Chris Garges is one of six Boston Marathon entrants testing Polar personal training gear and blogging about it for Boston.com

By Chris Garges, Boston.com Correspondent

Last weekend the Mid-Atlantic was treated to some phenomenal weather. Phenomenal weather brings hidden danger to marathoners-in-training, the first nice Spring-like days make it easy to overdo it. Adding a few miles to your run, perhaps adding an extra run or bike ride, maybe getting all those outside projects done that you never got to finish last year?

Then lose an hour of sleep for Daylight Savings Time on top of that and you’re on the edge of falling into the “trap” of overtraining.

The month of March falls at just the point in training where most plans begin to really log some training volume before tapering down and “sharpening the pencil” as race week approaches. March is also the time of year that the days are getting longer, kids activities are starting up, the weather’s getting nicer and training time is getting harder to find. The key at this point in training is to keep your life in balance and avoid the overtraining and injury that may creep up. Follow your plan, but don’t be a slave to it.

Last week I started to use the Polar RC3 GPS watch for my training. I typically train with a GPS watch and I have previously used a heart rate monitor for training, however in recent years it has collected dust on my shelf. The RC3 was easy to set up and I was amazed how comfortable the heart rate strap was, so I decided to give it a whirl.

Heart rate is a great tool to use when you’re monitoring your training, it allows you to recognize your gains in efficiency as training progresses. Arguably the bigger benefit is that it also allows you to see if you’ve crossed the line into overtraining (high resting heart rate, higher average heart rates, etc). Last week’s data showed me just where I stood in my fitness as I worked some goal marathon pace miles into my long run and watched my heart rate stay within a reasonable range. More importantly, it helped me on my recovery days where I focused not on how fast I was running but maintaining a low heart rate to recognize the benefits of the recovery runs.

Last week was the second week in a row of hitting my highest mileage of the year. I had two great workouts, one included three miles at threshold pace followed by seven miles at 15 seconds per mile faster than goal marathon pace.

The second workout was my 21-mile long run that included the last six miles at goal marathon pace. My recovery runs are done on a soft surface, mainly a gravel rail trail, which also helps to reduce the repetitive pounding on your already tired body.

I also included a total of five hours of easy riding on my bicycle to help recovery and maintain fitness.

This week is somewhat of a “down” week with less total mileage and a race next Sunday. I’ll use the race, the Caesar Rodney half-marathon, as an indicator of my current fitness and look for things that I need to work on in coming weeks.

I haven’t done much speed work this year so I’m not expecting a lighting fast race, but it will be a good point of comparison. The down week falls perfectly to allow my body to adjust to Daylight Savings Time and the darkness of the early morning runs.