While not all athletes are equally serious about running and cycling, the combination of the two is still quite popular. This is especially true of those training for a duathlon, or just looking to add variety to their daily exercise routine.

Some of the watches leading in the market come with attachments and accessories to make them versatile enough for bicycle use. For instance, the foot pod feature for running to measure stride length can be adapted for cycling use to measure pedal cadence. Having a digitally recorded and mapped report of the whole ride’s cadence provides essential information for competitive cyclers looking to improve their performance.

Other information recorded by some GPS running watches that is easily adapted to a cycling regimen is heart rate monitoring. Most high end watches come with (or are compatible with) a heart rate monitor in the form of a belt.

These belts are specifically designed to be comfortable enough to wear while running and cycling. They wirelessly transmit the pulse information to the wrist (or handlebar) display for instant feedback on how your body is responding.

This information is also recorded and included in the post-ride report that’s automatically analyzed when you plug the display into your computer at home. In fact, everything from distance, time, speed, heart rate, cadence (or stride length) is all analyzed together.

This means that GPS running watches don’t just help you see where you’ve been and how fast you’ve gone. They can show you how your heart rate and cycling cadence responded to changes in your route. Because the GPS signal (in some watches, not all) also records changes in altitude, you can see exactly how going up a hill impacts the way you ride and the way your body responds.

While these watches are more popular for runners, there is a strong segment of cycling use. Stationary bikes have long recorded this type of information, and those who enjoy riding outdoors and covering actual distance should be able to take advantage of technological development, and this type of watch certainly helps them do so.

If you’re running for distance, a watch with GPS can keep track for you how far you’ve gone. No more measuring out a run or keeping track of mile markers. Using a GPS receiver directly in the watch (often in conjunction with a foot-mounted device, as well), a watch can instantly display how far you’ve gone.

Many runners run for speed. Normally, you’d calculate how far you ran and how long it took to determine your average speed. But that speed fluctuates depending on incline, how long you’ve been running, etc.

GPS watches can use the GPS information to keep track of how your speed varies across your run. Some can even calculate changes in elevation, and therefore give you reports on when you were running uphill, and how that impacted your speed.

Cardiovascular fitness is a huge reason that many of us who run do so. If this is part of your motivation, make sure to look for a watch that also monitors your heart rate. This can be useful in two different ways:

Firstly,  heart rate monitoring is useful for beginning runners whose goal is to run a certain length of time each day, and to keep their heart rate in a certain zone. With instant feedback on how your heart is doing, you can make sure you’re working hard enough to improve heart strength, but not so hard to be putting yourself in danger.

With GPS running watches that monitor heart rate and also keep track of changes in elevation, you can see how your body responds to changes in your course. You can see how your heart rate changes on a certain incline, and then see how regular running changes that response as you build strength over time.

From simply timing yourself with an old-fashioned stopwatch to getting a top of the line watch with GPS, heart rate, and tracking, to everything in between, finding what’s right for you is just a matter of sitting down and deciding what you want.

If you only do runs on paths that are straight, flat, and marked with mile markers, then you probably don’t need as much technology as someone who runs a more dynamic course. You can simply look at the mile markers and keep track with a stop watch.

But that’s about all you can do. Adding a heart rate monitor to your workout adds a lot of information. You can tell how you’re doing by what zone you are in. (And you can make sure you’re working hard enough by keeping yourself in a specific zone.)

Then we get into GPS running watches. The jump from a simple heart monitor to a watch like this is a considerable one in terms of the capabilities you’re gaining. This type of watch is essentially a wrist-mounted (or bike mounted, if you buy the attachment) computer that keeps track of a number of things.

Firstly, the GPS monitoring keeps track of where you are. When you get home, you can plug it into your computer a see a precise map of your route. But the watch also tracks a number of other factors, too.

Tracking where you are and when you go there, these watches can then calculate your speed. Many also gauge not only latitude and longitude, but altitude: it can tell when you’re going up a hill, and how steep that hill is.

This is especially useful in conjunction with a heart rate belt, an accessory that many GPS running watches include. By analyzing your heart rate alongside your course, you can see exactly how your body responded to that big hill, and therefore, you can see how that response changes over time.