**What is the measurement frequency of the Apple Watch? Can I control it?**

Under normal circumstances, the Apple Watch will automatically measure your HRV (Heart Rate Variability) every 2 to 5 hours. If your watch is in low battery mode or if you have started a workout, it won't automatically monitor your HRV during these times. Therefore, the actual frequency of data collection can vary based on your daily activities.

Currently, the frequency of HRV monitoring by the Apple Watch is determined by the device itself. [Note] As developers, we do not have the ability to adjust the monitoring frequency of the Apple Watch.

However, for users in most countries (except mainland China), you can force your Apple Watch to check your HRV every 15 minutes to increase the monitoring frequency by:

1. Turning on the AFib (Atrial Fibrillation) history feature in the Apple Health app under Heart.
2. Then enabling AFib History in the Watch app under Heart section.

Be aware that this method will consume more battery than usual, cannot be enabled in mainland China, and is currently the only way to increase the HRV monitoring frequency of the Apple Watch.

Can manual measurements be triggered?

If you need to measure your current HRV value, you can trigger a measurement using the "Mindfulness" - "Breathe" feature.

Follow these steps:

• Open the "Breathe" session in the "Mindfulness" app on your Apple Watch.
• For accurate measurements, we recommend selecting a breathing duration of 3 minutes or longer.
• Press start, ensure the watch is properly fitted, and try not to move your body. Keep calm, breathe naturally without following the breathing guide.
• After completing the session, lock and then unlock your iPhone.
• Wait about a minute, and Era will receive your data and display it.

Note: Due to Apple Watch limitations, there might be instances where data cannot be immediately returned. Please be understanding.

If your data doesn't return right away, you might want to set your phone aside and check back later in StressWatch.

Why doesn’t the data update immediately after manual measurement?

If your data hasn't updated more than half an hour after following our measurement steps, it might be due to:

• Being in a state of movement or excitement during measurement, which may prevent the Apple Watch from recording HRV.