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Sleep HRV#

HRV#

Heart Rate Variability (HRV) is a measure of the variation in time between each heartbeat. Contrary to what some might think, a healthy heart does not beat like a metronome with exact intervals between beats. Instead, the time between your heartbeats varies. This variation is what we call HRV. HRV is an important indicator of your autonomic nervous system function and overall heart health.

Sleep HRV#

When it comes to sleep, HRV can be particularly insightful. During sleep, HRV patterns can reflect the quality of your rest and how well your body recovers from daily stressors.

HRV Range#

The HRV range is a set of values that help determine how your HRV compares to a standard or expected level. In the context of our app:

  • Initial Range

We first calculate an initial range based on your average HRV and its standard deviation (a measure of variability). This range is centered around your average HRV and extends one standard deviation both above and below this average. This range isn't rigid; it's more like a zone that represents a healthy variation for you. Think of it as a comfort zone for your heart's variability.

  • Updated Range

Over time, as more HRV data is collected (like from a new night's sleep), we update this range. The updated range is more personalized and can give a better picture of what's normal for you.

How Do We Measure if HRV is Good?#

To determine if your HRV is good, we compare your current HRV value to your personalized HRV range. Based on where your HRV falls within this range, we categorize it as follows:

  • Below Range - Pay Attention

If your HRV is below the lower limit of your range, it might indicate stress, fatigue, or potential health issues. This is a sign to pay attention to your body and lifestyle choices.

  • Lower Half of Range - Fair

If your HRV is in the lower half of your range but not below it, this is considered fair. It suggests that while you may not be at your best, you're within a normal variation for you.

  • Upper Half of Range - Good

An HRV in the upper half of your range is good. It often indicates that you're well-rested and that your body is managing stress effectively.

  • Above Range - Optimal

If your HRV is above the upper limit, this is optimal. It suggests excellent physical and mental well-being.

Remember, HRV can be influenced by many factors like stress, sleep, exercise, and lifestyle habits. Regular monitoring and understanding your personal HRV range can be a valuable tool for managing your health and well-being.

Sleep HRV Trend#

The Flowtime Brain Tag tracks your HRV throughout the night, providing insightful trends that can be pivotal in understanding your sleep quality and physiological state.

The sleep HRV trend feature in the Flowtime app visualizes the fluctuations in your HRV as you sleep. It displays:

  • Horizontal Axis (Time)

This axis charts the duration of your sleep, marked hourly to give a clear timeline of the night.

  • Vertical Axis (HRV)

The vertical axis represents HRV values, measured in milliseconds (ms).

By examining this trend, you can see how your HRV changes during different sleep stages and throughout the night.

Interpreting Sleep HRV Trends#

  • Observing Fluctuations

Normal HRV trends will show fluctuations, as HRV naturally varies during different sleep stages. Higher variability often indicates a more restful and undisturbed sleep.

  • Identifying Patterns

Look for consistent patterns or changes in your HRV. For instance, a generally higher HRV may suggest good sleep quality and autonomic nervous system balance.

  • Correlating with Other Metrics

Cross-reference your HRV trends with other metrics like sleep heart rate and brainwaves. This can help in understanding the interplay between different physiological signals during sleep.