Sudden anxiety can result from everyday situations or recurring problems. In severe cases it can lead to heart palpitations, shortness of breath, stomach aches, chest pain, nausea or dizziness. Fainting can also occur, due to increased blood pressure and blood flow. A person may feel overcome by a feeling of terror or fear. Symptoms that come on suddenly are often referred to as anxiety or panic attacks. People who experience them frequently have panic disorder, according to the Anxiety Panic Attack Resource Site.
The body has a natural fight-or-flight response inherited from our ancestors, who had to flee or attack when seeing a beast while hunting for food. Similar feelings are felt today when you see something that alarms you. Your heart rate and breathing speeds up as you prepare for the situation, the Mayo Clinic explains. These feelings may occur to people who suffer from panic attacks from various situations. But sudden anxiety can also result from seeing a stranger on a dark lonely street or something as simple as being called unexpectedly into the office.
Students and adults hoping to further their careers may be suddenly overwhelmed by sudden anxiety in the moments before taking an important test. Causes may include lack of preparation, poor study habits, poor time management or cramming the night before, according to the University at Buffalo, New York, Counseling Services. But even people who are well prepared may have worries about past performance on tests, how other students are doing or what will happen if they fail.
People who are fired or laid off can develop sudden anxiety similar to the fight-or-flight response. They may be overcome with fear about what the future holds and what will happen to them and their families. Their anxiety can be so strong it can harm their physical health, it was reported in the May 2009 issue of "Demography." Even people who were reemployed after losing a job had an increased risk of developing health conditions, according to Kate Strully, a sociologist at State University of New York in Albany.
Sudden anxiety can happen to people who have had previous bad experiences in certain situations. People with panic disorders, for example, may have panic attacks if they need to get onto an elevator, because they have developed a fear from a past experience, according to the Anxiety Panic Attack Resource Site. Post-traumatic stress disorder causes panic attacks in people who are reminded of violent, disturbing or abusive events in the past.