Does Time Dilation really mean that time p slowly in…..?

According to Einstein Lemon A would be older, time dilated for the traveller. However there there is a problem for an organism travelling at near the speed of light, his body would shorten in the direction of motion and his m would increase, it is doubtful that his organs could function under these conditions. Personally, I think that time is a man made made concept, he had to create it in order to to be able to calculate speed and distance of motion. Think about it. Earth is a mere speck in the universe. Why would it need time zones?