The blog
Early reading from Astrea
Calm, evidence-based writing on recovery, HRV, VO2 max, sleep, and female physiology. Every physiological claim traces back to a Sources list, and each piece is written and signed by one of us.
- Training Load & Periodization
- HRV, Recovery & Readiness
- VO2 Max & Endurance
- Sleep, Recovery & Longevity
- Data Ownership
- Female Recovery
- Connection & Longevity
- Behind Astrea
- Behind Astrea
Dev Log #3: It's All About Trends and Charts
Two weeks of building Astrea: the Trends tab is live across Recovery, Sleep, Fitness and Strain, we're waiting on Apple's Review, and charts were the hard part.
Marina · - Behind Astrea
Dev Log #2: Teaching the App What a Hard Day Actually Is
Two weeks of building Astrea: why the strain number took longer than everything else combined, and why a long day on your feet still doesn't count as training.
Marina · - Training Load & Periodization
Apple Watch's Effort Rating: Why It's Worth Turning On for Every Workout
Apple Watch scores effort automatically for about 17 cardio workout types. Strength training waits for a tap you may not know exists, and the gap shows.
Marina · - Training Load & Periodization
The Hybrid Athlete's Guide to Managing Training Load Across Strength and Endurance
Lifting and running do interfere with each other, but only modestly and mainly in lower-body strength. Here's how to sequence and track both so neither stalls.
Martin · - Female Recovery
Apple Just Changed Perimenopause Tracking. Here's Why Barely Anyone Outside Tech Press Noticed
Apple quietly added perimenopause and menopause tracking to iOS 27's Health app, but the automated alert only works for users 40 and older. Here's what changed.
Marina · - Behind Astrea
Dev Log #1: Why Astrea Started
Why we started Astrea: no subscription, no male-dominated biohacking framing, and why we're building the first line of code in public during Shipaton.
Marina · - Connection & Longevity
Why Social Connection Might Matter More Than Your Workout: The Science of Loneliness and Longevity
Weak social connection carries a mortality risk on par with smoking. Why gyms became the new third place, and how to build connection into your training.
Marina · - Training Load & Periodization
Acute vs Chronic Workload Ratio (ACWR) Explained: How to Avoid Overtraining
What the acute:chronic workload ratio actually measures, why the 0.8-1.3 sweet spot lowers injury risk, and where the ratio's math breaks down.
Martin · - Connection & Longevity
The "Longevity Bro" Problem: Why More Biomarkers Doesn't Mean a Longer Life
More biomarkers and pricier protocols don't buy a longer life. Why longevity culture skews male, and the women-led research reframing it around muscle and hormones.
Marina · - Sleep, Recovery & Longevity
Training for Longevity: How Athletes Can Build a Body That Lasts
Muscle mass and bone density start shifting in your 30s, well before 40. Here's what the research says about building a body that holds up decades from now.
Marina · - VO2 Max & Endurance
Can Wearables Accurately Estimate VO2 Max?
Apple Watch and Garmin VO2 max estimates carry real error, several points in either direction. Here's what recent validation studies found, and how to read your number.
Martin · - Data Ownership
Why You Own Your Training Data (and Most Apps Don't Let You Keep It)
Most apps make it easy to send your health data out and hard to get a real copy back — what GDPR, CCPA, and HIPAA actually protect, not just what they promise.
Martin · - Data Ownership
Why We Chose a One-Time Payment Over a Subscription
Astrea is a one-time purchase, not a subscription — we're bootstrapped, have no investors to please, and got tired of paying monthly to check our own vitals.
Marina · - HRV, Recovery & Readiness
Body First, Data Second: How to Balance Intuition and Recovery Metrics
When a recovery score and your body disagree, which do you trust? Here is how to use metrics without letting them override how you actually feel that day.
Marina · - Female Recovery
Nursing and Sleep: A Gentler Way to Track Recovery While Breastfeeding
Broken sleep while breastfeeding sinks most recovery scores. Here is a gentler way to track recovery that reads fragmented nights as expected, not failure.
Marina · - HRV, Recovery & Readiness
Readiness Score Explained: How Recovery Apps Calculate It
A readiness score is five simple ideas stacked together. Here is the plain-language arithmetic behind your number, so you can read it yourself, not a black box.
Martin · - Female Recovery
How Your Menstrual Cycle Affects HRV, Sleep, and Recovery
Your HRV, sleep, and recovery shift across your menstrual cycle in predictable ways. Here's what changes by phase, and why a hard week is expected, not a fault.
Marina · - Sleep, Recovery & Longevity
Masters Athletes: How to Train Hard and Recover Smart After 40
Recovery changes after 40, for women and men in different ways. Here is what the research shows about training hard and adjusting to how your body recovers now.
Martin · - VO2 Max & Endurance
What Is a Good VO2 Max for My Age and Sex?
What counts as a good VO2 max depends on your age and sex. Here are the reference ranges, what the number really tells you, and why your own trend matters more.
Martin · - HRV, Recovery & Readiness
Heart Rate Variability (HRV) for Athletes: The Complete Beginner's Guide
HRV, or heart rate variability, is one of the most useful recovery signals you can track. Here is what it measures, what moves it, and how to read your trend.
Marina ·