How often is it considered normal to get sick? A guide to understanding immune health

October 1, 2025 •

4 min read

According to the Centers for Disease Control and Prevention (CDC), the average adult catches two to three colds annually, making many wonder how often is it considered normal to get sick? This common concern highlights the natural variations in immune response, influenced by age, exposure, and lifestyle.

Quick Summary

This article explores the typical frequency of illnesses for adults and children. It delves into the key factors that can influence how often a person falls ill, including age, exposure to germs, lifestyle, and underlying health issues. Additionally, it helps you identify signs that might suggest you're getting sick more frequently than normal and when to consult a doctor. Practical tips for bolstering immune resilience are also provided.

Key Points

Normal Adult Frequency: A healthy adult can expect to catch about two to three common colds per year, typically between September and May.
Normal Child Frequency: Young children get sick far more often, with preschoolers averaging six to twelve illnesses annually as their immune systems develop.
Influencing Factors: Age, exposure to germs, chronic stress, poor sleep, and underlying health conditions are major factors that impact how frequently you get sick.
When to See a Doctor: Persistent symptoms, very frequent or severe infections, slow wound healing, and chronic fatigue could indicate a compromised immune system.
Boost Your Immunity: Healthy habits like getting sufficient sleep, managing stress, eating a nutritious diet, and proper hand hygiene are key to supporting your immune system.
Genetics Play a Role: Your individual genetic makeup can influence your natural resistance to certain pathogens, explaining some variation in sickness frequency among individuals.

Normal Frequency for Adults

For a healthy adult, experiencing a couple of illnesses per year is considered typical. The CDC estimates that most adults get about two to three common colds annually. These are often viral infections of the upper respiratory tract and can last between seven to ten days.

Several factors can influence this number, including your age and daily interactions. For example, adults aged 20 to 30, particularly women, may get sick more frequently if they are in close contact with children. Those over 60, who have built up immunity over a lifetime, tend to experience fewer than one cold per year on average.

Normal Frequency for Children

It can feel like a constant battle against germs when you have young children, and with good reason. Their immune systems are still developing and have not yet built up a wide range of immunity to common germs.

Infants and Preschoolers: It is perfectly normal for babies, toddlers, and preschoolers to experience six to eight colds per year, sometimes as high as 12 if they are in daycare. The close contact with other children in these settings significantly increases their exposure to new viruses.
School-Age Children: As children get older, their immune systems mature, and the frequency of colds decreases. School-age kids can average about five to six illnesses annually.
Teenagers: By the teenage years, illness frequency begins to approach adult levels, with teenagers experiencing around four colds a year.

Beyond respiratory infections, young children might also experience two to three stomach bugs annually. This cycle of frequent illness is a normal part of building a robust immune system for later in life.

Factors Influencing Sickness Frequency

Many elements contribute to how often someone falls ill. While some are unavoidable, others can be managed to improve overall immune resilience.

Lifestyle and Environmental Factors

Poor Sleep: Adequate sleep is crucial for a strong immune system. Studies show that individuals who sleep less than seven to nine hours per night have a significantly higher risk of catching a cold. Getting proper rest allows the body to release cytokines, proteins that help fight infection.
Chronic Stress: Long-term stress elevates cortisol levels, a hormone that can suppress immune function. This makes the body more vulnerable to infections. Managing stress through mindfulness, exercise, or hobbies is key to keeping your immune system robust.
Diet and Nutrition: A balanced diet rich in vitamins, minerals, and antioxidants provides the building blocks for a healthy immune response. Nutrient deficiencies, particularly low levels of Vitamin D or Zinc, can compromise immunity.
Hygiene Habits: Frequent and proper handwashing is one of the most effective ways to prevent the spread of germs. Avoiding touching your face also reduces the chances of transferring viruses to your eyes, nose, and mouth.
Exercise Levels: Moderate, regular exercise can improve blood circulation and stimulate immune cell production, helping to fight infections more effectively.

Health and Genetic Factors

Underlying Health Conditions: Chronic illnesses like diabetes, congestive heart disease, or autoimmune conditions can put a strain on the immune system, leading to more frequent infections.
Allergies and Asthma: These conditions cause inflammation and mucus buildup in the airways, creating a more favorable environment for viruses to thrive. Uncontrolled allergies can increase the rate of sinus infections.
Genetic Predisposition: Your unique genetic makeup, specifically variations in HLA genes, can affect your immune system's effectiveness against certain pathogens. This is why some families seem more or less susceptible to specific types of illness.

Comparison of Sickness Frequency by Age Group


Age Group	Normal Common Cold Frequency (per year)	Why the Difference?
Infants and Preschoolers	6-12	Immature immune system, high exposure in daycare settings
School-Age Children	5-6	Developing immunity, exposure at school
Teenagers	Approaching adult levels, around 4	Maturing immune system, decreased exposure compared to younger kids
Healthy Adults	2-3	Developed immune system, varies based on exposure and lifestyle
Adults 60+	Less than 1	Lifelong immunity built up to common strains, generally lower exposure

When to Consider Seeing a Doctor

While a few colds each year are normal, some signs might indicate that you are getting sick too often due to an underlying issue. It's advisable to consult a healthcare provider if you experience any of the following:

Persistent Symptoms: Colds that linger for weeks or never seem to fully go away.
Severe or Recurrent Infections: Having severe infections like pneumonia or needing antibiotics multiple times per year for issues like chronic sinus or ear infections.
Slow Wound Healing: Cuts and scrapes take an unusually long time to heal, which can signal a sluggish immune response.
Chronic Fatigue: Constant, overwhelming tiredness even with adequate sleep can be a symptom of a weakened immune system.
Digestive Problems: Frequent gas, diarrhea, or bloating, as a significant portion of the immune system resides in the gut.

Conclusion

Understanding how often is it considered normal to get sick is a matter of perspective, heavily influenced by age and lifestyle. For most, a handful of colds per year is simply part of having an active immune system that is constantly learning and defending the body. However, recognizing when frequent illness or lingering symptoms warrant professional medical advice is vital for maintaining long-term health. By adopting healthy habits—like prioritizing sleep, managing stress, and practicing good hygiene—you can give your immune system the best chance to function optimally and reduce the risk of falling ill. For additional information on disease prevention, the National Institutes of Health (NIH) offers extensive resources.

Frequently Asked Questions

A healthy adult typically gets about two to three common colds per year.

Young children, especially those in daycare or preschool, can get sick more frequently, averaging six to twelve colds or other respiratory infections per year.

Yes, adults who are in close contact with children, such as parents or caregivers, often have more exposure to germs and tend to get sick more frequently.

Yes, chronic or long-term stress can suppress your immune system, making you more susceptible to infections and other illnesses.

You should consider consulting a doctor if your infections are frequent, severe, and persistent, or if you experience chronic fatigue, slow healing, or digestive issues.

To reduce how often you get sick, focus on healthy habits like prioritizing sleep, managing stress, eating a balanced diet, regular exercise, and practicing good hygiene.

Yes, conditions like allergies and asthma can lead to chronic inflammation and mucus buildup in the airways, which can make you more susceptible to infections like colds and sinus infections.