Skin Temperature and Respiratory Rate

Rune 1 captures several quiet-body signals overnight. Three of the most useful are skin temperature deviation, respiratory rate, and the stress index curve.

Skin temperature deviation

Pulsyn reports the deviation from your 14-day rolling baseline. It does not show absolute skin temperature. The value is shown in degrees Celsius with a sign so rises and falls are clear.

A small positive deviation is normal during the luteal phase or after a warm environment. A larger sustained rise, especially with elevated resting heart rate and lower HRV, can flag a recovery or illness context.

Respiratory rate

Respiratory rate is the number of breaths per minute, estimated from heart-rate and movement signals during sleep. Most adults fall between 12 and 20 breaths per minute at rest.

Respiratory rate is one of the inputs to Biometric Age and helps confirm other recovery signals when it drifts from your baseline.

Stress index curve

The stress index curve is a 1–100 visualisation of autonomic load through the day. Higher values suggest more sympathetic activation; lower values suggest calmer or more parasympathetic states.

It tracks your nervous system's physiological response to activity, stress, rest, and recovery across the day. It is not a measure of mental health or anxiety.

How these signals are used

• Readiness Score uses skin temperature deviation as a contributor.
• Biometric Age uses skin temperature, respiratory rate, and stress as model inputs.
• Cycle Tracking uses temperature trends to contextualise the luteal phase.

Reading the signals

• Focus on multi-day trends rather than single readings.
• Pair temperature with HRV, resting heart rate, and how you feel.
• For sensor details, see the FAQ.

Wellness framing

These metrics are wellness and fitness signals. They are not intended to diagnose fever, respiratory illness, or any medical condition. If you have health concerns, consult a qualified professional.