Why isn’t this available on SE watch?

Olivers7 wrote:

Thanks! I guess I am a bit confused on what the “electrical heart sensor” is, then… since the Apple Watch has a heart rate monitor, and can do so with workouts, sleeping, etc.

Measuring heart rate uses a green LED and a matching photodiode optical sensor and that uses light to measure the changes in pressure of the circulating blood, while the pulse oximeter sensor necessarily uses a red LED and matching sensor to detect relative oxygenation of the blood, while the electro-cardiogram sensor uses an electrode located on the digital crown and a second electrode on the Watch case to detect the positive and negative currents leaking from the electrical activities surface of the heart.

… Monitor your heart rate with Apple Watch - Apple Support (includes some info on ECG)

… https://www.apple.com/healthcare/docs/site/Blood_Oxygen_app_on_Apple_Watch_October_2022.pdf

Watch SE lacks the electrodes, so no ECG.

There is an extra sensor that is in the digital crown that is needed. It’s an electrical sensor. That’s why you need to keep your finger on the Digital Crown if you want to use the ECG feature.

Take an ECG with the ECG app on Apple Watch - Apple Support

If ECG isn’t available on an Apple Watch, it’s because it doesn’t have the electrical heart sensor needed.

More info here:

Monitor your heart rate with Apple Watch - Apple Support

When you buy the least expensive model of any product, some features which appear on the more expensive models will be missing by design. As to whether Apple may add the hardware required for ECG to function on Apple Watch SE, we couldn't possibly know. This is a user to user only forum and no one here works for Apple or has any inside knowledge of Apple's future plans. I wouldn't count on it though. If you want ECG, you should pay for a watch which includes ECG.

I wasn't being sarcastic at all. You asked why Apple Watch SE doesn't have ECG. It's Apple's least expensive watch. Apple Watch Series 7 is a discontinued watch and was discontinued 8 months ago. And yes, the newest Apple Watch SE is different from the original SE, but Apple Watch SE is Apple's entry level watch, and as such some features on the more expensive watches will be missing. Apple's current lineup of watches in order of cost are:

Apple Watch SE 2nd Generation

Apple Watch 8 Aluminum

Apple Watch 8 Stainless Steel

Apple Watch Ultra

Whether you want GPS or GPS+ Cellular makes a difference as GSP+ Cellular costs more than GPS only.