Your thyroid is in charge of releasing thyroid hormones (duh), and controlling your metabolism. If your thyroid gland is under-producing, that could lead to weight gain and a total lack of energy, among other symptoms. "Hypothyroidism, or low thyroid function, is a common and under-diagnosed cause of fatigue," says Dr. Jennifer Haythe, cardiologist and assistant professor of medicine at Columbia University Medical Center. "Constipation, dry skin, weight gain, thinning hair, and depression are just some of the other side effects of an underactive thyroid."
If you're experiencing these symptoms, check with your doctor, who will perform a simple blood test to be sure. Treatment usually includes medication.
Diabetics don't process glucose properly, which is a major problem since glucose is the body's main source of fuel. "As a result, circulating blood sugar levels are high, resulting in excessive urination, dehydration, blurry vision, and thirst. This leads to fatigue and exhaustion," Dr. Haythe says. Diabetes affects more than 29 million Americans -- 8 million of whom go undiagnosed.
Type 2 diabetes is usually caused by a mix of genetics and lifestyle, and although the stereotype of a diabetic is an obese person guzzling soda all day, skinny people can get it, too. If you experience any of the symptoms listed above, have your doctor run blood tests to confirm.
Millions of Americans have depression, and one of its many effects can be feeling tired all the time. "Depression is a common cause of fatigue and low energy," Dr. Haythe says. "Depression can take on many forms. For some, excessive sleep, fatigue, and an inability to get out of bed is common."
Depression is more than just feeling sad; if you feel like you have no energy to get out of bed in the morning and face your day, and find yourself sleeping for hours on end, Dr. Haythe adds, make sure you seek professional help from your doctor or a psychiatrist.
Chronic Fatigue Syndrome
Chronic Fatigue Syndrome is exactly what it sounds like -- people who are always exhausted, to the point where they can't carry on with their everyday lives. Although doctors recognize this is a problematic condition, it's still mysterious, and there are no tests available to confirm its existence.
"A variety of abnormalities have been found in people with CFS, but none sufficiently consistent to help us understand the cause," Dr. Swartzberg says. "Without knowing the cause(s) or what the precise abnormalities are, we don’t know why people with this syndrome have such profound fatigue." Although it goes by other names -- myalgic encephalomyelitis (ME) and systemic exertion intolerance disease (SEID) -- they're all just as baffling and can't be medically explained. But that shouldn't stop you from trying to seek treatment; talk to your doctor to see if your symptoms fit the CFS criteria, and to work out an effective treatment plan.
Usually having a dip in energy or feeling sleepy one day isn't a huge deal; you could have a cold coming on, or maybe you drank too many beers the night before. But if it's a persistent problem, or something that interferes with your daily life and responsibilities, make sure you seek professional help.