The Corpus blog
Training & recovery
Recovery signals, HRV, resting heart rate, sleep quality, exist to answer one practical question: is today a day to push, or a day to back off? None of them answer that question alone. A single HRV reading means very little without your recent training load and how you actually feel; a rough night of sleep-stage data means less than a consistent pattern across a week.
The guides here focus on reading these signals together rather than treating any one of them as a green or red light, and on understanding what Apple Health can and cannot tell you about your recovery.
Resting Heart Rate by Age: A Chart Built From Real Data
A resting heart rate by age chart from US survey and wearable data: kids fall from 129 to 78 bpm, adults average 65–72 bpm, and women run a few beats higher.
How to Know When It's Time to Deload
Deloads exist to prevent overreaching before it happens, not to fix it after it does. Here's how to recognize the signs and what a useful deload week actually looks like.
HRV on Apple Watch: What the Number Means (and Doesn't)
How Apple Watch measures HRV, how accurate it actually is compared to lab equipment, and what to do with the number once you have it.
HRV, Sleep, and Training Readiness for Lifters
HRV can add useful recovery context, but it is not a green or red light by itself. Learn how to read a personal baseline alongside sleep and training load.
Common questions on this topic
What is a normal resting heart rate by age?
In US national survey data, mean resting pulse was 129 bpm under age 1, 96 bpm by age 5, 78 bpm in early adolescence, and about 72 bpm in adults. Within adulthood, individual variation is much larger than the difference between age groups.
Full guide: Resting Heart Rate by Age: A Chart Built From Real Data →Is resting heart rate different for women and men?
Yes. In a wearable study of 92,457 adults, mean resting heart rate differed significantly by sex, and a smartphone study of 66,788 people found female sex was associated with a higher heart rate.
Full guide: Resting Heart Rate by Age: A Chart Built From Real Data →How often should you deload?
There is no single evidence-based schedule. In interviews with 18 experienced strength and physique coaches, deloads were typically programmed every 4 to 6 weeks, but timing varied widely, and some coaches deload reactively when fatigue signs pile up.
Full guide: How to Know When It's Time to Deload →How long should a deload week be?
Coaches in the same study typically prescribed 5 to 7 days. The goal is enough reduced training for accumulated fatigue to dissipate before the next hard block.
Full guide: How to Know When It's Time to Deload →How accurate is Apple Watch HRV?
Validation studies show good agreement with ECG-based references at rest, and a study of Series 9 and Ultra 2 found good agreement with a Polar H10 chest strap under free-living conditions. It is reliable for a personal trend, not a clinical measurement.
Full guide: HRV on Apple Watch: What the Number Means (and Doesn't) →Where do I find HRV on Apple Watch?
Open the Health app on your iPhone, go to Browse, then Heart, then Heart Rate Variability. Readings are collected automatically in the background, mostly while you are still or asleep.
Full guide: HRV on Apple Watch: What the Number Means (and Doesn't) →What is a good HRV for my age?
There isn't a universal good number. HRV varies widely between people and devices, so the meaningful comparison is your reading against your own baseline built over several weeks on the same device.
Full guide: HRV, Sleep, and Training Readiness for Lifters →Should I train if my HRV is low?
Check for an obvious cause first, like poor sleep, a hard session, alcohol, or illness. With a clear one-off cause, most people can train as planned, maybe trimming the hardest sets. A dip lasting three or more days without a cause is a better reason to reduce training.
Full guide: HRV, Sleep, and Training Readiness for Lifters →Glossary terms