“Isaac said, “Behold now, I am old and I do not know the day of my death.””  

~ Gen. 27:2

Isaac would have been about 123 years old at this point.  Certainly his health was beginning to fail; his eyesight was already going if not gone completely, and the text tells us he had to rise up to eat, which may indicate he was bedridden to some extent – we do not know for sure.

Ever since the flood had occurred, life spans began to reduce rapidly.  A Midrash tells us that children do not necessarily expect to reach the age their parents did, which was likely part of Isaac’s concern.  Abraham lived to 175 years, however Sarah only lived to 127.  In reality, Isaac lived another 57 years and died at age 180 (Gen. 35:28-29)