Dr,can a below range haemoglobin level,below range hct %, cause dizziness, palpitations when walking fast, drowsiness and weakness during activities. blood test hgb 12.3 l while normal range 13.5. hct showed 38.8% while normal range 40% thanks?

I wouldn't assume this is the cause. This is marginally low and seldom if ever the cause of such a pattern of symptoms. It the hemoglobin were down in the 5-6 range I would expect it might, but not at 12. I would look for another reason as more likely.

All laboratory results need to be interpreted in the clinical context and the doctor who ordered the tests is usually in the best position to do that. Talk to the doctor who ordered the tests. Having said that, your hemoglobin is not low enough to cause symptoms, however it still needs to be investigated to avoid making matters worse. Wish you good health!