I'm trying to conceive. is it ok if i walk faster/climb stairs? i afraid that by walking fast may kill the sperm. pls advice.

Not related..: Your level of activity does not affect your ability to conceive. Doing more exercise does not kill sperm. If so, what exercise can do is getting you healthier and in a better shape to be able to get pregnant. If you have been trying to get pregnant for a long time and not successful talk to your doctor about your situation and to evaluate the need of getting tested.

OK to walk: Walking faster or climbing stairs should not harm the sperm.

Walk on: Typically by the time you would be walking and climbing stairs the sperm would be well out of harms way. Walk on !