Brief Answer:
investigation is required

Detailed Answer:
Hello,

faintness-dizziness can be caused by numerous disorders. I'll mention some of the most common ones. Please provide additional clues as suggested below.
- hypotension: measuring your blood pressure would be helpful to exclude that. It could be a drug side effect (if you take any).
- arrhythmia: usually also causes palpitations.
- vestibular disorders: may cause dizziness with spinning sensation, accompanied by nausea, vomiting and tinnitus.
- anemia: a low hematocrit may cause faintness, particularly during physical exertion.
- side effects: some drugs may cause dizziness and faintness. Please check the drugs' SPC or tell me which drugs you take (if you do) and I'll let you know if they're suspicious.
- blood loss: usually originating from the gastrointestinal tract (peptic ulcer, diverticula, etc). Black tarry stool or blood in the stool are clues to gastrointestinal bleeding.
- dehydration: loss of water without adequate water intake may cause dehydration. This is particularly common in the elderly and among patients who use diuretics or are bed-ridden.

If you'd like to provide any additional detail, particularly those mentioned in my analysis, I would be glad to comment more on your case.

I hope you find my answer helpful!
Please contact me, if you'd like further details or guidance.

Kind Regards!

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