Stress is often treated as a mental health issue, but its effects ripple far beyond the brain. When stress becomes chronic, it can disrupt immune function, making the body less efficient at fighting infections and recovering from illness.
“Stress triggers biological changes that were meant for short-term survival, not long-term exposure,” says Dr. Aaron Malik, an immunology researcher.
WHAT HAPPENS INSIDE THE BODY
Under stress, the body releases hormones such as cortisol and adrenaline. In brief bursts, these hormones are protective. Over time, however, elevated cortisol levels can suppress immune responses and increase systemic inflammation.
“Chronic cortisol exposure reduces the activity of white blood cells,” Dr. Malik explains. “That weakens the body’s first line of defense.”
WHY YOU GET SICK MORE OFTEN WHEN STRESSED
Research consistently shows that people under prolonged stress are more susceptible to colds, flu, and slower wound healing. Stress can also worsen existing conditions such as asthma, autoimmune disorders, and digestive problems.
“Stress doesn’t cause disease directly,” says Dr. Malik. “It creates the conditions where disease is more likely to take hold.”
SLEEP LOSS MAKES IT WORSE
Stress and poor sleep often form a feedback loop. Stress disrupts sleep, and lack of sleep further impairs immune function.
“Even a few nights of inadequate sleep can reduce antibody production,” Dr. Malik notes. “That’s a serious issue during cold and flu season.”
HOW TO PROTECT YOUR IMMUNE SYSTEM
Experts recommend focusing on habits that calm the nervous system and support recovery:
- Prioritise consistent sleep schedules
- Engage in regular physical activity
- Practice stress-reduction techniques such as meditation or breathing exercises
- Maintain social connections
- Eat nutrient-dense, minimally processed foods
“Managing stress isn’t optional, it’s preventive healthcare,” Dr. Malik says.
WHEN TO TAKE STRESS SERIOUSLY
Occasional stress is unavoidable. Persistent stress that affects sleep, appetite, immunity, or mood may require professional support.
“If stress is constant, the immune system never gets a chance to reset,” Dr. Malik explains. “That’s when long-term health consequences emerge.”
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