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Community User Author

Swim Data Accuracy

Hi all,


I am trying to loose weight and have taken up swimming.


I've had an apple watch 2 since its release and been swimming since last November. So far I have only lost 2kg and wanted to check the Swimming Data (Calories)


So, here are my stats


I am 48, and my weight is

92kg - 203 lbs

My pool is 25 meters

I generally swim breaststroke at 5'17 per 100m on average.


Today I went to the pool with my Apple Watch 2 and the results were :-


Active Calories = 665 Cal

Total Calories = 717 Cal

Distance = 1,020m

Total Time = 0:54:03

Avg Heart = 104 BPM


I also had a Fitbit 2 on my other wrists


The data from that is showing


Total Time = 0:43:31

Total Calories = 330 Cal

Distance = 1,250m


I was shocked to see the hue difference in calorie burn, so I went to some swimming calculator websites to check the approximate results


Putting in to the website the Apple Watch Distances etc here were the results


www.swimmingcalculator.com

Suggested that 367 Calories had been burnt, learning towards Fitbit


http://caloriesburnedhq.com/calories-burned-swimming/

Suggested that 461 Calories has been burnt, again significantly lower than apples reading


http://www.flaswim.com/calories-burned-swimming-calculator/

Suggest that 580 Calories has been burnt


It is clear that something is amis here, and may explain why I am am not loosing weight if those numbers from apple are used as part of my daily calorie exercise total.


Am pretty confused here, not sure which reading to take, apple or fitbit.


Anyone else experienced this or maybe my watch is faulty?


Ta

Mik - UK

iPhone 6s, iOS 9.2.1

Posted on Jan 31, 2017 2:11 AM

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3 replies
User profile for user: Jonathan UK
Jonathan UK
User level: Level 10
164,021 points

Jan 31, 2017 2:21 AM in response to Community User

Hi


During Pool Swim workouts, the Workout app on Apple Watch relies on your arm motion when estimating results. It also analyses your stroke efficiency over time to improve the accuracy of estimations.


Reported results can be affected by using training aids (eg wearing fins), when not using your arms at all (such as when using a kickboard) and when not using your arms in a recognised stroke action.


When comparing calorie data recorded by different devices and their apps, keep in mind that Apple Watch reports active energy / calories, whereas many other fitness devices and apps report total energy (resting + active calories).


Calorie estimations depend, in part, on your personal information. To check that this has been entered accurately and to update it over time to reflect any changes (such as in your weight):


On your iPhone, in the Watch app, go to: My Watch > Health > Edit (upper-right).


To help improve the accuracy of calorie and other various activity-related estimations made by Apple Watch, you can also calibrate it:


Calibration teaches your watch how your arm movements relate to your stride lengths at different speeds when you are walking and/or running. It does this - during outdoor walks and/or outdoor runs - by comparing data from the accelerometer with Location Services data.


To calibrate your watch - and to reset existing calibration data, if desired - follow the instructions here:


For the best performance from the heart rate sensor, ensure that you wear your watch snugly on the top of your wrist during workouts. Note that Apple advises that water may affect sensor readings during swimming workouts. Apple suggests that you consider tightening the band before starting a workout and loosening it again afterwards:


Your heart rate. What it means, and where on Apple Watch you’ll find it. - Apple Support


More information:

Use the Workout app on your Apple Watch - Apple Support

Use the Activity app on your Apple Watch - Apple Support

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Swim Data Accuracy

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