I was in the process of changing a flat tire on my truck and I was lifting the spare into position and I couldn't pick it up from a kneeling position so after a minute or two of intense struggle I stood up in a bent over position and finally got the damn thing on. At this point I stood up and that is when it hit me. I started to feel extremely lightheaded and began seeing spots. My heart started racing uncontrollably and I began to feel like I was about to faint. I remembered that I had a two liter of water in the car and I chugged like half of it and finally started to feel a bit normal. I've been feeling lightheaded and been having heart palpitations for the last couple of hours. I checked my blood pressure and it was 143/99 which is high for me. My question is what the fuck is going on?
You were probably holding your breath when you lifted. Happens when you're lifting weights at the gym, your using your muscles and CO2 is building up in your lungs. If you don't exhale all that CO2 will give you a headrush because of the lack of oxygen. That why you inhale before you lift then exhale as you're moving your muscles.