Every horror movie has the slow guy -- the one who falls behind everyone else... and you know what happens to him, right?

Zombie chow!

Out here in the real world, it's pretty much the same deal (minus the zombies) -- because it turns out the slowest walkers have the highest risk of death.

Australian researchers checked the walking speeds of 1,705 senior men and then tracked them for up to 21 years. They found that those who walked at 1.8 miles per hour or less were far more likely to die in that time that those who walked more quickly.

Those who topped 2 miles per hour, on the other hand, were 1.23 times less likely to die than the slowpokes -- while those who kept up a brisk 3-mph-pace had the lowest risk of death overall.

That's in line with a study last year that found that seniors who can walk at 2.2 mph outlive those who only go 1.3 mph or less -- with the benefits increasing along with the walking speed. (Read about that study here.)

In that study, researchers found that those who walk the fastest can live between 8 and 10 years longer than those who walk the slowest -- which gives you plenty of extra time for walking or whatever else you want to do.

Of course, there's more than just walking speed on the line here. People who walk slower tend to have other physical problems that can boost the odds of an early death.

Slow walking can be a sign of muscle weakness, which could lead to a fall and a devastating or even deadly bone break. It could also signify a neurological problem, including Parkinson's disease.

Circulation problems, pain, arthritis -- all of these conditions and more can also slow you down, diminish your quality of life, and maybe even allow the Grim Reaper to gain another step or two on you.

And that's someone you don't watch catching up.