This page is about what happens to your lungs when you exercise, and why exercise can help you.
The amount of air you need to breathe in depends on how active you are.
When you are sitting down you only take in about 15 breaths a minute, giving you around 12 litres of air (a litre is one and three-quarter pints). From this your lungs will extract just one fifth of a litre of oxygen.
During exercise your breathing and heart rate increase. Exercising flat out, a top-class athlete can expect to increase his or her breathing rate to around 40 to 60 breaths a minute. This means they take in an incredible 100 to 150 litres of air, extracting around five litres of oxygen every single minute.
Even those of us with more modest goals need to double our lung intake when we exercise. Our lungs must be able to respond to our body's increased demands for oxygen.
What happens when you exercise?
As you start to move about, the muscles in your body send messages to your brain that they need more oxygen. Your brain then sends signals to the muscles that control breathing - your diaphragm and the muscles between your ribs - so that they shorten and relax more often. This causes you to take more breaths.
More oxygen will be absorbed from your lungs and carried to the muscles you are using to exercise - mainly your arms and legs.
Why do muscles need more oxygen?
For you to become more active your muscles will need to produce more energy. They do this by breaking down glucose from your food, but to do this they need oxygen. If there is too little oxygen they will try to produce energy in a different way. But this can lead to a build-up of a chemical called lactic acid, which causes cramp - something that many athletes are all too familiar with.
Athletes train so that their lungs and muscles become more efficient and it takes longer for lactic acid to build up. This means that their muscles can work harder. In fact, everyone can benefit from exercise to strengthen their lungs and muscles.
What happens when your lungs don't work properly?
People with long-term lung problems such as COPD (chronic obstructive pulmonary disease) may find their lungs unable to provide enough oxygen for their muscles to perform even simple activities. When walking short distances their lungs may struggle to keep up, which causes breathlessness.
Through exercise you can train your body so that more oxygen is delivered to your muscles.
Unfortunately, many people with long-term lung problems are afraid to exercise. This is partly because they are worried that being breathless may be harming them. This isn't true. By gradually building up the exercise you take, you can help to improve your breathing and feel better.
People with severe lung problems benefit a lot from even small amounts of exercise, so it really is worth keeping as active as possible.
Begin slowly by doing arm and leg movements while you are sitting down. Then set yourself targets for walking about: from room to room, going to the front door, the bottom of the garden, down the road and so on. It's surprising how quickly you'll be able to do more.
Find out more about how to get active
Breathing control techniques are not suitable for everyone with COPD. Please check with your health professional whether you should use them.
Breathing control concentrates on using the lower chest with relaxation of the upper chest and shoulders. This encourages you to use the diaphragm more efficiently. Concentrate on allowing your abdomen (tummy) to move out as you breathe in, rather than allowing it to be sucked inwards. Practice breathing control with one hand on your abdomen.
Breathing control will help slow down your breathing rate and will reduce any anxiety if you do become breathless.
Discuss with your GP or chest specialist the possibility of being referred to a physiotherapist to help teach you breathing control and breathing exercises.
Can extra oxygen help you exercise?
Some people with chronic lung disease can exercise more if they receive extra oxygen. However, not everyone can benefit, so it is very important to be assessed by your health professional before receiving treatment.