1. Anemia
The fatigue caused by anemia is the result of a lack of red blood cells, which bring oxygen from your lungs to your tissues and cells. You may feel weak and short of breath. Anemia may be caused by an iron or vitamin deficiency, blood loss, internal bleeding, or a chronic disease such as rheumatoid arthritis, cancer, or kidney failure.
Women of childbearing age are especially susceptible to iron deficiency anemia because of blood loss during menstruation and the body’s need for extra iron during pregnancy and breastfeeding, explains Laurence Corash, M.D., adjunct professor of laboratory medicine at the University of California, San Francisco.
Symptoms include feeling tired or fatigued all the time is a major one. Others include extreme weakness, difficulty sleeping, lack of concentration, rapid heartbeat, chest pains, and headache. Simple exercise, such as climbing the stairs or walking short distances, can wipe you out.
A thorough evaluation for anemia includes a physical exam and blood tests, including a complete blood count (CBC), to check the levels of your red blood cells and the hemoglobin in your blood. It’s also standard to check the stool for blood loss.
As far as treatments go, anemia isn’t a disease; it’s a symptom that something else is going on in your body that needs to be resolved. So, treatment will vary depending on the underlying cause of anemia. It may be as simple as eating more iron-rich foods but talk to your doctor about the right treatment for you.
2. Thyroid disease
When your thyroid hormones are out of whack, even everyday activities will have you down for the count. The thyroid gland, about the size of the knot on a suit tie, is found in the front of the neck and produces hormones that control your metabolism. Too much thyroid hormone (hyperthyroidism), and metabolism speeds up. Too little (hypothyroidism), and metabolism slows down.
Hyperthyroidism causes muscle fatigue and weakness, which you may notice first in the thighs. Exercises such as riding a bike or climbing stairs become more difficult. Other thyroid symptoms include unexplained weight loss, feeling warm all the time, increased heart rate, shorter and less frequent menstrual flows, and increased thirst. Hyperthyroidism is most commonly diagnosed in women in their 20s and 30s, but it can occur in older women and men too, says Robert J. McConnell, M.D., co-director of the New York Thyroid Center at Columbia University Medical Center in New York City.
Hypothyroidism causes fatigue, an inability to concentrate, and muscle soreness, even with minor activity. Other symptoms include weight gain due to water retention, feeling cold all the time (even in warmer weather), heavier and more frequent menstrual flows, and constipation. Hypothyroidism is most common in women over age 50; in fact, as many as 10% of women past 50 will have at least mild hypothyroidism, says Dr. McConnell.
Thyroid disease can be detected with a blood test. “Thyroid disorders are so treatable that all people who complain of fatigue and/or muscle weakness should have the test done,” says Dr. McConnell. Thyroid disease treatments vary, but may include medications, surgery, or radioactive iodine.