Why do I need to run with a heart rate monitor?
PRsue is a smart, responsive coach that helps you train like an elite athlete. That means that every workout is finely tuned to build your fitness as effectively as possible. When you run with a heart rate monitor, PRsue knows exactly what intensity you’re achieving so it can guide you to slow down, stay right where you are, or speed up as needed to reach your workout goal.


Why don’t you use 220 – age to determine heart rate zones?
The formula 220-age is an estimate of maximum heart rate. Though this formula has long been a popular “one size fits all” approach in the exercise community, the reality is that an individual athlete’s maximum heart rate depends on more factors than just age.

Every athlete’s physiology is unique. At PRsue, our goal is to define the training zones that are unique to you. In our experience, setting your zones based on your Lactate Threshold Heart Rate (i.e., the intensity where your body starts to accumulate lactic acid in the bloodstream) provides training targets that are specific to your body’s physiology and current fitness level.


Why do you track volume (time spent running) instead of distance run?
Not all miles are created equal! When you head out for a run, the time it takes you to complete a certain distance may vary based on the terrain, weather conditions, your fatigue level, or the type of workout you are doing.

By tracking workouts based on minutes run, PRsue controls for these factors to systematically advance your volume for subsequent runs.


Why do my workouts have me spend so much time in Zone 2?
The body’s two most important energy systems are aerobic (requires oxygen) and anaerobic (in the absence of oxygen). In Zone 2, you train using only your aerobic system, so your body is forced to learn how to do that better. This builds a strong base of energy that is always available, at any speed. When you train in Zone 3, which is where most people spend their time, your body uses energy from both aerobic and anaerobic processes and neither system gets stressed enough to meaningfully improve.

Physiologically speaking, training in Zone 2 improves your ability to transport fuel and oxygen to your muscles. You also get better at using your body’s fat for fuel, which in turn allows you to conserve glycogen stored in your muscles. This improves your ability to race or perform over longer distances. Once you have built a strong aerobic base, you’re ready to benefit from the higher intensity workouts you will do as you progress.

Most runners—especially recreational runners—never run easy enough to stay in Zone2, and miss the opportunity to build the strong aerobic base that allows you to run faster for longer. Plus, if you train too hard all the time, you never allow your body to properly recover from training days, which can lead to fitness plateaus and sub-par performances on race day.


What’s the purpose of the 30min challenge?
The 30min challenge is a test workout we use to determine your heart rate at your estimated lactate threshold. PRsue uses the heart rate data from this workout to set your personalized training zones that will guide your training intensity for each workout in your training plan.


Can I use PRsue when I am running on a treadmill?
Yes! PRsue allows you to set your workout for a “Run Indoors.” If you are carrying your iPhone and wearing your heart rate monitor, PRsue will capture the number of minutes you run and give you heart rate feedback during your run. GPS will be disabled for indoor treadmill runs.

If you choose to perform your 30min challenge indoors, set your treadmill for a 1% grade to more accurately simulate outdoor running conditions.


What if I miss a workout?
Don’t worry—this is our sweet spot! PRsue will give you the option to complete the workout on an available training day later in the week. If you don’t have another training day available, PRsue will adjust your workouts to make sure that you stay on track to build your fitness and meet your goals.