Hi @hasmez and @souada
It is possible for a human being to accelerate to light speed without any severe consequences, even with a moderate acceleration of 1G (9,8 m/s) a traveler will reach close to lightspeed in approximately 350 days. (remember, 1g will feel like standing on mother earth) ;)
The tricky part is that you will have to carry with you energy in some form to propel your craft, and the amount of energy needed will be enormous. That's why the suggested craft in the article above weighs in at about 1 gram.
@erlendgroseth
For @onebitnews