Once you set your sights on a race, it changes your training.

The question today is, should we dream small or dream big?

The Contenders

The 5K is what gets a lot of runners off their couches and into shoes.

Running Isn’t Cheap

Marathons, on the other hand, are really, really tough.

And yet, with the right training, its an attainable distance.

Oprah Winfreyran a marathon in 1994, stunning and inspiring many.

footprints in the snow

By 2015,half a million Americanswere crossing marathon finish lines every year.

Theres been a bit of a backlash, though.

The 5K, not the marathon, is the ideal race, Christie Aschwandenwrites at Fivethirtyeight.

Your mileage, of course, may vary!

New runners are often around 40 minutes.

The world record is 12:57.

Either way, plan to run for 30-60 minutes, at least three times a week.

The Race:MarathonDistance:26.2 milesTime to Run It:4 hours and 22 minutes if you run a 10:00 pace.

The world record is 2:02:57.

The long runs distance creeps upward each week.

The longest run in most training plans is about 20 miles.

A few short runs a week, and youre covered.

Go ahead and run more!

In your shorter runs you might experiment with intervals,hills, orspeedwork on a track.

5K training is flexible.

Marathon training, on the other hand, is like having a part time job.

A ten-mile run will take about two hours, and your big 20-miler about four.

Dont train for a marathon unless youlovespending time on your feet.

Travel costs are as much or as little as you like.

No matter where you live, you could probably find a few nearby 5Ks.

Marathons are a different story.

Expect to pay $100 or more for your registration.

Some runners look for marathons in exotic locales, and plan a vacation around the race.

Marathon training ends up costing a lot, too.

Youll also rack up charges from little things like energy gels and bodyglide.

Pain and Suffering

Youll run faster in 5K training, but farther in marathon training.

The total mileage of a marathon program is much higher, though.

(Tip: learn to love dark nail polish.)

One small upside: youll have a really good excuse to get lots of massages.

Injuries are maybe a toss-up.

Psychologically, its easier to deal with injury if youre training for a 5K.

The Experience

A marathon is an experience to remember.

There are spectators cheering you on, in almost every mile.

Ive been handed orange slices and gummy worms and beer.

On a hot day, people were standing out on the street with garden hoses and sprinklers.

That was around mile 15 and those people were the best.

Youll run farther in one day than a lot of people drive.

Youll have major bragging rights.

Wear the shirtandthe medal to work on Monday.

Or you could run a 5K, I guess.

Its, like, a good workout.

If so,run a marathon.

Im happy that I did a marathon, and Id like to do another someday.

But Im really okay with sticking to short races most years.

Thats because, as much as I enjoyed the marathon experience, training was hell.

I really hate running long distances.

Try running long, and try running short, and see how you feel.

There are even distances beyond the marathon that you could aim for.

But if youd rather stick to shorter and faster workouts, theres no shame in that.

For a long-term goal, you might even make a season of it.

Run a 5K, adjust your training, and have a go at trigger the next one faster.

With enough training, you might start bringing home medals someday.

Like me, though, you dont have to pick one or the other.

you could run half-marathons, which have the same thrilling crowd but require only half as many black toenails.