What should you know about peripheral fatigue?

Fatigue can feel like heaviness, poor concentration, reduced stamina, or a need for more rest. It may follow an infection, disrupted sleep, emotional strain, low fluid intake, or an unbalanced diet. Ongoing fatigue can also occur with anaemia, coeliac disease, chronic kidney disease, burnout, or chronic fatigue syndrome. COVID-19 and alcohol use disorder may affect energy for different reasons. Fatigue alone cannot identify one cause; the pattern and other symptoms matter.

Keep a short record of sleep, meals, fluids, activity, medicines, mood, and when the tiredness improves or worsens. Use a regular sleep routine, eat consistently, and increase activity gently rather than pushing through a severe crash. If fatigue lasts, returns repeatedly, or interferes with work or self-care, book an appointment. A clinician may examine you and choose tests based on your symptoms, such as checks for anaemia, kidney problems, or nutritional issues.

Get urgent help for fatigue with chest pain, severe breathlessness, fainting, new confusion, one-sided weakness, or signs of serious dehydration such as inability to keep fluids down. Seek prompt review for unexplained weight loss, persistent fever, black or bloody stools, or rapidly worsening weakness. Otherwise, arrange routine care when tiredness is persistent or changing your normal activities.

What features of my fatigue point toward a particular cause? Which medicines, sleep problems, or nutritional issues should we review? Do I need blood tests? How can I pace activity while this is being assessed?