# Training load and Cardio Load (TRIMP)

Session-RPE load, and from the heart-rate stream the workout impulse, seven-day strain, tolerance and status.

Type: score · Unit: load units · Domain: Activities & Lifestyle · Accuracy: Calculated · Importance: Supporting

Also called: Cardio Load, training impulse, seven-day strain, load tolerance, cardio load status, acute chronic workload, training stress, maintaining, productive, detraining, sRPE, ACWR

## In one sentence

Two ways of adding up what your training asked of you: the session-RPE load, which any session has, and Cardio Load, which needs a heart-rate stream and gives the lower half of the activity sheet its five numbers.

## Session-RPE load

Your Borg rating times the minutes, for any session, with or without a device (Foster 2001). It is the load figure the engines use, because every session has it: the TDEE engine's activity term, the load side of Capacity and the Symptom Radar training confounder all read it.

## Cardio Load

When a session comes with a heart-rate stream, VT computes five figures from it. The *workout training impulse* (TRIMP) weights every minute by how high the heart rate sat between your resting and your maximum, with harder minutes counting more than proportionally, so that a long easy ride and a short hard one each get a fair number; it is the impulse of training in the fitness–fatigue model of Banister and colleagues, in which each dose of training produces a fitness response and a fatigue response that decay at different rates (Morton 1990). The *daily cardio load* sums the day's sessions. The [*seven-day strain*](https://vitalitytracker.app/knowledge/training-load-and-cardio-load) is the recent week's load. The *cardio load tolerance* is what your body has become used to over the last several weeks. And the [*cardio load status*](https://vitalitytracker.app/knowledge/training-load-and-cardio-load) is the ratio of strain to tolerance, shown with a word.

## The status words

From 0.80 to 1.00 the word is [*maintaining*](https://vitalitytracker.app/knowledge/training-load-and-cardio-load): this week asked about what your body is used to. Below 0.80 it is [*detraining*](https://vitalitytracker.app/knowledge/training-load-and-cardio-load): the week was light against your habit. Above 1.00 and up to 1.50 it is [*productive*](https://vitalitytracker.app/knowledge/training-load-and-cardio-load): more than usual, the zone in which fitness is built. Above 1.50 it is *overreaching*: a load your body has not yet adapted to. Until 21 of the last 28 days have data, the sheet says *calibrating*. The idea is Gabbett's acute:chronic workload ratio, proposed from team-sport data in which the athletes accustomed to high loads had fewer injuries than those training less, and in which excessive and rapid increases in load, rather than high load itself, went with most of the non-contact injuries (Gabbett 2016). The ratio has since been criticized on statistical grounds, and VT uses it for what it is good at: describing your week against your month, in your own units. It is not a forecast.

## Why it matters

The ratio, not the absolute load, is what tracks with fatigue. The founder's activity sheet of 28 October reads it plainly: an indoor cycle with a TRIMP of about 51, a daily load of about 127 across the day's sessions, a seven-day strain of about 86 against a tolerance of about 86, and a status of maintaining at a ratio of 1.00.

## What moves it

Everything you did, weighted by how hard; the age-based maximum heart rate the daily figures use (208 − 0.7 × age), which reads a few beats off for many people, the same way every day; a device that dropped the heart-rate signal, which lowers a session's TRIMP without lowering its effort (the session-RPE load is the backstop); and a week off, which lowers strain at once and tolerance slowly.

## How Vitality Tracker uses it

Shown on the activity sheet of each training that has heart rate, as the session's TRIMP, the day's load, the seven-day strain, the tolerance and the status; it stays on your phone, and no score or engine reads it. The engines read the session-RPE load; Cardio Load is the heart-rate view beside it.

## How far to trust the number

Calculated from a measured heart rate, your device's resting heart rate and an age-based maximum; consistent with itself on one device, and only comparable with your own history.

## Method

Session-RPE load = Borg × minutes. TRIMP (Banister) = Σ minutes × HRr × k × e^(b × HRr), with HRr = (HR − resting HR) ÷ (maximum HR − resting HR), k = 0.64 and b = 1.92 for men, k = 0.86 and b = 1.67 for women. Daily load = the day's sessions summed, overlapping recordings counted once; seven-day strain = average daily load over 7 days; tolerance = average daily load over 28 days; status = strain ÷ tolerance: below 0.80 detraining, 0.80 to 1.00 maintaining, above 1.00 to 1.50 productive, above 1.50 overreaching.

## Sources

1. Foster C, et al. A new approach to monitoring exercise training. J Strength Cond Res 2001;15:109–15 (PMID 11708692)
2. Morton RH, Fitz-Clarke JR, Banister EW. Modeling human performance in running. J Appl Physiol 1990;69:1171–7. [doi:10.1152/jappl.1990.69.3.1171](https://doi.org/10.1152/jappl.1990.69.3.1171)
3. Gabbett TJ. The training-injury prevention paradox: should athletes be training smarter and harder? Br J Sports Med 2016;50:273–80. [doi:10.1136/bjsports-2015-095788](https://doi.org/10.1136/bjsports-2015-095788)
4. Vitality Tracker, activity sheet (28 October 2026) and the Knowledge Base brief, catalogue E.

## Related

- [Perceived exertion: the Borg CR10 scale](https://vitalitytracker.app/knowledge/perceived-exertion-borg-cr10)
- [Maximum heart rate and heart-rate zones](https://vitalitytracker.app/knowledge/maximum-heart-rate-and-zones)
- [Activity Units](https://vitalitytracker.app/knowledge/activity-units)
- [Capacity: how much you can take on today](https://vitalitytracker.app/knowledge/capacity)
- [Reading the activity sheet](https://vitalitytracker.app/knowledge/reading-the-activity-sheet)
- [Symptom Radar and Symptom Trend](https://vitalitytracker.app/knowledge/symptom-radar-and-symptom-trend)

Reviewed October 2026 · v1

Source: https://vitalitytracker.app/knowledge/training-load-and-cardio-load