A cardiopulmonary exercise test produces dozens of outputs, and the headline VO2 number is only meaningful with the protocol, calibration and effort criteria next to it. This eCRF records the result and the evidence that it was a valid test.
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Test conditions
Ergometer and protocol
CPEQPGas and flow calibration passed
Peak results
Peak VO2
VO2PKPeak RER
RERPKMeets study effort criterion
Peak heart rate
HRPKReason test stopped
CPET data capture at a glance
The measure
Peak oxygen uptake is one of the strongest predictors of mortality and a standard outcome in exercise, cardiac rehabilitation, heart failure, metabolic and longevity trials. It is also easy to get wrong. The result depends on the protocol, the mask fit, the room conditions, the averaging window, calibration, and whether the participant truly gave maximal effort. A trial that records only the number can not separate a real change from a different test.
The form therefore has three groups of fields: the conditions (equipment and calibration), the results (peak and threshold values), and the validity evidence (effort criteria, symptoms, reason for stopping). Monitors and statisticians can then apply a pre-specified validity rule, and exclude or flag tests that fail it. See EDC for longevity clinical trials for how fitness endpoints sit alongside other ageing measures, and the 6-minute walk test form for a field-based comparison.
VO2max implies a plateau despite increased workload, which many participants, especially older or deconditioned ones, do not show. Most trials report peak VO2, the highest averaged value, and use effort criteria to judge whether it is a good estimate of the maximum. State in the protocol which term you use, the averaging interval (for example 30 seconds) and whether you report mL/kg/min, L/min or both. Relative values depend on body mass, so record weight on the day or link to the vital signs form.
Field by field
| Field | Type | Notes |
|---|---|---|
| Test date and time, operator | Date, time, text | Operator initials for site review |
| Ergometer and protocol | Dropdown | Treadmill or cycle; ramp or staged; ramp rate or stages |
| System, mask or mouthpiece | Text | Same system per site, software version noted |
| Calibration (gas, volume) and result | Single choice, text | Done before each test; pass or fail |
| Ambient conditions | Number | Temperature, pressure and humidity, if the system needs entry |
| Resting HR and BP | Number | Before the test |
| Averaging interval | Number, seconds | Applied to peak values |
| Peak VO2 | Number, mL/kg/min and L/min | Highest averaged value |
| Peak VCO2, peak VE | Number | L/min |
| Peak RER | Number | Ratio VCO2 to VO2, as reported by the system |
| Peak heart rate, peak BP | Number | bpm and mmHg |
| Peak work rate | Number | Watts or speed and grade |
| Ventilatory thresholds (VT1, VT2) | Number, text | VO2 at each, plus detection method |
| VE/VCO2 slope | Number | Where the protocol needs it |
| Perceived exertion at peak | Number | Borg 6 to 20 or CR10, scale named |
| Effort criteria met | Single choice, multi | Which criteria; derived in analysis from the raw values |
| Reason test stopped | Dropdown | Exhaustion, symptoms, ECG or BP criteria, equipment |
| Adverse events during test | Single choice, text | Link to the AE form if yes |
The list is a starting point. Match it to your protocol and the exact outputs your sites' systems print.
Build it in Capture
Build the form as a site-completed eCRF and place it on the baseline and follow-up visits. The site enters values from the system report right after the test.
Edit checks / auto-queries
2Type
Range High
Operator
Greater than
Value
180
Priority: High
Type
Range Low
Operator
Less than
Value
80
Priority: Normal
Query raised automatically
Value 192 violates limit (180). Please verify.
Setup
Choose ergometer, ramp or staged protocol, averaging interval and effort criteria, and write them into the protocol and the form's field help.
Add conditions, results and validity sections. Put units in field labels.
Use plausible low and high limits for the population as edit checks, and test them with an extreme value in the sandbox.
Branch on the reason stopped, and prompt on failed calibration.
Mark peak VO2, RER and heart rate for source data verification against the system report.
Approve the form and add it to the visits where fitness is assessed.
Define in the analysis plan how effort criteria classify a test as valid, and how peak VO2 is analysed when the rule fails.
Worked example
A participant reaches a peak VO2 of 31.4 mL/kg/min with a peak RER of 1.14 and a peak heart rate of 158 bpm, and stops from volitional exhaustion. The study's rule is peak RER of at least 1.10 or heart rate within 10 beats of the age-predicted maximum. The RER criterion is met, so the test is classed as valid even though heart rate is lower than predicted, which is common with beta-blocker use or in older adults.
A second participant stops at 24 mL/kg/min with a peak RER of 1.02 because of knee pain. The record shows symptoms as the reason stopped and the effort criteria not met, so the analysis plan treats it as a symptom-limited test. Without the reason and RER stored next to VO2, both tests would look the same in the dataset.
Tests entered
42
Calibration passed
41
Effort criteria met
34
Open queries
3
Before go-live
One type of metabolic cart and one protocol across visits and sites, or cross-calibration documented.
Gas and flow calibration results are recorded, with failure rules.
The protocol states what the participant takes, eats and avoids before testing, and the form records it.
Contraindications and stopping criteria are in the protocol and training; physician coverage is documented.
Effort criteria and handling of failures are fixed in the analysis plan.
Build the fields, set the checks and enter a sample test in the free sandbox. No credit card.
VO2max implies a plateau in oxygen uptake despite rising workload. Most trials report peak VO2, the highest averaged value, and use effort criteria to judge whether it approximates the maximum.
Peak RER, peak heart rate against the age-predicted maximum, perceived exertion and whether VO2 plateaued are widely used. Thresholds differ between labs, so define yours in the protocol and store the raw values.
No. These come from the metabolic system. Capture's calculated fields are a fixed set of clinical derivations such as BMI and eGFR. Enter the system's values, and derive effort flags in analysis.
CPET is a measurement method, not a copyrighted questionnaire, so there is no instrument licence to record. Equipment and software terms stay in your site agreements.
A failed or missing calibration can bias every number from that test. Recording it lets monitors query or exclude the test.
Use the separate 6-minute walk test form. It captures distance, vitals and symptoms rather than gas exchange.
Site staff, from the system report. It is a site-completed eCRF.
Build the form, set the checks and test an entry. Free sandbox, no credit card.