The best warm up to protect your airways before exercise

When you exercise hard, you breathe faster and deeper, and often through your mouth. That moves large volumes of air past your airways, drying and cooling them. In people prone to it, this dehydration of the airway lining triggers the release of inflammatory substances that make the airway muscles tighten. The result is the classic picture: coughing, wheezing, chest tightness, and breathlessness, usually peaking a few minutes after you stop rather than during the effort itself.

This is exercise-induced bronchoconstriction. It is very common in people with asthma, and it can also occur in people who do not have a general asthma diagnosis, including athletes. It is real, it is measurable, and it responds to the right preparation. Understanding the cause, drying and cooling of the airways, is what makes the fixes make sense.

Here is the part that surprises people. If you provoke a small, controlled airway response with a warm-up before your main session, your airways often become much less reactive for a while afterwards. This protected window is called the refractory period, and it can last up to around two hours. During it, the same exercise that would normally set off your symptoms causes far less trouble.

This is well recognised in clinical guidance. The official American Thoracic Society clinical practice guideline on exercise-induced bronchoconstriction recommends an interval or combination warm-up before exercise as one of the non-drug strategies that can reduce symptoms. It is not a folk remedy. It is a documented, guideline-backed tool.

Not all warm-ups are equal here. A systematic review of pre-exercise routines found that warm-ups involving higher intensity or variable, interval-style efforts were the most effective at reducing the drop in lung function that comes with exercise. Gentle, low-intensity continuous warm-ups were less reliable. In other words, a slow easy jog on its own may not be enough to open the protected window.

The practical version is a build-up that includes some short, brisker bursts, done well before your main effort so you have time to recover into the refractory window. Keep it controlled and stop if symptoms flare rather than pushing into a full attack.

1. Start easy for a few minutes. Begin with light movement to raise your heart rate gently and get your breathing going.
2. Add short, brisker bursts. Include several short efforts of around 30 seconds at a harder pace, with easy recovery between them. This variable, interval-style build-up is what the evidence favours.
3. Ease back down. Finish the warm-up with a few easy minutes so you settle into the calmer window before your main session.
4. Then begin your workout. Aim to start the main effort within the protected window rather than sitting around for a long time afterwards.

Because EIB is driven by the airways drying and cooling, the air around you matters as much as the effort. Cold, dry air is the classic trigger, which is why winter running and ice-rink sports are common culprits. A few simple choices reduce the load on your airways.

Breathe through your nose when you can

Your nose warms and humidifies air before it reaches your lungs. At easy and moderate intensities, favouring nasal breathing delivers gentler air to your airways than gulping it through your mouth.

Cover your mouth in the cold

A scarf, buff, or specialised mask over your nose and mouth traps some warmth and moisture, softening cold dry air before you breathe it in. It is a small change that many people find makes a real difference in winter.

Pick your setting when you can

Warmer, more humid environments are easier on reactive airways. Swimming is often well tolerated for this reason, though heavily chlorinated pools bother some people. If cold air is your trigger, an indoor session on a bad day is a sensible swap.

A warm-up is a helpful layer, not a treatment plan. For most people with EIB, the foundation is the medication and asthma action plan their doctor has set, and exercise should be built on top of that, not instead of it. The aim is to be active and enjoy it, which is entirely realistic for the great majority of people with well-managed asthma.

Always carry your reliever inhaler and know your asthma action plan. Many people are advised to use a prescribed inhaler shortly before exercise; that is a decision for you and your doctor, and the warm-up sits alongside it. Stop and use your reliever as instructed if symptoms come on, and seek urgent help for severe breathlessness, a reliever that is not working, or difficulty speaking in full sentences.