Frequent colds and infections

Also called: Low immune resilience; getting sick often

Relief and prevention Strength

Catching everything going. Moderate regular exercise improves immune surveillance measurably - and both doing nothing and training excessively impair it, which is why the relationship is a J-shaped curve rather than a straight line.

How common: Adults average 2-3 respiratory infections a year; frequent illness is a common complaint

Open the Everyday Immune Support routine All problems

What it is

Regular moderate exercise improves immune function. Each session mobilises immune cells into the circulation and into tissues, improving surveillance, and over time regular training is associated with fewer and shorter upper respiratory infections.

The relationship is not linear. Very high training loads - particularly prolonged, intense endurance work in athletes - are associated with a higher rate of upper respiratory symptoms, which is where the J-shaped curve idea comes from. For most people the relevant end is the sedentary one, where the risk is highest and the improvement easiest.

What it feels like

Picking up every cold that goes around, and taking longer to shake them off
Repeated chest or sinus infections through winter
Feeling run down for weeks at a time
Recovery from minor illness taking longer than it used to
A sense that everyone else gets over it faster

What causes it

Most people have more than one of these at once, and they feed each other. Read the list looking for the two or three that sound like your week rather than for the one true answer — the ones that describe you are the ones worth acting on.

Inactivity: Sedentary people have poorer immune surveillance and more upper respiratory infections than moderately active people. Each bout of exercise mobilises immune cells, and the absence of that is a real deficit.
Excessive training load: Very high volume, particularly prolonged intense endurance work, is associated with more upper respiratory symptoms in athletes. The mechanism is debated but the association is consistent.
Poor and short sleep: One of the most powerful influences on immune function. Sleeping under about six hours substantially raises the likelihood of catching a cold after exposure in controlled studies.
Chronic stress: Sustained cortisol suppresses several aspects of immune function and is consistently associated with more frequent and longer infections.
Low energy availability: Under-eating relative to demand impairs immune function directly. It is one of the reasons athletes in a deficit get ill more often.
Vitamin D deficiency: Common in winter at higher latitudes and associated with respiratory infection risk. Supplementation reduces infections modestly, more so in people who are deficient.
Ageing: Immune function declines with age - immunosenescence - which is part of why infections are more frequent and more serious in older adults. Regular exercise measurably slows that decline.
Smoking: Damages the respiratory lining and its clearance mechanisms, substantially raising respiratory infection risk.
Underlying medical causes: Diabetes, immunosuppressive medication, and rarely primary immunodeficiency all raise infection frequency. Unusually frequent, severe or unusual infections need investigating rather than exercising at.
Exposure: Not everything is immunity. Young children in the household, public transport and crowded workplaces all increase exposure, and more exposure means more infections in anyone.

Who tends to get it

Sedentary people, in whom infection rates are highest
Athletes in very high volume training blocks
Anyone sleeping under about six hours regularly
People under sustained stress or under-eating relative to their training
Older adults, in whom immune function declines with age

What makes it worse, and what settles it

Makes it worse

Doing nothing at all, which is the highest-risk end of the curve
Very high training volumes without adequate recovery
Short sleep, which is one of the strongest single influences
Chronic stress and under-eating
Training hard through an illness with systemic symptoms

Settles it

Regular moderate exercise, which reduces the frequency and duration of upper respiratory infections
Prioritising sleep, which has among the strongest effects on immune function of anything modifiable
Adequate energy and protein intake, particularly for people training hard
Getting vitamin D checked and corrected, particularly through winter
Managing training load with genuine recovery, for those at the high-volume end

What actually helps

The short version: Moderate regular exercise improves immune surveillance; both inactivity and excessive training volume impair it

Strength work: Full Body; moderate resistance training 2-3x/week

Stretching: Full Body

Massage: Professional Massage - for sleep and stress, which affect immunity more than massage does directly

Also worth doing: Sleep, which matters more than any exercise variable here; do not train hard while febrile

What the evidence says: Moderate regular exercise reduces respiratory infection frequency and severity. Very high training loads temporarily increase susceptibility - the relationship is a J-curve, not a straight line.

The names above are the Targets qFIT tracks — the Muscle Guide explains what each one does, and Quick Add switches on the Exercises you already have.

The qFIT routine for this

Ready-made routineEveryday Immune Support

qFIT already has this one built. It runs massage first, then stretching, then strength — the order that works on a body that is already sore — and every activity in it carries the reason it is there.

The button below opens your Checklist with this routine already selected, so instead of your whole list you land on just its Categories, Targets and Exercises, each with its checkbox, ready to tick as you work through them.

Open this routine in my Checklist

Have more than one problem? Tick yours under My Problems on My Profile and your Checklist's Routine list gains Recommended for my problems — every routine for the problems you picked, merged into one. Your picks stay private; that filter is the only thing they feed.

Get it checked if…

Fever with chest symptoms means no exercise. Frequent severe infections, or infections that will not clear, need medical investigation

And whatever the body part: chest pain or unusual breathlessness on exertion; a fever alongside the pain; unexplained weight loss; pain that is constant and unrelated to how you move; new numbness, weakness or loss of bladder or bowel control; or one calf that is swollen, warm and painful. Any of those, stop and get assessed.

How it usually goes

Regular moderate exercise reduces upper respiratory infection frequency and duration, with effects appearing over months of consistent activity. Sleep is at least as powerful a lever and is more often the problem. Unusually frequent, severe, unusual or persistent infections - or infections needing repeated antibiotics - warrant medical investigation rather than a fitness programme, since they can indicate an underlying immune problem.

Prevalence basis: Infectious disease surveillance

This is general information, not a diagnosis, and it cannot examine you. If it matches you, use it to ask better questions of a clinician rather than to replace one.

← All 267 problems 🪯 Muscle Guide