Nausea, headaches and dizziness

[sticky fingers]

Last week after BJJ class (first lesson back after 2 months) I had to sit in the carpark for 30 mins recovering from nausea and dizziness. I thought it was due to a drop in fitness cos I was away for a while. I did not feel the class was particularly taxing. During those 2 months I was still active in kungfu, badminton, hiking. I never get like that in those activites unless I go really hard.

Tonight, I made special emphasis before class to be well hydrated , stretched , warmed up and didn't go as hard as last week. I barely broke a sweat. During class I could feel the onset of the dizziness but was fine. However, when I got into the car I got a moderate headache for 15 mins. Heart rate not unusually fast or out of breath.

This is worrying me as it is affecting my training. I am sure fitness has a lot to do with it, but I think it is more than that. I can go very intense with other activities and not feel llike this.

I am suspecting a blood pressure problem so I will bring a monitor next week.

What do you guys think?

[gfx]

could it be the lack of oxygen?

If the place is not well ventilated, that could be it.