If you’ve ascended a flight or two of stairs, you likely know the feeling of being out of breath once you reach the top. It’s a common occurrence among folks of all ages and fitness abilities. But is it something to worry about? Experts told HuffPost there are a few points to keep in mind when it comes to this phenomenon. While it can be normal, it can also be cause for concern or even a fitness challenge to try and improve. Here’s what to know: Feeling out of breath after walking up a flight