The Build

Tools anyone can use today

Six interactive calculators based on the same protocols Matthew uses. Enter your numbers, get personalized results. Matthew’s Day 1 starting point and current values are shown alongside for comparison.

Tool 01 — Aerobic Training
Zone 2 Heart Rate Calculator
Find your personal Zone 2 training range — the cardiac efficiency zone that drives fat adaptation and aerobic base.
Day 1 RHR
—
Current RHR
—
years
bpm
Enter your age and resting HR to calculate your Zone 2 range.
Formula: Karvonen method (ACSM Guidelines, 11th ed.)
Tool 02 — Recovery Intelligence
HRV Baseline Interpreter
Enter your HRV and get training readiness guidance based on population norms and recovery science.
Day 1 HRV
—
Current HRV
—
years
ms (RMSSD)
Enter your age and HRV to get your readiness interpretation.
Norms: HRV4Training population data, Whoop research
Tool 03 — Nutrition Protocol
Protein Timing Calculator
Calculate your total protein target and optimal distribution across meals for maximum muscle protein synthesis.
Day 1 target
~190g
Current target
~190g
days/week
Enter your weight and training frequency to get a protein distribution plan.
Target: leucine threshold MPS research (Morton et al., 2018)
Tool 04 — Sleep Quality
Sleep Efficiency Scorer
Calculate how efficiently you're sleeping. Time in bed vs. time actually asleep — the metric sleep researchers care about most.
Day 1 sleep
—
Current sleep
—
minutes
× ~5 min each
Enter your sleep data to calculate efficiency.
Tool 05 — Weight Loss
Deficit Sustainability Calculator
Are you cutting too aggressively? Calculate your deficit percentage and get a timeline for sustainable fat loss without muscle wasting.
Day 1 weight
—
Current weight
—
cal/day
cal/day
lbs
lbs
Enter your TDEE and intake to analyze sustainability.
Tool 06 — Cardiorespiratory Fitness
VO2max Estimator
Estimate your VO2max from a 1-mile walk test (Rockport method). No lab required. Compare against age-group percentiles.
Day 1 VO2max
~42
Current VO2max
~42
years
lbs
: mm:ss
bpm
Walk 1 mile briskly, record your time and ending heart rate.
Estimated VO2max from walk/run tests has ±10-15% error. Lab testing (metabolic cart) is the gold standard.
Tool 07 — Getting Started
Start Your Own N=1 Experiment
What to track first. The minimum viable personal health data setup — before you build anything complex.
01
Daily weight (with trend, not single readings)
Start here — cheapest signal, highest information density per dollar
tool: Withings Body Comp ($99) or any wifi scale. Track 30-day trend, not daily swings.
02
Overnight HRV + resting HR
Recovery signal that changes behavior — skip training when red, push when green
tool: Whoop ($30/mo) or Oura Ring ($299 + $6/mo). Wear it every night.
03
Daily habits (3–5 non-negotiables)
Track what you're actually doing before optimizing anything
tool: Habitify or Streaks. Start with 3 habits maximum. Add when all 3 are consistent.
04
Food logging for 30 days (not forever)
One month of honest logging teaches your baseline better than any guide
tool: MacroFactor (adaptive TDEE) or Cronometer. Stop after 30 days if stressful.
05
One baseline blood panel
Know your starting biomarkers before you try to change them
service: Function Health, Marek Health, or your GP. Ask for: lipids, glucose, HbA1c, CBC, TSH.
06
Write down one hypothesis
"If I do X for 30 days, I expect to see Y in metric Z" — N=1 needs a thesis
example: "If I sleep before 10:30pm for 30 days, my 30d avg HRV will increase by 5ms."

After 90 days of consistent tracking: ask the platform → or see the full stack →