Immunity in autumn — what really works according to science (sleep, vitamin D, exercise, diet)

Autumn is the time when at the clinic we hear one question more often than any other: "how do I strengthen my immunity before the cold season?" There are plenty of answers online — from miracle supplements to "immunity detoxes". In this post we put things in order: we gather what has real backing in research, honestly say where the evidence is weak, and explain how our clinic can accompany you in all of this — without any promise that anything will make you "immune" to viruses.

Sleep — the cheapest and best-documented "supplement"

If you were to change one thing, change this one. In a study published in the journal Sleep (Prather et al., 2015), 164 healthy people wore sleep-measuring wristbands for a week and were then deliberately given a cold virus. The result: people sleeping less than 6 hours had roughly four times higher risk of getting ill than those sleeping more than 7 hours — regardless of age, stress, smoking or weight.

What this means in practice:

• aim for 7–9 hours of sleep, regularly, not only at the weekend,
• a fixed bedtime matters more than "catching up on sleep",
• screens and bright light in the evening delay falling asleep — this is not a myth, it is melatonin physiology.

Vitamin D — yes, but sensibly

In Poland from October to March the sun is too low for the skin to produce meaningful amounts of vitamin D. That is why the 2023 Polish guidelines (Płudowski et al., Nutrients) recommend that healthy adults who do not get adequate sun exposure take 1000–2000 IU daily as a supplement, with the dose adjusted to body weight — and ideally after checking the 25(OH)D level in the blood.

Two honest remarks:

1. The immune system needs vitamin D — that is a fact. But studies on whether supplementation prevents infections give moderate results: the greatest benefit is seen in people with a deficiency, in others the effect is small.
2. "More" does not mean "better". Doses of several thousand units without testing and consultation are not immunity, they are a risk.

Exercise — moderate, regular, outdoors

A study by Nieman et al. (2011, British Journal of Sports Medicine) followed over a thousand people through 12 weeks of autumn and winter. People doing aerobic exercise at least 5 days a week had 43% fewer days with an upper respiratory tract infection than people with a sedentary lifestyle, and their symptoms were milder.

The important word: moderate. A brisk walk, cycling, swimming, Nordic walking. Very intense training without recovery works the other way — after a marathon the risk of infection rises for several days. An autumn walk of 30–45 minutes a day is a really good investment.

Diet — no miracles, but with specifics

There is no product that "gives immunity". There is, however, a way of eating that supports the body:

• Vegetables and fruit at every meal — fibre and polyphenols feed the gut microbiota, and more and more studies link its condition with the functioning of the immune system.
• Fermented foods (pickles, natural yoghurt, kefir) — a source of probiotic bacteria.
• Protein in an adequate amount — antibodies and immune cells are built from it.
• Hydration — dry mucous membranes defend less well against viruses; in heated rooms it is easy to forget.

And vitamin C? A Cochrane review (Hemilä and Chalker, 2013; 29 studies, over 11 thousand people) is clear: in the general population it does not prevent colds. Taking it regularly shortens them by about 8% in adults (that is, from 7 days to 6.5), and reaching for it only once you fall ill — gives no consistent effect. It is worth knowing this before you spend money on "horse doses".

The boring things that work best

• Handwashing — most cold viruses enter the body through the hands and face, not through "getting chilled".
• Airing — in closed rooms the concentration of viruses in the air rises; 5 minutes of through-draught several times a day makes a difference.
• Humidifying the air — the heating season dries out mucous membranes (we wrote about this in connection with autumn smog and dust mites in the heating season).
• Cigarettes — smokers get ill more often and for longer; the airways begin to recover in the first weeks after quitting. If you are thinking of breaking the habit, autumn is a good moment — here we describe what anti-smoking therapy looks like at our clinic.
• Stress and overwork — chronic stress weakens the immune response; this is one of the reasons we "collapse" in the first week of a holiday.
• Flu vaccination — this is a decision to make with a doctor, especially for seniors, people with chronic diseases and pregnant women. Naturotherapy does not replace it.

How the AGAMED clinic can accompany you in this

Let us say it plainly: no treatment at our clinic "gives immunity" or replaces sleep, exercise, diet and medical care. What we offer is a complement — for people who want to take care of themselves more broadly.

• Bioresonance health therapies — a series of sessions with the BICOM Optima device, in which one of the aims, according to the assumptions of the method, is to support the body's balance, including in the area of immunity. Bioresonance is a complementary method: painless, non-invasive, drug-free — and without clinical evidence at the level of standard medicine. We tell every client this at the first visit.
• Hydrogen therapy H₂ — inhalation of molecular hydrogen, which we treat as a wellness element. Research on hydrogen as an antioxidant is ongoing; we do not promise health effects, we describe what the treatment involves.
• A conversation — very often what someone needs in autumn is not another treatment, but putting their sleep and habits in order. If that is the case, we will say so.

Important: the content of this post is educational. A fever lasting more than 3 days, shortness of breath, chest pain, severe weakness or infections recurring every few weeks are signs to see a doctor — not to experiment with supplements or treatments.

Frequently asked questions

Does bioresonance strengthen immunity?

Bioresonance is a complementary method. According to the assumptions of the method, a series of sessions is meant to support the body's balance; many of our clients return in autumn for such a series. There are, however, no clinical studies confirming that bioresonance prevents infections, and we do not say otherwise. Sleep, exercise, diet and vaccinations recommended by a doctor are the foundation — a treatment can be an addition.

How much vitamin D should I take in autumn?

The 2023 Polish guidelines for healthy adults without sufficient sun exposure: 1000–2000 IU daily, depending on body weight. Ideally after checking the 25(OH)D level and in consultation with a doctor or pharmacist — especially with chronic diseases or medications.

Does vitamin C protect against a cold?

According to the 2013 Cochrane review — not in the general population. Taking it regularly may shorten a cold by a few percent, but reaching for a large dose only after symptoms appear gives no consistent effect.

When does "weak immunity" require a visit to the doctor?

When infections return every few weeks, last long, come with a high fever, or are accompanied by weight loss, chronic fatigue or enlarged lymph nodes. These are situations for medical diagnostics, not for naturotherapy.

Sources

• Prather A.A. et al., Behaviorally Assessed Sleep and Susceptibility to the Common Cold, Sleep 2015 — pubmed.ncbi.nlm.nih.gov/26118561
• Płudowski P. et al., Guidelines for Preventing and Treating Vitamin D Deficiency: A 2023 Update in Poland, Nutrients 2023
• Nieman D.C. et al., Upper respiratory tract infection is reduced in physically fit and active adults, Br J Sports Med 2011 — pubmed.ncbi.nlm.nih.gov/21041243
• Hemilä H., Chalker E., Vitamin C for preventing and treating the common cold, Cochrane Database Syst Rev 2013 — cochranelibrary.com