Im 22. and yesterday i felt my lower abdomen pulse kinda like a heart beat. no pain and it happened once today again. could it be abdomen aneurysm? im very healthy and very fit and thin if that helps.

Normal anatomy: The aorta is the large artery leading from the heart, looping up and over then down through chest and abdomen. The pulsatile beating of the heart is transmitted down the aorta. This is normal. In a very fit and thin individual, the pulsations in the aorta can often be felt in the belly, especially when lying flat.

No. : No. Abdominal aortic aneurysms occur in older individuals usually over 50 y/o and smokers unless patient has a rare disease called Loeys-Dietz syndrome also some patients with Marfan's Syndrome or Turner Syndrome may develop aortic aneurysms at an early age.