# Heart Rate Zones, Visualized @icon(heart-pulse) @category(health) > Five training zones on one ladder, with your heart rate marked on it. Drag anything and every boundary moves. The tabs show where the numbers come from — including why "70%" means two different heart rates depending on who you ask. #training #running #cycling #health # You @icon(user) @skin(spec-sheet) @density(compact) age = 38 // years 15..90 @label(Age) @icon(calendar) resting heart rate = 58 // bpm 35..110 @label(Resting HR) @icon(moon) @note(Count it lying down, before you get out of bed) hr = 148 // bpm 40..220 @label(Heart rate to look up) @icon(watch) @note(Drag it — the ladder marks where it lands) basis = {hrr: 1} // radio({Karvonen: {hrr: 1}, Percent of max: {hrr: 0}}) @label(Zone basis) @icon(ruler) @advanced @note(Karvonen slices your reserve; Percent of max ignores your resting rate) mhrf = {b: 208, m: 0.7} // radio({Tanaka: {b: 208, m: 0.7}, Fox: {b: 220, m: 1}, HUNT: {b: 211, m: 0.64}, Gulati: {b: 206, m: 0.88}}) @label(Max-HR formula) @icon(calculator) @advanced @note(Tanaka fits the data best — the Max HR tab compares all four) use measured max = false // toggle() @label(I know my real max HR) @icon(medal) @advanced measured max = 190 // bpm 120..225 @label(Measured max HR) @advanced @note(From a field test or a hard race finish — beats every formula) # Engine @hidden _max heart rate = if(use_measured_max, measured_max, round(mhrf.b - mhrf.m * age)) _heart rate reserve = max(1, max_heart_rate - resting_heart_rate) _useh = basis.hrr _zoneBpm(p) = round(if(_useh == 1, resting_heart_rate + heart_rate_reserve * p, max_heart_rate * p)) _lo = [_zoneBpm(0.5), _zoneBpm(0.6), _zoneBpm(0.7), _zoneBpm(0.8), _zoneBpm(0.9)] _hi = [_zoneBpm(0.6), _zoneBpm(0.7), _zoneBpm(0.8), _zoneBpm(0.9), _zoneBpm(1)] _names = ["Recovery", "Aerobic", "Tempo", "Threshold", "VO₂ max"] _fills = ["fill-seq-1", "fill-seq-2", "fill-seq-3", "fill-seq-4", "fill-seq-5"] _ops = [1, 1, 1, 1, 1] _feel = ["you could sing", "full sentences", "short sentences", "a few words", "no talking"] _idx = sum(map(_lo, b => if(hr >= b, 1, 0))) _nbtick = [0, 2, 4, 5] _zbot = _lo[0] _ztop = _hi[4] _effort(t) = if(t < 10, 0.35 + 0.028 * t, if(t < 50, if(mod(t - 10, 10) < 4, 0.93, 0.6), 0.6 - 0.028 * (t - 50))) _sess(t) = _zoneBpm(_effort(t)) _ymin = floor(_zoneBpm(0.3) / 20) * 20 _ymax = ceil(max_heart_rate / 20) * 20 # Your zones @icon(circle-gauge) zone now = if(_idx == 0, "Below Zone 1 — that is rest", "Zone {_idx:plain:0} · {_names[_idx - 1]}") // @hero @label(Your heart rate is in) @icon(watch) zone ladder = svg(``) // @label(Your zone ladder) @wide # Why @tab @icon(lightbulb) > Two ideas do all the work. Your **reserve** is the only range you can train in, and a zone is a slice of that reserve — not a slice of your max. anatomy = svg(``) // @label(Where the zones actually sit) @wide /// A zone runs from `resting + reserve × lower%` up to `resting + reserve × upper%`. Every boundary on the ladder is that one line of arithmetic, run six times. the gap = round(resting_heart_rate * 0.3) // bpm @label(Two answers to 70% effort) @icon(triangle-alert) @accent @note(Karvonen adds your resting rate back in; plain % of max never sees it. The gap is exactly resting HR × (1 − intensity) — widest on easy days, zero at your maximum.) # Workout @tab @icon(activity) > Zones are horizontal bands, so any heart rate trace reads straight against them. This is a 4 × 4-minute interval session drawn through yours. session = graph([_sess, hrect(_lo[0], _hi[0], "1 · Recovery", {color: "seq-1"}), hrect(_lo[1], _hi[1], "2 · Aerobic", {color: "seq-2"}), hrect(_lo[2], _hi[2], "3 · Tempo", {color: "seq-3"}), hrect(_lo[3], _hi[3], "4 · Threshold", {color: "seq-4"}), hrect(_lo[4], _hi[4], "5 · VO₂ max", {color: "seq-5"})], 0, 60, 240, _ymin, _ymax) // @label(Minutes across, bpm up) @wide /// Warm-up, four hard efforts with recovery between, cool-down. Note how little of even a hard session sits in Zone 5 — sixteen minutes of the sixty. # Max HR @tab @icon(flask-conical) @skin(spec-sheet) @density(compact) > Every boundary on the ladder hangs off one number, and that number is a guess until you measure it. fox = 220 - age // bpm @label(Fox · 220 − age) @note(1971, never published as research — the famous one, and the least accurate) tanaka = round(208 - 0.7 * age) // bpm @label(Tanaka · 208 − 0.7 × age) @note(2001 meta-analysis of 351 studies — the current default) hunt = round(211 - 0.64 * age) // bpm @label(HUNT · 211 − 0.64 × age) @note(2013, measured on 3,320 healthy adults) gulati = round(206 - 0.88 * age) // bpm @label(Gulati · 206 − 0.88 × age) @note(2010, derived on 5,437 women) formula spread = max(fox, tanaka, hunt, gulati) - min(fox, tanaka, hunt, gulati) // bpm @label(The four disagree by) @icon(ruler) @accent /// Worse than the spread between formulas is the spread *between people*: any age-based estimate carries a standard deviation of roughly **±10 bpm**, so two people the same age can have true maxima 20 bpm apart and both be normal. Treat it as a starting point — then switch on **I know my real max HR** once you have seen a genuine max in a race or field test.