Apple Watch overestimating calorie burn after the update

Akvalkyrie wrote:

I have been doing water fitness/aerobics classes for at least five years. My calorie burn fell between 375-450/hour. With the new watch update, it says I am burning at least 500 calories and up to 720 on a hard hour class. This is not accurate. Has anyone else experienced this?

https://www.swim-central.uk/how-many-calories-do-30-minutes-of-aqua-aerobics-burn/

"REALISTIC CALORIE ESTIMATES: WHAT TO EXPECT

To give you a practical sense of numbers, here are typical estimates by intensity level:

• Light intensity: around 140–180 calories in 30 minutes for an average-weight person.
• Moderate intensity: around 220–280 calories in 30 minutes.
• Higher intensity or competitive rhythm: 300–350+ calories in 30 minutes for someone who is physically fit and pushing hard."

With each update, Apple tends to refine and try to improve its algorithms, I expect. How do you calculate or know that the newer numbers are less correct than the older ones?

Part of the calorie calculation is based on what the Watch measures to be intensity of arm movements. If Apple changed (or improved) that calculation, it could affect the calories significantly.

As far as the Apple Watch goes, since the calorie calculations depend on height, weight, age, gender, etc., I think all you can do is to check that all your personal physical characteristics are correctly entered.

Akvalkyrie wrote:

Okay. Thanks for this. This is an advanced class. My age and BMI are correct. So I guess being older and having a higher weight affects that number.

If you have a higher BMI that means you are burning more calories, especially when you move against the water. Being "older" might reduce the calories slightly, but keep in mind that calculating calories is much more straightforward for activities like outdoors running and cycling where GPS gives you the exact distance, elevation gain, and velocity, and air resistance can be calculated via well known algorithms, so calories (energy required) can be reasonably well calculated. In a pool, I can imagine this becomes much less straightforward.

I have had my Series 11 Watch for only several months and the first thing it did after I set it up was upgrade to 26.2.1 so I don't have any before vs. after comparisons I can make. But for calories, sleep, VO2 Max ... all those things where I read complaints that the "score has changed after the update," I would simply suggest watching trends and ignoring any "offset" that was a one-time thing that you can be fairly certain is associated with the new update. That's what I will do in the future myself when this happens again (and I am sure it will).

I can say that when I compare the Apple Watch with my Garmin bike computer, they agree closely on velocity, distance, elevation, elevation gain, 5-mile splits, and for calories as well. And at least for resting heart rate, my iPhone InstantHeartRate app gives the same heart rate as my Apple Watch. But my comparisons are for outdoor cycling where GPS is ubiquitous. [I must say I am a little mystified because the Watch never asked me how much my bicycle weighs, which would be needed I would think to properly calculate energy expended during climbs over hills and mountains that I ride, certainly the Garmin requires that input.]