How does low power mode affect sleep tracking?

Hello harshdeepm,

Low Power Mode on your Apple Watch does turn off a few features, you learn which features are turned off with Low Power Mode here: Use Low Power Mode on your Apple Watch - Apple Support

Based on what we were able to find, it doesn't look like Apple Watch uses your heart rate to track your sleep, but you may not be able to view "Comparisons" with Low Power Mode enabled. You can learn more here: Track your sleep on Apple Watch and use Sleep on iPhone - Apple Support

Thanks.