This article, published in Slate, suggests that there is an upper bound to human longevity - how long we will live. Simply put, everything eventually wears out and the body (yet!) hasn't been able to keep up repairs fast enough to halt the process. From the article:
Last month, a 114-year-old former schoolteacher from Georgia named Besse Cooper became the world's oldest living person. Her predecessor, Brazil's Maria Gomes Valentim, was 114 when she died. So was the oldest living person before her, and the one before her. In fact, eight of the last nine "world's oldest" titleholders were 114 when they achieved the distinction. Here's the morbid part: All but two were still 114 when they passed it on. Those two? They died at 115.
The whole article is very interesting and goes into greater depth on human longevity so I suggest you head over and read the whole thing.
On the other hand, there is this from ABC News
Scientists may be able to make substantial gains in extending not only the length of human life, but the quality of life as we age, according to many researchers. That won't be limited to breakthroughs in the laboratory. To a significant extent, it will depend on how we live our lives.
But remember, time is limited and your future is yours. We likely have only three or four decades left...
Have a truly wonderful day.