THE DREAM - I was in an exam. But it seemed absolutely impossible since it was a seven hour exam. The exam seemed linked to cooking something.

THE REALITY The dreamers health was deteriorating quickly. Now he realised that he could not keep up the pace like he used to. In particular he could not sustain an effort in the way he used to. The dreamer remembered that during an exam he would go at an insane pace not stopping for a second. It is this pace that he could never ever sustain at his age.

THE INTERPRETATION This seems like a health dream. It notes the changes in the dreamers body and his inability to go at a pace (exam pace) which he could manage when young. Notice that the exam was seven hours long and that is quite some time. It hints at the dreamers inability to sustain an effort over a longer period, which was true in real life.