Poor sleep
Anxiety
Depression
Viral infection
Anaemia
Hypothyroidism
Diabetes Mellitus
Drugs
Malignancy
Hemochromatosis
HIV
Hepatitis
Cardiomyopathy
Cardiac arrhythmias
Recreation drug/ alcohol use
End organ failure such as renal failure
Obstructive sleep apnea
Cushing’s syndrome
Addison disease
Coeliac disease
Fibromyalgia
Menopause
Pregnancy