Average power on your Apple Watch is the mean wattage you sustained over the course of a run, representing how much physical work your body produced during that workout. It’s displayed in watts and calculated by averaging your running power output from start to finish. If your workout summary shows 250 watts, that’s the average rate at which your body generated force to propel you forward across the entire session.
How Running Power Works
Apple defines running power as “the output of the work you’re doing when you run, measured in watts.” Think of it like a car engine’s horsepower, but for your legs. When you push off the ground, swing your arms, and drive yourself forward, your body is doing measurable mechanical work. The Apple Watch estimates that work using its built-in motion sensors, GPS, and accelerometer data, then converts it into a single number: watts.
Your watch tracks this wattage continuously throughout your run. At any given moment, your power might spike (running uphill, accelerating) or drop (slowing down, running downhill). The “average power” in your workout summary takes all of those moment-to-moment readings and collapses them into one representative number for the whole session.
Why Power Matters More Than You’d Think
Most runners already track heart rate, so a natural question is why power adds anything useful. The key difference: power measures how hard you’re actually working, while heart rate measures how your body responds to that work. Those aren’t always the same thing.
Heart rate lags behind your effort. If you start a hill sprint, your power output jumps immediately, but your heart rate takes 20 to 30 seconds to catch up. Power gives you real-time feedback. Heart rate is also influenced by heat, dehydration, caffeine, stress, fatigue, and altitude. A watt is a watt regardless of whether you slept poorly or it’s 90 degrees outside. That consistency makes power a more reliable way to gauge your true effort from one run to the next.
This doesn’t mean heart rate is useless. It tells you important things about how your cardiovascular system is coping. But if you want to know whether you actually ran harder today than last Tuesday, comparing average power gives you a cleaner answer than comparing average heart rate.
What Your Number Actually Tells You
There’s no universal “good” or “bad” average power number. A 180-pound runner will naturally produce more absolute watts than a 130-pound runner at the same pace, simply because moving a heavier body requires more energy. What matters is how your number changes relative to your own history.
Here’s what to look for. If your average power stays the same but your pace gets faster over weeks of training, you’re becoming more efficient: producing the same energy output but converting it into more speed. If your average power increases while your pace stays flat, you may be dealing with fatigue, poor form, or tougher conditions like wind or hills. Tracking these trends over time is where average power becomes genuinely useful rather than just a curiosity.
Some runners also look at power relative to body weight (watts per kilogram), which offers a fairer way to compare across different body sizes. Lighter runners need less power to maintain a given pace, while heavier runners produce more absolute watts. Losing weight doesn’t automatically improve performance either, since excessive weight loss can reduce the muscle mass that generates power in the first place.
A Note on Accuracy
There is no agreed-upon scientific standard for running power. Different companies calculate it differently. In comparative testing by DC Rainmaker, Apple Watch power numbers aligned more closely with Stryd (a dedicated running power meter worn on the foot) than with Garmin or Polar, which tend to read higher. The reason: Garmin and Polar include the energy from your body’s natural elastic rebound when your foot hits the ground, while Apple and Stryd appear to exclude it.
None of these approaches are objectively right or wrong. The practical takeaway is that you shouldn’t compare your Apple Watch power numbers directly against a friend’s Garmin numbers. The metrics are most valuable when compared against your own data over time, using the same device consistently.
One quirk worth knowing: Apple Watch reports zero watts during walking segments. If you take walk breaks during a run, those intervals show no power data at all rather than a low wattage reading. This means your average power reflects only the portions where you were actually running.
How to View and Customize Power Data
Running power doesn’t appear on your watch face by default. To see it during a run, you need to add it to your workout views. Open the Workout app on your Apple Watch, scroll to the running workout you use, and tap the pencil icon. From there, scroll through the available workout views and tap “Include” next to any power-related screens. You can also customize which specific metrics appear in your main display by tapping into a metrics tile and swapping in power. Apple Watch Ultra models allow up to five metrics per screen instead of the standard four.
After your run, the Fitness app on your iPhone shows average power in the workout summary alongside pace, distance, heart rate, and other data. You can also see a power graph that shows how your output fluctuated throughout the run, which is helpful for spotting patterns like fading power in the final miles or power spikes on hills.
Using Average Power for Pacing
One of the most practical applications is race pacing. Instead of targeting a specific pace per mile (which varies with terrain, wind, and fatigue), you can target a consistent power output. Running uphill at 280 watts and downhill at 280 watts means you’re maintaining an even effort, even though your pace will be slower going up and faster going down. This approach helps prevent the common mistake of going out too fast early in a race and paying for it later.
To use this strategy, you first need several weeks of training data to understand your own power ranges. Note your average power on easy runs, tempo runs, and hard intervals. Over time, you’ll develop a sense of what wattage corresponds to what effort level for your body. That personal baseline is far more useful than any generic chart of “ideal” running power.