Table 1. HR (bpm) and VO2 (ml/kg/min) drift during bicycle exercises. inconsistency in the HR-VO2 relationship during dynamically changing ex- ( ), who made a linear steady state HR-VO2 model for bicycle ergometer exercise. As tables 2 indicates there is a stronger significant relationship between heart beat and the aerobic capacity. However, simple linear regression analysis. Another chart from TopEndSports shows the average resting heart rate for men and But there is a way estimate your VO2max, given the linear relationship.
However, it should be noted that due to small numbers, data were not analysed separately on patients achieving stage 5 on the CST or in those taking part on a 25 cm step height.
Out of the patients, patients were stratified as high multi-factorial risk mean risk score The patients attended Demographic variables can be seen in table 1. A subgroup analysis demonstrated that patients taking part in a 15 cm step height significantly increased their predicted VO2max from Overall changes in predicted VO2 max on a 15 cm and 20 cm step height Changes in predicted O2 pulse Overall, O2 pulse increased from On a 15 cm step height, O2 pulse significantly increased at EOP assessment from Table 2 demonstrates the overall changes in O2 pulse.
In the subgroup analysis, HR on average decreased by —2. These trends were similar for a 20 cm step height with smaller reductions in HR at stage 1 —3.
Discussion The aim of this study was to apply the O2 pulse ratio to determine if the improvement in exercise performance on the CST is related to a true physiology adaptation following the Westminster MyAction programme. The O2 pulse significantly increased from One of the main mechanisms that contributed towards both the improvement in predicted VO2max and O2 pulse in this study was related to the reduction in the submaximal HR response on each stage of the CST table 3.
A reduction in the submaximal HR is a classical physiological training adaptation and is suggestive of an adjustment in the autonomic balance between parasympathetic and sympathetic nervous activity, resulting in the proficiency of the myocardium to accomplish a similar cardiac output at a lower myocardial oxygen demand.
Overall changes in heart rate response on each stage of the CST The magnitude of the reduction in the submaximal HR response appears to be dependent on the exercise training intensity and volume.
In the present study, patients attended a supervised exercise session once per week for up to 12 weeks and they were encouraged to participate in a home exercise programme two to three times per week.Fitbit Charge 2 - BPM, Heart Rate Zones and Fitness Level
There were insufficient numbers to calculate a meaningful reduction in submaximal HR at stage 5. However, one patient who completed stage 5 on a 25 cm step height achieved a 24 bpm reduction in their submaximal HR response after completing the MyAction programme. The second limitation is that the data were collected from clinical practice with no control group and it needs to be verified in a randomised prospective study design.
The third limitation is related to O2 pulse, which is normally measured through direct gas analysis during maximal cardiopulmonary exercise testing.
Such predictions in VO2 using metabolic calculations are open to considerable individual variability, especially in patients with known heart disease. Future research is needed to control for these variables and should also confirm what difference would be clinically meaningful to the patient. Acknowledgement The authors would like to acknowledge the support of Paul Bassett, Imperial College London, for his help with the statistical analysis.
Conflict of interest None declared. Key messages This service analysis demonstrates that the Westminster MyAction cardiovascular prevention and rehabilitation programme favourably influenced predicted VO2max and submaximal O2 pulse An increase in predicted VO2 and submaximal O2 pulse appears to be driven by a reduction in the submaximal heart rate response across 4 stages of the Chester step test CST at three different step heights Patients following a week structured exercise programme consisting of a supervised exercise session and a home programme performed two to three times per week can expect to save up to seven heart beats on the CST, which could potentially reduce myocardial ischaemia and lower risk of arrhythmias during exercise References 1.
British Association for Cardiovascular Prevention and Rehabilitation. Association of Chartered Physiotherapists in Cardiac Rehabilitation.
Oxygen Consumption Results
Standards for physical activity and exercise in the cardiac population. Effect of encouragement on walking test performance. Reproducibility and safety of the incremental shuttle walking test for cardiac rehabilitation. Int J Cardiol ; The 6-minute walk test in outpatient cardiac rehabilitation: Using a heart rate walking speed index to report truer physiological changes when using walking performance tests in cardiac rehabilitation. J Cardiopulmon Rehabil Prevent ; Predicting cardiovascular risk in England and Wales: Chester College of Higher Education, Principles of Exercise Testing and Interpretation: Including Pathophysiology and Clinical Applications.
Lippincott Williams and Wilkins, Even with different equipment, the same amount of oxygen is consumed. If we had measured the subjects walking up stairs or a similar type of work, we would have found that the VO2 was different for individuals of different sizes doing the same exercise.
Note that our resting energy expenditures vary quite a bit. Mainly this is because points at zero watts were taken both at complete rest and with the subject peddling against zero resistance. But also this because the resting energy expenditure depends on body size. As a result there is a small effect of size on the data.
Most points somewhat below the line are for the smallest subjects and most above the line for the largest. VO2max Given that all of our subjects gave an excellent effort, the highest VO2 recorded for each individual is close to the VO2max for that individual.
And looking at population averages, the numbers are as expected for fit young adults. The actual number is strongly dependent on the size of the individual.
Oxygen Consumption Results
In this type of protocol, it is typically not possible to see the points reach a plateau. Finer gradations around the VO2max would be required.
Factors Influencing VO2max The maximal oxygen uptake also depends on a person's genetics and level of training for endurance exercise. For example, looking at the table below taken from the respiratory system handout you will see that the VO2max for the world class athletes averaged 5. Note that the two groups are matched by body size.
They probably averaged about 70 kg or so. This is important since VO2 max depends proportionately on the size of the individual. The arterial oxygen content, of course, is proportional to the amount of hemoglobin in the blood.
The arterial-venous O2 difference increases when the muscles are able to extract a larger fraction of the oxygen in the blood. This occurs when there are more mitochondria relative to the amount of blood passing through the muscles. Look down the chart and observe what one factor correlates best with the magnitude of the VO2max.
A recent clinical study with older patients found that VO2max is one of the best predictors of mortality, especially if cardiovascular disease is present. Now let's focus on the results from one subject Thursday, To the right are the VO2 measurements for this subject, who we will continue analyzing below.
The red line is the same as in the graph above for all lab sections. Notice that the points follow a linear relationship at lower levels of work. This, of course, is as expected, since proportionately more ventilation is required to deliver more oxygen to the alveoli. But above about watts there is a change, with ventilation increasing considerably more than expected based on the earlier relationship.
As we discussed on the previous page, this is because the subject has passed the lactate threshold anaerobic thresholdin which lactic acid begins accumulating in the body.
This causes a disproportionate increase in breathing through stimulation of the peripheral chemoreceptor. Thus the exhausted subject's PaCO2 is actually lower than at the beginning of the exercise. Lab Only The R. If a person is burning pure carbohydrate the ratio will be 1. For fat alone the ratio is about 0. At rest, our subject had an R. This is just as expected in a resting person. Typically, we are burning about half carbohydrates and half fats when we are at rest and not exercising, although this depends on the individual.
Our subject was near the average for carbohydrates and fats.
In one respect this subject was a little unusual in that he was not hyperventilating a little at rest. This is usually the case as the subject anticipates the upcoming exercise.
With hyperventilation, the R. This is what we usually observe at rest as the subject is anticipating the exercise.
Then as the subject begans to exercise at lower rates, the R. But above the lactate threshold we expect the R.