That sounds plausible. Exercise has great benefits all around.
physical exercise prior to a chess game increases

It is very likely. I have observed increased insight from students during test taking and in chess after physical exertion. What I believe happens is an increased rapid blood flow to the brain and major centers around the body, heightened awareness of your surroundings, increased neuro receptor rates, and any multitude of other deviations from the normal resting rates the body produces.
Note however, that endured physical exertion may have the opposite effect. If you take yourself over the limit physically, you will be effected mentally. Make sure you stay within practiced parameters which can only be judged by you.

It is very likely. I have observed increased insight from students during test taking and in chess after physical exertion. What I believe happens is an increased rapid blood flow to the brain and major centers around the body, heightened awareness of your surroundings, increased neuro receptor rates, and any multitude of other deviations from the normal resting rates the body produces.
What he said!
i found that physical exercise prior to a chess game increases my concentration and i play better chess games. By 150% !