A perceptually regulated, graded exercise test predicts peak oxygen uptake during treadmill exercise in active and sedentary participants

The Reliability of a Single-Trial Measurement of Maximal Accumulated Oxygen Deficit Determined via Perceptually-Regulated Exercise

Purpose: The aim of this study was to evaluate the reliability of a single-trial determination of maximal accumulated oxygen deficit (MAOD) achieved via the aid of perceptually-regulated incremental exercise. Methods: 14 trained male cyclists (age: 45 ± 8 yrs; height: 1.82 ± 0.06 m; mass: 79.7 ± 6.7 kg; V ˙ O 2 max : 4.09 ± 0.57 L·min-1) performed three trials of a submaximal incremental cycling test followed by a test to exhaustion at 116% of predicted V ˙ O 2 max . The intensity for each stage of the incremental test was regulated by participants to elicit perceived exertion levels of 9-15 on the Borg (6-20) scale. Linear regression was used to estimate V ˙ O 2 max at a perceived exertion level of 19. MAOD was calculated from the difference between predicted and actual oxygen demand in the test to exhaustion, reported in oxygen equivalents (O2 eq). A separate incremental test was used to measure V ˙ O 2 max directly. Results: Correlation coefficients between perceived exertion and V ˙ O 2 across trials were strong (r ≥0.99), and there were no between-trial differences in predicted V ˙ O 2 max (4.03 ± 1.04, 3.76 ± 0.53, and 3.69 ± 0.64 L·min-1, respectively; p = .142) or MAOD (2.75 ± 2.28, 2.50 ± 1.53, and 2.93 ± 1.40 L O2 eq, respectively; p = .633). Nevertheless, the coefficients of variation for predicted V ˙ O 2 max (14.2%) and MAOD (142.8%) were poor. Conclusions: The prediction of V ˙ O 2 max from perceptually-regulated exercise displays a level of test-retest reliability which prevents its use as a means of evaluating MAOD reliably in a single-trial.

The Rating of Perceived Exertion-Pediatric (RPE-P) Scale: Preliminary Validation

Physical activity is critical to functional rehabilitation for youth with chronic pain, which may be especially true for those with co-occurring obesity. To facilitate the development of physical activity interventions for youth with chronic pain, the newly developed "Rating of Perceived Exertion-Pediatric" scale was modeled after the widely used pain numeric rating scale-11. This study is an initial evaluation of the scale in a sample of adolescents (n = 157, 13-17 years, 51% female) with four subgroups: (1) healthy controls (healthy weight/no pain); (2) chronic pain/healthy weight; (3) obese (no pain); (4) chronic pain/obese. Participants rated perceived exertion using the new scale and the Borg 6-20 Scale of Perceived Exertion while holding a three-minute yoga pose (Warrior II). In the whole sample, the Perceived Exertion-Pediatric scale showed good concurrent (p < 0.001), convergent (all ps < 0.05), discriminant (p = 0.431), and known-groups validity (all ps < 0.05). The chronic pain subgroup also showed good concurrent (p < 0.001), mixed convergent (ps < 0.001 to 0.315), and good discriminant validity (p = 0.607). Limitations include the restricted age range, lack of diversity, and lack of test-retest reliability. The RPE-P shows promise as an assessment tool for perceived exertion in adolescents with and without chronic pain.

Use of the speed achieved on the 6MWT for programming aerobic training in patients recovering from severe COVID-19: an observational study

INTRODUCTION

Patients who suffered severe COVID-19 need pulmonary rehabilitation. Training may be prescribed objectively based on the maximum speed in the six-minute walk test. The objective of this study was to determine the effects of a personalized pulmonary rehabilitation program based on the six-minute walk test speed for post-COVID-19 patients.

METHODS

Observational quasi-experimental study. The pulmonary rehabilitation program consisted of 8 weeks of training, twice a week for 60 minutes per session of supervised exercise. Additionally, the patients carried out home respiratory training. Patients were evaluated by exercise test, spirometry and the Fatigue Assessment Scale before and after the eight-week pulmonary rehabilitation program.

RESULTS

After the pulmonary rehabilitation program, forced vital capacity increased from 2.47 ± 0.60 to 3.06 ± 0.77 L (p < .001) and the six-minute walk test result increased from 363.50 ± 88.87 to 480.9 ± 59.25 m (p < .001). In fatigue perception, a significant decrease was observed, from 24.92 ± 7.01 to 19.10 ± 7.07 points (p < .01). Isotime evaluation of the Incremental Test and the Continuous Test showed a significant reduction in heart rate, dyspnoea and fatigue.

CONCLUSION

The eight-week personalized pulmonary rehabilitation program prescribed on the basis of the six-minute walk test speed improved respiratory function, fatigue perception and the six-minute walk test result in post-COVID-19 patients.KEY MESSAGESCOVID-19 is a multisystem disease with common complications affecting the respiratory, cardiac and musculoskeletal systems.The 6MWT speed-based training plan allowed for increased speed and incline during the eight-week RP program.Aerobic, strength and flexibility training reduced HR, dyspnoea and fatigue in severe post-COVID-19 patients.

Assessment of Exercise Intensity for Uphill Walking in Healthy Adults Performed Indoors and Outdoors

BACKGROUND

Borg's rating of perceived exertion (BRPE) scale is a simple, but subjective tool to grade physical strain during exercise. As a result, it is widely used for the prescription of exercise intensity, especially for cardiovascular disease prevention. The purpose of this study was to assess and compare relationships between BRPE and physiological measures of exercise intensity during uphill walking indoors and outdoors.

METHODS

134 healthy participants [median age: 56 years (IQR 52-63)] completed a maximal graded walking test indoors on a treadmill using the modified Bruce protocol, and a submaximal 1 km outdoor uphill cardio-trekking test (1 km CTT). Heart rate (HR) and oxygen consumption (V̇O2) were continuously measured throughout both tests. BRPE was simultaneously assessed at the end of each increment on the treadmill, while the maximal BRPE value was noted at the end of the 1 km CTT.

RESULTS

On the treadmill, BRPE correlated very high with relative HR (%HRmax) (ρ = 0.88, p < 0.001) and V̇O2 (%V̇O2max) (ρ = 0.89, p < 0.001). During the 1 km CTT, a small correlation between BRPE and %HRmax (ρ = 0.24, p < 0.05), respectively %V̇O2max was found (ρ = 0.24, p < 0.05).

CONCLUSIONS

Criterion validity of BRPE during uphill walking depends on the environment and is higher during a treadmill test compared to a natural environment. Adding sensor-based, objective exercise-intensity parameters such as HR holds promise to improve intensity prescription and health safety during uphill walking in a natural environment.

Arterial Stiffness and Cardiorespiratory Fitness Are Associated With Cognitive Function in Older Adults

Age-related cognitive impairment has been associated with arterial stiffening and decreased cardiorespiratory fitness. The aims of this cross-sectional study were to compare cognitive function domains and cardiovascular parameters in older adults (≥ 65 years old) with high and normal aortic stiffness (via carotid-femoral pulse wave velocity, cfPWV) and to explore relationships among cfPWV, carotid intima-media thickness, cardiorespiratory fitness, and cognitive function. Vascular and cognitive function were measured in older adults with either normal or high cfPWV. Cognitive function was measured via an intensive one-time neuropsychological battery, while cfPWV by applanation tonometry, carotid intima-media thickness and function (i.e., distensibility) by ultrasonography, and cardiorespiratory fitness (i.e., VO₂peak) by a submaximal exercise test. Correlations among age, VO₂peak, carotid intima-media thickness, cfPWV, and cognitive function were performed along with a series of multivariate analyses of variance. Compared with NAS, participants with HAS had greater aortic, carotid, and brachial blood pressures but similar cardiorespiratory fitness and carotid intima-media thickness and distensibility. Participants with NAS exhibited better neuropsychological performance in executive function and attention and overall cognitive function than those with HAS. When controlling for age, visual scanning and perception scores were correlated with cfPWV and VO₂peak. Our findings suggest that certain cognitive domains for older adults are associated with their cardiorespiratory fitness and aortic stiffness.

25 Years of Session Rating of Perceived Exertion: Historical Perspective and Development

The session rating of perceived exertion (sRPE) method was developed 25 years ago as a modification of the Borg concept of rating of perceived exertion (RPE), designed to estimate the intensity of an entire training session. It appears to be well accepted as a marker of the internal training load. Early studies demonstrated that sRPE correlated well with objective measures of internal training load, such as the percentage of heart rate reserve and blood lactate concentration. It has been shown to be useful in a wide variety of exercise activities ranging from aerobic to resistance to games. It has also been shown to be useful in populations ranging from patients to elite athletes. The sRPE is a reasonable measure of the average RPE acquired across an exercise session. Originally designed to be acquired ∼30 minutes after a training bout to prevent the terminal elements of an exercise session from unduly influencing the rating, sRPE has been shown to be temporally robust across periods ranging from 1 minute to 14 days following an exercise session. Within the training impulse concept, sRPE, or other indices derived from sRPE, has been shown to be able to account for both positive and negative training outcomes and has contributed to our understanding of how training is periodized to optimize training outcomes and to understand maladaptations such as overtraining syndrome. The sRPE as a method of monitoring training has the advantage of extreme simplicity. While it is not ideal for the precise recording of the details of the external training load, it has large advantages relative to evaluating the internal training load.

The Effects of Acute Exercise on Driving and Executive Functions in Healthy Older Adults

The benefits of exercise on cognitive functioning in older adults are well recognized. One limitation of the current literature is that researchers have almost exclusively relied on well-controlled laboratory tasks to assess cognition. Moreover, the effects of a single bout of aerobic exercise in older adults have received limited attention. The proposed study addresses these limitations by assessing the effects of a single bout of exercise on a more ecologically valid task - driving. Seventy-one participants (M _age = 66.39 ± 4.70 years) were randomly allocated to 20min cycling at moderate intensity or sitting and watching driving videos. Participants were then tested on their driving performance using a driving simulator. Driving performance was measured with three different scenarios assessing decision making, driving errors, reaction time, and attention. On a subsequent session, all participants were tested on executive functioning before and after a fitness test. Non-significant effects of exercise were observed on driving performance. However, participants performed better on the Trail Making Test (Cohen's d = 0.25) and Stroop test (d = 0.50) after the fitness test compared to their baseline. These results suggest that post-exercise cognitive improvements do not transfer to improved driving performance among healthy older adults. This study also highlights the importance of assessing expectations as a possible moderator of the effects of acute exercise on activities of daily living. Future studies must examine other relevant ecologically valid tasks and ensure similar expectations between experimental and control groups to further advance the knowledge base in the field.

Generalized Approach to Translating Exercise Tests and Prescribing Exercise

Although there is evidence supporting the benefit of regular exercise, and recommendations about exercise and physical activity, the process of individually prescribing exercise following exercise testing is more difficult. Guidelines like % heart rate (HR) reserve (HRR) require an anchoring maximal test and do not always provide a homogenous training experience. When prescribing HR on the basis of % HRR, rating of perceived exertion or Talk Test, cardiovascular/perceptual drift during sustained exercise makes prescription of the actual workload difficult. To overcome this issue, we have demonstrated a strategy for "translating" exercise test responses to steady state exercise training on the basis of % HRR or the Talk Test that appeared adequate for individuals ranging from cardiac patients to athletes. However, these methods depended on the nature of the exercise test details. In this viewpoint, we combine these data with workload expressed as Metabolic Equivalent Task (METs). We demonstrate that there is a regular stepdown between the METs during training to achieve the same degree of homeostatic disturbance during testing. The relationship was linear, was highly-correlated (r = 0.89), and averaged 71.8% (Training METs/Test METs). We conclude that it appears possible to generate a generalized approach to correctly translate exercise test responses to exercise training.

Physiological and Perceived Exertion Responses during Exercise: Effect of β-blockade

PURPOSE

This study investigated the effect of β-blockade on physiological and perceived exertion (RPE) responses during incremental treadmill exercise.

METHODS

Sixteen healthy participants (n = 8 men; age, 25.3 ± 4.6 yr) performed a maximal treadmill exercise test after ingestion of 100 mg metoprolol or placebo, with a double-blind, randomized, and counterbalanced design. Heart rate (HR), ventilatory, and gas exchange variables were measured continuously, and participants reported RPE at the end of each minute. Physiological and RPE responses during each condition were compared at the ventilatory threshold (VT), respiratory compensation point, and at maximal exercise using repeated-measures ANOVA. Linear regression modeled relationships between perceived exertion and physiological variables.

RESULTS

The HR and V˙O2 at the VT, respiratory compensation point, and maximal exercise were all significantly lower after β-blockade (P < 0.05). However, when standardized to within condition peak values, differences were no longer significant. The RPE associated with VT was higher after β-blockade (12.9 ± 1.0 vs 12.3 ± 1.2, P < 0.05) but lower at maximal exercise (19.1 ± 0.6 vs 19.4 ± 0.5, P < 0.05). Increases in RPE relative to HR were greater after β-blockade and remained significant when expressed relative to peak HR. There was no difference in the growth of the relationship between RPE and V˙O2 across conditions, although the origin of the relationship was higher with β-blockade.

CONCLUSIONS

Although β-blockade resulted in a significant reduction in exercising HR and V˙O2, the RPE for a given relative intensity remained unchanged. The relationship between RPE and V˙O2 was not affected by β-blockade. The results provide evidence that RPE is a useful and reliable measure for exercise testing and prescription in patients prescribed β-blockade therapy.

Brain activity during self-paced vs. fixed protocols in graded exercise testing

Electroencephalography research surrounding maximal exercise testing has been limited to male subjects. Additionally, studies have used open-looped protocols, meaning individuals do not know the exercise endpoint. Closed-loop protocols are often shown to result in optimal performance as self-pacing is permitted. The purpose of this study was to compare brain activity during open- and closed-loop maximal exercise protocols, and to determine if any sex differences are present. Twenty-seven subjects (12 males, ages 22.0 ± 2.5 years) participated in this study. A pre-assembled EEG sensor strip was used to collect brain activity from specific electrodes (F3/F4: dorsolateral prefrontal cortex, or dlPFC; and C3/Cz/C4: motor cortex, or MC). Alpha (8-12 Hz) and beta (12-30 Hz) frequency bands were analyzed. Subjects completed two maximal exercise tests on a cycle ergometer, separated by at least 48 h: a traditional, open-loop graded exercise test (GXT) and a closed-loop self-paced VO_2max (SPV) test. Mixed model ANOVAs were performed to compare power spectral density (PSD) between test protocols and sexes. A significant interaction of time and sex was shown in the dlPFC for males, during the GXT only (p = 001), where a peak was reached and then a decrease was shown. A continuous increase was shown in the SPV. Sex differences in brain activity during exercise could be associated with inhibitory control, which is a function of the dlPFC. Knowledge of an exercise endpoint could be influential towards cessation of exercise and changes in cortical brain activity.

Combining perceptual regulation and exergaming for exercise prescription in low-active adults with and without cognitive impairment

BACKGROUND

Exercise adherence in already low-active older adults with and without mild cognitive impairment (MCI) remains low. Perceptual regulation and exergaming may facilitate future exercise behaviour by improving the affective experience, however evidence that this population can perceptually regulate is lacking. To explore this, we investigated 1) perceptual regulation of exercise intensity during either exergaming or regular ergometer cycling and 2) explored affective responses.

METHODS

Thirty-two low active older adults (73.9 ± 7.3 years, n = 16, 8 females) with or without MCI (70.9 ± 5.5 years, n = 16, 11 females) participated in a sub-maximal fitness assessment to determine ventilatory threshold (VT) and two experimental sessions (counterbalanced: exergaming or regular ergometer cycling). Experimental sessions consisted 21-min of continuous cycling with 7-min at each: RPE 9, 11 and 13. Oxygen consumption (VO2), heart rate (HR), and affect (Feeling Scale) were obtained throughout the exercise.

RESULTS

VO2 (p < 0.01) and HR (p < 0.01) increased linearly with RPE, but were not significantly different between exercise modes or cognitive groups. At RPE 13, participants worked above VT in both modes (exergaming: 115.7 ± 27.3; non-exergaming 114.1 ± 24.3 VO2 (%VT)). Regardless of cognitive group, affect declined significantly as RPE increased (p < 0.01). However on average, affect remained pleasant throughout and did not differ between exercise modes or cognitive groups.

CONCLUSIONS

These results suggest low-active older adults can perceptually regulate exercise intensity, regardless of cognition or mode. At RPE 13, participants regulated above VT, at an intensity that improves cardiorespiratory fitness long-term, and affect remained positive in the majority of participants, which may support long-term physical activity adherence.

Exergaming: Feels good despite working harder

Strategies to encourage exercise have led to research on cycle ergometer ‘exergaming’, as a means of enhancing exercise enjoyment. This research has typically prescribed the exercise intensity and used one exercise mode. The aim of this study was to compare self-selected exercise intensity on a cycle ergometer with and without exergaming modes activated. A total of 20 participants aged between 18–40 years (M = 24.2 ± 5.9) completed a sub-maximal exercise test. Participants returned two days later to complete one 45 minute session of self-selected exercise with 15 minutes in each of ‘control’ (standard ergometer), ‘track’, and ‘game’ modes, with order randomized. Heart rate, work rate, perceived exertion, and affective valence were recorded during exercise. Dissociation and enjoyment were recorded in the rest interval between each mode. Participants exercised above ventilatory threshold (VT) in all three modes (track, M = 9.5 ± 12%; game, M = 6.2 ± 12%; and control, M = 4.4 ± 14% above VT) and at higher work rates (P < 0.05) exergaming (track, M = 94.5 ± 27.9; game, M = 96.2 ± 32.8 watts) than control (M = 86.6 ± 26.5 watts). Despite exercising at a higher intensity, participants perceived exercise during the exergaming modes to be most pleasant (P < 0.01), with greater enjoyment (P < 0.01) and dissociation (P < 0.01) in the game than track mode, and both modes higher on these variables than the control mode. Findings support the use of exergaming as a strategy to encourage individuals to exercise, with participants choosing to work harder physiologically, but reporting more positive psychological responses during and following the exercise.

Submaximal, Perceptually Regulated Exercise Testing Predicts Maximal Oxygen Uptake: A Meta-Analysis Study

BACKGROUND

Recently, several authors have proposed the use of a submaximal 'perceptually regulated exercise test' (PRET) to predict maximal oxygen uptake ([Formula: see text]). The PRET involves asking the individual to self-regulate a series of short bouts of exercise corresponding to pre-set ratings of perceived exertion (RPE). The individual linear relationship between RPE and oxygen uptake (RPE:[Formula: see text]) is then extrapolated to the [Formula: see text], which corresponds to the theoretical maximal RPE (RPE20). Studies suggest that prediction accuracy from this method may be better improved during a second PRET. Similarly, some authors have recommended an extrapolation to RPE19 rather than RPE20.

OBJECTIVES

The purpose of the meta-analysis was to examine the validity of the method of predicting [Formula: see text] from the RPE:[Formula: see text] during a PRET, and to determine the level of agreement and accuracy of predicting [Formula: see text] from an initial PRET and retest using RPE19 and RPE20.

DATA SOURCES

From a systematic search of the literature, 512 research articles were identified.

STUDY ELIGIBILITY CRITERIA

The eligible manuscripts were those which used the relationship between the RPE≤15 and [Formula: see text], and used only the Borg's RPE scale.

PARTICIPANTS AND INTERVENTIONS

Ten studies (n = 274 individuals) were included.

STUDY APPRAISAL AND SYNTHESIS METHODS

For each study, actual and predicted [Formula: see text] from four subgroup outcomes (RPE19 in the initial test, RPE19 in the retest, RPE20 in the initial test, RPE20 in the retest) were identified, and then compared. The magnitude of the difference regardless of subgroup outcomes was examined to determine if it is better to predict [Formula: see text] from extrapolation to RPE19 or RPE20. The magnitude of differences was examined for the best PRET (test vs retest).

RESULTS

The results revealed that [Formula: see text] may be predicted from RPE:[Formula: see text] during PRET in different populations and in various PRET modalities, regardless of the subgroup outcomes. To obtain greater accuracy of predictions, extrapolation to RPE20 during a retest may be recommended.

LIMITATIONS

The included studies reported poor selection bias and data collection methods.

CONCLUSIONS AND IMPLICATIONS OF KEY FINDINGS

The [Formula: see text] may be predicted from RPE:[Formula: see text] during PRET, especially when [Formula: see text] is extrapolated to RPE20 during a second PRET.

Validity of Submaximal Step Tests to Estimate Maximal Oxygen Uptake in Healthy Adults

BACKGROUND

Aerobic capacity (VO2max) is a strong predictor of health and fitness and is considered a key physiological measure in the healthy adult population. Submaximal step tests provide a safe, simple and ecologically valid means of assessing VO2max in both the general population and a rehabilitation setting. However, no studies have attempted to synthesize the existing knowledge regarding the validity of the multiple step-test protocols available to estimate VO2max in the healthy adult population.

OBJECTIVES

The objective of this study was to systematically review literature on the validity and reliability of submaximal step-test protocols to estimate VO2max in healthy adults (age 18-65 years).

DATA SOURCES AND STUDY SELECTION

A systematic literature search of the MEDLINE, EMBASE, Scopus, Web of Science, and Cochrane Library databases was performed. The search returned 690 studies that underwent the initial screening process. To be included, the study had to (1) have participants deemed to be healthy and aged between 18 and 65 years; (2) assess VO2max by means of a submaximal step test against a graded exercise test (GXT) to volitional exhaustion; and (3) be available in English. Reference lists from included articles were screened for additional articles.

DATA ANALYSIS AND STUDY APPRAISAL METHODS

The primary outcome measures used were the validity statistics between the actual measured VO2max and predicted VO2max values, and the reported direction of the statistically significant difference between the measured VO2max and the predicted VO2max. The Quality Assessment Tool for Quantitative Studies was used to assess the risk of bias in each included study, and was adapted to the type of quantitative study design used.

RESULTS

The combined database search produced 690 studies, from which 644 were excluded during the screening process. Following full-text assessment, a further 39 studies were excluded based on the eligibility criteria detailed previously. Four additional studies were located via the reference lists of the included studies, leaving 11 studies that fulfilled the inclusion criteria and which compared eight different step-test protocols against a direct measure of VO2max incurred during a maximal GXT. Validity measures varied, with a broad range of correlation coefficients reported across the 11 studies (r = 0.469-0.95). Of the 11 studies, two reported reliability measures, demonstrating good test-retest reliability [mean -0.8 ± 3.7 mL kg(-1) min(-1) (±7.7 % of the mean measured VO2max)].

CONCLUSIONS

Considering the relationship between VO2max and various markers of health, the use of step tests as a measure of health in both the general adult population and rehabilitation settings is advocated. Step tests provide a simple, effective and ecologically valid method of submaximally assessing VO2max that can be implemented in a variety of situations within the general adult population. Future research is needed to assess the reliability of the majority of the step-test procedures reviewed. Based on the validity measures, submaximal step-test protocols are an acceptable means of estimating VO2max in the generally healthy adult population. For tracking changes in cardiorespiratory fitness, the Chester Step test appears to be an appropriate tool due to its high test-retest reliability.

Validity of a perceptually-regulated step test protocol for assessing cardiorespiratory fitness in healthy adults

PURPOSE

To determine whether maximal oxygen uptake (VO₂max) could be predicted accurately and reliably from a 2-step, perceptually-regulated exercise test (PRET) in healthy adults.

METHODS

Sixteen participants (31.7 ± 11.3 years, 3 females) completed three PRETs (separated by 24-72 h) and one maximal, perceptually-regulated, graded exercise test (PRETmax) on a motorized treadmill. Oxygen uptake (VO₂) and heart rate (HR) were recorded during each test. VO₂ values for RPE range 9-15 were extrapolated to RPE 20 and age-predicted maximal HR (HRmax) using individual linear regression analysis to predict VO₂max values compared to measured VO₂max.

RESULTS

VO₂ and HR values were consistent between each of four RPE levels of the PRET. ICC values ranged between 0.76 and 0.85. Predicted VO₂max from both methods were lower than measured VO₂max (p < 0.01). Limits of agreement (LoA) for measured (41.4 ± 5.3 ml kg^-1 min^-1) versus predicted VO₂max from each of the three PRETs using RPE20 were -1.2 ± 15.6, -1.0 ± 7.2 and -2.1 ± 5.5 and for HRmax were -1.8 ± 4.2; -2.6 ± 4.2 and -2.4 ± 4.4 ml kg^-1 min^-1 for PRET 1, 2 and 3, respectively.

CONCLUSIONS

The step PRET elicited significant and reliable increases in VO₂ across the four RPE levels, but under-estimated treadmill VO₂max. However, there was better agreement between measured and predicted VO₂max when extrapolated to HRmax. As evidence indicates the underestimation of VO₂max is explained by the difference in the mode of exercise, the step PRET provides a simple and convenient test of cardiorespiratory fitness.

Cross-validation of Peak Oxygen Consumption Prediction Models From OMNI Perceived Exertion

This study cross-validated statistical models for prediction of peak oxygen consumption using ratings of perceived exertion from the Adult OMNI Cycle Scale of Perceived Exertion. 74 participants (men: n=36; women: n=38) completed a graded cycle exercise test. Ratings of perceived exertion for the overall body, legs, and chest/breathing were recorded each test stage and entered into previously developed 3-stage peak oxygen consumption prediction models. There were no significant differences (p>0.05) between measured and predicted peak oxygen consumption from ratings of perceived exertion for the overall body, legs, and chest/breathing within men (mean±standard deviation: 3.16±0.52 vs. 2.92±0.33 vs. 2.90±0.29 vs. 2.90±0.26 L·min(-1)) and women (2.17±0.29 vs. 2.02±0.22 vs. 2.03±0.19 vs. 2.01±0.19 L·min(-1)) participants. Previously developed statistical models for prediction of peak oxygen consumption based on subpeak OMNI ratings of perceived exertion responses were similar to measured peak oxygen consumption in a separate group of participants. These findings provide practical implications for the use of the original statistical models in standard health-fitness settings.

Prediction of peak oxygen uptake in children using submaximal ratings of perceived exertion during treadmill exercise

Purpose

This study assessed the utility of the Children’s Effort Rating Table (CERT) and the Eston–Parfitt (EP) Scale in estimating peak oxygen uptake (\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\dot{V}{\text{O}}_{{2{\text{peak}}}}$$\end{document}V˙O2peak) in children, during cardiopulmonary exercise testing (CPET) on a treadmill.

Methods

Fifty healthy children (n = 21 boys; 9.4 ± 0.9 years) completed a continuous, incremental protocol until the attainment of \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\dot{V}{\text{O}}_{{2{\text{peak}}}}$$\end{document}V˙O2peak. Oxygen uptake (\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\dot{V}{\text{O}}_{2}$$\end{document}V˙O2) was measured continuously, and ratings of perceived exertion (RPE) were estimated at the end of each exercise stage using the CERT and the EP Scale. Ratings up to- and including RPE 5 and 7, from both the CERT (CERT 5, CERT 7) and EP Scale (EP 5, EP 7), were linearly regressed against the corresponding \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\dot{V}{\text{O}}_{2}$$\end{document}V˙O2, to both maximal RPE (CERT 10, EP 10) and terminal RPE (CERT 9, EP 9).

Results

There were no differences between measured- and predicted \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\dot{V}{\text{O}}_{{2{\text{peak}}}}$$\end{document}V˙O2peak from CERT 5, CERT 7, EP 5 and EP 7 when extrapolated to either CERT 9 or EP 9 (P > 0.05). Pearson’s correlations of r = 0.64–0.86 were observed between measured- and predicted \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\dot{V}{\text{O}}_{{2{\text{peak}}}}$$\end{document}V˙O2peak, for all perceptual ranges investigated. However, only EP 7 provided a small difference when considering the standard error of estimate, suggesting that the prediction of \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\dot{V}{\text{O}}_{{2{\text{peak}}}}$$\end{document}V˙O2peak from EP 7 would be within 10 % of measured \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\dot{V}{\text{O}}_{{2{\text{peak}}}}$$\end{document}V˙O2peak.

Conclusions

Although robust estimates of \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\dot{V}{\text{O}}_{{2{\text{peak}}}}$$\end{document}V˙O2peak may be elicited using both the CERT and EP Scale during a single CPET with children, the most accurate estimates of \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\dot{V}{\text{O}}_{{2{\text{peak}}}}$$\end{document}V˙O2peak occur when extrapolating from EP 7.

The functional and clinical outcomes of exercise training following a very low energy diet for severely obese women: study protocol for a randomised controlled trial

Background

Clinical practice guidelines globally recommend lifestyle modification including diet and exercise training as first-line treatment for obesity. The clinical benefits of exercise training in adults with obesity is well-documented; however, there is no strong evidence for the effectiveness of exercise training for weight loss in class II and class III obesity. The purpose of the randomised controlled trial described in this protocol article is to examine the effect of exercise training, in addition to a very low energy diet (VLED), in clinically severe obese women for changes in body composition, physical function, quality of life, and markers of cardiometabolic risk.

Methods/Design

Sixty women, aged 18–50 years with a body mass index (BMI) greater than 34.9 kg.m² and at least one obesity-related co-morbidity, will be recruited for this 12-month study. Participants will be randomised to either exercise plus energy restriction (n = 30), or energy restriction alone (n = 30). All participants will follow an energy-restricted individualised diet incorporating a VLED component. The exercise intervention group will also receive exercise by supervised aerobic and resistance training and a home-based exercise programme totalling 300 minutes per week. Primary outcome measures include body composition and aerobic fitness. Secondary outcome measures include: physical function, cardiometabolic risk factors, quality of life, physical activity, and mental health. All outcome measures will be conducted at baseline, 3, 6 and 12 months.

Discussion

Previous research demonstrates various health benefits of including exercise training as part of a healthy lifestyle at all BMI ranges. Although clinical practice guidelines recommend exercise training as part of first-line treatment for overweight and obesity, there are few studies that demonstrate the effectiveness of exercise in class II and class III obesity. The study aims to determine whether the addition of exercise training to a VLED provides more favourable improvements in body composition, physical function, quality of life, and markers of cardiometabolic risk for women with clinically severe obesity, compared to VLED alone.

Trial registration

Australian New Zealand Clinical Trials Registry (ACTRN12611000694910). Date registered: 4 July 2011

Prediction of maximal or peak oxygen uptake from ratings of perceived exertion

Maximal or peak oxygen uptake (V˙O2 max and V˙O2 peak , respectively) are commonly measured during graded exercise tests (GXTs) to assess cardiorespiratory fitness (CRF), to prescribe exercise intensity and/or to evaluate the effects of training. However, direct measurement of CRF requires a GXT to volitional exhaustion, which may not always be well accepted by athletes or which should be avoided in some clinical populations. Consequently, numerous studies have proposed various sub-maximal exercise tests to predict V˙O2 max or V˙O2 peak . Because of the strong link between ratings of perceived exertion (RPE) and oxygen uptake (V˙O2), it has been proposed that the individual relationship between RPE and V˙O2 (RPE:V˙O2) can be used to predict V˙O2 max (or V˙O2 peak) from data measured during submaximal exercise tests. To predict V˙O2 max or V˙O2 peak from these linear regressions, two procedures may be identified: an estimation procedure or a production procedure. The estimation procedure is a passive process in which the individual is typically asked to rate how hard an exercise bout feels according to the RPE scale during each stage of a submaximal GXT. The production procedure is an active process in which the individual is asked to self-regulate and maintain an exercise intensity corresponding to a prescribed RPE. This procedure is referred to as a perceptually regulated exercise test (PRET). Recently, prediction of V˙O2max or V˙O2 peak from RPE:V˙O2 measured during both GXT and PRET has received growing interest. A number of studies have tested the validity, reliability and sensitivity of predicted V˙O2 max or V˙O2 peak from RPE:V˙O2 extrapolated to the theoretical V˙O2 max at RPE20 (or RPE19). This review summarizes studies that have used this predictive method during submaximal estimation or production procedures in various populations (i.e., sedentary individuals, athletes and pathological populations). The accuracy of the methods is discussed according to the RPE:V˙O2 range used to plot the linear regression (e.g., RPE9–13 versus RPE9–15 versus RPE9–17 during PRET), as well as the perceptual endpoint used for the extrapolation (i.e., RPE19 and RPE20). The V˙O2 max or V˙O2 peak predictions from RPE:V˙O2 are also compared with heart rate-related predictive methods. This review suggests that V˙O2 max (or V˙O2 peak ) may be predicted from RPE:V˙O2 extrapolated to the theoretical V˙O2 max (or V˙O2 peak) at RPE20 (or RPE19). However, it is generally preferable to (1) extrapolate RPE:V ˙ O 2 to RPE19 (rather than RPE20); (2) use wider RPE ranges (e.g. RPE ≤ 17 or RPE9–17) in order to increase the accuracy of the predictions; and (3) use RPE ≤ 15 or RPE9–15 in order to reduce the risk of cardiovascular complications in clinical populations.

Prediction of VO2 peak using OMNI Ratings of Perceived Exertion from a submaximal cycle exercise test

The primary aim of this study was to develop statistical models to predict peak oxygen consumption (VO2 peak) using OMNI Ratings of Perceived Exertion measured during submaximal cycle ergometry. Male (M = 20.9 yr., SE = 0.4) and female (M = 21.6 yr., SE = 0.5) participants (N = 81) completed a load-incremented maximal cycle ergometer exercise test. Simultaneous multiple linear regression was used to develop separate VO2 peak statistical models using submaximal ratings of perceived exertion for the overall body, legs, and chest/breathing as predictor variables. VO2 peak (L·min(-1)) predicted for men and women from ratings of perceived exertion for the overall body (3.02 ± 0.06; 2.03 ± 0.04), legs (3.02 ± 0.06; 2.04 ± 0.04), and chest/breathing (3.02 ± 0.05; 2.03 ± 0.03) were similar to measured VO2 peak (3.02 ± 0.10; 2.03 ± 0.06, ps > .05). Statistical models based on submaximal OMNI Ratings of Perceived Exertion provide an easily administered and accurate method to predict VO2 peak.

Ramp-incremented and RPE-clamped test protocols elicit similar VO2max values in trained cyclists

PURPOSE

The present study compared the efficacy of ramp incremented and ratings of perceived exertion (RPE)-clamped test protocols for eliciting maximal oxygen uptake (VO2max).

METHODS

Sixteen trained cyclists (age 34 ± 7 years) performed a ramp-incremented protocol and an RPE-clamped protocol 1 week apart in a randomized, counterbalanced order. The RPE-clamped protocol consisted of five, 2-min stages where subjects self-selected work rate and pedal cadence to maintain the prescribed RPE. After completing both test protocols subjects were asked which they preferred.

RESULTS

The mean ± SD test time of 568 ± 72 s in the ramp protocol was not significantly different to the 600 ± 0 s in the RPE-clamped protocol (mean difference = 32 s; p = 0.09), or was the VO2max of 3.86 ± 0.73 L min(-1) in the ramp protocol significantly different to the 3.87 ± 0.72 L min(-1) in the RPE-clamped protocol (mean difference = 0.002 L min(-1); p = 0.97). Furthermore, no significant differences were observed for peak power output (p = 0.21), maximal minute ventilation (p = 0.97), maximal respiratory exchange ratio (p = 0.09), maximal heart rate (p = 0.51), and post-test blood lactate concentration (p = 0.58). The VO2max attained in the preferred protocol was significantly higher than the non-preferred protocol (mean difference = 0.14 L min(-1); p = 0.03).

CONCLUSION

The RPE-clamped test protocol was as effective as the ramp-incremented protocol for eliciting VO2max and could be considered as a valid alternative protocol, particularly where a fixed test duration is desirable.

Use of a perceptually-regulated test to measure maximal oxygen uptake is valid and feels better

A maximal, perceptually-regulated exercise test (PRETmax) whereby participants control the intensity according to preset ratings of perceived exertion (RPE) may induce more positive affective responses than a conventional 'experimenter controlled' incremental ramp test (Iramp). The authors aimed to assess (1) if a PRETmax could be used to measure VO(2max) and (2) if affective responses differed between the PRETmax and Iramp. Sixteen participants (age 20.5, s=1.2 y) completed a PRETmax which required them to adjust the resistance on a recumbent cycle ergometer to correspond to prescribed RPEs of 9, 11, 13, 15, 17 and 20 and an Iramp. Both tests ended with volitional exhaustion. Affect was recorded every minute throughout exercise using the Feeling Scale (FS). There was no difference (P>0.05) between VO(2max) measured by PRETmax (43.5, s=4.1 ml kg(-1) min(-1)) and Iramp (44.3, s=4.9 ml kg(-1) min(-1)). Participants reported feeling significantly less negative (P<0.001) throughout the PRETmax compared to Iramp (average mean difference FS = 1.4, s=0.1). The PRETmax has application in situations where the direct measurement of VO(2max) is required and the affective responses of the individual are considered to be important.

Development and evaluation of a treadmill-based exercise tolerance test in cardiac rehabilitation

Cardiac rehabilitation exercise prescriptions should be based on exercise stress tests; however, limitations in performing stress tests in this setting typically force reliance on subjective measures like the Duke Activity Status Index (DASI). We developed and evaluated a treadmill-based exercise tolerance test (ETT) to provide objective physiologic measures without requiring additional equipment or insurance charges. The ETT is stopped when the patient's Borg scale rating of perceived exertion (RPE) reaches 15 or when any sign/symptom indicates risk of an adverse event. Outcomes of the study included reasons for stopping; maximum heart rate, systolic blood pressure, and rate pressure product; and adverse events. We tested equivalence to the DASI as requiring the 95% confidence interval for the mean difference between DASI and ETT metabolic equivalents (METs) to fall within the range (-1, 1). Among 502 consecutive cardiac rehabilitation patients, one suffered a panic attack; no other adverse events occurred. Most (80%) stopped because they reached an RPE of 15; the remaining 20% were stopped on indications that continuing risked an adverse event. Mean maximum systolic blood pressure, heart rate, and rate pressure product were significantly (P < 0.001) below thresholds of the American Association of Cardiovascular and Pulmonary Rehabilitation. Two patients' heart rates exceeded 150 beats per minute, but their rate pressure products remained below 36,000. The mean difference between DASI and ETT METs was -0.8 (-0.98, -0.65), indicating equivalence at our threshold. In conclusion, the ETT can be performed within cardiac rehabilitation, providing a functional capacity assessment equivalent to the DASI and objective physiologic measures for developing exercise prescriptions and measuring progress.

Brain activity and perceived exertion during cycling exercise: an fMRI study

BACKGROUND/AIM

Currently, the equipment and techniques available to assess brain function during dynamic exercise are limited, which has restricted our knowledge of how the brain regulates exercise. This study assessed the brain areas activated during cycling by making use of a novel cycle ergometer, constructed to measure functional MRI (fMRI) brain images during dynamic exercise. Furthermore, we compared brain activation at different levels of ratings of perceived exertion (RPE) generated during the exercise.

METHODS

Seven healthy adults performed cycling exercise in a novel MRI compatible cycle ergometer while undergoing brain  fMRI. Participants completed a cycling block protocol comprising six trials of 2 min cycling with 16-s intervals between trials. Participants reported their RPE every minute through an audio link. The MRI cycling ergometer transferred the torque generated on the ergometer through a cardan system to a cycling ergometer positioned outside the MRI room. For data analysis, the effects of cycling as opposed to rest periods were examined after motion correction.

RESULTS

The multiparticipant analysis revealed in particular the activation of the cerebellar vermis and precentral and postcentral gyrus when periods of cycling versus rest were compared. Single participant analysis in four participants revealed that activation of the posterior cingulate gyrus and precuneus occurred in cycling blocks perceived as 'hard' compared with exercise blocks that were less demanding.

CONCLUSIONS

The present study offers a new approach to assess brain activation during dynamic cycling exercise, and suggests that specific brain areas could be involved in the sensations generating the rating of perceived exertion.

The perceptually regulated exercise test is sensitive to increases in maximal oxygen uptake

The aim of this study was to assess the sensitivity of a perceptually regulated exercise test (PRET) to predict maximal oxygen uptake (VO₂max) following an aerobic exercise-training programme. Sedentary volunteers were assigned to either a training (TG n = 16) or control (CG n = 10) group. The TG performed 30 min of treadmill exercise, regulated at 13 on the Borg Rating of Perceived Exertion (RPE) Scale, 3× per week for 8 weeks. All participants completed a 12-min PRET to predict VO₂max followed by a graded exercise test (GXT) to measure VO₂max before and after training. The PRET required participants to control the speed and incline on the treadmill to correspond to RPE intensities of 9, 11, 13 and 15. Predictive accuracy of extrapolation end-points RPE19 and RPE20 from a submaximal RPE range of 9-15 was compared. Measured VO₂max increased by 17 % (p < 0.05) from baseline to post-intervention in TG. This was reflected by a similar change in [VO₂max predicted from PRET when extrapolated to RPE 19 (baseline VO₂max: 31.3 ± 5.5, 30.3 ± 9.5 mL kg(-1) min(-1); post-intervention VO₂max: 36.7 ± 6.4, 37.4 ± 7.9 mL kg(-1) min(-1), for measured and predicted values, respectively). There was no change in CG (measured vs. predicted VO₂max: 39.3 ± 6.5; 40.3 ± 8.2 and 39.2 ± 7.0; 37.7 ± 6.0 mL kg(-1) min(-1)) at baseline and post-intervention, respectively. The results confirm that PRET is sensitive to increases in VO₂max following aerobic training.