Feeling tired now and then is completely normal, and it's usually down to poor sleep, stress, an unusually busy period, or simply not getting enough downtime. Improving sleep habits, eating regular meals, staying active and cutting back on alcohol and caffeine are sensible first steps for most people.
If tiredness is severe, has dragged on for several weeks even with decent sleep, or comes with other symptoms like unexplained weight change, breathlessness or low mood, it's worth a GP visit - persistent fatigue can occasionally point to something like anaemia, an underactive thyroid, or a mental health condition, all of which respond well to treatment once identified.
See also our pages on sleeping problems and energy.
Common questions
What's usually behind ordinary, everyday tiredness?
Poor sleep, stress, an especially busy stretch, or simply not enough time to rest and recharge.
When does ongoing tiredness need a GP's attention?
If it is severe, has lasted several weeks despite good sleep, or comes with other symptoms such as unexplained weight change or breathlessness.