Fatigue Recovery Curve Calculator
Free Fatigue recovery curve Calculator for rehabilitation recovery. Enter your stats to get performance metrics and improvement targets.
Reviewed for accuracy by Sher, Sports Science & Nutrition Specialist
Fatigue Recovery Curve Calculator
Calculator
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Formula: Fatigue(t) = Peak × 0.5^(t/half-life)
Worked example — Full recovery ~50 hours
Formula
Fatigue(t) = Peak × 0.5^(t/half-life)
Fatigue decays exponentially. Half-life varies: light exercise ~8h, moderate ~12h, heavy/DOMS ~24-48h.
Worked Examples
Example 1: Heavy workout
Problem:80% fatigue, 12h half-life
Solution:6h: 56%, 12h: 40%, 24h: 20%, 48h: 5%
Result:Full recovery ~50 hours
Example 2: Light recovery run
Problem:30% fatigue, 8h half-life
Solution:6h: 20%, 12h: 15%, 24h: 8%
Result:Full recovery ~20 hours
Frequently Asked Questions
What affects recovery speed?
Sleep (7-9h optimal), protein intake (1.6-2.2g/kg), hydration, age, training experience, and stress levels all significantly affect recovery rate.
How is the fatigue recovery curve calculated?
Fatigue(t) = Peak × 0.5^(t / half-life). This exponential decay model mirrors real physiological recovery, where the rate of recovery slows as fatigue decreases. The half-life is the time required for fatigue to drop by exactly 50%.
What is the half-life of fatigue after exercise?
Half-life varies by intensity: light activity about 8 hours, moderate exercise about 12 hours, intense training about 24 hours, and DOMS-inducing eccentric work about 36-48 hours. Individual responses vary based on fitness level and recovery practices.
Why is fatigue modeled as an exponential decay rather than a straight line?
Physiological recovery processes such as glycogen resynthesis, inflammatory clearance, and neuromuscular restoration all slow as the body approaches baseline, producing exponential rather than linear decay. In practice the first few hours after a hard session clear a large share of fatigue quickly, while the last portion lingers noticeably longer, matching the common experience of feeling mostly recovered within a day but not fully back to 100 percent for two or three days.
How does this curve differ across training ages and fitness levels?
Trained athletes generally show shorter fatigue half-lives than untrained individuals for a comparable relative workload, thanks to better mitochondrial density, buffering capacity, and repair efficiency built up over years of training. Two athletes performing the same absolute heavy session may start at a similar peak fatigue percentage, but the trained athlete typically reaches a safe training-readiness threshold sooner.
References
Reviewed for accuracy by Sher, Sports Science & Nutrition Specialist · Editorial policy
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