When a person feels faint, it means there is an inadequate flow of blood to the brain temporarily according to the Mayo Clinic. Feeling faint can be caused by many things including stress and anxiety.
Other reasons that can cause a person to feel faint include allergies, the flu, a cold, shortness of breath and substance abuse as stated by WebMD. Since the causes can range from minor to severe, repeated bouts of fainting should be reported to a doctor. To relieve faintness or lightheaded feelings, a person can sit or lie down. Placing the head between the knees also helps in some instances.