The immune system is our first line of defence against illnesses and infections. If you have ever wondered how to strengthen it or improve your natural defences, this guide will help you understand which practical steps you can take, supported by scientific evidence.

Understanding our immune system

Our immune system is a complex network of cells, tissues and organs that work together to protect us from pathogens such as viruses and bacteria. It functions like a highly specialised army, identifying and fighting potential threats to keep our bodies healthy.

Strategies to strengthen your natural defences

Smart nutrition

Diet plays a fundamental role in supporting our immune system. Key nutrients include:

Vitamin C, found in citrus fruits, peppers and broccoli, contributes to the production of white blood cells. However, there is no need to consume very high doses; one orange or kiwi a day may provide the necessary amount.

Vitamin D, which can be obtained through moderate sun exposure—around 10 to 15 minutes a day—and by eating oily fish such as salmon, is essential for optimal immune function.

Probiotics, found in fermented foods such as natural yoghurt and kefir, support a healthy gut microbiome, which is closely linked to our immune defences.

Regular physical activity

Moderate exercise supports the immune system in several ways:

• It improves blood circulation, allowing immune cells to move around the body more efficiently.
• It reduces chronic inflammation.
• It helps remove bacteria from the respiratory tract.

Physical activity is essential for strengthening the body’s natural defences, but its intensity and type should be adapted to each person’s needs, abilities and age. Rather than following a single general formula, it is better to consider age-specific recommendations.

For children and adolescents aged 5 to 17, it is advisable to complete at least one hour of moderate-to-vigorous physical activity every day. This should include aerobic exercise and activities that strengthen muscles and bones at least three times a week, such as running, jumping or playing team sports.

For adults aged 18 to 64, between two and five hours of moderate aerobic exercise per week is recommended, or between one and two hours of moderate-to-vigorous activity. This should be combined with muscle-strengthening exercises at least twice a week. Suitable activities may include brisk walking, swimming, yoga and strength training.

Adults aged 65 and over should aim to complete at least two hours of moderate aerobic activity per week. It is also important to include balance and muscle-strengthening exercises three times a week to help prevent falls and maintain mobility.

A balanced and personalised approach maximises the benefits of exercise for the immune system while reducing the risks associated with physical inactivity. It allows each person to work towards the best possible level of physical well-being.

Restorative sleep

While we sleep, our bodies produce and distribute essential immune cells. Adults generally need between seven and nine hours of quality sleep each night. To improve your sleep:

• Maintain a regular sleep schedule.
• Keep your bedroom dark and cool.
• Avoid screens for at least one hour before going to bed.
• Limit caffeine consumption after midday.

Stress management

Chronic stress can significantly weaken the immune system. Effective strategies for managing stress include:

• Practising mindful breathing or meditation.
• Exercising regularly.
• Maintaining meaningful social connections.
• Making time for enjoyable activities.

Proper hydration

Water is essential for the optimal functioning of our immune system. It helps to:

• Produce lymph, the fluid that transports immune cells around the body.
• Remove toxins.
• Keep the mucous membranes moist, supporting one of our first barriers against pathogens.

What can weaken our immune system?

Certain habits can weaken the immune system:

• Smoking directly damages the body’s natural defences and increases the risk of infection.
• Excessive alcohol consumption can interfere with the production of immune cells.
• Consuming large amounts of refined sugar may suppress the immune response.
• Chronic sleep deprivation reduces the production of protective immune cells.

Signs of a weakened immune system

Pay attention to signs such as:

• Frequent infections.
• Wounds that take a long time to heal.
• Persistent fatigue.
• Frequent digestive problems.

If you experience these symptoms repeatedly, it is important to consult a healthcare professional.

Strengthening the immune system does not require extreme measures or expensive supplements. The most effective strategies are those that form part of a healthy lifestyle: a balanced diet, regular exercise, sufficient rest and effective stress management.

Remember that sustainable and moderate changes are more effective than drastic short-term measures. Introduce these habits gradually and remain consistent to achieve long-lasting benefits for your immune health.