Your breathing difficulty could be a laughing matter -- at least indirectly. Do you often find it difficult to take a deep breath? Do you feel as though you cannot 'catch' your breath? It might feel like 'air hunger' or a sensation of not having enough air. These are common symptoms of a disorder called chronic hyperventilation, or hyperventilation syndrome. One of the things that laughing makes us do is hyperventilate. It is unlikely that laughing is the cause of your breathing troubles, but it might make your symptoms worse.
Chronic hyperventilation occurs when the amount you breathe is greater than what your body actually needs to meet its metabolic demands. No one is entirely certain why this occurs, but some people seem to have a predisposition to over-breathing. It usually starts (or becomes symptomatic) after a traumatic event or when life itself has been very stressful. One of the first signs is a breathing difficulty; like feeling unable to take a deep breath.
If this is a sensation you are familiar with and it is with you much of the time, you may have acquired a disordered breathing pattern. Instead of breathing quietly at rest using your diaphragm, which is the main muscle of restful breathing, people with chronic hyperventilation tend to use their upper chest to breathe. Normal restful breathing goes like this; breathe in and the tummy rises up (the diaphragm descends and this makes your tummy swell outwards); breathe out and the tummy relaxes back down. If you have the opposite breathing pattern; your tummy sucks in when you breathe in; or your tummy barely moves at all when you breathe in but your upper chest rises up, then you have a disordered breathing pattern. You will likely experience this as a breathing difficulty; specifically, a difficulty with breathing in.
You may notice this most when you are under pressure, worried or anxious. Because you tend to breathe with your upper chest, your neck and shoulder muscles are working all the time. They are being overworked because they are helping you breathe. Although one of the functions of your neck and shoulder muscles is to assist with respiration (breathing), they are really only designed to be recruited for this purpose under conditions of peak demand -- in emergencies or when you are working so hard you need a lot of additional air. You may not look or feel like you are breathing heavily, unless you really focus on the parts of your body that move when you breathe.
Upper chest breathers also have a tendency not to empty their lungs properly on the out-breath. The lungs are supposed to retain some air in them after a breath out, but people who do not diaphragmatically breathe well, which includes people with asthma, tend to have more air left in the lungs after a breath out than is considered normal. The term for this is hyperinflation and it is often progressive which means the lungs have more and more air left in them with each consecutive out-breath.
If this is how you unknowingly breathe, day in and day out, what happens when you really do need to take a bigger breath? Because you already have tension in the upper chest and abdominal area, and your lungs are already partially filled, you experience this need to take a deeper breath as an inability to do so. It is a problem of body mechanics as well as physiology. If you try to pack more air into a balloon that is already filled with air, the balloon would feel this as tension and resistance. You are experiencing the same sensations the balloon would feel. "No more air please, I already have enough and my chest walls cannot accommodate any more."
Chronic hyperventilation is not uncommon - it affects 6-10% of the population - but it is commonly misdiagnosed. This is because the symptoms are not well defined, they vary between people, and they are easily confused with other disorders. For example, common chronic hyperventilation symptoms like dizziness and chest pain can be mistaken for heart problems. If you have a breathing difficulty your doctor will want to rule out these other causes. If tests do not reveal any other cause for your distress then it is highly likely you have a breathing pattern disorder called hyperventilation syndrome.
Treatment for hyperventilation syndrome involves learning to breathe less and to relearn a healthy, diaphragmatic breathing pattern. This is not always easy because your brain has adapted to over-breathing and it will try to maintain the status quo - even when changing things is the better option. But with good coaching and regular practice you can overcome your body's resistance and start to breathe freely again.