From ac6364ae28320c3449342a08a02f7dd8ee52f8b7 Mon Sep 17 00:00:00 2001
From: Alexander Bocken <alexander@bocken.org>
Date: Mon, 23 Mar 2026 10:23:00 +0100
Subject: [PATCH] fitness: add kcal estimation based on Lytle et al. (2019)
 regression model

Estimate strength workout energy expenditure using the Lytle et al. multiple
linear regression model. Maps all 77 exercises to 7 studied categories with
confidence levels. Shows kcal on stats page (cumulative), session cards,
workout detail, and workout completion screen. Supports sex/height demographics
via profile section on measure page. Includes info tooltip with DOI reference.
---
 src/lib/components/fitness/SessionCard.svelte |  30 +-
 src/lib/data/kcalEstimate.ts                  | 410 ++++++++++++++++++
 src/lib/js/fitnessI18n.ts                     |   7 +
 src/models/FitnessGoal.ts                     |   6 +-
 src/routes/api/fitness/goal/+server.ts        |  21 +-
 .../api/fitness/stats/overview/+server.ts     |  38 +-
 .../[id]/+page.svelte                         |  35 +-
 .../[measure=fitnessMeasure]/+page.server.ts  |   8 +-
 .../[measure=fitnessMeasure]/+page.svelte     |  97 +++++
 .../fitness/[stats=fitnessStats]/+page.svelte |  83 +++-
 .../[active=fitnessActive]/+page.svelte       |  34 +-
 11 files changed, 745 insertions(+), 24 deletions(-)
 create mode 100644 src/lib/data/kcalEstimate.ts

diff --git a/src/lib/components/fitness/SessionCard.svelte b/src/lib/components/fitness/SessionCard.svelte
index cf8adce6..b21abe28 100644
--- a/src/lib/components/fitness/SessionCard.svelte
+++ b/src/lib/components/fitness/SessionCard.svelte
@@ -1,7 +1,8 @@
 <script>
 	import { page } from '$app/stores';
 	import { getExerciseById, getExerciseMetrics } from '$lib/data/exercises';
-	import { Clock, Weight, Trophy, Route, Gauge } from 'lucide-svelte';
+	import { estimateWorkoutKcal } from '$lib/data/kcalEstimate';
+	import { Clock, Weight, Trophy, Route, Gauge, Flame } from 'lucide-svelte';
 	import { detectFitnessLang, fitnessSlugs } from '$lib/js/fitnessI18n';
 
 	const lang = $derived(detectFitnessLang($page.url.pathname));
@@ -115,6 +116,27 @@
 		return { points, viewBox: `0 0 ${vbW} ${vbH}` };
 	});
 
+	/** Estimate kcal for this session */
+	const kcalResult = $derived.by(() => {
+		/** @type {import('$lib/data/kcalEstimate').ExerciseData[]} */
+		const exercises = [];
+		for (const ex of session.exercises) {
+			const exercise = getExerciseById(ex.exerciseId, lang);
+			const metrics = getExerciseMetrics(exercise);
+			if (metrics.includes('distance')) continue; // skip cardio
+			const weightMultiplier = exercise?.bilateral ? 2 : 1;
+			const sets = ex.sets
+				.filter((/** @type {any} */ s) => s.reps > 0)
+				.map((/** @type {any} */ s) => ({
+					weight: (s.weight ?? 0) * weightMultiplier,
+					reps: s.reps ?? 0
+				}));
+			if (sets.length > 0) exercises.push({ exerciseId: ex.exerciseId, sets });
+		}
+		if (exercises.length === 0) return null;
+		return estimateWorkoutKcal(exercises);
+	});
+
 	/** Check if this session has any cardio exercise with GPS data */
 	const hasGpsCardio = $derived(session.exercises.some(ex => {
 		const exercise = getExerciseById(ex.exerciseId, lang);
@@ -190,6 +212,9 @@
 		{:else if session.totalVolume}
 			<span class="stat"><Weight size={14} /> {session.totalVolume >= 1000 ? `${(session.totalVolume / 1000).toFixed(1)}t` : `${Math.round(session.totalVolume).toLocaleString()} kg`}</span>
 		{/if}
+		{#if kcalResult}
+			<span class="stat kcal"><Flame size={14} /> {kcalResult.kcal} &plusmn; {kcalResult.kcal - kcalResult.lower} kcal</span>
+		{/if}
 		{#if session.prs && session.prs.length > 0}
 			<span class="stat pr"><Trophy size={14} /> {session.prs.length} PR{session.prs.length > 1 ? 's' : ''}</span>
 		{/if}
@@ -272,6 +297,9 @@
 		color: var(--color-primary);
 		font-weight: 700;
 	}
+	.stat.kcal {
+		color: var(--nord12);
+	}
 	.stat.pr {
 		color: var(--nord13);
 	}
diff --git a/src/lib/data/kcalEstimate.ts b/src/lib/data/kcalEstimate.ts
new file mode 100644
index 00000000..c3fe9e65
--- /dev/null
+++ b/src/lib/data/kcalEstimate.ts
@@ -0,0 +1,410 @@
+/**
+ * Kilocalorie estimation for strength training based on:
+ *
+ *   Lytle, J.R. et al. (2019) "Predicting Energy Expenditure of an Acute
+ *   Resistance Exercise Bout in Men and Women."
+ *   Med. Sci. Sports Exerc., 51(7), pp.1532–1537.
+ *   DOI: 10.1249/MSS.0000000000001925
+ *
+ * The paper provides a multiple-linear-regression model trained on indirect
+ * calorimetry (VO₂) from 52 subjects performing 7 resistance exercises at
+ * 60–70 % 1RM.  The model predicts **net** kilocalories (total minus resting
+ * metabolic cost) from demographic and training-volume variables.
+ *
+ * ─── Total bout equation (R² = 0.773, SEE = 28.5 kcal) ───────────────────
+ *
+ *   Net kcal = 0.874·height_cm − 0.596·age_yr − 1.016·fat_mass_kg
+ *            + 1.638·lean_mass_kg + 2.461·(TV / 1000) − 110.742
+ *
+ * where TV = Σ(sets × reps × weight_kg) across the workout.
+ *
+ * NOTE: The published abstract prints the TV scaling factor as "×10⁻²" but
+ * verification against the paper's own reported means (male = 161.2 kcal)
+ * shows the correct factor is **×10⁻³** (i.e. TV / 1000).  The Table 2
+ * column header "Volume m³ (kg)" confirms this.
+ *
+ * ─── Individual exercise equations (Table 2) ─────────────────────────────
+ *
+ * Seven exercise-specific equations are also provided.  In these, the
+ * "Weight (kg)" coefficient applies to the exercise weight / 100 and the
+ * "Volume" coefficient applies to exercise TV / 1000.  (Verified by
+ * back-calculating against the study's reported demographics and means.)
+ *
+ * ─── Limitations & uncertainty ────────────────────────────────────────────
+ *
+ * • Calibrated on Keiser pneumatic machines, 60–70 % 1RM, 2–3 sets of
+ *   8–12 reps.  Accuracy degrades for very different protocols.
+ * • Demographics limited to ages 20–58.
+ * • We map all 77 app exercises to the 7 studied exercises.  Exercises that
+ *   are close analogues (e.g. incline bench → chest press) inherit the
+ *   equation directly; distant mappings (e.g. hip thrust → leg press)
+ *   carry additional uncertainty.
+ * • Bodyweight exercises (pull-ups, dips, push-ups) add a fraction of
+ *   body mass to the logged weight before computing TV.
+ * • When height, age, or body composition are unknown, defaults are used
+ *   (175 cm, 30 yr, 22 % body fat) which adds ~±10 kcal per workout
+ *   to the uncertainty.
+ */
+
+// ── Individual exercise regression coefficients (Table 2) ──────────────
+
+interface ExerciseCoeffs {
+	h: number;   // height (cm)
+	age: number; // age (yr)
+	g: number;   // gender (male=1, female=0)
+	fm: number;  // DEXA fat mass (kg)
+	lm: number;  // DEXA lean mass (kg)
+	w: number;   // exercise weight / 100
+	v: number;   // exercise TV / 1000
+	c: number;   // constant
+	see: number; // standard error of estimate (kcal)
+}
+
+const LYTLE_EXERCISES: Record<string, ExerciseCoeffs> = {
+	'leg-press': {
+		h: 0.120, age: -0.093, g: 0, fm: 0, lm: 0.297,
+		w: 1.169, v: 0, c: -13.837, see: 4.4
+	},
+	'chest-press': {
+		h: 0.186, age: -0.317, g: -0.198, fm: 0, lm: 0.271,
+		w: 4.211, v: 0, c: -28.468, see: 4.7
+	},
+	'leg-curl': {
+		h: 0, age: -0.129, g: 0, fm: 0, lm: 0.245,
+		w: 5.189, v: -0.100, c: 6.633, see: 5.36
+	},
+	'lat-pulldown': {
+		h: 0, age: -0.165, g: 0, fm: -0.128, lm: 0.187,
+		w: 4.725, v: 0, c: 8.483, see: 4.96
+	},
+	'leg-extension': {
+		h: 0, age: -0.08, g: -1.635, fm: -0.185, lm: 0.394,
+		w: 4.252, v: 0, c: 1.444, see: 5.31
+	},
+	'triceps-pushdown': {
+		h: 0.255, age: 0, g: -5.124, fm: -0.239, lm: 0.390,
+		w: 1.919, v: 0, c: -44.891, see: 4.99
+	},
+	'biceps-curl': {
+		h: 0.292, age: -0.091, g: -7.068, fm: 0, lm: 0.351,
+		w: 1.510, v: -0.156, c: -44.262, see: 5.60
+	},
+};
+
+// ── Total bout equation coefficients ───────────────────────────────────
+
+const TOTAL_BOUT = {
+	h: 0.874,
+	age: -0.596,
+	fm: -1.016,
+	lm: 1.638,
+	tv: 2.461,   // applied to TV / 1000
+	c: -110.742,
+	see: 28.465,
+	r2: 0.773,
+};
+
+// ── Exercise → Lytle category mapping ──────────────────────────────────
+//
+// confidence: 'direct' = very close analogue of the studied exercise
+//             'close'  = same movement pattern / muscle group
+//             'distant' = best available but mechanically different
+
+type MappingConfidence = 'direct' | 'close' | 'distant';
+
+interface ExerciseMapping {
+	lytleKey: string;
+	confidence: MappingConfidence;
+	bwFraction?: number; // fraction of bodyweight to add (for bodyweight exercises)
+}
+
+export const EXERCISE_MAP: Record<string, ExerciseMapping> = {
+	// === CHEST → chest-press ===
+	'bench-press-barbell':            { lytleKey: 'chest-press', confidence: 'direct' },
+	'incline-bench-press-barbell':    { lytleKey: 'chest-press', confidence: 'close' },
+	'decline-bench-press-barbell':    { lytleKey: 'chest-press', confidence: 'close' },
+	'bench-press-close-grip-barbell': { lytleKey: 'chest-press', confidence: 'close' },
+	'bench-press-dumbbell':           { lytleKey: 'chest-press', confidence: 'close' },
+	'incline-bench-press-dumbbell':   { lytleKey: 'chest-press', confidence: 'close' },
+	'chest-fly-dumbbell':             { lytleKey: 'chest-press', confidence: 'distant' },
+	'chest-dip':                      { lytleKey: 'chest-press', confidence: 'close', bwFraction: 0.90 },
+	'push-up':                        { lytleKey: 'chest-press', confidence: 'close', bwFraction: 0.64 },
+	'cable-crossover':                { lytleKey: 'chest-press', confidence: 'distant' },
+
+	// === BACK → lat-pulldown ===
+	'bent-over-row-barbell':  { lytleKey: 'lat-pulldown', confidence: 'close' },
+	'deadlift-barbell':       { lytleKey: 'leg-press', confidence: 'distant' }, // full-body → leg-press as largest compound
+	'pull-up':                { lytleKey: 'lat-pulldown', confidence: 'direct', bwFraction: 1.0 },
+	'chin-up':                { lytleKey: 'lat-pulldown', confidence: 'direct', bwFraction: 1.0 },
+	'lat-pulldown-cable':     { lytleKey: 'lat-pulldown', confidence: 'direct' },
+	'seated-row-cable':       { lytleKey: 'lat-pulldown', confidence: 'close' },
+	'dumbbell-row':           { lytleKey: 'lat-pulldown', confidence: 'close' },
+	't-bar-row':              { lytleKey: 'lat-pulldown', confidence: 'close' },
+	'incline-row-dumbbell':   { lytleKey: 'lat-pulldown', confidence: 'close' },
+	'face-pull-cable':        { lytleKey: 'lat-pulldown', confidence: 'distant' },
+
+	// === SHOULDERS → chest-press (pressing) or lat-pulldown (pulling) ===
+	'overhead-press-barbell':  { lytleKey: 'chest-press', confidence: 'close' },
+	'overhead-press-dumbbell': { lytleKey: 'chest-press', confidence: 'close' },
+	'lateral-raise-dumbbell':  { lytleKey: 'biceps-curl', confidence: 'distant' }, // isolation, similar load range
+	'lateral-raise-cable':     { lytleKey: 'biceps-curl', confidence: 'distant' },
+	'front-raise-dumbbell':    { lytleKey: 'biceps-curl', confidence: 'distant' },
+	'reverse-fly-dumbbell':    { lytleKey: 'biceps-curl', confidence: 'distant' },
+	'upright-row-barbell':     { lytleKey: 'lat-pulldown', confidence: 'distant' },
+	'shrug-barbell':           { lytleKey: 'lat-pulldown', confidence: 'distant' },
+	'shrug-dumbbell':          { lytleKey: 'lat-pulldown', confidence: 'distant' },
+
+	// === ARMS (biceps) → biceps-curl ===
+	'bicep-curl-barbell':          { lytleKey: 'biceps-curl', confidence: 'direct' },
+	'bicep-curl-dumbbell':         { lytleKey: 'biceps-curl', confidence: 'direct' },
+	'hammer-curl-dumbbell':        { lytleKey: 'biceps-curl', confidence: 'close' },
+	'preacher-curl-barbell':       { lytleKey: 'biceps-curl', confidence: 'close' },
+	'concentration-curl-dumbbell': { lytleKey: 'biceps-curl', confidence: 'close' },
+	'cable-curl':                  { lytleKey: 'biceps-curl', confidence: 'close' },
+
+	// === ARMS (triceps) → triceps-pushdown ===
+	'tricep-pushdown-cable':              { lytleKey: 'triceps-pushdown', confidence: 'direct' },
+	'skullcrusher-dumbbell':              { lytleKey: 'triceps-pushdown', confidence: 'close' },
+	'skullcrusher-barbell':               { lytleKey: 'triceps-pushdown', confidence: 'close' },
+	'overhead-tricep-extension-dumbbell': { lytleKey: 'triceps-pushdown', confidence: 'close' },
+	'tricep-dip':                         { lytleKey: 'triceps-pushdown', confidence: 'close', bwFraction: 0.90 },
+	'kickback-dumbbell':                  { lytleKey: 'triceps-pushdown', confidence: 'close' },
+
+	// === LEGS (quad-dominant) → leg-press or leg-extension ===
+	'squat-barbell':                  { lytleKey: 'leg-press', confidence: 'close' },
+	'front-squat-barbell':            { lytleKey: 'leg-press', confidence: 'close' },
+	'leg-press-machine':              { lytleKey: 'leg-press', confidence: 'direct' },
+	'lunge-dumbbell':                 { lytleKey: 'leg-press', confidence: 'close' },
+	'bulgarian-split-squat-dumbbell': { lytleKey: 'leg-press', confidence: 'close' },
+	'leg-extension-machine':          { lytleKey: 'leg-extension', confidence: 'direct' },
+	'goblet-squat-dumbbell':          { lytleKey: 'leg-press', confidence: 'close' },
+	'hack-squat-machine':             { lytleKey: 'leg-press', confidence: 'close' },
+
+	// === LEGS (hamstring/posterior) → leg-curl ===
+	'leg-curl-machine':            { lytleKey: 'leg-curl', confidence: 'direct' },
+	'romanian-deadlift-barbell':   { lytleKey: 'leg-curl', confidence: 'close' },
+	'romanian-deadlift-dumbbell':  { lytleKey: 'leg-curl', confidence: 'close' },
+	'hip-thrust-barbell':          { lytleKey: 'leg-press', confidence: 'distant' },
+	'nordic-hamstring-curl':       { lytleKey: 'leg-curl', confidence: 'close', bwFraction: 0.70 },
+
+	// === LEGS (calves) → leg-extension (closest isolation) ===
+	'calf-raise-machine':  { lytleKey: 'leg-extension', confidence: 'distant' },
+	'calf-raise-standing': { lytleKey: 'leg-extension', confidence: 'distant' },
+
+	// === CORE → biceps-curl (similar isolation load range) ===
+	'plank':              { lytleKey: 'biceps-curl', confidence: 'distant' },
+	'decline-crunch':     { lytleKey: 'biceps-curl', confidence: 'distant' },
+	'flat-leg-raise':     { lytleKey: 'biceps-curl', confidence: 'distant' },
+	'crunch':             { lytleKey: 'biceps-curl', confidence: 'distant' },
+	'hanging-leg-raise':  { lytleKey: 'biceps-curl', confidence: 'distant' },
+	'cable-crunch':       { lytleKey: 'biceps-curl', confidence: 'distant' },
+	'russian-twist':      { lytleKey: 'biceps-curl', confidence: 'distant' },
+	'ab-wheel-rollout':   { lytleKey: 'biceps-curl', confidence: 'distant', bwFraction: 0.50 },
+
+	// === OTHER ===
+	'clean-and-press-barbell': { lytleKey: 'leg-press', confidence: 'distant' },
+	'farmers-walk':            { lytleKey: 'leg-press', confidence: 'distant' },
+};
+
+// ── Confidence penalty for uncertainty ──────────────────────────────────
+// Additional SEE (kcal) added per exercise based on mapping confidence.
+// 'direct' = same exercise, no additional error.
+// 'close'  = same pattern, small extrapolation error.
+// 'distant' = different pattern, larger extrapolation.
+const CONFIDENCE_SEE: Record<MappingConfidence, number> = {
+	direct: 0,
+	close: 2,
+	distant: 5,
+};
+
+// ── Demographics type ──────────────────────────────────────────────────
+
+export interface Demographics {
+	heightCm?: number;     // default: 175
+	ageYr?: number;        // default: 30
+	isMale?: boolean;      // default: true (gender=1)
+	bodyWeightKg?: number; // default: 80
+	bodyFatPct?: number;   // default: 22
+}
+
+const DEFAULTS: Required<Demographics> = {
+	heightCm: 175,
+	ageYr: 30,
+	isMale: true,
+	bodyWeightKg: 80,
+	bodyFatPct: 22,
+};
+
+function resolveDemographics(d?: Demographics) {
+	const heightCm = d?.heightCm ?? DEFAULTS.heightCm;
+	const ageYr = d?.ageYr ?? DEFAULTS.ageYr;
+	const isMale = d?.isMale ?? DEFAULTS.isMale;
+	const bodyWeightKg = d?.bodyWeightKg ?? DEFAULTS.bodyWeightKg;
+	const bodyFatPct = d?.bodyFatPct ?? DEFAULTS.bodyFatPct;
+	const fatMassKg = bodyWeightKg * bodyFatPct / 100;
+	const leanMassKg = bodyWeightKg - fatMassKg;
+	const gender = isMale ? 1 : 0;
+
+	// Track how many fields used defaults (for uncertainty)
+	let defaultCount = 0;
+	if (d?.heightCm == null) defaultCount++;
+	if (d?.ageYr == null) defaultCount++;
+	if (d?.bodyWeightKg == null) defaultCount++;
+	if (d?.bodyFatPct == null) defaultCount++;
+
+	return { heightCm, ageYr, gender, fatMassKg, leanMassKg, bodyWeightKg, defaultCount };
+}
+
+// ── Per-exercise set data ──────────────────────────────────────────────
+
+export interface SetData {
+	weight: number; // external load in kg (already ×2 for bilateral)
+	reps: number;
+}
+
+export interface ExerciseData {
+	exerciseId: string;
+	sets: SetData[];
+}
+
+// ── Core estimation functions ──────────────────────────────────────────
+
+/**
+ * Compute effective weight for a set, adding bodyweight fraction where applicable.
+ */
+function effectiveWeight(exerciseId: string, externalWeight: number, bodyMassKg: number): number {
+	const mapping = EXERCISE_MAP[exerciseId];
+	if (mapping?.bwFraction) {
+		return externalWeight + bodyMassKg * mapping.bwFraction;
+	}
+	return externalWeight;
+}
+
+/**
+ * Estimate kcal for a single exercise using the individual Lytle equation.
+ */
+function estimateExerciseKcal(
+	exerciseId: string,
+	sets: SetData[],
+	demo: ReturnType<typeof resolveDemographics>
+): { kcal: number; see: number } {
+	const mapping = EXERCISE_MAP[exerciseId];
+	if (!mapping) return { kcal: 0, see: 0 };
+
+	const coeffs = LYTLE_EXERCISES[mapping.lytleKey];
+	if (!coeffs) return { kcal: 0, see: 0 };
+
+	// Compute average exercise weight and total TV for this exercise
+	let totalTV = 0;
+	let totalWeightedWeight = 0;
+	let totalReps = 0;
+	for (const s of sets) {
+		if (s.reps <= 0) continue;
+		const w = effectiveWeight(exerciseId, s.weight, demo.bodyWeightKg);
+		totalTV += w * s.reps;
+		totalWeightedWeight += w * s.reps;
+		totalReps += s.reps;
+	}
+	if (totalReps === 0) return { kcal: 0, see: 0 };
+
+	const avgWeight = totalWeightedWeight / totalReps;
+
+	const kcal = coeffs.h * demo.heightCm
+		+ coeffs.age * demo.ageYr
+		+ coeffs.g * demo.gender
+		+ coeffs.fm * demo.fatMassKg
+		+ coeffs.lm * demo.leanMassKg
+		+ coeffs.w * (avgWeight / 100)
+		+ coeffs.v * (totalTV / 1000)
+		+ coeffs.c;
+
+	const see = Math.sqrt(coeffs.see ** 2 + CONFIDENCE_SEE[mapping.confidence] ** 2);
+
+	return { kcal: Math.max(0, kcal), see };
+}
+
+/**
+ * Estimate kcal for an entire workout using the total bout equation.
+ *
+ * Returns point estimate and 95% confidence interval.
+ */
+export function estimateWorkoutKcal(
+	exercises: ExerciseData[],
+	demographics?: Demographics
+): { kcal: number; lower: number; upper: number; see: number } {
+	const demo = resolveDemographics(demographics);
+
+	// Compute total TV across all exercises
+	let totalTV = 0;
+	for (const ex of exercises) {
+		for (const s of ex.sets) {
+			if (s.reps <= 0) continue;
+			const w = effectiveWeight(ex.exerciseId, s.weight, demo.bodyWeightKg);
+			totalTV += w * s.reps;
+		}
+	}
+
+	const kcal = TOTAL_BOUT.h * demo.heightCm
+		+ TOTAL_BOUT.age * demo.ageYr
+		+ TOTAL_BOUT.fm * demo.fatMassKg
+		+ TOTAL_BOUT.lm * demo.leanMassKg
+		+ TOTAL_BOUT.tv * (totalTV / 1000)
+		+ TOTAL_BOUT.c;
+
+	// Uncertainty: model SEE + demographic default uncertainty
+	// Each defaulted demographic adds ~3-4 kcal of uncertainty (height ±10cm = ±8.7,
+	// age ±10yr = ±6.0, body comp ±5% = ±5-8 kcal; halved for ±1σ)
+	const demoUncertainty = demo.defaultCount * 4;
+	const see = Math.sqrt(TOTAL_BOUT.see ** 2 + demoUncertainty ** 2);
+
+	const point = Math.max(0, kcal);
+	return {
+		kcal: Math.round(point),
+		lower: Math.max(0, Math.round(point - 1.96 * see)),
+		upper: Math.round(point + 1.96 * see),
+		see: Math.round(see * 10) / 10,
+	};
+}
+
+/**
+ * Estimate kcal per exercise within a workout (using individual equations).
+ * Useful for showing which exercises contributed most.
+ */
+export function estimatePerExerciseKcal(
+	exercises: ExerciseData[],
+	demographics?: Demographics
+): { exerciseId: string; kcal: number; see: number; confidence: MappingConfidence }[] {
+	const demo = resolveDemographics(demographics);
+
+	return exercises.map((ex) => {
+		const { kcal, see } = estimateExerciseKcal(ex.exerciseId, ex.sets, demo);
+		const confidence = EXERCISE_MAP[ex.exerciseId]?.confidence ?? 'distant';
+		return { exerciseId: ex.exerciseId, kcal: Math.round(kcal * 10) / 10, see: Math.round(see * 10) / 10, confidence };
+	});
+}
+
+/**
+ * Estimate cumulative kcal across multiple workouts.
+ * Uncertainty decreases relative to the total as errors partially cancel.
+ */
+export function estimateCumulativeKcal(
+	workoutResults: { kcal: number; see: number }[]
+): { kcal: number; lower: number; upper: number } {
+	let totalKcal = 0;
+	let sumSeeSquared = 0;
+
+	for (const w of workoutResults) {
+		totalKcal += w.kcal;
+		sumSeeSquared += w.see ** 2;
+	}
+
+	// Cumulative SEE = sqrt(sum of individual SEE²)
+	// This assumes errors are independent across workouts
+	const cumulativeSee = Math.sqrt(sumSeeSquared);
+
+	return {
+		kcal: Math.round(totalKcal),
+		lower: Math.max(0, Math.round(totalKcal - 1.96 * cumulativeSee)),
+		upper: Math.round(totalKcal + 1.96 * cumulativeSee),
+	};
+}
diff --git a/src/lib/js/fitnessI18n.ts b/src/lib/js/fitnessI18n.ts
index bc4d01cf..7f23122d 100644
--- a/src/lib/js/fitnessI18n.ts
+++ b/src/lib/js/fitnessI18n.ts
@@ -71,8 +71,14 @@ const translations: Translations = {
 	workout_singular: { en: 'Workout', de: 'Training' },
 	workouts_plural: { en: 'Workouts', de: 'Trainings' },
 	lifted: { en: 'Lifted', de: 'Gehoben' },
+	est_kcal: { en: 'Est. kcal', de: 'Gesch. kcal' },
+	kcal_set_profile: { en: 'Set sex & height in', de: 'Geschlecht & Grösse unter' },
 	distance_covered: { en: 'Distance Covered', de: 'Zurückgelegt' },
 	workouts_per_week: { en: 'Workouts per week', de: 'Trainings pro Woche' },
+	sex: { en: 'Sex', de: 'Geschlecht' },
+	male: { en: 'Male', de: 'Männlich' },
+	female: { en: 'Female', de: 'Weiblich' },
+	height: { en: 'Height (cm)', de: 'Grösse (cm)' },
 	no_workout_data: { en: 'No workout data to display yet.', de: 'Noch keine Trainingsdaten vorhanden.' },
 	weight: { en: 'Weight', de: 'Gewicht' },
 
@@ -167,6 +173,7 @@ const translations: Translations = {
 
 	// Measure page
 	measure_title: { en: 'Measure', de: 'Messen' },
+	profile: { en: 'Profile', de: 'Profil' },
 	new_measurement: { en: 'New Measurement', de: 'Neue Messung' },
 	edit_measurement: { en: 'Edit Measurement', de: 'Messung bearbeiten' },
 	weight_kg: { en: 'Weight (kg)', de: 'Gewicht (kg)' },
diff --git a/src/models/FitnessGoal.ts b/src/models/FitnessGoal.ts
index 74bfa335..dff27b3e 100644
--- a/src/models/FitnessGoal.ts
+++ b/src/models/FitnessGoal.ts
@@ -3,7 +3,9 @@ import mongoose from 'mongoose';
 const FitnessGoalSchema = new mongoose.Schema(
   {
     username: { type: String, required: true, unique: true },
-    weeklyWorkouts: { type: Number, required: true, default: 4, min: 1, max: 14 }
+    weeklyWorkouts: { type: Number, required: true, default: 4, min: 1, max: 14 },
+    sex: { type: String, enum: ['male', 'female'], default: 'male' },
+    heightCm: { type: Number, min: 100, max: 250 }
   },
   { timestamps: true }
 );
@@ -11,6 +13,8 @@ const FitnessGoalSchema = new mongoose.Schema(
 interface IFitnessGoal {
   username: string;
   weeklyWorkouts: number;
+  sex?: 'male' | 'female';
+  heightCm?: number;
 }
 
 let _model: mongoose.Model<IFitnessGoal>;
diff --git a/src/routes/api/fitness/goal/+server.ts b/src/routes/api/fitness/goal/+server.ts
index 0052f04e..1b939cb6 100644
--- a/src/routes/api/fitness/goal/+server.ts
+++ b/src/routes/api/fitness/goal/+server.ts
@@ -14,31 +14,36 @@ export const GET: RequestHandler = async ({ locals }) => {
 
 	// If no goal set, return early
 	if (weeklyWorkouts === null) {
-		return json({ weeklyWorkouts: null, streak: 0 });
+		return json({ weeklyWorkouts: null, streak: 0, sex: goal?.sex ?? 'male', heightCm: goal?.heightCm ?? null });
 	}
 
 	const streak = await computeStreak(user.nickname, weeklyWorkouts);
-	return json({ weeklyWorkouts, streak });
+	return json({ weeklyWorkouts, streak, sex: goal?.sex ?? 'male', heightCm: goal?.heightCm ?? null });
 };
 
 export const PUT: RequestHandler = async ({ request, locals }) => {
 	const user = await requireAuth(locals);
-	const { weeklyWorkouts } = await request.json();
+	const body = await request.json();
+	const { weeklyWorkouts, sex, heightCm } = body;
 
 	if (typeof weeklyWorkouts !== 'number' || weeklyWorkouts < 1 || weeklyWorkouts > 14 || !Number.isInteger(weeklyWorkouts)) {
 		return json({ error: 'weeklyWorkouts must be an integer between 1 and 14' }, { status: 400 });
 	}
 
+	const update: Record<string, unknown> = { weeklyWorkouts };
+	if (sex === 'male' || sex === 'female') update.sex = sex;
+	if (typeof heightCm === 'number' && heightCm >= 100 && heightCm <= 250) update.heightCm = heightCm;
+
 	await dbConnect();
 
-	await FitnessGoal.findOneAndUpdate(
+	const goal = await FitnessGoal.findOneAndUpdate(
 		{ username: user.nickname },
-		{ weeklyWorkouts },
-		{ upsert: true }
-	);
+		update,
+		{ upsert: true, new: true }
+	).lean() as any;
 
 	const streak = await computeStreak(user.nickname, weeklyWorkouts);
-	return json({ weeklyWorkouts, streak });
+	return json({ weeklyWorkouts, streak, sex: goal?.sex ?? 'male', heightCm: goal?.heightCm ?? null });
 };
 
 async function computeStreak(username: string, weeklyGoal: number): Promise<number> {
diff --git a/src/routes/api/fitness/stats/overview/+server.ts b/src/routes/api/fitness/stats/overview/+server.ts
index d8379016..47a3bbf7 100644
--- a/src/routes/api/fitness/stats/overview/+server.ts
+++ b/src/routes/api/fitness/stats/overview/+server.ts
@@ -5,6 +5,8 @@ import { dbConnect } from '$utils/db';
 import { WorkoutSession } from '$models/WorkoutSession';
 import { BodyMeasurement } from '$models/BodyMeasurement';
 import { getExerciseById, getExerciseMetrics } from '$lib/data/exercises';
+import { estimateWorkoutKcal, estimateCumulativeKcal, type ExerciseData, type Demographics } from '$lib/data/kcalEstimate';
+import { FitnessGoal } from '$models/FitnessGoal';
 
 export const GET: RequestHandler = async ({ locals }) => {
 	const user = await requireAuth(locals);
@@ -36,7 +38,23 @@ export const GET: RequestHandler = async ({ locals }) => {
 		}
 	]);
 
-	// Lifetime totals: tonnage lifted + cardio km
+	// Fetch user demographics for kcal estimation
+	const [goal, latestMeasurement] = await Promise.all([
+		FitnessGoal.findOne({ username: user.nickname }).lean() as any,
+		BodyMeasurement.findOne(
+			{ createdBy: user.nickname, weight: { $ne: null } },
+			{ weight: 1, bodyFatPercent: 1, _id: 0 }
+		).sort({ date: -1 }).lean() as any
+	]);
+
+	const demographics: Demographics = {
+		heightCm: goal?.heightCm ?? undefined,
+		isMale: (goal?.sex ?? 'male') === 'male',
+		bodyWeightKg: latestMeasurement?.weight ?? undefined,
+		bodyFatPct: latestMeasurement?.bodyFatPercent ?? undefined,
+	};
+
+	// Lifetime totals: tonnage lifted + cardio km + kcal estimate
 	const allSessions = await WorkoutSession.find(
 		{ createdBy: user.nickname },
 		{ 'exercises.exerciseId': 1, 'exercises.sets': 1 }
@@ -44,23 +62,38 @@ export const GET: RequestHandler = async ({ locals }) => {
 
 	let totalTonnage = 0;
 	let totalCardioKm = 0;
+	const workoutKcalResults: { kcal: number; see: number }[] = [];
+
 	for (const s of allSessions) {
+		const strengthExercises: ExerciseData[] = [];
 		for (const ex of s.exercises) {
 			const exercise = getExerciseById(ex.exerciseId);
 			const metrics = getExerciseMetrics(exercise);
 			const isCardio = metrics.includes('distance');
 			const weightMultiplier = exercise?.bilateral ? 2 : 1;
+			const completedSets: { weight: number; reps: number }[] = [];
 			for (const set of ex.sets) {
 				if (!set.completed) continue;
 				if (isCardio) {
 					totalCardioKm += set.distance ?? 0;
 				} else {
-					totalTonnage += (set.weight ?? 0) * weightMultiplier * (set.reps ?? 0);
+					const w = (set.weight ?? 0) * weightMultiplier;
+					totalTonnage += w * (set.reps ?? 0);
+					if (set.reps) completedSets.push({ weight: w, reps: set.reps });
 				}
 			}
+			if (completedSets.length > 0) {
+				strengthExercises.push({ exerciseId: ex.exerciseId, sets: completedSets });
+			}
+		}
+		if (strengthExercises.length > 0) {
+			const result = estimateWorkoutKcal(strengthExercises, demographics);
+			workoutKcalResults.push({ kcal: result.kcal, see: result.see });
 		}
 	}
 
+	const kcalEstimate = estimateCumulativeKcal(workoutKcalResults);
+
 	const weightMeasurements = await BodyMeasurement.find(
 		{ createdBy: user.nickname, weight: { $ne: null } },
 		{ date: 1, weight: 1, _id: 0 }
@@ -141,6 +174,7 @@ export const GET: RequestHandler = async ({ locals }) => {
 		totalWorkouts,
 		totalTonnage: Math.round(totalTonnage / 1000 * 10) / 10,
 		totalCardioKm: Math.round(totalCardioKm * 10) / 10,
+		kcalEstimate,
 		workoutsChart,
 		weightChart
 	});
diff --git a/src/routes/fitness/[history=fitnessHistory]/[id]/+page.svelte b/src/routes/fitness/[history=fitnessHistory]/[id]/+page.svelte
index 559524ba..5d36037f 100644
--- a/src/routes/fitness/[history=fitnessHistory]/[id]/+page.svelte
+++ b/src/routes/fitness/[history=fitnessHistory]/[id]/+page.svelte
@@ -1,12 +1,13 @@
 <script>
 	import { goto, invalidateAll } from '$app/navigation';
 	import { page } from '$app/stores';
-	import { Clock, Weight, Trophy, Trash2, Pencil, Plus, Upload, Route, X, RefreshCw, Gauge } from 'lucide-svelte';
+	import { Clock, Weight, Trophy, Trash2, Pencil, Plus, Upload, Route, X, RefreshCw, Gauge, Flame } from 'lucide-svelte';
 	import { detectFitnessLang, fitnessSlugs, t } from '$lib/js/fitnessI18n';
 
 	const lang = $derived(detectFitnessLang($page.url.pathname));
 	const sl = $derived(fitnessSlugs(lang));
 	import { getExerciseById, getExerciseMetrics, METRIC_LABELS } from '$lib/data/exercises';
+	import { estimateWorkoutKcal } from '$lib/data/kcalEstimate';
 	import ExerciseName from '$lib/components/fitness/ExerciseName.svelte';
 	import SetTable from '$lib/components/fitness/SetTable.svelte';
 	import ExercisePicker from '$lib/components/fitness/ExercisePicker.svelte';
@@ -17,6 +18,27 @@
 
 	const session = $derived(data.session);
 
+	const kcalResult = $derived.by(() => {
+		if (!session?.exercises) return null;
+		/** @type {import('$lib/data/kcalEstimate').ExerciseData[]} */
+		const exercises = [];
+		for (const ex of session.exercises) {
+			const exercise = getExerciseById(ex.exerciseId, lang);
+			const metrics = getExerciseMetrics(exercise);
+			if (metrics.includes('distance')) continue;
+			const weightMultiplier = exercise?.bilateral ? 2 : 1;
+			const sets = ex.sets
+				.filter((/** @type {any} */ s) => s.completed && s.reps > 0)
+				.map((/** @type {any} */ s) => ({
+					weight: (s.weight ?? 0) * weightMultiplier,
+					reps: s.reps ?? 0
+				}));
+			if (sets.length > 0) exercises.push({ exerciseId: ex.exerciseId, sets });
+		}
+		if (exercises.length === 0) return null;
+		return estimateWorkoutKcal(exercises);
+	});
+
 	function checkDark() {
 		if (typeof document === 'undefined') return false;
 		const t = document.documentElement.dataset.theme;
@@ -500,6 +522,12 @@
 					<span>{Math.round(session.totalVolume).toLocaleString()} kg</span>
 				</div>
 			{/if}
+			{#if kcalResult}
+				<div class="stat-pill kcal">
+					<Flame size={14} />
+					<span>{kcalResult.kcal} &plusmn; {kcalResult.kcal - kcalResult.lower} kcal</span>
+				</div>
+			{/if}
 			{#if session.prs?.length > 0}
 				<div class="stat-pill pr">
 					<Trophy size={14} />
@@ -878,6 +906,11 @@
 		font-size: 0.8rem;
 		color: var(--color-text-secondary);
 	}
+	.stat-pill.kcal {
+		color: var(--nord12);
+		border-color: var(--nord12);
+		background: color-mix(in srgb, var(--nord12) 10%, transparent);
+	}
 	.stat-pill.pr {
 		color: var(--nord13);
 		border-color: var(--nord13);
diff --git a/src/routes/fitness/[measure=fitnessMeasure]/+page.server.ts b/src/routes/fitness/[measure=fitnessMeasure]/+page.server.ts
index 9cb4865b..1a40ec84 100644
--- a/src/routes/fitness/[measure=fitnessMeasure]/+page.server.ts
+++ b/src/routes/fitness/[measure=fitnessMeasure]/+page.server.ts
@@ -1,13 +1,15 @@
 import type { PageServerLoad } from './$types';
 
 export const load: PageServerLoad = async ({ fetch }) => {
-	const [latestRes, listRes] = await Promise.all([
+	const [latestRes, listRes, goalRes] = await Promise.all([
 		fetch('/api/fitness/measurements/latest'),
-		fetch('/api/fitness/measurements?limit=20')
+		fetch('/api/fitness/measurements?limit=20'),
+		fetch('/api/fitness/goal')
 	]);
 
 	return {
 		latest: await latestRes.json(),
-		measurements: await listRes.json()
+		measurements: await listRes.json(),
+		profile: goalRes.ok ? await goalRes.json() : {}
 	};
 };
diff --git a/src/routes/fitness/[measure=fitnessMeasure]/+page.svelte b/src/routes/fitness/[measure=fitnessMeasure]/+page.svelte
index 23527456..132ca869 100644
--- a/src/routes/fitness/[measure=fitnessMeasure]/+page.svelte
+++ b/src/routes/fitness/[measure=fitnessMeasure]/+page.svelte
@@ -14,6 +14,39 @@
 	let measurements = $state(data.measurements?.measurements ? [...data.measurements.measurements] : []);
 	let showForm = $state(false);
 	let saving = $state(false);
+
+	// Profile fields (sex, height) — stored in FitnessGoal
+	let profileSex = $state(data.profile?.sex ?? 'male');
+	let profileHeight = $state(data.profile?.heightCm != null ? String(data.profile.heightCm) : '');
+	let profileSaving = $state(false);
+	let profileDirty = $derived(
+		profileSex !== (data.profile?.sex ?? 'male') ||
+		profileHeight !== (data.profile?.heightCm != null ? String(data.profile.heightCm) : '')
+	);
+
+	async function saveProfile() {
+		profileSaving = true;
+		try {
+			/** @type {Record<string, unknown>} */
+			const body = {
+				weeklyWorkouts: data.profile?.weeklyWorkouts ?? 4,
+				sex: profileSex
+			};
+			const h = Number(profileHeight);
+			if (h >= 100 && h <= 250) body.heightCm = h;
+			const res = await fetch('/api/fitness/goal', {
+				method: 'PUT',
+				headers: { 'Content-Type': 'application/json' },
+				body: JSON.stringify(body)
+			});
+			if (res.ok) {
+				const d = await res.json();
+				data.profile = d;
+			}
+		} finally {
+			profileSaving = false;
+		}
+	}
 	/** @type {string | null} */
 	let editingId = $state(null);
 
@@ -231,6 +264,28 @@
 <div class="measure-page">
 	<h1>{t('measure_title', lang)}</h1>
 
+	<section class="profile-section">
+		<h2>{t('profile', lang)}</h2>
+		<div class="profile-row">
+			<div class="form-group">
+				<label for="p-sex">{t('sex', lang)}</label>
+				<select id="p-sex" bind:value={profileSex}>
+					<option value="male">{t('male', lang)}</option>
+					<option value="female">{t('female', lang)}</option>
+				</select>
+			</div>
+			<div class="form-group">
+				<label for="p-height">{t('height', lang)}</label>
+				<input id="p-height" type="number" min="100" max="250" placeholder="175" bind:value={profileHeight} />
+			</div>
+			{#if profileDirty}
+				<button class="profile-save-btn" onclick={saveProfile} disabled={profileSaving}>
+					{profileSaving ? t('saving', lang) : t('save', lang)}
+				</button>
+			{/if}
+		</div>
+	</section>
+
 	{#if showForm}
 		<form class="measure-form" onsubmit={(e) => { e.preventDefault(); saveMeasurement(); }}>
 			<div class="form-header">
@@ -375,6 +430,48 @@
 		color: var(--color-text-secondary);
 	}
 
+	/* Profile */
+	.profile-section {
+		background: var(--color-surface);
+		border-radius: 8px;
+		box-shadow: var(--shadow-sm);
+		padding: 0.75rem 1rem;
+	}
+	.profile-section h2 {
+		margin: 0 0 0.5rem;
+		font-size: 0.9rem;
+	}
+	.profile-row {
+		display: flex;
+		gap: 0.75rem;
+		align-items: flex-end;
+	}
+	.profile-row select {
+		padding: 0.4rem 0.5rem;
+		border: 1px solid var(--color-border);
+		border-radius: 6px;
+		background: var(--color-bg-elevated);
+		color: inherit;
+		font-size: 0.85rem;
+	}
+	.profile-save-btn {
+		padding: 0.4rem 0.75rem;
+		background: var(--color-primary);
+		color: white;
+		border: none;
+		border-radius: 6px;
+		font-weight: 600;
+		font-size: 0.8rem;
+		cursor: pointer;
+		white-space: nowrap;
+		align-self: flex-end;
+		margin-bottom: 0.4rem;
+	}
+	.profile-save-btn:disabled {
+		opacity: 0.6;
+		cursor: not-allowed;
+	}
+
 	/* Form */
 	.measure-form {
 		background: var(--color-surface);
diff --git a/src/routes/fitness/[stats=fitnessStats]/+page.svelte b/src/routes/fitness/[stats=fitnessStats]/+page.svelte
index 57258ba0..062dbdf5 100644
--- a/src/routes/fitness/[stats=fitnessStats]/+page.svelte
+++ b/src/routes/fitness/[stats=fitnessStats]/+page.svelte
@@ -1,9 +1,9 @@
 <script>
 	import { page } from '$app/stores';
 	import FitnessChart from '$lib/components/fitness/FitnessChart.svelte';
-	import { Dumbbell, Route, Flame, Zap } from 'lucide-svelte';
+	import { Dumbbell, Route, Flame, Zap, Weight, Info } from 'lucide-svelte';
 	import { onMount } from 'svelte';
-	import { detectFitnessLang, t } from '$lib/js/fitnessI18n';
+	import { detectFitnessLang, fitnessSlugs, t } from '$lib/js/fitnessI18n';
 
 	const lang = $derived(detectFitnessLang($page.url.pathname));
 
@@ -38,6 +38,8 @@
 	let goalInput = $state(4);
 	let goalSaving = $state(false);
 
+	const hasDemographics = $derived(data.goal?.sex != null && data.goal?.heightCm != null);
+
 	function startGoalEdit() {
 		goalInput = goalWeekly ?? 4;
 		goalEditing = true;
@@ -134,10 +136,24 @@
 			<div class="card-label">{(stats.totalWorkouts ?? 0) === 1 ? t('workout_singular', lang) : t('workouts_plural', lang)}</div>
 		</div>
 		<div class="lifetime-card tonnage">
-			<div class="card-icon"><Flame size={24} /></div>
+			<div class="card-icon"><Weight size={24} /></div>
 			<div class="card-value">{stats.totalTonnage ?? 0}<span class="card-unit">t</span></div>
 			<div class="card-label">{t('lifted', lang)}</div>
 		</div>
+		{#if stats.kcalEstimate}
+			<div class="lifetime-card kcal">
+				<a href="https://doi.org/10.1249/MSS.0000000000001925" target="_blank" rel="noopener" class="info-trigger">
+					<Info size={14} />
+					<span class="info-tooltip">Lytle et al. (2019)<br/>Med. Sci. Sports Exerc.<br/>DOI: 10.1249/MSS.0000000000001925</span>
+				</a>
+				<div class="card-icon"><Flame size={24} /></div>
+				<div class="card-value">~{stats.kcalEstimate.kcal.toLocaleString()}<span class="card-unit">kcal</span></div>
+				<div class="card-label">{t('est_kcal', lang)}</div>
+				{#if !hasDemographics}
+					<div class="card-hint">{t('kcal_set_profile', lang)} <a href="/fitness/{fitnessSlugs(lang).measure}">{t('measure_title', lang)}</a></div>
+				{/if}
+			</div>
+		{/if}
 		<div class="lifetime-card cardio">
 			<div class="card-icon"><Route size={24} /></div>
 			<div class="card-value">{stats.totalCardioKm ?? 0}<span class="card-unit">km</span></div>
@@ -210,7 +226,7 @@
 
 	.lifetime-cards {
 		display: grid;
-		grid-template-columns: repeat(4, 1fr);
+		grid-template-columns: repeat(5, 1fr);
 		gap: 0.6rem;
 	}
 	.lifetime-card {
@@ -224,7 +240,6 @@
 		box-shadow: var(--shadow-sm);
 		text-align: center;
 		position: relative;
-		overflow: hidden;
 	}
 	button.lifetime-card {
 		border: none;
@@ -247,6 +262,9 @@
 		background: var(--color-primary);
 	}
 	.lifetime-card.tonnage::before {
+		background: var(--nord10);
+	}
+	.lifetime-card.kcal::before {
 		background: var(--nord12);
 	}
 	.lifetime-card.cardio::before {
@@ -269,6 +287,10 @@
 		background: color-mix(in srgb, var(--color-primary) 15%, transparent);
 	}
 	.tonnage .card-icon {
+		color: var(--nord10);
+		background: color-mix(in srgb, var(--nord10) 15%, transparent);
+	}
+	.kcal .card-icon {
 		color: var(--nord12);
 		background: color-mix(in srgb, var(--nord12) 15%, transparent);
 	}
@@ -305,8 +327,57 @@
 		opacity: 0.7;
 		margin-top: 0.1rem;
 	}
+	.card-hint {
+		font-size: 0.55rem;
+		color: var(--color-text-secondary);
+		opacity: 0.7;
+		margin-top: 0.1rem;
+		line-height: 1.3;
+	}
+	.info-trigger {
+		position: absolute;
+		top: 0.45rem;
+		right: 0.45rem;
+		color: var(--color-text-secondary);
+		opacity: 0.4;
+		cursor: help;
+		z-index: 2;
+		padding: 0.25rem;
+		text-decoration: none;
+	}
+	.info-trigger:hover {
+		opacity: 0.8;
+	}
+	.info-tooltip {
+		display: none;
+		position: absolute;
+		top: 100%;
+		right: 0;
+		margin-top: 0.25rem;
+		background: var(--color-surface);
+		border: 1px solid var(--color-border, var(--nord3));
+		border-radius: 8px;
+		padding: 0.5rem 0.65rem;
+		font-size: 0.65rem;
+		font-weight: 400;
+		line-height: 1.4;
+		color: var(--color-text-secondary);
+		white-space: nowrap;
+		box-shadow: 0 4px 12px rgba(0, 0, 0, 0.2);
+		z-index: 20;
+		text-transform: none;
+		letter-spacing: 0;
+	}
+	.info-trigger:hover .info-tooltip {
+		display: block;
+	}
 
-	@media (max-width: 600px) {
+	.card-hint a {
+		color: var(--nord12);
+		text-decoration: underline;
+	}
+
+	@media (max-width: 750px) {
 		.lifetime-cards {
 			grid-template-columns: repeat(2, 1fr);
 		}
diff --git a/src/routes/fitness/[workout=fitnessWorkout]/[active=fitnessActive]/+page.svelte b/src/routes/fitness/[workout=fitnessWorkout]/[active=fitnessActive]/+page.svelte
index dcfaf50a..89a59bd9 100644
--- a/src/routes/fitness/[workout=fitnessWorkout]/[active=fitnessActive]/+page.svelte
+++ b/src/routes/fitness/[workout=fitnessWorkout]/[active=fitnessActive]/+page.svelte
@@ -1,7 +1,7 @@
 <script>
 	import { goto } from '$app/navigation';
 	import { page } from '$app/stores';
-	import { Plus, Trash2, Play, Pause, Trophy, Clock, Dumbbell, Route, RefreshCw, Check, ChevronUp, ChevronDown } from 'lucide-svelte';
+	import { Plus, Trash2, Play, Pause, Trophy, Clock, Dumbbell, Route, RefreshCw, Check, ChevronUp, ChevronDown, Flame } from 'lucide-svelte';
 	import { detectFitnessLang, fitnessSlugs, t } from '$lib/js/fitnessI18n';
 
 	const lang = $derived(detectFitnessLang($page.url.pathname));
@@ -9,6 +9,7 @@
 	import { getWorkout } from '$lib/js/workout.svelte';
 	import { getWorkoutSync } from '$lib/js/workoutSync.svelte';
 	import { getExerciseById, getExerciseMetrics } from '$lib/data/exercises';
+	import { estimateWorkoutKcal } from '$lib/data/kcalEstimate';
 	import ExerciseName from '$lib/components/fitness/ExerciseName.svelte';
 	import SetTable from '$lib/components/fitness/SetTable.svelte';
 	import ExercisePicker from '$lib/components/fitness/ExercisePicker.svelte';
@@ -192,6 +193,24 @@
 			};
 		});
 
+		// Estimate kcal for strength exercises
+		/** @type {import('$lib/data/kcalEstimate').ExerciseData[]} */
+		const kcalExercises = [];
+		for (const ex of local.exercises) {
+			const exercise = getExerciseById(ex.exerciseId, lang);
+			const metrics = getExerciseMetrics(exercise);
+			if (metrics.includes('distance')) continue;
+			const weightMultiplier = exercise?.bilateral ? 2 : 1;
+			const sets = ex.sets
+				.filter((/** @type {any} */ s) => s.completed && s.reps > 0)
+				.map((/** @type {any} */ s) => ({
+					weight: (s.weight ?? 0) * weightMultiplier,
+					reps: s.reps ?? 0
+				}));
+			if (sets.length > 0) kcalExercises.push({ exerciseId: ex.exerciseId, sets });
+		}
+		const kcalResult = kcalExercises.length > 0 ? estimateWorkoutKcal(kcalExercises) : null;
+
 		return {
 			sessionId: saved._id,
 			name: local.name,
@@ -201,7 +220,8 @@
 			totalTonnage,
 			totalDistance,
 			exerciseSummaries,
-			prs
+			prs,
+			kcalResult
 		};
 	}
 
@@ -366,6 +386,13 @@
 					<span class="comp-stat-label">{t('distance', lang)}</span>
 				</div>
 			{/if}
+			{#if completionData.kcalResult}
+				<div class="comp-stat kcal">
+					<Flame size={18} />
+					<span class="comp-stat-value">{completionData.kcalResult.kcal} &plusmn; {completionData.kcalResult.kcal - completionData.kcalResult.lower} kcal</span>
+					<span class="comp-stat-label">{t('est_kcal', lang)}</span>
+				</div>
+			{/if}
 		</div>
 
 		{#if completionData.prs.length > 0}
@@ -605,6 +632,9 @@
 		text-transform: uppercase;
 		letter-spacing: 0.04em;
 	}
+	.comp-stat.kcal {
+		color: var(--nord12);
+	}
 
 	.prs-section {
 		background: color-mix(in srgb, var(--nord13) 8%, transparent);