Why does my apple watch glow red?
The Watch uses that glow to measure the amount of oxygen in your blood. And, Apple hopes, that measurement could provide entirely new ways of understanding your own wellbeing. That red glow comes from LEDs on the back of the watch, which shine out, through your skin and into the blood.
The red dot on your Apple Watch is a signal that shows you have unread notifications.
I saw a brief red glow or light from under my watch. What, if anything, does it mean? That is the sensors for the heart monitor and the blood oxygen monitor.
Like the green lights, the red lights also indicate another health tracking feature, in this case, blood oxygen monitoring. The Apple Watch Series 6 and later are able to measure the wearer's blood oxygen (SpO2) levels.
To optimize for evening conditions, Apple Watch Ultra features a Night Mode that turns the interface red and removes retina-altering blue light from the display to ease strain on your eyes in the dark.
But in reality, the green snake of death error represents a scenario where your Apple Watch is charging but you cannot use your watch even after hours and hours of charging. This usually appears once the red snake error has gone and your watch has started charging again giving you a lot of hope.
Your Apple Watch uses a combination of red and green LED lights and infrared lights and shines them onto your wrist. Photodiodes then measure the amount of light that's reflected back. Your Apple Watch then calculates the data to calculate the color of your blood. The color is used to determine your blood oxygen level.
Why is the green light on my Apple Watch on when I'm not wearing it? Even if you aren't wearing your Apple Watch, you may occasionally notice the green light emanating from the rear sensors. This is because an app may be active and trying to monitor your heart rate.
Most fitness bands and smartwatches pack red and/or green sensor technology. It is with this that they track heart rate and blood oxygen levels. This is done via a 150-year old process called photoplethysmography (PPG). In short, an LED on the underside of a watch shines a green or red light onto the skin.
Sleep Mode will turn off the Watch's display and lock it so it won't wake you up. To turn Sleep Mode on or off, swipe up from the Clock screen then scroll to and select the Focus icon then select Sleep.
Why is there a little red light on my phone?
It is used by the phone to detect the range of your skin, and as such determine if the display needs to be illuminated. Example: If it detects that your face is within inches of the display, it will darken to save power (not go to Sleep Mode).
Go to Settings > Display & Brightness, then select Dark to turn on Dark Mode, or select Light to turn it off.

It's showing that your microphone is active . the green dot shows that your camera is active . If microphone is active should be orange but mine is red .
About 1.5 hours to 100%
Charge times are from 0–80% and 0–100% using the included Apple Watch Magnetic Fast Charging USB-C Cable.
The easiest way to tell is to watch when you plug your Apple Watch up to a charging station. Once the watch connects to the charger, a green lightning bolt will appear on the screen for a few seconds to let you know the watch is charging.
Give it an hour on the charger then it will take about a minute to start up.
The Apple Watch is capable of tracking many health-related aspects of your body, including heart rate. While it's not as precise as the measurement a person would get in a hospital or medical setting, numerous studies over the past few years suggest the Apple Watch's readings have a decent accuracy rate.
Luminous paints such as those used on watch dials make use of chemicals that can absorb visible light and re-emit it over a protracted period. This phenomenon was first noted in the 1500s when stones were discovered near Bologna in Italy which glowed after having been exposed to sunlight.
Always On is turned on by default on Apple Watch Series 5 and later, including Apple Watch Ultra. * In this mode, the time is always visible, along with your watch face or the most recent active app.
Wear your watch to bed, and Apple Watch can estimate the time you spent in each sleep stage—REM, Core, and Deep—as well as when you might have woken up. When you wake up, open the Sleep app to learn how much sleep you got and see your sleep trends over the past 14 days.
What is the green snake of death on the Apple Watch?
As ominous as it sounds, the Green Snake of Death is not a new error and is an issue that users have encountered for years. The Green Snake, which is actually a representation of the Apple Watch magnetic charger with a green lightning bolt, indicates extremely low battery levels.
Your Apple Watch's green light is an optical heart sensor that indicates your heart rate. Apple did this with the help of the green light because blood is an excellent absorber of this particular color.
Pigments based on photoluminescent material (like strontium aluminate) are what are most commonly used for watch lume today. This non-radioactive material is painted onto hands, numerals and dials, then glows in the dark (in usually a green or blue hue) by absorbing light then re-emitting light.
On your Apple Watch, open the Settings app, then scroll down to and tap Privacy & Security. Scroll down to and tap Health. Tap Heart Rate. Tap the toggle next to Heart Rate to turn the green lights on or off.