NU504 Assignment 6: Impact of Sleep Deprivation on Cold Susceptibility

NU504 Assignment 6: Impact of Sleep Deprivation on Cold Susceptibility

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Purdue University Global

NU504 Scientific and Analytic Approaches to Advanced Evidence-Based Practice

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How Sleep Deprivation Increases the Risk of the Common Cold: An Evidence-Based Review

Introduction

Getting enough quality sleep is one of the most effective ways to support a healthy immune system and reduce the risk of common infections such as the common cold. Research consistently shows that adults who sleep fewer than seven hours per night are generally more likely to develop upper respiratory infections than those who regularly achieve the recommended amount of sleep. Adequate sleep strengthens immune function, supports the production of protective immune cells, and helps the body recover more efficiently from illness.

Sleep is a fundamental biological process that influences nearly every aspect of physical and mental health. During sleep, the body repairs tissues, regulates hormones, consolidates memory, and activates immune responses that protect against viruses and bacteria. Chronic sleep deprivation disrupts these essential processes, making individuals more susceptible to infections while slowing recovery after illness.

Health organizations recommend that most healthy adults obtain 7–9 hours of quality sleep each night to maintain optimal health and immune function. Unfortunately, modern lifestyles, work schedules, stress, and excessive screen time have contributed to widespread sleep deficiency, increasing the prevalence of weakened immunity and respiratory illnesses.

Evidence from clinical trials, cohort studies, and systematic reviews suggests that inadequate sleep is associated with increased vulnerability to viral infections, including the common cold. While a small number of studies report mixed findings, the overall body of evidence supports the importance of healthy sleep habits as a preventive healthcare strategy.

Why Sleep Is Essential for Immune Health

Sleep and immunity are closely connected. During sleep, the immune system produces and releases proteins known as cytokines, which help regulate inflammation and coordinate the body’s defense against infections. Certain cytokines increase during periods of infection, injury, or stress, enabling the immune system to respond effectively.

Insufficient sleep can reduce the production of these protective cytokines while also decreasing infection-fighting antibodies and immune cells. As a result, individuals who consistently experience sleep deprivation may have a reduced ability to fight viruses and recover from illness.

Research has shown that poor sleep may contribute to:

• Reduced immune response

• Increased susceptibility to viral infections

• Slower recovery from illness

• Higher levels of inflammation

• Greater physical and mental fatigue

• Increased risk of chronic diseases

These physiological changes explain why sleep quality has become an important consideration in preventive healthcare and evidence-based nursing practice.

Key Evidence: Multiple clinical studies have found that sleeping fewer than seven hours per night is associated with a higher likelihood of developing respiratory infections compared with sleeping seven to nine hours consistently.

Refined PICOT Question

The PICOT framework helps healthcare professionals develop focused clinical questions that guide evidence-based research.

The refined PICOT question for this review is:

• Population (P): Adults

• Intervention/Exposure (I): Sleeping fewer than five hours per night

• Comparison (C): Adults sleeping seven or more hours each night

• Outcome (O): Likelihood of developing a common cold or upper respiratory infection

• Time (T): During the months of November through February

The clinical question can therefore be stated as:

Among adults, does sleeping fewer than five hours per night, compared with sleeping seven or more hours, increase the likelihood of developing the common cold during the winter months?

This question focuses on determining whether inadequate sleep contributes to increased vulnerability to respiratory infections.

Literature Search Strategy

A comprehensive literature search was conducted using evidence-based healthcare databases to identify studies examining the relationship between sleep deprivation and susceptibility to respiratory infections.

The primary databases included:

• PubMed

• Cochrane Library

• Academic nursing library databases

The following keywords were used during the search:

• Sleep deprivation

• Sleep and immunity

• Sleep duration

• Sleep quality

• Common cold

• Upper respiratory infection

• Sleep hygiene

• Immune function

To improve the quality of evidence, the search was limited to:

• Peer-reviewed publications

• Full-text articles

• Human studies

• English-language publications

• Recent research whenever available

The initial search identified thousands of potentially relevant studies. After removing duplicate articles and studies unrelated to respiratory infections or sleep duration, four high-quality studies were selected for detailed evaluation because they directly examined the relationship between sleep and susceptibility to illness.

This structured search process ensured that the review relied on credible, clinically relevant evidence.

Evidence Review: Sleep Disturbance After Hospitalization and Critical Illness

One of the most comprehensive systematic reviews evaluating sleep disturbances after hospitalization was conducted by Altman and colleagues (2017). The review examined how sleep quality changes following discharge from intensive care and serious illness.

Researchers searched multiple medical databases, including PubMed, MEDLINE, and EMBASE, identifying more than 2,000 unique publications. Following screening and eligibility assessment, 22 studies met the inclusion criteria.

The review included:

• Twenty-one prospective cohort studies

• One cross-sectional study

Researchers assessed sleep using validated questionnaires, polysomnography, and actigraphy to evaluate both subjective and objective sleep quality.

Results demonstrated that sleep disturbances remained common long after hospital discharge.

Reported prevalence included:

• 50–66.7% within one month after discharge

• 34–64.3% between one and three months

• 22–57% between three and six months

• 10–61% after six months

These findings suggest that sleep disruption may persist for months following critical illness.

The review also highlighted the important physiological benefits of healthy sleep, including:

• Enhanced immune regulation

• Improved memory consolidation

• Balanced neuroendocrine function

• Reduced inflammation

• Better overall recovery

Conversely, chronic sleep disruption has been associated with increased risks of:

• Cardiovascular disease

• Depression

• Cognitive impairment

• Reduced immune function

• Increased mortality

Although this review focused primarily on hospitalized patients rather than healthy adults, it reinforces the essential role of sleep in immune recovery and overall health.

Clinical Insight: Persistent sleep disturbances after hospitalization may delay immune recovery and contribute to poorer long-term health outcomes.

Critical Appraisal and Error Analysis

Evaluating the quality of evidence is essential when applying research findings to clinical practice.

The systematic review demonstrated several methodological strengths.

Researchers excluded studies involving:

• Burn injuries

• Neurosurgical patients

• Postsurgical recovery

• Non-English publications

• Case reports

• Opinion articles

• Narrative reviews

These exclusions helped improve the overall quality of the evidence.

However, several limitations were identified.

First, the included studies used different sleep assessment methods, making direct comparison difficult. Some relied on patient questionnaires, while others used objective sleep-monitoring devices.

Second, the studies varied considerably in patient populations, follow-up duration, and measurement tools.

Third, relatively small sample sizes prevented researchers from performing a formal meta-analysis.

Despite these limitations, the systematic review provides valuable evidence supporting the importance of sleep quality during recovery from severe illness.

Quantitative Study: Sleep Duration and Upper Respiratory Infection in Military Recruits

Wentz et al. (2018) investigated whether inadequate sleep increased the likelihood of upper respiratory infections among British Army recruits undergoing basic military training.

The study included 651 healthy recruits, with an average age of approximately 22 years.

Participants completed questionnaires before and after training describing their usual sleep duration.

Researchers also collected information regarding:

• Smoking status

• Alcohol use

• Body mass index

• Seasonal recruitment

• Sex

Medical records were reviewed to identify physician-diagnosed upper respiratory infections during training.

The study found that sleep duration declined substantially during military training.

Before training:

• Only 13% reported sleeping fewer than seven hours.

During training:

• Approximately 38% reported sleeping fewer than seven hours each night.

After adjusting for potential confounding variables, recruits sleeping less than six hours per night were approximately four times more likely to develop upper respiratory infections than recruits sleeping the recommended 7–9 hours.

These findings suggest that insufficient sleep significantly increases vulnerability to respiratory illness during periods of physical and psychological stress.

The study’s strengths include its relatively large sample size, standardized medical diagnoses, and adjustment for important lifestyle variables.

However, because the participants were military recruits rather than members of the general population, the findings may not be fully generalizable to all adults.

Research Highlight: Adults consistently sleeping fewer than six hours per night may face a substantially higher risk of upper respiratory infections compared with those obtaining seven to nine hours of sleep.

Sleep Habits and Susceptibility to the Common Cold

One of the most influential studies examining the relationship between sleep and immunity was conducted by Cohen et al. (2009). The researchers investigated whether sleep duration and sleep efficiency affected an individual’s likelihood of developing the common cold after exposure to a rhinovirus.

The study included 153 healthy adults between the ages of 21 and 55 years. Participants were free from significant medical conditions before enrollment to minimize factors that could influence immune function.

Researchers monitored participants’ sleep for 14 consecutive days before exposing them to a rhinovirus. Sleep data were collected using questions adapted from the Pittsburgh Sleep Quality Index (PSQI) and the Pittsburgh Sleep Diary.

Participants reported:

• Average nightly sleep duration

• Sleep efficiency (percentage of time in bed spent sleeping)

• Whether they felt rested after sleeping

Following the monitoring period, participants received nasal drops containing a rhinovirus under controlled laboratory conditions. They were then quarantined and monitored for five days for objective signs and symptoms of the common cold.

Researchers evaluated several clinical outcomes, including:

• Nasal congestion

• Runny nose

• Sneezing

• Sore throat

• Cough

• Mucus production

• Viral antibody response

• Nasal mucociliary clearance

The results showed a clear relationship between inadequate sleep and susceptibility to infection. Individuals who slept less than seven hours per night were nearly three times more likely to develop a clinically confirmed cold than participants who slept eight hours or more.

Interestingly, participants’ subjective feeling of being rested did not significantly predict whether they became ill. Instead, sleep duration and sleep efficiency were stronger predictors of immune resistance.

These findings suggest that objective measures of sleep quality are more reliable indicators of immune health than self-perceived sleep satisfaction.

Clinical Insight: Consistently obtaining fewer than seven hours of sleep may significantly reduce the body’s ability to resist viral infections, even in otherwise healthy adults.

Swedish Cohort Study: Sleep, Physical Activity, and Respiratory Infections

Ghilotti et al. (2018) conducted a large prospective cohort study to evaluate whether sleep duration, sleep quality, and physical activity influenced the risk of respiratory infections.

The study included 2,038 employed adults aged 25–64 years, making it the largest study included in this evidence review.

Participants completed detailed questionnaires regarding:

• Sleep duration

• Sleep quality

• Physical activity

• Work environment

• Lifestyle behaviors

• Family structure

• Overall health

Sleep duration was categorized into three groups:

• Short sleep: Five hours or less

• Normal sleep: Six to seven hours

• Long sleep: Eight hours or more

Participants were followed for nine months, spanning the peak respiratory virus season from September through May.

Whenever participants experienced symptoms such as fever or upper respiratory illness, they completed an online symptom questionnaire. Researchers also collected nasal swabs to identify common respiratory viruses using polymerase chain reaction (PCR) testing.

Unlike the previous studies, this investigation did not identify a statistically significant association between sleep duration, sleep quality, or physical activity and respiratory infections.

Although the study had several strengths—including a large sample size, random participant selection, and laboratory confirmation of viral infections—it differed from other studies in its methodology and outcome measures. Variations in participant characteristics, exposure risks, and data collection methods may explain why its findings were inconsistent with much of the existing evidence.

Overall, this study demonstrates that while many investigations support a connection between sleep and immunity, individual study results may vary because of differences in research design and population characteristics.

Evidence Summary: Most available research suggests that inadequate sleep increases susceptibility to respiratory infections, although not every study reaches the same conclusion.

Application to Nursing Practice

The evidence reviewed highlights the importance of promoting healthy sleep as part of routine patient care and disease prevention. Nurses and advanced practice providers play a critical role in educating patients about the health consequences of chronic sleep deprivation.

One of the most effective interventions is sleep hygiene education, which focuses on behaviors and environmental factors that promote restorative sleep.

Key sleep hygiene recommendations include:

• Maintain a consistent sleep and wake schedule.

• Aim for 7–9 hours of sleep each night.

• Limit caffeine and nicotine several hours before bedtime.

• Reduce exposure to electronic screens before sleep.

• Create a quiet, dark, and comfortable sleeping environment.

• Engage in regular physical activity during the day.

• Avoid large meals and alcohol immediately before bedtime.

• Practice relaxation techniques to reduce stress.

Hospitalized patients are particularly vulnerable to sleep disruption due to noise, lighting, medical procedures, and frequent nighttime interruptions. Healthcare teams can improve patient outcomes by minimizing unnecessary disturbances and coordinating nursing activities to allow uninterrupted periods of rest.

For advanced practice nurses and family nurse practitioners, incorporating sleep assessments into routine health evaluations can help identify individuals at increased risk of immune dysfunction, fatigue, and chronic disease.

Sleep promotion should also be integrated into patient education for individuals with:

• Recurrent respiratory infections

• Chronic stress

• Diabetes

• Cardiovascular disease

• Obesity

• Mental health disorders

• Shift-work schedules

Encouraging healthy sleep habits represents a simple, cost-effective intervention that may improve both short-term recovery and long-term health outcomes.

Evaluation of the Evidence

This evidence review examined findings from four major research studies investigating the relationship between sleep deprivation and respiratory infections.

Overall, the evidence demonstrated:

• Three studies found that inadequate sleep significantly increased the risk of respiratory illness.

• One large cohort study reported no statistically significant relationship between sleep duration and upper respiratory infections.

• The strongest evidence came from controlled experimental research involving rhinovirus exposure.

• Multiple studies identified sleep duration and sleep efficiency as important predictors of immune function.

The overall quality of evidence supports the conclusion that insufficient sleep is associated with reduced immune resistance and greater susceptibility to viral infections.

Validity

The reviewed studies generally used well-established research methods, standardized sleep assessment tools, and objective clinical outcomes. These factors strengthen the credibility of their findings.

Reliability

Despite differences in study populations and methodologies, several independent investigations reported similar conclusions regarding the relationship between poor sleep and increased infection risk.

Applicability

The participants included healthy adults, military personnel, hospitalized patients, and community populations, making the findings broadly applicable to many healthcare settings. Nurses can confidently incorporate sleep education into routine preventive care.

Research consistently demonstrates that:

• Sleeping fewer than seven hours is associated with increased susceptibility to viral infections.

• Sleep efficiency influences immune system performance.

• Healthy sleep behaviors can support disease prevention and recovery.

• Patient education regarding sleep should be considered an essential component of evidence-based nursing practice.

Conclusion

Current evidence suggests that obtaining sufficient, high-quality sleep is an important factor in maintaining a healthy immune system and reducing susceptibility to upper respiratory infections, including the common cold. Although one cohort study did not identify a significant association, the majority of high-quality evidence supports the conclusion that inadequate sleep weakens immune defenses and increases the likelihood of illness.

Evidence-based nursing emphasizes the use of the best available research to guide clinical decision-making. This review demonstrates that sleep should be considered a modifiable health behavior that deserves greater attention during patient assessments and health education.

Healthcare professionals should routinely encourage adults to obtain the recommended 7–9 hours of quality sleep each night, practice good sleep hygiene, and recognize sleep as an essential component of disease prevention and overall wellness.

Sleep is not simply a period of rest—it is a critical biological process that strengthens immunity, promotes recovery, and supports long-term health.

Frequently Asked Questions

Does sleeping less than seven hours increase the risk of getting a cold?

Yes. Multiple clinical studies have found that adults who consistently sleep fewer than seven hours per night are more likely to develop upper respiratory infections than those who regularly obtain seven to nine hours of sleep.

Why does sleep affect the immune system?

During sleep, the body produces cytokines, antibodies, and immune cells that help fight infections. Chronic sleep deprivation reduces these protective responses, making it more difficult for the body to defend itself against viruses.

How many hours of sleep do adults need?

Most healthy adults should aim for 7–9 hours of quality sleep each night, according to sleep medicine recommendations.

Can improving sleep reduce illness?

Healthy sleep habits may strengthen immune function, improve recovery, and reduce the likelihood of respiratory infections. While sleep alone cannot prevent all illnesses, it is an important component of overall health.

What are the best sleep hygiene practices?

Effective sleep hygiene includes maintaining a consistent sleep schedule, limiting caffeine before bedtime, reducing screen time, creating a comfortable sleep environment, exercising regularly, and managing stress.

Research consistently indicates that adequate sleep supports immune function and may reduce susceptibility to common respiratory infections.

Clinical evidence suggests that adults sleeping fewer than seven hours each night have a greater likelihood of developing the common cold than individuals who obtain the recommended amount of sleep.

Sleep hygiene interventions represent a practical, evidence-based strategy that healthcare professionals can use to promote wellness and improve patient outcomes.

References

Altman, M. T., Knauert, M. P., & Pisani, M. A. (2017). Sleep disturbance after hospitalization and critical illness: A systematic review. Annals of the American Thoracic Society, 14(9), 1457–1468. https://doi.org/10.1513/AnnalsATS.201702-148SR

Asif, N., Iqbal, R., & Nazir, C. F. (2017). Human immune system during sleep. American Journal of Clinical and Experimental Immunology, 6(6), 92–96. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5806561/

Cohen, S., Doyle, W. J., Alper, C. M., Janicki-Deverts, D., & Turner, R. B. (2009). Sleep habits and susceptibility to the common cold. Archives of Internal Medicine, 169(1), 62–67. https://doi.org/10.1001/archinternmed.2008.505

NU504 Assignment 6: Impact of Sleep Deprivation on Cold Susceptibility

Ghilotti, F., Pesonen, A. S., Raposo, S. E., Winell, H., Nyrén, O., Trolle Lagerros, Y., & Plymoth, A. (2018). Physical activity, sleep and risk of respiratory infections: A Swedish cohort study. PLoS ONE, 13(1), e0190270. https://doi.org/10.1371/journal.pone.0190270

Irish, L. A., Kline, C. E., Gunn, H. E., Buysse, D. J., & Hall, M. H. (2015). The role of sleep hygiene in promoting public health: A review of empirical evidence. Sleep Medicine Reviews, 22, 23–36. https://doi.org/10.1016/j.smrv.2014.10.001

Mazurek Melnyk, B., & Fineout-Overholt, E. (2019). Evidence-based practice in nursing & healthcare: A guide to best practice (4th ed.). Wolters Kluwer.

Riva, J. J., Malik, K. M., Burnie, S. J., Endicott, A. R., & Busse, J. W. (2012). What is your research question? An introduction to the PICOT format for clinicians. Journal of the Canadian Chiropractic Association, 56(3), 167–171. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3430448/

Wentz, L. M., Ward, M. D., Potter, C., Oliver, S. J., Jackson, S., Izard, R. M., Greeves, J. P., & Walsh, N. P. (2018). Increased risk of upper respiratory infection in military recruits who report sleeping less than 6 h per night. Military Medicine, 183(11–12), e699–e704. https://doi.org/10.1093/milmed/usy090