaccine at 65, and a shingles vaccine after 60—simple boosters that greatly reduce serious respiratory and viral illnesses in older adults. (Healthline)
- Order a comprehensive metabolic panel to uncover organ or electrolyte issuesThe HNL guide explains that a CMP screens kidney, liver, electrolyte, and glucose status; identifying abnormalities can clarify why infections linger or why medications may be contributing to feeling constantly ill. (HNL)
How can Eureka’s AI doctor support me when I feel another cold coming on?
Eureka’s symptom-checker analyzes your age, chronic diseases, and current meds in seconds. "Our AI flags concerning patterns—like three chest infections in one season—and suggests labs you can order from home," says the team at Eureka Health.
- Real-time triage of cough, fever, and fatigueHelps decide whether you need same-day urgent care or supportive care at home.
- Personalized vaccine remindersPush notifications align with CDC schedules and your last recorded dose.
- Automatic drug-interaction scanAI reviews your medication list to spot immune-suppressing combinations instantly.
- Secure chat with clinicians within 2 hoursIf AI suggests antibiotics, a licensed practitioner reviews and, if appropriate, sends an e-prescription.
Why are older users rating Eureka highly for infection prevention?
Among adults over 55 who used Eureka for at least three months, 84 % reported fewer sick days, and women using Eureka for menopause rate the app 4.8 / 5 stars. "People feel heard, and the plan is easy to follow," observes Sina Hartung, MMSC-BMI.
- Private, HIPAA-compliant data handlingYour symptom logs and lab results stay encrypted and never sold.
- Step-by-step action plans you can printDaily checklists remind you to hydrate, medicate, and rest without guesswork.
- Progress tracking graphsSpot trends like declining sleep before every sinus infection.
- Free to use, no credit card requiredHelps remove barriers to regular health monitoring.
Frequently Asked Questions
Is catching a cold every month normal after age 65?
Up to 8 viral upper-respiratory infections per year can be normal, but more than one antibiotic-treated infection each quarter warrants evaluation.
Does the annual high-dose flu shot work better for seniors?
Yes. It triggers about 24 % more protective antibodies than the standard vaccine in adults over 65.
Can stress alone explain my frequent illnesses?
Chronic stress elevates cortisol, which can cut natural killer cell activity by half, so it can be a major contributor.
Will zinc or vitamin C supplements stop me getting sick?
Evidence shows only modest benefits; zinc lozenges may shorten colds by one day if taken within 24 hours, but they don’t prevent infections.
How often should I ask for blood work if I’m otherwise healthy?
An annual CBC and CMP are reasonable; add immunoglobulin testing or HbA1c if you have frequent infections or chronic disease.
Do antihistamines weaken my immune system?
First-generation antihistamines mainly cause drowsiness; they do not meaningfully suppress immunity, unlike corticosteroids.
Is it dangerous to exercise when I have a mild cold?
Light activity such as walking is safe if symptoms are above the neck only (runny nose, sore throat) and no fever is present.
Could my recurrent UTIs be linked to low estrogen?
Post-menopausal estrogen loss thins the bladder lining, increasing UTI risk; topical estrogen may reduce recurrences—discuss with your clinician.
What air purifier specs help reduce viral spread at home?
Look for a HEPA filter with a Clean Air Delivery Rate (CADR) that matches your room size; aim for 5 air exchanges per hour.
References
- Mayo: https://mcpress.mayoclinic.org/healthy-aging/aging-and-the-immune-system/
- NIH: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1931833/
- NJH: https://www.nationaljewish.org/education/health-information/health-lifestyle-tips/how-aging-affects-your-immune-system
- NIH: https://pmc.ncbi.nlm.nih.gov/articles/PMC3061194/
- GSK: https://www.gsk.com/en-gb/behind-the-science-magazine/age-related-decline-immunity-infectious-disease
- AAFP: https://www.aafp.org/pubs/afp/issues/2001/0115/p257.html
- UpToDate: https://www.uptodate.com/contents/approach-to-infection-in-the-older-adult
- NHLBI: https://www.nhlbi.nih.gov/news/2021/study-explains-how-age-related-changes-white-blood-cells-increase-risk-different-types
- MarketWatch: https://www.marketwatch.com/story/prepare-for-a-sick-old-age-twice-as-many-older-people-will-suffer-from-four-or-more-diseases-by-2035-2018-01-25
- NCBI: https://www.ncbi.nlm.nih.gov/books/NBK51842/
- NIH: https://medlineplus.gov/ency/article/004008.htm
- WaPo: https://www.washingtonpost.com/wellness/2024/12/16/immune-system-aging-strong-boost/
- Healthline: https://www.healthline.com/health/flu/boost-immune-system-over-65
- TurnerMD: https://michaelturnermd.com/wp-content/uploads/2025/01/Stop-Getting-Sick.pdf
- Healthline: https://www.healthline.com/health/senior-health-tests
- HNL: https://www.hnl.com/resources/blog/lab-tests-for-healthy-aging