Someone with this ability can become more durable and resistant to physical damage naturally. They are not immune to physical attacks, but the ability allows them to be able to withstand the affects of attacks much longer, or for physical attacks to not be have as much of an impact upon them. This also means that they can take more pain than any normal human. In Nathan's case, the ability may have also made him slightly more resilient to the Shanti virus, enabling him to last longer before displaying any symptoms and before becoming critical.