Interesting.I fainted after the Manchester Marathon in 2021 (after a bath at home), but put it down to the exertion of the marathon. A month later I fainted again after a 1km uphill run to a club training session. I knew then that something was up, so had tests and they detected low iron, with no obvious cause. I've been on 420mg of ferrous fumarate per day ever since.
I should have realised something was wrong when it took 37 minutes to complete a Parkrun. I just got on with marathon training though. I kind of wished my marathon was without the iron deficiency, because it definitely affected my time.
Symptoms before were lethargy and breathlessness. They disappeared as soon as my iron levels were sorted, and no more fainting episodes.
I'd definitely noticed my energy levels aren't at all what they should be lately, but one factor could be awful sleep.
I've always thought that perhaps I'm iron deficient. Might book something in at the docs.
Any mention of adding more Iron to your diet or is that just not feasible (absorption etc)?