COPD

What it is

COPD limits airflow out of the lungs, producing breathlessness on exertion that worsens over years. What is less well known is that the muscles are as much of the problem: quadriceps strength in COPD predicts survival better than lung function does.

Muscle dysfunction develops from inactivity, systemic inflammation, low oxygen, steroids and poor nutrition. That is why pulmonary rehabilitation - supervised exercise plus education - produces improvements in breathlessness, exercise capacity and quality of life larger than any drug, without changing lung function at all.

What it feels like

• Breathlessness on exertion, progressively at lower levels of activity
• A chronic cough, often with sputum
• Wheeze and chest tightness
• Exhaustion, and legs that give out as much as the breathing does
• A spiral of doing less because it is breathless, and becoming breathless doing less

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.

Airflow limitation

Damaged airways and lost lung elasticity make it hard to get air out, so the lungs stay partly inflated. That hyperinflation is a major cause of the sensation of breathlessness.

Peripheral muscle dysfunction

Muscle mass, oxidative capacity and strength are all reduced. Quadriceps strength predicts survival better than lung function does, which tells you how central it is.

The inactivity spiral

Breathlessness leads to less activity, which produces weaker muscles, which means more breathlessness for the same task. This loop drives most of the progressive disability.

Smoking

The dominant cause in most cases, and stopping remains the only intervention that slows the decline in lung function.

Systemic inflammation

COPD is not confined to the lungs. Circulating inflammatory markers drive muscle wasting, and they are part of why weight loss and muscle loss are common in advanced disease.

Corticosteroids

Repeated courses for exacerbations cause muscle wasting and bone loss, compounding the muscle problem.

Poor nutrition and low body weight

Eating is effortful when breathless and energy expenditure is raised. Low body weight in COPD is associated with worse outcomes.

Air pollution and occupational exposure

Dusts, fumes and biomass smoke are significant causes, particularly in non-smokers and in lower-income settings.

Alpha-1 antitrypsin deficiency

A genetic cause producing COPD at a younger age, often in non-smokers. It is worth testing for in early-onset disease.

Fear of breathlessness

Breathlessness is frightening, and avoiding it is the natural response. It is also the response that drives the spiral, which is why the education part of pulmonary rehabilitation matters as much as the exercise.

Who tends to get it

• Current and former smokers, which is the majority
• Anyone with occupational dust or fume exposure
• People exposed to biomass smoke indoors
• Anyone with alpha-1 antitrypsin deficiency
• Older adults, in whom prevalence rises steeply

What makes it worse, and what settles it

No ready-made routine for this one yet

249 of the 267 problems here have a routine already built, and this is not one of them — usually because the work that helps is covered by a general routine rather than needing its own. What actually helps above names the muscles and the work involved, which is enough to put it together yourself.

Get it checked if…

Increasing breathlessness, fever or colored sputum suggests exacerbation - medical review before exercising

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

Pulmonary rehabilitation produces substantial improvements over six to twelve weeks and the benefits fade over months without ongoing exercise, which makes maintenance the key. Lung function itself does not improve - the gains come from the muscles, the breathing pattern and confidence, which is why it works despite the diagnosis. It is one of the most effective and most under-used treatments in respiratory medicine, and it is worth asking for a referral rather than waiting.

Prevalence basis: Respiratory epidemiology

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.