What is the protocol for conducting a submaximal exercise test to assess cardiovascular fitness?

From the Guidelines

To conduct a submaximal exercise test for assessing cardiovascular fitness, the protocol should be tailored to the individual to yield a fatigue-limited exercise duration of 8 to 12 minutes, using a protocol such as the Balke and Ware or Naughton et al, which involve modest increases in treadmill elevation at a constant speed, as recommended by Arena et al 1. When selecting an appropriate exercise test protocol, it is crucial to consider the individual's fitness level and health status to ensure a safe and effective assessment. The goal is to achieve a submaximal heart rate of approximately 70-85% of the estimated maximum heart rate, which can be calculated using the formula 0.70[(220-age) - resting heart rate] + resting heart rate or 0.85(220-age) 1. Some key points to consider when conducting a submaximal exercise test include:

• Using a protocol with modest increases in workload, such as the Balke and Ware or Naughton et al, to ensure a stronger relationship between measured V˙ O2 and work rate 1
• Avoiding handrail support during treadmill exercise testing to prevent discrepancies between estimated and actual V˙ O2 1
• Monitoring heart rate at regular intervals and observing for signs of excessive fatigue or discomfort
• Allowing for a proper cool-down period after completion of the test
• Calculating cardiovascular fitness by analyzing the relationship between heart rate response and workload, which indicates how efficiently the heart and circulatory system deliver oxygen during exercise 1. It is essential to note that submaximal exercise testing may not provide an accurate determination of aerobic capacity, and maximal exercise testing in a clinical laboratory setting is recommended when an accurate assessment is imperative 1. However, for most populations, particularly those with health concerns or who are beginning fitness programs, submaximal testing is a safer and still valuable approach for assessing cardiovascular fitness.

From the Research

Protocol for Conducting a Submaximal Exercise Test

The protocol for conducting a submaximal exercise test to assess cardiovascular fitness involves several factors, including:

• The population being tested and its specific needs in terms of safety, supervision, and accuracy and repeatability of the VO(2max) estimation 2
• The parameters upon which the prediction is based, such as heart rate, power output, and rating of perceived exertion (RPE) 2
• The appropriate test modality, which should meet the above-mentioned requirements and be in line with the functional mobility of the target population 2

Considerations for Test Selection

When selecting a submaximal exercise test protocol, several factors should be considered, including:

• The need for high repeatability in sports settings to track training-induced seasonal changes 2
• The need for special attention to test modality in clinical settings, where multiple physiological parameters often need to be measured during test execution 2
• The effects of medication on heart rate-based submaximal protocols 2
• The need for accessibility and lack of supervision in home settings, where the use of sensors such as accelerometers and heart rate monitors can result in protocol-free VO(2max) assessments 2

Types of Submaximal Exercise Tests

There are several types of submaximal exercise tests, including:

• Predictive tests, which are used to predict maximal aerobic capacity 3
• Performance tests, which involve measuring the responses to standardized physical activities that are typically encountered in everyday life 3
• Tests such as the submaximal modified Bruce treadmill, Astrand-Ryhming cycle ergometer, and Chester step tests, which have been compared to peak cardiopulmonary exercise testing (CPET) results 4

Safety and Validity of Submaximal Exercise Tests

Submaximal exercise tests have been shown to be safe and valid for assessing cardiovascular fitness, with no severe adverse events reported in several studies 4 The step test appears to be a valid and safe method for assessing group-level mean changes in V̇O2 peak among patients in cardiovascular rehabilitation 4 The Duke Activity Status Index (DASI) also appears to be a valid and practical questionnaire for assessing cardiovascular fitness 4