If i am a relief or newbie ..... i will work gradually upwards .
7 hours ...... then 8 hours per day .... then 9 hours .... then 10 hours per day .
Upwards .
In between , if one felt fatigue after 10 hours , next day down 9 hours . Continue 9 hours for the next few days . Never stretch your body too far
It will be very damaging to health to start from driving 14hours , down 13 , down 12 , down 11 ......
Let your body do a run in ..... from smaller gear to bigger gear , like our car . In between , lower down your gear , etc etc then up gear .
After your body run in nicely , then u say u are working nicely .