Even if you pay for a fancy fitness studio workout—or a fancy fitness tracker, for that matter—you can't necessarily trust what the machines (or the instructors) say your calorie burn comes out to. (Flywheel fanatics will recall that the studio recently rolled out new, more accurate calorie counts...that basically revealed they'd been overestimating calorie counts by almost double — womp womp.)
A study from the University of California-San Francisco found that all of the cardio machines at the gym overestimate the number of calories you burn — sometimes by more than 40%.
Machines use something that's not much better than a one-size-fits-all formula to estimate calorie burn, but the reality is that individual results vary a ton based on factors like your weight, gender, age, how much muscle you have on your body, and more, says Greg Justice, an exercise physiologist at AYC Health & Fitness in Kansas City.
“Most companies aren’t trying to intentionally inflate their numbers, but in the end, it’s important to remember that the algorithms they’re using to measure your workout are just estimates,” says exercise physiologist and ACE certified personal trainer Pete McCall.
While Women's Health isn't really about hardcore calorie counting—and is all about all the benefits of working out that have nothing to do with the number of calories you burn—it can be understandably frustrating if you're trying to lose weight and aren't seeing the number on the scale budge, all because you think your body is using way more cals than it actually is.
But if you can't trust the treadmill, your fitness instructor, or your tracker, what can you trust? The exercise ~science~.
You'll be able to call BS on crazy calorie claims yourself if you know how to get a ballpark idea of the number of calories you're really burning.
“If you’re doing a high-intensity workout—like an eight or a nine out of 10 in terms of difficulty—you’ll end up burning around eight or nine calories per minute,” says McCall. “On the other hand, if you’re doing a more moderate workout—a six or a seven out of 10—then you’ll likely burn around four or five calories per minute."
High-intensity workout = 8-9 cals/minute / Low-intensity workout = 4-5 cals/minute
So...Are Any Trackers Accurate?
To be clear, there are many great reasons to use fitness tracker. Often, simply seeing how many steps you’ve walked (or haven’t) is enough to get you moving instead of couching it for the rest of the night. That said, fitness trackers are a bit weak in the calorie-counting department. A recent study from Stanford found that the most accurate tracker is off by 27%, and the least accurate tracker is off by 93%.
If you really care about getting the most accurate calorie-counting data, make sure you're choosing a tracker with a heart rate monitor. Justice is partial to the Fitbit Alta HR and the Smart Watch Apple Watch Series 3.
“If you’re thinking about cost value, I’d go with the Fitbit Alta HR, because it’s their most recent model and has great features, but it’s still much less expensive than the Apple Watch," says Justice. "The Apple Watch has more features, though, so it really depends on what else you’re looking for.”
Another option: Throw it back to the pre-wrist era and go for a chest tracker, McCall’s gadget of choice. “Wrist-based monitors aren’t as accurate as a chest strap, largely because wrist-based monitors move around when you sweat, whereas a chest tracker stays put.” His suggestion: the Polar Heart Rate Monitor.
What Can You Do To Improve The Accuracy On Cardio Machines?
Plug. In. Your. Stats. “The more information you put into the machine at the beginning of your workout, the better the reading will be,” says Justice. So put it all in there—your gender, your height, and any other info you have—and you’ll be that much closer to accuracy.
Remember, at the end of the day, you’re still not going to get a 100% accurate number—but that’s okay. “When it comes to exercise, a little bit of info is always better than a whole lot of nothing," says McCall.
This article originally appeared on Women's Health US