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This older Kefiw page is kept for reference, marked noindex, and removed from the primary sitemap. The current Kefiw experience is focused on property decisions: cost, quotes, damage, buying, selling, owning, and packets.
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Health calculators for body metrics, caffeine timing, alcohol clearance, sleep timing, and warning-sign checks. Formula-based estimates, not medical advice.
Formula-based planning tools across five sub-systems. Each one shows assumptions clearly and returns an estimate. No diagnosis, no treatment plans, no sponsored products, no account required.
I. Biological Maintenance
Energy baseline and sleep-window planning with conservative health limits.
Metabolic Floor · BMR / TDEE
Calculate your Basal Metabolic Rate and Total Daily Energy Expenditure using Mifflin-St Jeor. Power-consumption view with cut / maintain / bulk zones.
REM-Sync · Sleep Cycles
Find the optimal bedtime or wake time based on 90-minute sleep cycles. Wake at the end of a cycle, not the middle.
II. Health & Body Composition
Tape-measure body-composition estimates and everyday hydration planning.
III. Structural Output
1RM, relative power, heart-rate zones, kinetic expenditure.
Max Load Capacity · Brzycki 1RM
Estimate one-rep maximum from a sub-max set using the Brzycki formula. Recovery / Hypertrophy / Strength zones.
Strength-to-Weight Efficiency · Wilks
Wilks coefficient — the powerlifting gold-standard for comparing lifters across bodyweight classes.
Operational Heart Rate Zones · Karvonen
Calculate the five training zones using Karvonen (heart-rate reserve) method. More accurate than %HRmax alone.
Kinetic Expenditure · MET
Calories burned per activity using the MET (Metabolic Equivalent of Task) method from the Compendium of Physical Activities.
IV. Bio-Chemical Logistics
Fuel split, waist-to-height context, sweat replacement, and protein planning.
Fuel Partitioning · Macros
Daily protein, fat, and carb targets anchored to bodyweight and training goal. Protein-first, fat floor second, carbs fill.
Metabolic Incline · Waist-to-Height
Waist-to-height ratio — better predictor of cardiometabolic risk than BMI. "Keep your waist under half your height."
Ion Balance · Electrolyte Loss
Sodium, potassium, chloride, and magnesium lost through sweat over a training session. Replacement targets for endurance events.
Anabolic Trigger · MPS Bolus
Per-meal protein bolus that maximises muscle protein synthesis. 0.25-0.40 g/kg per feeding, 1.6-2.2 g/kg daily.
V. Environmental Stressors
UV, CO₂, heat, cold — the four atmospheric loads that degrade performance.
UV Exposure Delta · Fitzpatrick MED
Minutes to a Minimum Erythemal Threshold by Fitzpatrick skin type and UV Index. Protected time via SPF.
CO₂ Cognitive Tax
Indoor CO₂ ppm to cognitive decline mapping. 1400 ppm halves strategic decision-making performance.
Thermal Failure · WBGT
Wet-bulb globe temperature — the heat-stress index used by OSHA, ACGIH, and military for work/rest cycle decisions.
Insulation Logic · Clo Units
Required clothing insulation in clo units for air temperature and activity level. Suggested garment stack.
Health topics
Curated guides — when to use which tool, and how the numbers interact.
Biological Maintenance
Energy baseline and sleep-window planning with conservative limits.
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