Cold therapy for recurrent respiratory infections
Evidence review
Overview
A pragmatic Dutch RCT randomized 3018 adults without severe comorbidity to end their daily shower with 30, 60 or 90 seconds of cold water (about 50-54 F) for 30 days or to control; self-reported sickness absence from work was 29% lower, but the primary outcome of illness days did not differ. In preschool children with frequent colds, 12 months of daily warm-and-cold hydrotherapy did not reduce cold incidence or duration in a randomized trial. Small uncontrolled studies of cold affusions in COPD and children reported fewer infections, and in a survey of 2343 adults, physically active cold-water swimmers less often reported frequent respiratory infections but did not have lower COVID-19 incidence. A 2025 healthy-adult meta-analysis summarized immune effects as non-significant short term.
Key findings
- RCT, 3018 healthy adults: sickness absence IRR 0.71 (P=0.003) for hot-to-cold showers vs control; no significant effect on illness days; no dose response across 30/60/90 s (Buijze 2016).
- RCT, children aged 3-7 with 6 or more colds in the prior year: colds 4.1 +/- 3.3 with hydrotherapy vs 4.8 +/- 3.5 control, not significant (Grüber 2003).
- Uncontrolled study, 20 COPD patients: infection frequency lower during follow-up after 10 weeks of cold affusions and washings (Goedsche 2007).
- Survey, 2343 adults: acute respiratory infection more than twice a year RR 0.258 (95% CI 0.138-0.483) in cold-water swimmers; COVID-19 incidence RR 1.074 (0.710-1.625) (Bielik 2021).
- Meta-analysis, healthy adults: no significant immune effect immediately (SMD -0.16) or 1 h post-immersion (SMD -0.18) (Cain 2025).
Every study we reviewed
3 mixed results · 2 found no effect · 1 found benefit
Each study was checked on PubMed. The colored edge shows the direction of the result. The research library lists 18 studies on respiratory infections, across all heat and cold therapies, including case reports and older work not graded here.
The Effect of Cold Showering on Health and Work: A Randomized Controlled Trial.
Buijze GA et al. PLoS One. 2016. PubMed 27631616 · DOI · Free full text
- Who
- adults aged 18-65 without severe comorbidity and no cold-showering routine
- What
- usual warm shower ending with 30, 60 or 90 s at the coldest available temperature, daily for 30 days, then optional for 60 days, vs control
- Protocol
- 50-54 (tap water) °F · 0.5-1.5 min · 7/wk · 4.3 (then 8.6 optional)
- Measured
- illness days and sickness absence from work (primary); quality of life, productivity, adverse reactions
- Result
- Sickness absence reduced 29% vs control (IRR 0.71, P=0.003); no significant group effect on illness days; no difference between 30, 60 and 90 s groups (P=0.992). No related serious adverse events; persistent cold sensation in up to 13%.
- Limitations
- unblinded; self-reported outcomes; healthy volunteers; illness days null
The effect of hydrotherapy on the incidence of common cold episodes in children: a randomised clinical trial.
Grüber C et al. Eur J Pediatr. 2003. PubMed 12655421 · DOI
- Who
- children aged 3-7 with 6 or more common colds in the previous 12 months (diaries from 65 intervention, 81 control)
- What
- daily hydrotherapy (warm and cold water stimulation) plus saline inhalation vs saline inhalation alone
- Protocol
- 7/wk · 52 wk
- Measured
- incidence, duration and severity of common colds (parent diary)
- Result
- No significant differences: 4.1 +/- 3.3 vs 4.8 +/- 3.5 episodes; duration 7.6 +/- 3.8 vs 7.7 +/- 3.5 days.
- Limitations
- pediatric; mixed warm/cold hydrotherapy; diary attrition
[Repeated cold water stimulations (hydrotherapy according to Kneipp) in patients with COPD].
Goedsche K et al. Forsch Komplementmed. 2007. PubMed 17596696 · DOI
- Who
- patients with COPD (mean FEV1 62% predicted), no acute exacerbation
- What
- self-administered cold water affusions (3/week) and cold upper-body washings (2/week), a traditional hydrotherapy regimen
- Protocol
- 5/wk · 10 wk
- Measured
- lung function, lymphocytes, quality of life, respiratory infections
- Result
- PEF and lymphocyte count increased during treatment; frequency of infections lower during 3-month follow-up than before and during therapy.
- Limitations
- uncontrolled; n=20; infection counts not given in abstract
The Effect of Cold-Water Hydrotherapy According to Sebastian Kneipp for Immune Stimulation: A Nonrandomized, Controlled, Explorative, Mixed-Methods Clinical Study.
Schulte K et al. J Integr Complement Med. 2022. PubMed 35649190 · DOI
- Who
- children aged 3-6 (20 intervention, 18 control)
- What
- home cold-water arm affusions by parents, traditional hydrotherapy regimen, vs no intervention
- Protocol
- 6 wk
- Measured
- missed kindergarten days, fever days, respiratory infections
- Result
- No significant differences; intermediate effect sizes for fewer missed days (d=0.67) and lower respiratory infections (d=0.60), but more fever days in the intervention group.
- Limitations
- non-randomized; underpowered; local arm cold only
Effects of cold-water immersion on health and wellbeing: A systematic review and meta-analysis.
Cain T et al. PLoS One. 2025. PubMed 39879231 · DOI · Free full text
- Who
- healthy adults (11 randomized trials)
- What
- cold shower, ice bath or plunge at 45-59 F for 30 s to 2 h
- Protocol
- 45-59 °F
- Measured
- immune function, inflammation
- Result
- No significant immune effect immediately (SMD -0.16, 95% CI -0.82 to 0.51) or 1 h after (SMD -0.18, 95% CI -1.09 to 0.74); narrative synthesis cites the 29% sickness-absence reduction; acute rise in inflammation immediately (SMD 1.03) and 1 h after (SMD 1.26).
- Limitations
- healthy adults; few RCTs
A Possible Preventive Role of Physically Active Lifestyle during the SARS-CoV-2 Pandemic; Might Regular Cold-Water Swimming and Exercise Reduce the Symptom Severity of COVID-19?
Bielik V et al. Int J Environ Res Public Health. 2021. PubMed 34281096 · DOI · Free full text
- Who
- Slovak adults aged 18-65 (online survey), physically active cold-water swimmers vs controls
- What
- habitual cold-water swimming combined with a physically active lifestyle
- Measured
- COVID-19 incidence and severity; self-reported frequency of acute respiratory infection
- Result
- No lower COVID-19 incidence (RR 1.074, 95% CI 0.710-1.625); fewer people with acute respiratory infection more than twice a year (RR 0.258, 0.138-0.483) and more with at most one per year (RR 1.923) among cold-water swimmers; asymptomatic COVID-19 RR 2.321 (0.836-6.442).
- Limitations
- cross-sectional anonymous survey; self-selected and self-reported; cold-water swimming not separable from exercise; not in patients with recurrent infections
Protocols used in the studies
Adults ended a normal warm shower with 30-90 seconds of cold tap water (about 50-54 F) daily for 30 days. Pediatric and COPD studies used traditional cold affusions and washings several times per week for 6-52 weeks, with water temperature not reported in the abstracts.
What is still unknown
Whether cold exposure reduces infection incidence (rather than absence) in people with recurrent infections or chronic lung disease; mechanism; blinding-resistant outcome measures.
Safety
Cautions for cold therapy in this condition
- No related serious adverse events among 3018 adults; persistent cold sensation in body, hands or feet in up to 13% (Buijze 2016, PMID 27631616).
- Cold-water immersion produces an acute rise in inflammatory markers (Cain 2025, PMID 39879231).
- Patients with COPD or other chronic lung disease were studied only in small uncontrolled cohorts; individual assessment is needed. See general cold safety entry.
For clinicians
Suggested rationale
In a large randomized trial in healthy adults, adding a brief cold finish to the daily shower reduced self-reported sickness absence by 29% but did not reduce illness days (Buijze 2016); evidence in patients with recurrent respiratory infections is limited to a null pediatric RCT and small uncontrolled studies.
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