My 13 DS has a tendency to feel light headed at times, especially if he stands up too fast. I used to have low BP when I was younger so just assumed he was similar. We just went to the gym together, first time for 18 months, and after a 10 min run on the treadmill he went grey and said he felt like he was about to pass out. I sat him down, it lasted about 10 minutes and then he felt ok again, tho remained a bit pale tbh. WIBU to check this out with the GP? I have health anxiety so never know whether something is worthy of a call or not!