There can be many reasons why a person can feel weak and light-headed. Most of these can be treated quickly and aren't serious; however, sometimes these symptoms can signal a more serious condition. Treatment will depend on the reason for these symptoms. Always seek medical treatment if someone becomes unconscious.

Hypoglycemia

Hypoglycemia is the medical terms used to describe low blood sugar. According to the MayoClinic.com, hypoglycemia most often occurs in people with diabetes. Signs and symptoms include weakness, light-headedness, double or blurred vision, confusion, unconsciousness, anxiety, sweating and hunger. Treatment includes consuming high-sugar foods that will raise blood sugar levels or taking prescribed medications for diabetes. Diabetics should follow their doctor's instructions on how to prevent hypoglycemia. For those who do not have diabetes, consuming small, frequent meals throughout the day can help prevent hypoglycemia. If the condition does not improve, medical attention may be needed.

Anemia

Anemia occurs when there are not enough red blood cells in the body. According to Medline Plus, red blood cells are made in the bone marrow and contain hemoglobin, the protein that carries oxygen to the blood, making the blood red. Signs and symptoms of anemia include light-headedness, headaches, fatigue, chest pain, constipation, shortness of breath and difficulty concentrating. Anemia can be caused by pregnancy, poor diet, large amounts of blood loss, some medications, cancer and kidney failure. Treatment will depend on the cause of the anemia, but generally consists of supplements of iron, B-12 vitamin, folic acid, corticosteroids and sometimes blood transfusions.

Anxiety Disorder

Each year, 40 million Americans are affected by an anxiety disorder, reports The National Institute for Mental Health. Anxiety disorders last at least six months and may require medical treatment or therapy. Anxiety disorders include panic disorder, obsessive-compulsive disorder, post-traumatic stress disorder, social phobia and others. According to the MayoClinic.com, signs and symptoms can include excessive worrying, feeling restless, fatigue, trouble concentrating, muscle aches, shortness of breath, nausea, vomiting, diarrhea and light-headedness. Most treatments include psychotherapy to talk about the issues causing stress, and an antidepressant or an anti-anxiety medication.