Here's why:

* Higher mass: Massive stars have much more gravity pulling inward, causing their cores to be incredibly hot and dense. This leads to much faster nuclear fusion rates.

* Faster fuel consumption: The intense fusion reactions in massive stars consume their hydrogen fuel at a much quicker pace.

* Shorter lifespan: Due to their rapid fuel consumption, massive stars have significantly shorter lifespans compared to smaller stars. They may only exist for a few million years, while smaller stars can live for billions of years.

Example:

* A star 10 times more massive than our Sun will only live for about 10 million years.

* Our Sun, a medium-sized star, is expected to live for about 10 billion years.

Note: While massive stars burn out faster, they also experience more dramatic and spectacular endings, often ending their lives in powerful supernova explosions.