What Are the Causes of Being Tired?

People that only feel tired at night get sleepy because of a natural hormone called melatonin. Being consistently tired during the day is known as chronic fatigue and may not just be a result of your laziness to get off the couch and exercise. Sometimes chronic fatigue is a symptom of serious underlying conditions like hypothyroidism and sleep apnea.

Hypothyroidism

• Doctors use blood tests to test for hypothyroidism.

  People with hypothyroidism have thyroids that do not produce enough thyroid hormones, according to the Mayo Clinic. Thyroxine and triiodothyronine are the two types of hormones secreted by the thyroid gland. Inflammation of the thyroid gland is the most common cause of hypothyroidism, according to Medline Plus. Symptoms of hypothyroidism include fatigue, decreased hearing, weight gain, dry skin and sensitivity to cold, according to the University of California, San Francisco, Medical Center. Women are 10 times more likely than men to get hypothyroidism, according to the University of Maryland Medical Center. And according to The New York Times, approximately 15 million Americans have an undiagnosed thyroid disease.

High Caffeine Intake

• Think twice before consuming seven cups of coffee throughout your workday.

  Most people associate caffeine with high energy levels, but taking too much can have the opposite effect, according to the Journal of Adolescent Health.

Melatonin

• Melatonin production is stimulated by dimly lit environments at night.

  Melatonin is a hormone produced by the pineal grand in the brain, according to the Mayo Clinic. Melatonin regulates the circadian rhythm otherwise known as the sleep wake cycle, according to the University of Maryland Medical Center. Melatonin is usually produced around 8:00 p.m., which is what makes people tired at night. Exposure to bright lights at night can decrease melatonin production. Taking melatonin supplements can help promote healthy sleep patterns, according to the Journal of Neuroendocrinology.

Alcohol Withdrawal

• Heavy drinkers are at risk for liver failure.

  Rapid alcohol withdrawal by heavy drinkers can cause excessive daytime fatigue, according to the Health Services at Columbia University. Most people that undergo severe alcohol withdrawal achieve full recovery, according to Medline Plus. Alcohol may interfere with the sleep wake cycle, according to a study by the National Institute on Alcohol Abuse and Alcoholism. Heavy drinkers should consult their doctor about quitting slowly instead of stopping abruptly.

Obesity

• Losing weight helps increase energy levels.

  Obesity or just being overweight can lead to chronic fatigue, according to the New York Academy of Sciences. Severely obese individuals experience chronic fatigue because of the added stress imposed on their body and heart by their weight, according to the University of Maryland Medical Center. Being overweight makes it significantly harder for the heart to pump blood throughout the body.

Sleep Apnea

• Sleep apnea is a disorder where a person stops breathing for short periods of time at night, according to the University of Maryland Medical Center. Sleep apnea can cause daytime fatigue and increases the risk for heart disease.