health and stamina

Today I had a job interview from 7:30 am to 4 pm. The interview itself started around 10 am to 3:45 pm, the rest were tour, presentation, and breaks. By the end of the day, I was so exhausted and I lost my voice -__-;;

It amazes me how singers (like HYDE and Keita!) can sing non-stop for 3-4 hours almost everyday for practices and concerts. To be able to stay fit without losing their voice, they must have taken care of their health very seriously. And to have such a strong stamina, they must have worked out consistently. They are just amazing ^^