Close view of a fitness watch showing heart-rate data on the wrist of a mature athlete during a walk

BIOMARKERS

Numbers are observations, not verdicts.

Published 10 September 2026 · By Daniel Hart, MSc, Solace contributing editor

Heart rate, resting trends, pace, perceived exertion, and sleep data can help describe a training week. None should be treated as a standalone diagnosis or a complete account of readiness.

Reading a signal carefully

Signal	Useful question	Limit
Resting heart rate trend	Has baseline shifted alongside illness or stress?	Hydration, heat, and measurement timing influence it.
Perceived effort	Does the same pace feel meaningfully different?	Memory and mood affect reporting.
Sleep estimate	Is the routine supporting recovery?	Consumer devices infer rather than directly measure stages.

Training notebook with handwritten heart-rate observations beside a pen and smartphone chart

Keep the record simple

Choose a small number of repeatable observations and review them over weeks. If data increases anxiety or encourages unsafe decisions, step back and discuss the pattern with a qualified professional.