The asthma symptom that you experience is going to largely depend on the type you have and what you are doing when it strikes. Many individuals find that it hits most when they are exercising with some intensity and if it occurs then, they need to abruptly stop exercise in order to seek treatment.
In general when an attack happens the asthma symptom that will be most present is a tightening in the chest type of feeling. What is virtually happening here is the muscles around the neck are tightening and causing the airways to become swollen and inflamed. A thick mucus may also be produced in large volumes that are not otherwise seen.
Another big asthma symptom that is often seen is a wheezing or severe coughing that won't stop. The individual will likely have a great deal of trouble getting air into and out of the body and may also experience a great deal of chest pressure. Their neck muscles may start to tighten and feelings of panic will set in. Overall an attack is a very traumatic experience and is scary for not only the person experiencing it, but those who are around as well. If they do not get help quickly, their lips could turn blue and their face will likely get pale and sweaty.
This would describe a more severe attack however and generally speaking, most are less intense. They may not come on for quite a while and then when a trigger is seen, progress almost instantly. This is why it is incredibly important that those who have this condition keep treatment methods with them (usually an inhaler) at all times.
Some times there are some warning signs that an attack is on the way. These would include difficulties concentrating, trouble sleeping, a persistent cough, feelings of anxiety or increased breathing rate. If you notice any of these occurring, they you should definitely be taking precaution. It is great if you can recognize the warning signs because then you can hopefully prevent a full-blown attack and save yourself much suffering.