Real-time SAC Rate

[AquanutAlex]

My understanding is that the air-integrated Shearwater computers can display a "real-time" or "instantaneous" SAC rate (not truly real-time/instantaneous, but rather averaged over the last minute or so) while diving. Are there any other dive computers out there which do this? It seems like an incredibly useful feature for those of us working on improving our SAC rates

 

[happy-diver]

We have diving stuff on ScubaBoard too

 

[Edward3c]

My understanding is that the air-integrated Shearwater computers can display a "real-time" or "instantaneous" SAC rate (not truly real-time/instantaneous, but rather averaged over the last minute or so) while diving. Are there any other dive computers out there which do this? It seems like an incredibly useful feature for those of us working on improving our SAC rates

I think all the air integrated do, the Suunto EON Steel and Black do. Providing you tell it what size cylinder you’re using. I don’t use the feature during a dive, but monitor SAC rate over time as a fitness indicator.

 

[gmerick]

Obsessing about your SAC rate will get you in DEEP trouble. Struggling with your breathing rate will cause a big risk of CO2 retention. Instead, track your after-dive stats, and work on improving your O2 uptake by improving your overall fitness. Cycling, jogging, or just the 10K steps each day will do wonders. Also, learning how to simply relax, obtain neutral buoyancy, and efficiently kick will get your SAC rate where you wish it was.

 

[LFMarm]

I don’t know if aerobic fitness translates into good SAC rate. A few of my buddies are athletes and have “normal” SAC rates — they should be in the top quartile if fitness was a factor. I thought that being very ephysically fit means high muscle capillarization which means high O2 consumption.

The other factors mentioned on the other hand such as good trim, buoyancy, propulsion, being relaxed, moving slowly, are all beneficial for SAC rate.

I am not advocating not to be fit but I just don’t think it helps on this specific topic.

 

[Pearlman]

What about supplements like iron and L-Citrulline for oxygen uptake? I once had a “PopEye” moment decades back when I was regularly cycling a little strenuously every day. I happened to consume a big bowl of steamed spinach salad the night before and the next day I found the same cycling route effortless and my aerobic capacity and stamina seemed to skyrocket. I found myself able to power through the slight uphill stretches and felt invincible that day…

 

[AquanutAlex]

Thanks all for the replies. I'm not looking for tips on improving my SAC rate though- there are already plenty of discussions on this in this forum. I'm just looking for a straightforward answer on whether other dive computers besides the Shearwaters provide instantaneous SAC rate. Can anyone confirm that the Suuntos do? What about Garmin computers and Aqualung?

 

[Pearlman]

I think the Sunnto Eon Core does it. It’s been a while since I went diving so don’t remember the UI OTOH but this is what the manual says :

4.19. Gas consumption
Gas consumption refers to your real-time consumption rate of gas during a dive. In other words, it is the amount of gas a diver would use in one minute on the surface. This is commonly known as your surface air consumption or SAC rate. Gas consumption rate is measured in liters per minute (cubic feet per minute). This is an optional field and needs to be added to your custom dive mode views in Suunto app. In the classic view below, gas consumption rate is in the bottom right corner.

5.8. How to enable gas consumption metering

When you customize your Suunto EON Core in Suunto app to include the gas consumption info field in the switch window, this information will always be available and visible during a dive where you use the gas to which the Tank POD is attached.

 

[dmaziuk]

I don’t know if aerobic fitness translates into good SAC rate.

It can, but mostly by keeping slower steadier breathing rate at higher exertion levels. With no exertion you're pretty much bound by your lung capacity: smaller lungs = lower SAC. E.g. kicking against the current is where it should make a difference.