I have found HRV to be remarkably accurate at 'predicting' illness (seeming to indicate that HRV is impacted before I notice symptoms). Do others see the same?

I have found HRV to be remarkably accurate at 'predicting' illness (seeming to indicate that HRV is impacted before I notice symptoms). Do others see the same? I do need to account for 3 other variables: + did i drink alcohol that night + did i eat a large meal right before bed + did i go on a long run (20+ minutes) that day Those 3 significantly decrease my HRV (alcohol the most). On the other side, not eating within ~6 hours of bedtime significantly increases my HRV, and moderate exercise increases my HRV. Curious what others are seeing? I have measured with watches and rings - both which only measure at night.