Cardio load showing zero for swimming activity

[LGOlders]

My cardio load updates with all activity I undertake other than swimming, which for some reason continually shows zero despite showing active mins, distance, heart rate for the workout. Any ideas? 🤔

[TigerTim1959]

Hi LGOlders, I’m having the same issue, it works ok for walking cycling and believe it or not housework. But not swimming, I swim a mile 3x times a week so thought it would count for something. A friend said it’s because we don’t use enough Cardio in swimming but I disagree. Also after swimming my floor climbed count is in the hundreds 🤪 typical Fitbit in afraid, some work done don’t, if you study the forum you’ll see that everyone that owns a Fitbit has some issue or other.😢

[DavidFitbit]

Hi @TigerTim1959 and welcome @LGOlders to the Fitbit Community! It's great to have you here!

Let me explain to you the impact swimming activities have on cardio load stat.

Cardio load doesn’t accumulate during swimming exercises because heart rate tracking is disabled.

To determine your heart rate, the optical heart-rate sensor in your Fitbit device flashes its green LEDs many times per second and uses light-sensitive photodiodes to detect these volume changes in the capillaries above your wrist. 

Water causes some refraction/reflexion changes of the light when summerged underneath or exposed to it. That's the reason why you may not see heart rate data while swimming.

In addition, Fitbit users experiencing zero issues with their devices usually don't visit the community Forums. 

I wish you both a sporty 2025!

[TigerTim1959]

Thanks for that, regs the swimming, can you answer the bit as to why it’s all of a sudden started registering mega floor climbed counts ( in the hundreds) after swimming?

[DavidFitbit]

Hi @TigerTim1959, thank you for your reply.

I apologize for having missed this point.

Water resistance is needed so your Versa 4 can be submerged under water. To do so the access to the altimeter is temporarily blocked. This block/unblock may cause a pressure change that could be registered like floors are being climbed. This can be an expected behavior under certain circumstances.

I recommend that you follow our Fitbit Product Care suggestions and to contact our tech support if you are unsatisfied with the performance of your device.

Have a great day!

[LGOlders]

Thank you for letting me know 😊 

[TigerTim1959]

Hasn’t done it before since I’ve had the watch, probably have swam 40 or more 1 Mile swims, only started happening since the latest cardio load update.
FYI I have had several other problems with the watch which I have taken up with Fitbit customer services, after long drawn out emails and pictures back and forth eventually I was offered a reconditioned replacement😢
I’ve only had the watch since October 2024, I turned the offer down as I expect that if a brand new one wasn’t right from the start I don’t have much confidence in a reconditioned one being any better. Needless to say I will not be buying another Fitbit product again and I certainly will encourage anyone who is thinking about getting one to read the Fitbit community / Forum before making their mind up.
Still a nice try from you.🫣
Sent From My IPhone.

[Anitajoy]

@LGOlders @DavidFitbit @@I have the same issue. I swim 1500m or so three times a week; my fit bit seems to record my heart rate right through; gives me plenty of active minutes per session ; records it as intense activity but no cardio load. Then the next day my target message says :you have been under training! Two days again I was told I’m been training too much ( I went for a not very fast walk a couple of times) This is so frustrating. My main cardio training doesn’t register - how is this useful: it is actually quite confusing 

[TigerTim1959]

Sounds about right, but I bet David@fitbit will probably suggest you are doing something wrong or it’s just an anomaly…Never ever god forbid could it be your Fitbit is rubbish like mine. Good luck 👍

[Anitajoy]

I suspect that Fitbit developers don’t swim and don’t realise how many people do. I certainly have always had trouble with accuracy of records such as distance etc. can’t tell the difference between swimming and the shower you take afterwards - doesn’t accurately measure kick board laps etc etc even when you start and finish it manually. But to not count it as cardio training is absolutely ridiculous. Surely the load could be determined es from the active minutes per session??

[TigerTim1959]

Exactly,  if you look at most complaints on the Fitbit community irrespective of what Fitbit you have they are mostly about discrepancies in accuracy across the board. Being a swimmer you are probably aware that there is an equation (Depending on you fitness levels) that swimming 1600mtrs (1 mile) is roughly equivalent to a average fitness jogger / running 5kms, so it should be able to able to work that out. ?.

[LGOlders]

It is certainly annoying and a shame that Fitbit can't set a 'standard' cardio load number for swimming it is better than nothing I guess.

[sharpsam]

What a bogus response David. I get the issue, but how can we rectify or work around?  Swimming is one of the best cardio exercises going around. I don't trust your loads as I am more than meeting the load through my swimming. How can I true t off to not provide me with misleading data?

[DavidFitbit]

Hi everyone. We are constantly trying to improve the offer of our Fitbit products and services. Thank you for your feedback!

I understand how important swimming is to the heart. If you believe that cardio load does not currently provide benefit to your needs, you can delete the data registered. To delete your cardio load data, follow  the instructions below :

- From the Today tab in the Fitbit app, tap the Cardio load tile.
- Tap the menu icon and then Manage data.
- Tap Delete Data and then Cardio load.
- Select all data
- Tap Delete.

You may also refer to our help article What are cardio load and target load? below the section "How is cardio load calculated?". 

Have a great day.

[Anitajoy]

I am curious to know whether you normally see some sort of heart rate record when you swim. I do ; and  usually get between 60 and 90 active zone minutes per 40 min session. This is way more than I get for an equivalent walk ; this @DavidFitbit why doesn’t this translate to a cardio load. If the Fitbit isn’t recording heart rate how does it get the active zone minutes. It continues to be frustrating as the cardio load readings for me are low on days when I have worked hard…..also have tried to delete it as it is obviously inaccurate for me, but it keeps coming back…..

[HakunaMancheste]

I usually get it registering heart rate during short swim but not if a long swim.

I agree with previous posts that at least giving a generic cardio load score would help, or even let user pick if mild, moderate intense swim

[LGOlders]

Thank you for the detailed explanation. If this is the case with cardio load, how do I still manage to still get active minutes with a heart rate trace too when swimming?

---

Totally agree, my Fitbit still records my heart rate and active minutes while swimming but not cardio load. I too have the issue of it saying under training. Very frustrating to have as a metric if it can't be used for a main sport. I have tried deleting the cardio load on the home page but Fitbit still gives me a message about not meeting cardio load. 

[Anitajoy]

Exactly! I too have tried deleting and for a few days it disappears and then today it’s back saying “you’re at risk of under training!” This sort of message is very discouraging even when one knows it isn’t true! 

[LGOlders]

Agree totally!

[Mark111111]

Closest I can get

Do not start your swim activity before swimming (this turns off the heart rate monitor)

Swim and after manually put in your swim. The cardio load will be added roughly from the heart rate monitor still running.

It'll show no cardio load from the swim but the day will give you it from the heart rate