Being tired is natural. It is normal to be tired after a busy day at work or exercising. Fatigue is more intense than just being tired. Signs of fatigue are tiredness no matter how much you rest. The majority of people need seven to nine hours of sleep a night.

If you have persistent, crippling fatigue that lasts 6 months or longer, you may have chronic fatigue syndrome.

Those with chronic fatigue syndrome may experience symptoms like:

• Muscle aches
• Difficulty sleeping
• Flu-like symptoms including joint pain and swollen lymph nodes
• Attention and memory problems

While there is no cure for chronic fatigue syndrome, it can be managed with cognitive behavioral therapy and medication like sleep aids.

Itchiness is not usually a complaint with a cold, but it is the hallmark of an allergy problem. Coughing, wheezing, difficulty breathing, and other respiratory symptoms. Recurrent red, itchy, dry, sometime scaly rashes in the creases of the skin, wrists, and ankles also may indicate an allergy.

• Hormone imbalances
• Anemia (iron deficiency)
• Sleep apnea (disorder where your breathing is interrupted during sleep)
• Pregnancy (especially in the first trimester, progesterone is produced which can cause you to feel tired)
• Diabetes
• Depression
• Adrenal insufficiency
• Underactive thyroid (hypothyroidism)
• Chronic kidney disease
• Bacterial or viral infection (if your body is fighting an infection or straining your immune system)
• Nutritional deficiencies (a deficiency in vitamin B12 or vitamin D, specifically)

Jet lag, also called jet lag disorder, is a temporary sleep problem that can affect anyone who quickly travels across multiple time zones. Your body has its own internal clock (circadian rhythms) that signals your body when to say awake and when to sleep. Jet lag occurs because your body’s clock is still synced to your original time zone, instead of to the time zone where you’ve traveled. The more time zones crossed, the more likely you are to experience jet lag.