From the Guidelines
To conduct a submaximal exercise stress test, the most recent and highest quality study recommends using a protocol that involves gradually increasing the workload in stages, typically lasting 3-5 minutes each, until reaching a predetermined submaximal heart rate, typically 70-85% of age-predicted maximum heart rate, calculated as 220 minus age, as stated in the study by 1. The test should be tailored to the individual to yield a fatigue-limited exercise duration of 8 to 12 minutes. Some key points to consider when conducting a submaximal exercise stress test include:
- Ensuring the participant is healthy enough for exercise by screening for contraindications
- Using a treadmill, stationary bike, or step test while monitoring heart rate
- Starting at a low intensity and gradually increasing the workload in stages
- Recording heart rate, perceived exertion, and blood pressure if equipment is available
- Continuing until reaching a predetermined submaximal heart rate or when the participant reaches a moderate-to-hard exertion level
- Concluding with a 5-minute cool-down of decreasing intensity It's also important to note that the test should be supervised by a qualified health professional who is appropriately trained to administer exercise tests, as stated in the study by 1. Additionally, the test administrator should be certain that the subject understands the risks and benefits of the test, and written informed consent should be obtained, as stated in the study by 1. The American Heart Association recommends that exercise testing should be performed under the supervision of a qualified health professional, as stated in the study by 1. Overall, a submaximal exercise stress test is a valuable tool for assessing cardiovascular fitness and providing fitness data while being safer than maximal testing, making it appropriate for most populations, including older adults, those new to exercise, or people with controlled medical conditions, as stated in the study by 1.
From the Research
Protocol for Conducting a Submaximal Exercise Stress Test
The protocol for conducting a submaximal exercise stress test involves several key considerations, including:
- Selecting the appropriate test modality based on the population being tested and their specific needs in terms of safety, supervision, and accuracy and repeatability of the test results 2
- Using measurements such as heart rate, blood pressure, exertion, and pain to evaluate test performance and safely monitor patients 3
- Considering the effects of medication on heart rate-based submaximal protocols 2
- Choosing a test that meets the functional mobility of the target population and is in line with the available equipment 2
Test Modalities
Different test modalities can be used for submaximal exercise testing, including:
- Step test: a cheap and portable option that is suitable for field tests, with relatively little anxiety or learning required from subjects 4
- Bicycle ergometer: a laboratory-based test that is suitable for arm immobilization, but may develop significant anaerobic metabolism at loads of more than 55% of aerobic power 4
- Treadmill test: a test that can be used to determine maximal oxygen uptake, but may not be suitable for submaximal testing due to anxiety and learning effects 4
Test Procedures
The test procedure for submaximal exercise testing typically involves:
- A progressive test, in which the exercise load is increased at regular intervals, such as every 3 minutes 4
- A steady-state test, in which the subject exercises at a constant intensity for a prolonged period, such as 20-25 minutes 5
- Measurements of heart rate, blood pressure, and other physiological parameters during the test 3, 2, 5
Safety Considerations
Safety considerations are crucial when conducting submaximal exercise testing, particularly for individuals with chronic disease or disability 6. This includes: