September 2026

I Keep Getting Sick or Rundown: Stress, Under-Eating and Immunity

There's a particular kind of frustration in catching yet another cold while everyone around you seems fine, or feeling permanently a bit run-down without ever quite tipping into "properly sick." If this has become a pattern rather than a one-off unlucky stretch, it's worth looking at what's been happening with your stress levels and eating rather than assuming it's just bad luck with germs.

The stress-immunity connection

Your immune system and your stress response are closely linked, not separate systems working in isolation. Short bursts of stress can actually give immune function a brief boost, useful in a genuine emergency. Chronic, ongoing stress works differently: sustained elevated cortisol gradually suppresses immune function, making you more susceptible to infections and slower to recover from them. This is a well-established area of research, not a loose wellness claim, the relationship between prolonged stress and reduced immune resilience is one of the more consistently replicated findings in the field.

Why under-eating compounds the problem

Immune function requires energy and specific nutrients, protein, zinc, vitamin C, vitamin D, and iron among them, to actually produce and maintain the cells involved in fighting off infection. Chronic under-eating, whether from a deliberate deficit, a busy schedule squeezing out proper meals, or simply not having much appetite during a stressful period, removes the raw materials immune function depends on, right when the stress response is already placing extra demand on the body.

Other common contributors

Poor sleep is a big one, it's when a significant amount of immune system repair and regulation happens, and chronic short or poor-quality sleep is one of the most consistent predictors of increased susceptibility to illness. Overtraining without adequate recovery can have a similar effect, temporarily suppressing immune function, a pattern sometimes seen in people training hard while also under other forms of stress. Low vitamin D plays a role too, since it's genuinely involved in immune regulation, and deficiency is common, particularly for people spending most of their time indoors. And it's worth acknowledging constant low-grade exposure as its own factor, young children in the house, frequent air travel, shared workspaces all genuinely increase exposure regardless of how well your immune system is functioning, rather than it always being about immunity itself.

What tends to help

Start by addressing chronic stress directly rather than treating it as background noise, this might mean genuinely reducing commitments, building in recovery time, or seeking support for an ongoing stressful situation rather than assuming it will resolve on its own. Eating enough, consistently, matters just as much, particularly protein and a reasonable variety of fruits and vegetables, since under-eating during a stressful period is common and tends to make things worse rather than better.

Sleep deserves the same priority as any other health intervention, given it's one of the most powerful, evidence-backed levers available for immune resilience, and it's worth checking your vitamin D status with your doctor too, particularly heading into the colder months or if you spend most of your time indoors. Finally, build in genuine recovery, whether that's from training, work, or general life demands, chronic depletion without recovery is a pattern immune function doesn't tolerate well long-term.

When to see a doctor

If you're getting sick unusually often, taking a long time to recover, or experiencing symptoms alongside persistent fatigue or other changes, it's worth discussing with your doctor rather than assuming it's simply bad luck, there may be underlying factors worth investigating properly.

The bottom line

Getting sick often or feeling permanently run-down is frequently a sign that chronic stress and inadequate nutrition have been quietly wearing down immune resilience, rather than simply catching more germs than everyone else. Addressing stress, sleep, and eating consistency together tends to make a real difference over time.

This article is general health information only and is not medical advice, and does not diagnose, treat, cure or prevent any disease. If illness is frequent or prolonged, speak with your doctor.