Two questions

What are the different colours of tires shown in the time charts? sometimes blue or red, what is the difference?

Also what does youre drivers health have effect on? also it stops going down at 55%, how come?

The colour of your tyres is showing what temperatue they are running at. If they ar bright red, they're too hot.. and you'll be very slow, and if they are dark blue, they're too cold. You want your tyres in the grey region as that's the optimal range.

Health explains itself really. If a driver is unhealthy, they won't perform as well.

Health will drop to 1%, if you are training Physical and/or health that will restore it so possibly that is why it isn't going down?

thanks a lot.
Is there something i can do to get the tempeture right with the tires?

change your push level, the lower the push level the cooler the tires.  depending on temps and the wear rate of the track you may have to change to a harder or softer tire to get the temps right.