Does Stress Weaken the Immune System? The Psychological Side of Getting Ill Often

Does stress weaken the immune system, why do cold sores appear on hard days, and why do we fall ill on holiday? Read about stress and immunity in plain words.

Two days before a project deadline you feel that familiar tingling at the corner of your lip, and within a few hours a cold sore appears. Or a busy period in which you have been gritting your teeth for months comes to an end, you go on holiday and on the first morning at the hotel you wake up with a fever. These experiences are so common that at some point many people ask the same question: does stress weaken the immune system? In short, yes, stress can affect the immune system; but this effect is not as simple as "there's stress, so immunity is zero". In this article I explain the link between the mind and immunity, the psychological side of falling ill often and what can be done to break this cycle. Let me remind you from the outset that the first port of call for your physical complaints is always your doctor.

Does Stress Weaken the Immune System? What Does Science Say?

The field that studies the relationship between the mind and the immune system is called psychoneuroimmunology. Studies in this field have long shown that the brain, hormones and immune cells are in constant communication. The hormones released when we are stressed, such as cortisol and adrenaline, also affect how immune cells work.

There is an important distinction here. Short-term stress can mobilise the immune system for a while. The body prepares itself for the possibility of an injury or infection. That is why the tension felt on the morning of an exam or before an important presentation will not, on its own, make you ill.

The picture changes when stress lasts for weeks and months. Under long-term stress, the regulation of the immune system can be disrupted: some defence functions weaken while low-grade inflammatory processes in the body may increase. Research has shown that in people under long-term stress wounds may heal more slowly, susceptibility to colds may increase and the response to vaccines may weaken. So when the question is "does stress weaken the immune system", the honest answer is this: short-term stress does not weaken it much; long-term, unresolved stress, however, can upset the balance of immunity.

Does Stress Weaken the Immune System, or Is It Our Routine That Breaks Down?

Someone who falls ill often usually first thinks of a vitamin deficiency, the change of season or the air conditioning at work. These may of course play a role and should be assessed by a doctor. But in clinical interviews another pattern stands out: periods of illness very often coincide with the busiest periods of life.

The only reason for this is not hormones. Our behaviour also changes during stressful periods:

• Sleep gets shorter and more broken. A large part of the immune system's repair work takes place during sleep.
• Eating becomes chaotic. Skipping meals, snacking on the go and turning to sugary and processed foods increase.
• Movement decreases. "I don't have time to go to the gym" is the stock phrase of busy periods.
• Rest is postponed. When a slight sore throat starts, instead of resting at home we say, "let me finish this job first, then."
• Supportive relationships are pushed into the background. Loneliness and social disconnection can also keep the body on alert for longer.

So stress touches immunity both directly through biological routes and through our daily routines. This is actually good news, because the second route shows us areas where we can make changes.

Cold Sores, Flu and Holiday Illness: Familiar Patterns

Why do cold sores always appear on hard days?

The virus that causes cold sores stays silently in the body once it has been caught. The immune system keeps it under control. When intense stress, fatigue, lack of sleep, sun or a feverish illness upsets this balance, the virus can become active again. That is why it is no coincidence that many people get a cold sore during wedding preparations, in the week of a house move or right before an important exam. If cold sores recur frequently or are widespread, it is essential to consult a doctor.

Why do we fall ill on the first day of a holiday?

Some people hold out for months without falling ill and then take to their beds just as they are about to relax. This is sometimes referred to as the "let-down effect". Although exactly how it happens is not fully clear, one possible explanation is this: during the busy period the body is kept on its feet by alarm hormones, and when the alarm switches off, the accumulated fatigue and suppressed symptoms become visible. Falling ill at the start of the New Year holiday, Bayram (religious holiday) or summer leave is therefore a familiar story for many people.

For someone who notices this pattern, the message is clear: rather than saving rest for the holiday, building small rest breaks into the busy period shakes the body up less.

Thinking you constantly have the flu

Another picture is this: the person constantly feels weak, achy and slightly feverish, but no fever shows up on the thermometer. Here the fatigue, muscle aches and headache produced by stress itself may be interpreted as "I'm getting ill again". It is important to have these symptoms medically assessed; when the assessment comes back clear, it is time to look at the psychological side of the fatigue.

The relationship works both ways: illness also affects mood

There is another, less commonly discussed side. While the immune system fights an infection, it also sends signals to the brain, and these signals change our behaviour. When you have the flu, not only your body but also your mood collapses: you don't want to see people, everything feels meaningless and heavy, and even your favourite series doesn't interest you. This is an old mechanism the body uses to devote its energy to healing.

This knowledge is useful in two ways. First, it helps you not to interpret the pessimism of your sick days as "I'm never going to get better"; this feeling usually passes along with the illness. Second, it shows how the picture can turn into a vicious cycle for someone who falls ill often: stress strains immunity, illness lowers mood, low mood makes it harder for the person to look after themselves, and this paves the way for a new illness. Listlessness and lack of enjoyment that last for weeks even after the illness has passed, however, are something that needs to be assessed separately.

Busy Periods and the Body in Turkey

For many people in Turkey, the year passes in certain waves of stress. September, when schools open; the spring months spent with children preparing for the LGS and YKS (Turkey's national high-school and university entrance exams); year-end closings; rent renewal periods; and Bayram preparations are just a few of them. In years when these waves pile on top of each other, it is not surprising that one or more family members say "they never got better this winter".

Crowded workplaces, packed public transport and the germs children bring home from nursery or school also play their part. So stress is not the only reason for falling ill often; but stress can affect how prepared your body will be when you encounter these factors. In this respect it is also meaningful that, after the 6 February 2023 earthquakes, many people said for months, "I just can't pull myself together, I keep catching something." Prolonged uncertainty, grief, displacement and disrupted sleep also wear down the body's line of defence. In such periods, falling ill often shows not the person's weakness but the weight of the load they are carrying.

Then there is the question of caregiving. People who look after a sick mother or father while having to deal with their children and their work at the same time are the last to notice their own body's signals. They usually ignore symptoms, saying "I can't afford to be ill". This attitude is also a common part of burnout; for details, you can read the article on burnout syndrome.

How to Cope with Stress to Support Your Immunity

The suggestions below are not a treatment list; they are evidence-based steps, adaptable to everyday life, aimed at softening the mark stress leaves on the body. Leave decisions about supplements or medication to your doctor.

Don't make sleep negotiable

Sleep is the first thing sacrificed during busy periods. Yet sleep is one of the most basic supporters of immunity. Keeping your bedtimes and waking times as fixed as possible, spending the last half hour before bed screen-free and not turning your bed into a workplace is a good start. If sleep problems last a long time, you can also look at the suggestions in the article how to overcome insomnia.

Break rest into small pieces

Instead of waiting for a holiday, build short pauses into your day. A ten-minute walk at lunchtime, a few calm breaths looking out of the window between two meetings, leaving your phone in another room for an hour in the evening. These seem small, but they bring the body's alarm level down throughout the day.

Imagine you are a school administrator handling the rush of school reports, graduations and enrolments in June, and that every year you fall ill in the first week of July. Setting aside a non-negotiable half-hour "closing time" every evening throughout June, that is, switching off the computer and brewing tea, taking a short walk or playing with your child, may help you spend July differently. The aim is not to ignore the load, but to leave the body gaps within the load in which to breathe.

Take the first signal of illness seriously

When your throat starts to burn, slowing down a little that day, drinking fluids and going to bed early, rather than saying "it's nothing" and increasing the load, often means a shorter illness. Giving yourself permission is not laziness; it is care.

Protect your relationships

Talking to someone you trust, eating together or just sitting quietly in the same room helps the stress system calm down. Calling a friend at times when you feel lonely can also be a good investment for your immunity.

Move your body, but don't wear it out

Regular, moderate movement supports immunity. However, pushing yourself with heavy training during a very tired and sleepless period can put an additional load on the body. Walking, stretching and light exercise are more suitable for these periods.

Don't carry worry all day long

Constantly circling worries also keep the body constantly on alert. Putting your worries down on paper for a short time at the same hour every day can allow the mind to be a little freer for the rest of the day.

When Should You Seek Professional Support?

If you fall ill often, or if you experience prolonged fever, unexplained weight loss, night sweats, wounds that won't heal or frequently recurring infections, see a doctor first. These symptoms should be medically assessed before being explained by stress.

After a medical assessment, it may be helpful to see a mental health professional in the following situations:

• If you have felt exhausted, tense and unrested for a long time,
• If your sleep problems have been going on for weeks,
• If fear of falling ill or constant body checking occupies your day,
• If you don't feel entitled to rest, to say no or to ask for help,
• If inability to enjoy things, hopelessness or listlessness are also present.

How Are Stress and Frequent Illness Addressed in Therapy?

Therapy is not a method that directly strengthens immunity; but it can be a powerful tool for reducing the long-term stress that strains immunity. In therapy, the sources of stress and how the person copes with that stress are first examined together. Sometimes the problem is external circumstances; sometimes it is the rules the person has set for themselves: "I have to do everything myself", "I must go to work even if I'm ill", "If I rest, things will fall behind."

In cognitive behavioural therapy these rules are recognised, questioned and replaced with more flexible alternatives. Relaxation skills, sleep patterns and rest breaks in daily life are planned. With a schema therapy perspective, the deep-rooted patterns that lead a person to systematically push their own needs into the background can be addressed. Patterns such as self-sacrifice or unrelenting standards may be the psychological background to running the body for years without rest.

Before your body stops you by making you ill, it is possible for you to let it rest.

An individual therapy process focused on stress management, boundary setting and self-care can help you plan these steps in a way that suits your own life.

Frequently Asked Questions

Does stress weaken the immune system, or is that a myth?

It is not a myth. That long-term stress can affect the regulation of the immune system is a well-established scientific finding. Short-term stress, on the other hand, generally does not weaken immunity. What matters is how long stress lasts, how intense it is and how you cope with it.

I get cold sores often; is the cause just stress?

Stress is one of the factors that trigger cold sores, but it is not the only one. Sun, fatigue, feverish illnesses and other health conditions may also play a role. If they recur often, it is important to consult a doctor.

Will getting psychological support reduce how often I fall ill?

Therapy is not a direct immune treatment. However, by helping to reduce stress, sleeplessness and burnout, it can lighten your body's load. Results vary from person to person, and it does not replace medical follow-up.

What can I do to avoid falling ill on holiday?

Instead of continuing the busy period without a break right up to your holiday, try spreading rest throughout the year. Reducing your workload as much as possible in the last days before the holiday and getting your sleep in order can also soften the transition. If your body often tells you to "stop", listening to that voice together with a professional is also one of your options.

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• #getting ill often
• #cold sores
• #chronic stress

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Eda Erkan Alapala

Klinik Psikolog. İstanbul Kent Üniversitesi Klinik Psikoloji Tezli Yüksek Lisans mezunu; bilişsel davranışçı terapi, çocuk merkezli oyun terapisi ve çocuk-ergen psikoterapisi alanlarında eğitimlerini tamamlamıştır.

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