Metrics glossary
Feature comparisons reflect each product's publicly documented features as of October 2026.
Product names are trademarks of their respective owners. Tempo is not affiliated with, endorsed by, or sponsored by any of them.
Tempo shows a lot of numbers. This page defines each one: what it measures, how Tempo derives it, and — where a value is a judgement rather than a measurement — what counts as a normal range. These are the definitions the in-app tooltips give, collected in one place so you can read them end to end instead of hunting for the information icon.
A note on naming before the list. Tempo calls the training-load family Load, Fitness, Fatigue and Form; the research literature and most other platforms call the last three CTL, ATL and TSB. Both names appear throughout, because you will meet both.
Metric values are visible to everyone. Premium adds all metric status badges, including availability states such as No Data or Building Baseline and classifications such as Moderate or Developing. On Performance, the entire metric badge requires Premium, including W/kg and J/kg. Main values, source selectors, dates, workout links, and the Power Duration Curve remain visible to everyone; the lock opens the upgrade options.
Training load
These are not independent measurements. Load is the measured quantity; everything else in this section is an average of it, or arithmetic on those averages.
| In Tempo | Also called | What it is | Window |
|---|---|---|---|
| Load | TSS | one session's training stress | a single workout |
| Fitness | CTL | average daily Load | 42 days |
| Fatigue | ATL | average daily Load | 7 days |
| Strain | ACR, ACWR | Fatigue ÷ Fitness | today |
| Form | TSB | Fitness − Fatigue | today |
Load
Load quantifies how much stress a workout put on your body, combining how hard and how long you trained. For a ride with power it comes from Norm Power against your FTP; for workouts without power, Tempo derives it from heart rate against your threshold heart rate instead.
A workout's Load badge classifies the session by comparing its Load with your Fitness on the day before the workout — the load your body was accustomed to going in. The higher that ratio, the bigger the day was relative to what you are adapted to. With Fitness below 20 there is no established baseline to compare against, so the badge falls back to absolute Load values instead of a ratio.
Fitness (CTL)
Fitness, or Chronic Training Load, is a rolling 42-day average of daily training stress. Higher means greater long-term fitness. It moves slowly by design: one big weekend barely shifts it, and a month off drags it down steadily. The ranges Tempo shows are relative rather than strict categories — a Fitness of 60 means something different for a first-year rider than for someone eight seasons in.
Fatigue (ATL)
Fatigue, or Acute Training Load, is a 7-day average of daily training stress. High Fatigue means recent training has been hard. Because the window is short, it rises and falls within days, which is exactly what makes it useful next to Fitness.
Form (TSB)
Form, or Training Stress Balance, is freshness against fatigue. Negative values mean you are carrying fatigue; positive values mean you are fresh. It is the number to look at before a race, and the one that tells you whether a bad week is fatigue or something else.
Tempo shows Form two ways, and the toggle matters:
- Abs is Fitness minus Fatigue using rounded values, in load points:
round(CTL) − round(ATL). - % expresses that same difference relative to your Fitness:
((round(CTL) − round(ATL)) ÷ max(round(CTL), 25)) × 100.
The percentage view scales the zones to your current fitness, so it is easier to compare against yourself as fitness changes. The trade-off is that when fitness is low it exaggerates Form and can push you into the extreme zones on an ordinary day — the floor of 25 in the denominator limits this while you are still ramping up, but prefer the absolute value unless you train a lot. The same day can land in a different zone depending on which view you have selected.
The zones are High Risk below −30, Optimal −30 to −10, Grey Zone −10 to +5, Fresh +5 to +25 (+20% in the % view), Transition above that.
Strain (ACR)
Strain is the ratio of Fatigue to Fitness, known in the literature as the Acute:Chronic Workload Ratio (ACWR) or Acute:Chronic Ratio (ACR). It monitors how much recent load you are carrying relative to what you are adapted to. 0.8–1.3 is considered optimal; above 1.5 may increase the risk of injury or overtraining.
Two caveats. Some sources use "strain" to mean Foster strain, which is load multiplied by monotony — a different quantity from this one. And Tempo shows "Insufficient Data" rather than a number when your Fitness is below the minimum the ratio needs to be reliable, which is typically your first several weeks of training: a small denominator makes the ratio swing wildly on a single ride.
Ramp Rate
Ramp Rate is the change in Fitness across the last 7 days, expressed in CTL per week. Positive values mean training load is building, negative values mean it is coming down.
Building faster than your current fitness supports increases injury and illness risk, so the bands scale with Fitness rather than sitting at one number for everyone: Low Risk is 3 CTL/week or less below a Fitness of 45, 4 or less up to 70, and 5 or less above that. The bands above Low Risk step up with it — below a Fitness of 45 they are Moderate 4 to 6, High 7, and Extreme 8 and above, each moving up by one in the 45-to-70 range and by one again above 70. So a rider at 80 is still in Low Risk at 5 CTL per week, where a rider at 40 is already at Moderate.
Monotony
Monotony answers "how varied has your training been?" It is your average daily load over the last 7 days divided by the standard deviation of those daily loads. Lower is better, because a low number means you are mixing hard days, easy days and rest rather than riding the same moderate session every day.
Persistently high monotony above 2.0 is associated with increased illness and overtraining risk, particularly when total training load is also high (Foster, 1998). Tempo's status bands are: Low <1.5, Moderate 1.5-1.9, High 2.0-2.4, Very High >=2.5.
Monotony complements Strain: Strain asks how much recent load you are carrying relative to your fitness, and Monotony asks how evenly you spread it.
Readiness
Readiness blends Form, Strain, Sleep, HRV, Resting HR and recent training-load changes (Ramp Rate and the change in Form) into a single 0-100% score. Higher suggests you are well recovered; lower suggests prioritising recovery. Large deviations in HRV or resting heart rate from your own baseline pull the score down hard, which is deliberate — those are the two signals that most often precede illness.
Training Status
Training Status names your current phase — Building, Maintaining, Peaking and so on — from Ramp Rate and Form. The risk badge beside it indicates overreaching and overtraining risk from Strain and Form.
Power
FTP
Functional Threshold Power is the highest power you can sustain for approximately one hour. It is the anchor for training zones and for Load, so an FTP that is badly wrong makes every downstream number wrong with it. The badge classifies your FTP into a Coggan-inspired tier based on absolute watts.
Tempo scores each ride against the FTP that was in effect on the day you rode it, so reprocessing an old workout no longer rewrites its intensity with today's number. Your FTP history lists every change, newest first, whether you set the value yourself or accepted an estimate.
Estimated FTP
Estimated FTP is calculated from your power outputs and updated automatically as you complete workouts. Tempo estimates it two ways, at two different scopes.
Per workout, when a ride contains a strong sustained effort, Tempo projects from your best sustained effort in the 8 minute to 1 hour range using typical Critical Power curve percentages, since longer efforts map closer to FTP than shorter ones. Anchors shorter than 8 minutes are excluded so that strong anaerobic power does not inflate the estimate. Treat this as a per-ride FTP projection based on typical power-duration relationships.
Critical Power and W′ on the Performance page are calculated separately, as described next. Recalculating them does not automatically update your training FTP or zones.
Critical Power
Critical Power is the asymptote of the two-parameter power-duration model, P(t) = CP + W′/t. Tempo automatically uses your best 3-minute and 12-minute average powers within the selected period, whether they come from deliberate tests or normal workouts. The two efforts can come from the same ride or different rides. No test tagging or workout selection is needed.
With P3 and P12 in watts, CP = (4 × P12 − P3) / 3 and W′ = 240 × (P3 − P12) joules. For example, 518 W for three minutes and 403 W for twelve minutes give approximately 365 W CP and 27.6 kJ W′. A new best at either duration recalculates both values; improving one effort does not necessarily increase both parameters.
Both durations are required. Other durations do not influence the calculation, and Tempo does not switch to another model when one is missing. The contributing-efforts list shows the workouts supplying each best.
Research supports a three- and twelve-minute maximal-test protocol, but recorded workout bests are not necessarily maximal. These remain estimates. The selected period controls the lookback (91 days by default on the web Performance page); older bests can reflect different fitness. When W′ fails Tempo's plausibility checks, both CP and W′ show “Estimate unavailable” because the same two efforts determine both estimates. The details say why and what to do next: ride an all-out 3-minute and an all-out 12-minute effort, then mark each one under Maximal efforts on its workout. The selected period has to include both workouts. Their recorded powers and workout links remain available, as does the independently calculated estimated FTP. This applies whether the efforts come from one workout or two; Tempo does not discard the powers or substitute unconfirmed historical efforts to make the fit pass.
If that pair fails, Tempo can use the strongest athlete-confirmed maximal effort at each duration within the same selected filters. Confirm each duration in the completed cycling workout's Power section, below the collapsible power-duration curve, using the All-out toggle only if it was a dedicated all-out effort for that full duration, not a segment of a longer test. Both confirmations are required, and the alternative must still pass the checks. Its details are labeled Confirmed maximal efforts. If no supported alternative is available, both estimates remain unavailable. A confirmation is ignored if reprocessing changes the recorded power; you can also remove it in the Power section.
When a stronger earlier three- or twelve-minute effort falls outside your selected period, Tempo explains that exclusion alongside CP and W′. Open the contributing efforts to see the dates and powers of both the current and older efforts. A lower estimate alone does not establish a loss of fitness; you may simply not have repeated a maximal effort recently. A fresh three- and twelve-minute maximal test helps reassess your current performance.
W-prime
W-prime, written W′, is the finite work you can do above Critical Power, measured in kilojoules. Once you exceed Critical Power you spend it; when you drop below, it recharges. A larger W′ means a bigger matchbook for attacks and supra-threshold efforts. The same quantity appears on the Performance page as above-threshold energy.
The badge classifies your body-mass-normalised W′ in joules per kilogram using Tempo’s guidance bands: below 150 developing, 150 to under 250 recreational, 250 to under 350 trained, 350 to under 450 strong, and 450 or more elite. These are guidance ranges rather than a published standard. When a fitted W′ falls outside physiological bounds — which can happen when the three-minute effort is not truly maximal — Tempo withholds both CP and W′ and the cards explain why.
Peak Power
Peak Power is your highest stored one-second average cycling power in the selected Performance period. The separate five-second best covers a longer effort. The Peak Power badge shows historical W/kg when available; the tooltip explains the one-second measurement duration. Open the supporting workout from the Power Duration Curve chart. A recorded best is not necessarily an all-out sprint; the badge does not grade sprint ability.
Watts per kilogram uses the weight saved with that workout; watts remain available when historical weight is missing. Newly processed recordings require supported one-second timestamp intervals. Existing curve values remain available; older workouts used a one-sample-per-second assumption until reprocessed.
Norm Power
Norm Power is a weighted average that estimates the physiological cost of an effort by weighting surges more heavily than coasting. A steady hour and a ragged hour at the same average power are not the same ride, and this is the number that says so.
Intensity
Intensity is the ratio of Norm Power to FTP. 1.0 is an hour at threshold by definition; endurance rides sit far below it and short races can exceed it.
Durability
Durability estimates Critical Power from valid three-minute and twelve-minute efforts that start after 40 kJ/kg of mechanical work in a single ride, using the saved workout weight. The card shows the estimate in watts and, when a reference is available, its percentage of CP from the same selected period. This reference is not a verified fresh test. Independently estimated values may exceed 100%; Tempo displays them without clipping.
The workload is measured from recorded power, not food energy or work accumulated across rides. It describes observed performance under that workload, not a universal durability grade: prior intensity and whether the efforts were maximal also matter. Missing recordings, weight, or qualifying efforts mean insufficient data, not poor durability. An available watt estimate remains visible even when reference CP is unavailable.
Power curve
Your power curve is your best power at every duration, from sprints to endurance. Toggle between watts and watts per kilogram, and click any point to jump to the workout it came from; the dashed line overlays a wider time range for comparison.
On a single workout, the same chart shows that ride's maximum average power at each duration. The highlighted 3-20 minute band is the range used for FTP estimation, because maximal efforts there best reflect threshold power.
The power profile chart is the same data grouped into Sprint, Attack and Climb durations, which is the view that shows where your strengths sit. Your rider profile classifies that curve across sprint, attack and sustained efforts.
Power zones
Power zones use the Joe Friel 7-zone system, as percentages of FTP. Each zone is a different training intensity. Sweet Spot is a commonly prescribed range that straddles the top of Tempo's zone 3 and the bottom of threshold rather than being a step of its own.
Power-to-weight
W/kg values display up to two decimal places without trailing zeros: 3, 3.1, or 3.14. This changes presentation only; calculations retain their original values.
Power-to-weight, in watts per kilogram, is a decisive performance metric in cycling, and the one that predicts climbing. Tempo classifies it using the Allen & Coggan power-profile system. Note that the short-duration badges (5 seconds, 30 seconds, 1 minute) use sprint and anaerobic thresholds, which are several times higher than the FTP figure — a 5-second W/kg of 15 is not the same achievement as an FTP W/kg of 15.
Work
Work is the total mechanical work done during a ride, in kilojoules — one second at 300 watts is 300 joules. This is work at the cranks, not metabolic energy: cycling is only about 21-23% efficient, so the calories your body actually burned are roughly 4-5 times larger.
Work above FTP counts only the seconds where instantaneous power exceeded your FTP. It is sensitive both to how long you spent above threshold and to how far above it you rode.
Efficiency and pacing
These metrics compare two things you already have — usually power against heart rate, or the first half of a ride against the second — and they are most informative on steady, sub-threshold efforts. On an interval session or a race they mostly report the shape of the session.
Efficiency Factor
Efficiency Factor is Norm Power divided by average heart rate. Higher means more normalized watts per heartbeat, which is the signature of improving aerobic fitness. It is most useful for tracking base training over weeks, and only valid for steady, sub-threshold efforts.
Power:HR ratio
The ratio of average power to average heart rate. The same idea as Efficiency Factor but using average power rather than Norm Power, so it is slightly blunter and slightly easier to reason about. Joe Friel describes this ratio as one of the better measures of fitness change — it works rather like miles per gallon for an engine.
Cardiac drift
Cardiac drift, also called aerobic decoupling or Pw:HR, measures how much your heart rate rises relative to power output over the course of a ride. Tempo compares the Efficiency Factor of the first half with the second half.
Under 3% indicates strong aerobic fitness and efficient pacing. 3-5% is normal for longer efforts. Above 5% suggests cardiovascular fatigue, dehydration or overheating — which is why it is worth reading next to Heat Load on a hot day.
Power fade
Power fade measures how much your power dropped from the first half of a workout to the second. Positive values mean power fell. Near 0% or negative — a negative split — indicates good pacing. Above 5% suggests fatigue, a poor pacing strategy, or under-fuelling.
Variability Index
Variability Index measures how smooth or how variable your power output was: Norm Power divided by average power. A steady, even effort such as a time trial should have a VI of 1.05 or less. In a criterium it may be 1.2 or higher.
Heart-rate recovery
Heart-rate recovery is an adaptation of the clinical HRR60 protocol to continuous ride data. Tempo scans every 60-second window whose start is at near-peak effort — at or above 95% of threshold HR when set, otherwise ≥85% of max HR — and whose end is above your resting heart rate, then takes the largest drop. The threshold tolerance accounts for normal sensor and day-to-day threshold variation. The calculation needs resting heart rate and either threshold or maximum heart rate set on your profile.
Higher is better, and rising over time indicates improving fitness and parasympathetic recovery. The trend chart plots one point per workout for the selected period.
VO₂ max
VO₂ max is maximal oxygen uptake in millilitres per kilogram per minute, a measure
of aerobic capacity. When Tempo processes a cycling workout's FIT file or recorded
power streams, it estimates VO₂ max from the five-minute value in its power-duration
curve and your profile weight: VO₂ max = 16.6 + 8.87 × (W·kg⁻¹).
A valid estimate needs a positive, finite five-minute power value and a profile weight between 20 and 200 kg (exclusive). No FTP setting, minimum whole-ride intensity, or 30-minute workout is required. This cycling formula does not apply to running workouts, even when they include power data.
The value is saved on the workout and in the existing daily wellness history. If several workouts produce estimates on the same local day, the highest value is retained for that day. Home and Wellness show the highest reading from the selected day or the prior 90 days, with the date of the selected reading. Ties use the newer date. A lower estimate from an easy ride does not replace a stronger recent estimate on the cards. When all estimates are older than 90 days, the cards show no recent best. The Wellness chart defaults to the last six months. Use its date picker to view older daily readings; days without a new estimate remain empty on the chart.
The Sitko et al. (2022) equation was developed using a maximal five-minute test in cyclists. An ordinary workout's best effort may be submaximal, so a lower estimate does not necessarily mean your aerobic capacity has fallen. Treat the value as an estimate rather than a laboratory measurement or a result with a guaranteed individual error range.
Performance summary
The performance summary is your overall fitness trajectory over the last 56 days, taken from the trends in estimated FTP, estimated VO₂ max, 5 minute power, 20 minute power, Power:HR ratio, Efficiency Factor, cardiac drift, power fade and heart-rate recovery. Metrics remain listed when no qualifying value or comparison is available so the summary can explain what data is missing. Trends compare the most recent 28 days with the preceding 28 days. When only one period has qualifying data, the available value is shown as Current or Previous, with an explanation of which period is missing; no trend can be calculated until both have data. Heart-rate recovery is shown for context but does not contribute to the overall Improving, Steady or Declining assessment.
Wellness
Resting heart rate
Resting heart rate, in beats per minute, is your heart rate when completely at rest. Lower values typically indicate better cardiovascular fitness, and it feeds the calculation of your heart-rate training zones. What matters day to day is change rather than level: a jump above your own baseline is a common early signal of fatigue or illness. The Resting HR status compares today with your average over the prior 28 days, leaving out days you reported being ill, in bands sized to how much your readings usually vary (Balanced is within half of that spread, Slightly within one, Low or High within two). Until 14 readings exist in the window it uses fixed percent bands instead.
HRV
Heart rate variability is the variation in time between heartbeats, and a proxy for
autonomic balance. Tempo shows it as an HRV Score calculated as ln(RMSSD) × 20, the
standard transformation used by most HRV apps, which produces an intuitive figure —
typically 50-100 for healthy adults — where higher indicates better recovery. The HRV
Score status compares today with your average score over the prior 28 days, leaving out
days you reported being ill, in bands sized to how much your score usually varies
(Balanced is within half of that spread, Slightly within one, Low or High within two).
Until 14 readings exist in the window it uses fixed bands of ±2, ±4 and ±6 points.
Normalized HRV
Normalized HRV adjusts your HRV for the heart rate it was measured at. Because a lower heart rate mechanically allows more variability, raw HRV can look high simply because your pulse was slow that morning. This compares your HRV with what would be expected given your heart rate, which is what isolates the meaningful changes.
Tempo learns that relationship from your own readings over the 60 days before today. It needs at least 30 of those days with both a plausible resting heart rate and an HRV reading; until then the card's badge says "Calibrating", and the details view shows how many days it has collected. Readings with an implausible resting heart rate are left out, so one bad morning cannot tilt the line. When your HRV and resting heart rate are not coupled closely enough to fit — common when the two come from different devices — Tempo compares today's HRV with your recent average instead, and the explanation says so.
The percentage is how far today's HRV sits from that expected value. How big a deviation has to be to matter depends on how much your HRV usually moves from day to day, so Tempo classifies it in units of your own variability — the standard deviation (SD) of your recent readings around the fitted line — rather than in fixed percentages:
| State | Where today sits |
|---|---|
| Strongly Suppressed | More than 2 SD below expected |
| Suppressed | 1 to 2 SD below expected |
| Slightly Suppressed | 0.5 to 1 SD below expected |
| Balanced | Within 0.5 SD of expected: your usual range |
| Slightly Elevated | 0.5 to 1 SD above expected |
| Elevated | 1 to 2 SD above expected |
| Strongly Elevated | More than 2 SD above expected |
Because the bands are measured in your own variability, the same −15% can be Balanced for an athlete whose HRV swings widely and Suppressed for one whose HRV is steady. The details view translates each band into your personal percentages, which are asymmetric — 1 SD below expected is a smaller percentage drop than 1 SD above is a rise — because HRV varies multiplicatively. The cut-offs follow the individual-variability approach of the HRV-monitoring literature (Plews et al. 2013; Buchheit 2014), but they are display bands Tempo has chosen, not validated thresholds for training decisions.
The labels describe the reading, not its cause. A high HRV a day or two after hard training is usually a recovery rebound, which is a good sign; a similar reading alongside fatigue that persists for weeks can accompany overreaching; and at a very low resting heart rate HRV can plateau or fall without anything being wrong. Sleep, alcohol, illness and travel move it too. Read the state alongside your resting heart rate, recent training and how you feel. A connected AI assistant also receives the 7-day average of your readings in the same SD units, since weekly trends carry more of the training signal than a single day.
Sleep
Sleep duration in hours. Sleep is where adaptation actually happens, and athletes typically need 7-9 hours a night. It is one of the inputs to Readiness.
Weight, body fat and hydration
Body weight is stored in kilograms and displayed in your preferred units. It matters both for power-to-weight and as context for hydration and body composition changes. The Weight card shows the most recent measurement from the past 90 days when no weight was recorded today, with the measurement date shown in a tooltip on the Wellness card and Home tiles. Daily charts still show only days with an actual measurement.
Body fat percentage correlates with power-to-weight in cycling; athletes often range from 8-15%.
Hydration is total body water as a percentage of body weight. Tempo compares it with your recent baseline and with sex- and age-adjusted thresholds — roughly below 50% for men and below 45% for women, slightly lower with age. Read it alongside recent weight rather than on its own.
Body Mass Index is a height-and-weight measure of body fat. It is imperfect for athletes, who carry more muscle than the population it was derived from, but it is a useful guide to a healthy weight range; for adults, 18.5 to 24.9 is generally considered healthy.
Heart-rate zones
Heart-rate zones use the Andy Coggan 5-zone model, as percentages of your threshold and maximum heart rate.
Threshold heart rate is the highest heart rate you can hold steady without fatiguing, typically the average over a 20-30 minute time-trial-style effort. Tempo keeps separate cycling and running values, because they differ for most people, plus a general value used for strength, walking, hiking and other workouts — the general value also seeds the two sport-specific ones until you set them.
Maximum heart rate is the highest rate you can reach under exercise stress. It is often estimated as 220 minus age, but that formula has a wide error margin and a measured value is much better.
Fueling
BMR and baseline daily energy
Basal Metabolic Rate is the energy your body needs at rest to maintain basic function. Tempo calculates it with the Mifflin-St Jeor equation, which is generally the most accurate for most people.
Baseline daily energy is your non-exercise daily burn: BMR multiplied by an activity factor describing how active you are on an ordinary day, not counting workouts. Pick that factor from your job and lifestyle; most athletes choose 1.2 to 1.4, because Tempo adds workout calories on top rather than assuming them.
Calories burned, consumed and balance
Calories burned is your total daily burn: BMR plus non-exercise activity plus exercise calories from completed workouts and events. On the Energy page the tile carries a pill comparing burn so far with your baseline of BMR plus non-exercise activity: Baseline means little exercise yet, Elevated is 10%+ above baseline, High is 35%+ above.
Calories consumed is total dietary energy from logged intake, added manually or synced from the Tempo mobile app. Its pill grades intake against total burn: 95%+ well fueled, 80–95% slightly under, below 80% under-fueled.
Calorie balance is consumed minus total burned. This is not the same as energy availability, which subtracts only exercise calories and divides by fat-free mass.
Energy availability
Energy availability is the energy left to run your body once training has taken its share:
EA = (intake kcal − exercise kcal) ÷ fat-free mass in kg
Sustained low energy availability is linked to Relative Energy Deficiency in Sport (REDs), whose consequences include impaired bone health, endocrine disruption and suppressed immunity (Loucks 2004; Mountjoy 2014/2018/2023). It is the metric on this page with the clearest health stakes, which is why Tempo shows it as a 7-day average rather than a daily figure — one low day is a Tuesday, three low weeks is a problem.
| EA (kcal/kg fat-free mass/day) | Zone | Meaning |
|---|---|---|
| 40+ for men, 45+ for women | Optimal | The level recommended for hard training |
| 30 up to optimal | Moderate | Subclinical low EA; may impair recovery |
| Below 30 | Low | Clinical low energy availability and REDs risk |
The threshold below 30 applies to everyone; the optimal threshold differs by sex because the research behind the higher figure was derived in women (Melin et al. 2019). Where sex is unspecified Tempo uses the more conservative 45.
Carbohydrate targets
Your daily carbohydrate target is periodised against your training load: hard days target 8–10 g/kg, moderate 6–8, easy 3–5 (Burke 2018).
Mechanically, Tempo builds the number as a rest-day baseline plus the carbohydrate needed
to replace what the day's workout burned, so the total scales automatically with what you
actually did: total = base × weight + workout calories ÷ 4. The rest-day baseline is
typically 2–3.5 g/kg. At low intensity fat covers around 55% of fuel, so easy days come
out lower than a naive "calories ÷ 4" would suggest, and harder sessions shift the mix
toward carbohydrate.
Protein and fat targets
Protein targets 1.6–2.2 g/kg for endurance athletes and stays flat across training days — protein needs do not vary meaningfully by training phase (Schoenfeld & Aragon 2018; Phillips & Van Loon 2011; IOC consensus).
Fat targets 1.0–1.5 g/kg as a minimum, or 20–35% of total energy intake (ACSM and IOC guidance). It is the remainder macronutrient, set after carbohydrate and protein, and it is not periodised.
Session and recovery fueling
Next-session targets are pre-, in- and post-workout fueling figures in grams of carbohydrate, protein, fluid and sodium. The defaults follow Burke 2018 and Jeukendrup 2014, and become personalised once your sweat rate and tested carb tolerance are set.
For recovery, within 60–90 minutes of a hard session: replace glycogen at roughly 1.0–1.2 g/kg of carbohydrate per hour and trigger muscle protein synthesis with about 0.3–0.4 g/kg of leucine-rich protein (Schoenfeld & Aragon 2018; Alghannam 2018).
Sweat rate, sodium and carb tolerance
Sweat rate, in millilitres per hour, determines your hourly fluid replacement target. Tempo accepts 200–3000; run a sweat test to establish yours rather than guessing (McCubbin 2020).
Sweat sodium concentration, in milligrams per litre, pairs with sweat rate to compute hourly sodium needs. The accepted range is 200–2000, and individual variation here is larger than most riders expect.
Carb tolerance is the highest in-workout carbohydrate intake, in grams per hour, that you have comfortably tolerated. It caps the recommender, so Tempo never advises more than your gut has actually trained for (Jeukendrup 2014).
Heat
Heat Load
Heat Load measures the thermal stress you carried, adding up your heat strain across the whole session. The scale is anchored to the Heat Strain Index: one hour spent at the very top of the strain scale scores 100. In practice an hour of genuinely hard thermoregulation lands near 30, and a long day in the heat can pass 60.
Heat Load sits alongside Load rather than inside it. The same ride done in the heat and in the cold is the same training stress — your power and duration have not changed — but the recovery cost is very different. Folding heat into Load would blur that distinction and make your Fitness incomparable across seasons.
One caveat worth knowing: the Heat Load cutoffs are absolute, not personal. Load is classified against your own Fitness, but there is no equivalent heat-acclimation baseline yet, so an acclimated rider and an unacclimated one get the same band for the same ride. Read the bands as a description of the session, not of how well you coped with it.
Heat adaptation time
Heat adaptation time is time spent at High or Extremely High heat strain, meaning a strain index of 3.0 and above. That is the range that drives heat adaptation — a bigger plasma volume and an earlier, heavier sweat response — typically over one to two weeks of repeated exposure.
Rehydration guidance after a hot session replaces about one and a half times your estimated sweat loss, because fluid taken without sodium is largely passed rather than retained. When your profile has a measured sweat rate, the target is calculated from it and the session's duration.
Where heat data comes from
Heat metrics come from a CORE body temperature sensor, and they need a FIT file to reach Tempo. That means they appear for workouts synced from Garmin, Wahoo or Hammerhead, or uploaded directly. Strava's API does not carry core temperature or heat strain, so rides that arrive that way show no heat data even when you were wearing the sensor.
Training summary
The Reports page adds up what each workout already stores over a period you choose. Its totals are plain sums; these are the parts that need a definition. Open it from Reports in the sidebar, right after Workouts.
Weekly average
A period total scaled to seven days: the total × 7 ÷ the number of calendar days in the period. Weeks run Monday to Sunday, and a week cut short by the start or end of the period is drawn lighter so it does not read as a slack week.
Time in zone
Seconds in each power zone and each heart-rate zone, summed across the period. Power and heart rate are kept apart and never added together. Each percentage is a share of that channel's own recorded zone time, not of all training time, and each chart states how many activities it is drawn from.
Intensity distribution
Time in zone grouped into three bands: Low is below the first threshold (Z1 and Z2), Moderate is between the thresholds (Z3 and Z4, including Sweet Spot), and High is above the second threshold (Z5 and up). The label names the shape of the distribution:
| Label | Rule |
|---|---|
| High intensity | High is a third or more of the time, and more than Moderate |
| Polarized | mostly low with more high than moderate and a polarization index above 2.00 |
| Base | 80% or more low |
| Threshold | 35% or more moderate, and more than High |
| Pyramidal | more Low than Moderate, and more Moderate than High |
| Mixed | anything else |
The rules are checked in that order and the first match wins. A label needs at least three activities with zone data. Heart rate rarely records time above the second threshold, so power is the better basis when you have it.
Polarization index
A single number for how polarized a distribution is: log₁₀(Low ÷ Moderate × High × 100), with the three bands as fractions. Above 2.00 counts as polarized. It is 0 when there is no High time, and it is not calculated when there is more High than Low. The index and the polarized rule come from Treff et al. (2019); the other label cut-offs are Tempo's own.
Ride detail
A few numbers on a workout page are worth a line each.
- Average power is the arithmetic mean across the whole ride, including coasting and recovery. Unlike Norm Power it makes no allowance for surges.
- Maximum power is the highest instantaneous power recorded, usually a sprint.
- Average and maximum heart rate gauge overall cardiovascular effort, and the maximum is a useful check on whether your zone settings are right.
- Cadence is pedalling revolutions per minute; most cyclists sit around 80-100 rpm. Lower cadence at higher force loads the muscles more, higher cadence shifts the cost to the cardiovascular system.
- Left/right balance is the share of power from each leg. A perfectly balanced rider reads 50/50, and small imbalances up to about 52/48 are common and usually not a concern.
- Elevation is total gain, a rough proxy for how much climbing the ride contained.
- Calories are estimated from workout type, duration and weight. The meal-equivalent figure beside them assumes 600 calories per meal.
- Distance comes from GPS or sensor data.
Sources
The definitions above follow the published work each metric comes from. The main references are Coggan & Allen on training load and the power-duration profile, Foster (1998) on monotony and strain, Gabbett (2016) on acute-to-chronic workload ratios, Jones & Vanhatalo (2017) on Critical Power and W′, Sitko et al. (2022) on estimating VO₂ max from 5-minute power, Treff et al. (2019) on the polarization index, and Burke (2018), Jeukendrup (2014), Loucks (2004) and Mountjoy et al. (2014, 2018, 2023) on fueling and energy availability. Each in-app tooltip links to the specific article behind its metric.
Where Tempo departs from a published standard — the W′ guidance bands, and the Heat Load scale — this page says so rather than presenting the choice as settled science.