Week 7: Submax Testing in the Field Flashcards
Cardiorespiratory Fitness (CRF)
“CRF reflects the integrated ability to transport oxygen from the atmosphere to
the mitochondria to perform physical work. It therefore quantifies the functional
capacity of an individual and is dependent on a linked chain of processes that
include pulmonary ventilation and diffusion, right and left ventricular function (both systole and diastole), ventricular-arterial coupling, the ability of the
vasculature to accommodate and efficiently transport blood from the heart to
precisely match oxygen requirements, and the ability of the muscle cells to
receive and use the oxygen and nutrients delivered by the blood, as well as to
communicate these metabolic demands to the cardiovascular control centre.”
(Ross et al., 2016)
Benefits of Improving CRF (5)
Reduced risk of:
1. Developing dementia and Alzheimer disease
2. Adverse health outcomes such as developing prediabetes, metabolic
syndrome, and type II diabetes
3. Developing cardiovascular disease
4. Developing breast cancer, lung cancer, and cancers of the gastrointestinal
system
5. Disability later in life
Maximal Oxygen Uptake- What is VO2 Max?
-VO2max is the measurement of the maximum (max) rate of volume (V) of oxygen (O2) your body can use during exercise.
-An individual’s VMO2max is determined by measuring gas exchange during intense physical exercise.
-The VMO2max test involves incrementally increasing exercise intensity (work rate) to ensure maximal aerobic energy transfer.
-How much oxygen can person convert into energy
How do we Measure VO2 Max? (4)
The 4 different ways of measuring CRF are:
1. Cardiopulmonary exercise tests (CPET)
2. Maximal Exercise Test (GXT)
3. Submaximal Exercise Test
4. Estimated CRF (eCRF)
Submaximal Exercise Testing
-Measures VO2 max indirectly through predictive equations based on the HR –
workload relationship
-Not as accurate as VO2max prediction from max tests
-Uses submaximal work rates (i.e., less than 85% HR max)
-Limited diagnostic capabilities
-More accessible in the community or clinical setting:
-easier to administer
-less expensive
-safer(?)
*not diagnostic tests- a beginning level test
*Aim: to determine the HR response to one or more submaximal work rates and use the results to predict VO2max
Factors that can increase HR during submaximal testing (5)
- Caffeine: Drinking caffeine within 3 hours of completing your test can increase your heart rate at rest and during activity
- After eating a meal: After eating a meal, your heart rate will increase. Your heart needs to pump additional blood to the stomach to aid digestion. After eating and digesting food, your heart rate should return to normal
- Feeling anxious: Any form of emotional stress can increase your heart rate.
- Smoking: Smoking damages the cardiovascular system and can affect the heart by increasing blood pressure, narrowing the arteries, and increasing heart rate.
- Humid weather/environment: High temperatures and high humidity result in more blood flow to the skin as the body attempts to cool itself off. This can cause the heart to beat faster while circulating twice as much blood per minute than on a normal day.
Disadvantages of Submaximal Tests (4)
- For some people, this type of test could be a maximal test.
- The Individual’s motivation and pacing strategy during the test can have a profound effect on the final outcome
- Does not allow comprehensive monitoring of both HR and BP during the test.
- Relatively large standard error of the estimate (SEE) ± 10% - 15%
Note: Field tests (submaximal exercise tests) are generally not recommended for sedentary individuals who have been identified in pretesting screening to be at moderate or high risk of cardiorespiratory or musculoskeletal complications.
Measuring VO2 Max- Ceiling and Floor Effects
Ceiling effect: the test is too easy to produce sufficient CV response to get an accurate functional capacity (e.g., not enough stages or peak intensity).
Floor effect: the test is too difficult (from a vascular or physical perspective) so
that the test is not limited by the cardiovascular system but by other barriers
(e.g., anxiety, peripheral claudication, exercise specificity (e.g., lactic acid buildup in LE muscles during cycle ergometry testing or in UEs during arm ergometery
testing, osteoarthritis).
Objective Measures Collected for Submax Tests (6)
- HR
- BP
- Workload
- RPE
- SpO2
- Symptoms
How do we obtain the most accurate estimate of VO 2max?
-A steady state HR is obtained for each exercise work rate
-A linear relationship exists between HR and work rate
-The difference between actual and predicted maximal HR is minimal
-Mechanical efficiency (i.e., VO2 at a given work rate) is the same for everyone
-The client is not on any HR altering medications
-The client is not consuming high quantities of caffeine, is ill or in a high-temperature environment
Safety – Heart rate
-HR increases with progressive workloads at a rate of approx. 10 bpm per 1 MET
-HR should decrease by at least 12 beats during the first minute of recovery
-HR should decrease by 22 beats by the end of the second minute of recovery
Safety – Blood pressure
-SBP increases with increasing workloads at a rate of approx. 10 mm Hg per 1 MET
-Normally no change in DBP or slight decrease during exercise
-Stop exercise if:
-Hypertensive response: an SBP > 250 mm Hg
-Hypotensive response: a decrease of SBP below the pretest resting value or by >20 mm Hg after initial increase
-DBP > 115 mm Hg
-Post-exercise SBP returns to pre-exercise levels or lower by 6 minutes of recovery
Safety - Symptoms
-Dyspnea (shortness of breath)
-Wheezing
-Leg cramps
-Claudication
-Angina
-Signs of poor perfusion: light-headedness, confusion, ataxia, pallor, cyanosis, nausea, or cold and clammy skin
-Noticeable change in heart rhythm by palpation or auscultation
-Participant requests to stop
-Physical or verbal manifestations of severe fatigue
Indications for terminating a submaximal exercise test
-The onset of angina or angina-like symptoms
-Drop in SBP of ≥10 mm Hg with an increase in work rate or if SBP decreases below the value obtained in the same position prior to
testing
-Excessive rise in BP:
-systolic pressure >250 mm Hg and/or
-diastolic pressure >115 mm Hg
-Shortness of breath, wheezing, leg cramps, or claudication
-Signs of poor perfusion: light-headedness, confusion, ataxia, pallor, cyanosis, nausea, or cold and clammy skin
-Failure of HR to increase with increased exercise intensity
-Noticeable change in heart rhythm by palpation or auscultation
-SpO2 ≤80%
-Client requests to stop
-Physical or verbal manifestations of severe fatigue
-Failure of the testing equipment
*Note: the indications listed above assume that testing is nondiagnostic and is being performed without electrocardiogram monitoring
Submax Tests in the Field (2)
- Rockport Fitness Walking Test (One-mile track walk test)
- 20-meter shuttle test (Beep test)
Rockport Fitness walking test (one-mile track walk test)
-Developed for a wide age range (30-79 years) of males and females
-Prediction equations developed using sex, age, weight, time and HR
Advantages:
-Applicable to a wide range of individuals
-Limited equipment needed (track)
-Familiar activity
Disadvantages:
-Inability to monitor physiological variables during test
20-meter shuttle test (Beep test)
-Multi-stage shuttle run test used to estimate VO2max and maximal aerobic
speed (pushing sub max)
Advantages:
-Multiple stages allows for a wide range of fitness levels to be tested
-Limited amount of equipment needed
-More than one participant can be tested at once
-Paces individuals with pre-recorded sound signals
Disadvantages:
-Frequent stopping and starting
-Pacing
-Inability to monitor physiological variables during test
-How do we ensure this is a submaximal test?
