My marathon training plan has me running pretty high mileage during the week. I usually have at least one 7-mile run midweek and in the coming weeks I’ll be logging upwards of 20 miles between my runs on Tuesday, Wednesday and Thursday. While my training plan is a little more aggressive than a typical first-time marathoner training schedule, many marathon training plans, no matter the experience level of the runner, have at least one high mileage day during the week. If you’re like me and have a pretty busy work schedule, it’s hard to log the mileage in one run so I opt to split it up during the day and run what’s referred to as a double, or running twice in one day, a.k.a. two-a-days.

At first, I was weary about doing this because I thought I might not be getting the full benefit of a 7 or 8-mile run on a Wednesday, but after asking around and a little research, I learned running doubles actually has more pros than cons. If done correctly, running a double can boost fitness and build mileage (without feeling like you’ve been running forever).

When I have a double day on my schedule, like I did on Wednesday, I like to make one run a “workout” and the other an easy, recovery run. Since I’m training for Big Sur, my workout focus was on hills. I had to run a total of 7 miles for the day but instead went out for a 6 mile run at lunch that included two intense hills with an elevation grade that looks like this:

Since I already got 6-miles of my daily mileage total done, after work I only had to run a mile so I opted for a slow, recovery run at the gym followed by tons of stretching and some strength exercises.

This was a more intense double day than I usually do. Usually I’ll split up a 7-mile run into a 4-mile tempo run at lunch followed by a 3-mile recovery run after work. I prefer to do my second run at the gym because then I’m able to get some strength training in after but you can do it outside too.

One tip I have for running doubles is to make sure you do some dynamic stretching before your second run. You’re muscles are going to be a little tight from your first run, especially if it was a workout, so you want to make sure you warm up before going right into the run. Then, as always, be sure to stretch out after your second run and hydrate- running twice in one day takes more out of you than you think!

Still not convinced about the benefits of two-a-days? Don’t you fret, of course I asked Twitter for its opinion on the pros and cons of running doubles. Here’s what people had to say:

@fithappygirl it’s great when working around busy work schedules! Also seems to build up endurance (running on tired legs for the second).

— emily favret (@iliveinyellow) March 21, 2013

@fithappygirl Pro: You can easily log double digits for a day w/o having to reserve a large block of time before or after work.

— Sun Torke (@storke10) March 21, 2013

@fithappygirl PROS: You get extra mileage in. I like doing one easy run and a workout type run! Tempo/Intervals etc!

— Ashley Byron (@runningbun) March 21, 2013

@fithappygirl Two runs in a day is great for getting the miles in – one good session and one good recovery. It also allows good off days…

— JMG (@julianmcgrath) March 21, 2013

There are also some cons though, although the majority seem to revolve around having to shower twice in one day.

@fithappygirl Cons: Two showers/day, plus an unending appetite :)

— Laura Schwecherl (@lschwech) March 21, 2013

@fithappygirl Pro: Boosts fitness. Con: Two showers. Two clothes-changings. General pain in butt.

— Meghan G. Loftus (@meghgrace) March 21, 2013

@fithappygirl Con: Morning, evening – you feel like you’re always running!

— Sun Torke (@storke10) March 21, 2013

@fithappygirl The only one I can think of is having to take time to shower twice.

— Casey Ferrier (@caseyferrier) March 22, 2013

So if you can get past showering twice in one day, endless hunger and not to mention some extra laundry, two-a-days really aren’t that bad. At the end of the day you have to ask yourself: how bad do you want it and how much are you willing to work for your goal?