HR-VO2 Relationship Research Articles

The ability of heart rate or perceived exertion to predict oxygen uptake varies across exercise modes in persons with tetraplegia.

Descriptive study. To examine grouped and intra-individual relationships between 1) exercise intensity and heart rate (EI-HR); 2) EI and oxygen uptake (EI-VO2); 3) VO2 and HR (VO2-HR); and 4) perceived exertion and VO2 (PE-VO2) in persons with tetraplegia (C4/5-C8) during different modes of exercise. Community in Winnipeg, Canada. Participants exercised at 3 graded intensities during arm ergometry (ERG), wheeling indoors on cement (MWC), or hand-cycling outdoors (HC). EI (Watts, km/hr) and VO2, HR and PE were recorded. 22 persons completed ERG, 14/22 also completed MWC and 5/22 completed ERG, MWC and HC. Regression analysis of grouped data showed a significant relationship between EI-VO2 but not for EI-HR or HR-VO2. Intra-individual analyses showed a strong correlation (r or ρ > 0.7) for VO2-HR for 16/22 during ERG. In the participants completing multiple exercise modes, a strong VO2-HR relationship was present in 12/14 in ERG, but in only 6/14 in MWC. The 5 persons exercising with all 3 modes had a strong HR-VO2 relationship in 5/5 for ERG, 2/5 in MWC and 1/5 in HC. A strong relationship for PE-VO2 was observed in a higher proportion of participants (versus HR-VO2) during MWC (9/14) and HC (2/4). Within the same individual, the HR-VO2 relationship varies across modes, despite exercising over similar ranges of steady-state VO2. HR appears less able to predict VO2 compared to PE. Based on these new findings, systematic investigation of the HR-VO2 relationship across modes of exercise in tetraplegia is warranted.

Relationship Between Heart Rate, Oxygen Consumption, and Energy Expenditure in Futsal.

The primary aim of this study was to compare the measured oxygen consumption (Measured-VO2) in a simulated futsal game (S-Game) with the estimated oxygen consumption (Estimated-VO2) through a regression equation between heart rate (HR) and oxygen consumption (VO2) (HR-VO2) in treadmill running, and a secondary aim was to calculate the total energy expenditure (EE) in S-Game. Ten professional players (22.20 ± 3.22 years) were evaluated. HR-VO2 was determined individually in the continuous test on the treadmill (ContTest). The Measured-VO2 in S-Game was compared with the Estimated-VO2 in the ContTest. Alactic and lactic pathways were estimated by VO2. The Estimated-VO2 presented no statistically significant difference with the Measured-VO2, using the paired t-test (p = 0.38). However, the correlation between Estimated- and Measured-VO2 was very weak (r = −0.05), and it presented poor agreement (concordance correlation coefficient = −0.04). In addition, a Bland–Altman plot presented bias of −2.8 ml/kg/min and individual difference as large as 19 ml/kg/min. The HR-VO2 determined by the ContTest was not a good individual predictor of VO2. The high intensity and intermittent nature of the futsal game possibly caused dissociation in the HR-VO2 relationship. ContTest is not recommended for estimating VO2 and calculating individual EE in the futsal game. This is recommended only for the group mean. The total EE in S-Game was 13.10 ± 1.25 kcal.min−1 (10.81 ± 1.57 metabolic equivalents). The contributions from the metabolic pathways were as follows: aerobic (93%), alactic (5%), and lactic (2%).

Heart rate and VO2 responses to treadmill running with body weight support using the GlideTrak™

Background/ObjectiveThe heart rate (HR) and metabolic (VO2) responses to treadmill running using the GlideTrak™ body weight support system have not been reported. The purpose of this study was to compare the submaximal and maximal HR and VO2 responses to normal-weight treadmill running (TMR) to treadmill running with body weight support provided by the GlideTrak™ (GTR). MethodsTwenty participants (11 males; 9 females) 18 to 26 years of age voluntarily participated in this study. Each participant completed two exercise tests in each mode of running: a maximal graded exercise test to compare maximal HR and VO2 values and a submaximal exercise test to compare the HR-VO2 relationship. ResultsMaximal HR and VO2 values were significantly (p < 0.001) lower during GTR (183.4 ± 9.1 bpm, 38.1 ± 7.2 mL kg−1 min−1) compared to TMR (194.3 ± 8.6 bpm, 49.5 ± 8.9 kg−1 min−1). There was a significant difference in the HR-VO2 relationship between GTR and TMR. Compared to TMR, exercising at a HR of 140 bpm resulted in a VO2 that was 4.0 mL kg−1 min−1 lower during GTR. At the VO2 associated with a HR of 140 bpm during TMR, the HR during GTR was 16 bpm higher. During GTR at intensities of exercise up to an RER of 1.0, only 8 participants achieved vigorous intensities of aerobic exercise defined as 64-90% of VO2max. ConclusionExercising with the GlideTrak™ body weight support system may not provide the same cardiorespiratory training stimulus as normal-weight treadmill running.

The Gravity-Loading countermeasure Skinsuit (GLCS) and its effect upon aerobic exercise performance

The Russian Pingvin suit is employed as a countermeasure to musculoskeletal atrophy in microgravity, though its 2-stage loading regime is poorly tolerated. The Gravity-Loading Countermeasure Skinsuit (GLCS) has been devised to comfortably compress the body via incrementally increasing longitudinal elastic-fibre tensions from the shoulders to the feet. We tested whether the Mk III GLCS was a feasible adjunct to sub-maximal aerobic exercise and resulting VO2Max predictions. Eight healthy subjects (5♂, 28±6yr) performed cycle ergometry at 75% VO2Max (derived from an Astrand-Rhyming protocol) whilst wearing a GLCS and gym clothing (GYM). Ventilatory parameters, heart rate (HR), core temperature (TC), and blood lactate (BL) were recorded along with subjective perceived exertion, thermal comfort, movement discomfort and body control. Physiological and subjective responses were compared over TIME and between GYM and GLCS (ATTIRE) with 2-way repeated measures ANOVA and Wilcoxon tests respectively. Resultant VO2Max predictions were compared with paired t-tests between ATTIRE. The GLCS induced greater initial exercise ventilatory responses which stabilised by 20min. HR and TC continued to rise from 5min irrespective of ATTIRE, whereas BL was greater in the GLCS at 20min. Predicted VO2Max did not differ with ATTIRE, though some observed differences in HR were noteworthy. All subjective ratings were exacerbated in the GLCS. Despite increased perception of workload and initial ventilatory augmentations, submaximal exercise performance was not impeded. Whilst predicted VO2Max did not differ, determination of actual VO2Max in the GLCS is warranted due to apparent modulation of the linear HR-VO2 relationship. The GLCS may be a feasible adjunct to exercise and potential countermeasure to unloaded-induced physiological deconditioning on Earth or in space.

Measurement of Energy Expenditure among Free Living Active and Sedentary Women (18-23 Years): Results of Objective and Self-Reported Assessment

Background: Heart rate monitoring has been advocated for assessing energy expenditure in field studies. The aim of the study is to determine and compare the energy requirements by heart rate method and factorial method and measure PWC170 for young active and sedentary women. Methods: A cross-sectional study on 30 collegiate women (18-23 years) was conducted. Young active (Group A) (n=15) and age matched sedentary women (Group S) (n=15) were selected based on an inclusion criterion. Using standard procedures, data was collected on general information, anthropometry, blood pressure, body composition, PWC170, HR-VO2 relationship, diet and physical activity to compute energy requirements. Results: Individual HR- VO2 equations were developed. Mean TDEE by factorial method for Group A was 2256 ±246 kcal and for Group S was 1772 ± 163 kcal. Mean TDEE by heart rate method of Group A was 1952 ± 68 kcal and of Group S was 1579 ± 116 kcal. Mean PWC170 for Group A and Group S were 94.8 ± 6.9 and 93.5 ± 13.9 watts respectively. PAL for Group A was 32% higher than Group S. Conclusion: The heart rate technique is a useful tool for computing energy requirement of active groups because of its simplicity and potential use in free living conditions.

Energy Expenditures During Wheelchair Propulsion Derived From A Body-worn Sensor Versus Heart Rate-estimated Equations

The SenseWear™ armband has been shown to be a valid and practical tool to assess energy expenditure (EE) for upright, ambulatory adults. However, we have previously demonstrated that the SenseWear™ armband (AB) overestimated VO2 and energy expenditure compared to indirect calorimetry during different speeds and gradients of treadmill wheelchair propulsion. PURPOSE: This study compared measures of exercise energy expenditure obtained from AB-estimated versus HR-derived VO2 during outdoor, overground wheelchair propulsion. METHODS: Ten individuals with spinal cord injury (SCI) performed overground wheelchair propulsion at a "slow" pace, self-selected pace and "fast" pace over a 746±4 m outdoor test course measured by GPS. EE was estimated concurrently from HR-derived VO2 and the AB. HR-derived VO2 was calculated from each individual's HR-VO2 relationship, measured by indirect calorimetry during 14 different speeds and gradients of treadmill wheelchair propulsion. RESULTS: Across all three paces (n=30), AB and HR-derived VO2 or EE were well correlated (r=0.81, P<0.05). Although AB slightly overestimated mean EE (14.6±4.4 kJ) and VO2 (0.71±0.22 ml·min-1) compared to individually-calculated HR-derived EE (13.9±4.1 kJ) and VO2 (0.67±0.20 ml·min-1), this difference was not significant. However, correlations between AB-estimated versus HR-derived EE and VO2 were poor at the "slow" pace chosen by wheelchair users (r=0.27, P>0.05) and the highest (r=0.85, P<0.05) at their "fast" pace. CONCLUSION: This study revealed that an arm-mounted multi-sensor device developed for upright ambulatory movements adequately estimated energy expenditure compared with HR-derived measures of exercise metabolism during overground wheelchair propulsion. However, when the upper-limb movements were slowest, during the "slow" wheelchair pace, the accuracy of the AB was low, with significant overprediction of exercise EE. If the AB is to be deployed as a component of exercise prescription for SCI individuals, it is necessary to develop wheelchair-specific algorithms for the armband to enhance its accuracy of estimating energy expenditures during wheelchair exercise.

ECG recording and energy expenditure estimated by HR-VO2 relationship during triathlon competition

ECG recording and energy expenditure estimated by HR-VO2 relationship during triathlon competition

Effects of age on ventilatory threshold and peak oxygen uptake normalised for regional skeletal muscle mass in Japanese men and women aged 20–80 years

Ventilatory threshold (VT) is an important predictor of cardiorespiratory fitness, such as peak oxygen uptake (VO2peak) and is a valuable index of aerobic exercise intensity. However, little is known about the role of skeletal muscle (SM) mass in the age-associated decline of VT. Therefore, the present study was performed to investigate the effects of age on cardiopulmonary fitness normalised for regional SM mass in 1,463 Japanese men and women, and to determine the relevance of VT normalised to SM mass based on age and gender. Total, trunk and thigh SM mass were measured using an ultrasound method, while VO2peak and VT were determined during treadmill walking. VO2peak was estimated using the predicted maximum heart rate (HR) and the HR-VO2 relationship for sub-maximal treadmill walking. There were significant negative correlations between VT normalised for body mass and age in men and women (P < 0.001). Age-associated declines were also observed in VT normalised for body mass in both men and women; however, VT normalised for SM mass was not significantly different with age. Significant correlations were also observed between thigh SM mass and VT in both men and women. These results suggest that thigh SM mass is closely associated with VO2peak and/or VT in both men and women, and the decrease in VT with age is predominantly due to an age-related decline of SM mass. Moreover, this study provides normative cardiorespiratory fitness data regarding VT normalised SM mass in healthy men and women aged 20-80 years.

The individual relationship between heart rate and oxygen uptake in people with a tetraplegia during exercise

Descriptive study. To examine the individual heart rate-oxygen uptake (HR-VO(2)) relationship during exercise in persons with tetraplegia (TP). Rehabilitation Centre Heliomare, Wijk aan Zee, The Netherlands. The HR-VO(2) relationship was determined in untrained subjects with motor complete TP (C5 or C6, n=10 and C7 or C8, n=10) during a discontinuous graded exercise hand cycle test. The mean HR and VO(2) of the final 60 s of 2-min exercise blocks were used for calculation of the individual correlation coefficient and the standard error of the estimate (SEE). Two subjects of the C5-C6 group were not able to complete the test. Individual Pearson's correlation coefficients (r) ranged from 0.68 to 0.97 and SEE from 2.6 to 22.4% VO(2)-Reserve (VO(2)R). The mean Pearson's r and SEE were 0.81+/-0.12 and 10.6+/-5.6% VO(2)R in the C5-C6 group and 0.91+/-0.07 and 7.0+/-3.2% VO(2)R in the C7-C8 group, respectively. Two subjects of the C5-C6 group and six subjects of the C7-C8 group attained a linear HR-VO(2) relationship with an acceptable SEE (< or =6.0%) and r (>0.90). The HR-VO(2) relationship appeared linear in only eight out of 18 subjects. An individual analysis of the HR-VO(2) relationship is necessary to determine whether HR can be used to quantify exercise intensity. The use of HR to prescribe training intensity should be reconsidered in persons with TP. This study is supported from a grant by ZON-MW.

Validation of the Polar S410 Heart Rate Monitor for Estimating Energy Expenditure in Women

PURPOSE: To determine the effect of ambient temperature on the validity of the Polar S410 heart rate (HR) monitor for estimating energy expenditure. (EE) METHODS: EE estimates obtained during cycling at 30%, 60%, and 80% of maximal oxygen uptake (VO2max) in 25°C, 30°C, and 35°C ambient temperatures were compared with indirect calorimetry (IC). Three different methods of estimating EE using the monitor were compared: (a) the AHR method used the actual values for HRmax and VO2max, (b) the PHR method used the HRmax and VO2max predicted by the “OwnIndex” software, with resting HR measured in the ambient temperature for the test, (c) and the PHRTM method used the HRmax and VO2max predicted by the “OwnIndex” software, with resting HR measured in thermoneutral (22°C) conditions. The traditional method of using individualized heart rate-VO2 relationship to estimate EE was also compared to IC and the Polar S410 methods. RESULTS: In the 25°C, 30°C, and 35°C conditions AHR overestimated (means ± SD) EE from IC by 4% ±11, 7% ±11, and 9% ±8; PHR overestimated EE from IC by 17% ±21,18% ±22, and 19% ±19; PHRTM overestimated EE from IC by 20% ±21, 22% ±21, and 24% ±19; and the HR-VO2method underestimated EE from IC by 8% ±12, 4% ±12, and 1.4%±11. CONCLUSION: We conclude that the Polar S410, using the actual values for HRmax and VO2max programmed into the Polar S410 (AHR), provides estimates of EE for a group of young women that are within 10% of those from IC. These EE estimates are similar in accuracy (i.e. 4%–9% difference) to estimates from the traditional HR-VO2 relationship (i.e. 1.4%–8% difference). Estimates of EE from the Polar S410 based on estimates of VO2max and HRmax (PHR and PHRTM) are unacceptably high (>10%), with errors ranging from 17%–24%. Ambient temperatures above 25°C increase the error of EE estimates from the Polar S410 due to the dissociation of HR from VO2, resulting in EE estimates that are significantly different from IC.

Validity of Using Heart Rate as a Predictor of Oxygen Consumption in Dance

The validity of predicting oxygen uptake (VO2) from heart rate (HR) was examined in 19 professional modern dancers of both genders ranging in age from 21 to 29 years. The subjects were measured on two occasions; once during a multi-stage graded treadmill test and again during their usual modern dance class. The data showed significant differences during both the treadmill test or dance class at lower intensities of less than 20 ml·kg-1·min-1 (p ≤ 0.03) and paradoxically no significant differences between the relationships at intensities greater than 20 ml·kg-1·min-1. However results also identified large individual variability and when taken into account the great variability, it would seem unacceptable to predict the VO2 from HR values in dance, based on the HR-VO2 relationship established from a progressive treadmill protocol. Furthermore, given that dance is a non-steady-state activity and is executed at low to moderate intensities with occasional anaerobic bursts, it seems unlikely that the HR-VO2 relationship established from a steady-state laboratory test can be relied upon as a predictor of VO2 in dance.

Development, Reliability, and Validity of a Multistage Dance Specific Aerobic Fitness Test (DAFT)

The aim of this study was to design a multistage dance-specific aerobic field-test that would indicate whether a dancer had the cardiorespiratory capabilities to cope with the demands of dance class and performance. The test consisted of five progressively demanding dance sequences. The technical level of each stage was kept as simple as possible to reduce the effect of economy of movement so that the emphasis of the test was physiologically based rather than skill orientated. The reliability of the stage workloads was measured via oxygen uptake and heart rate using a tele-metric gas analyzer. After an initial familiarization trial, subjects (n = 56: 24 males and 32 females) undertook the test twice within 48 hours. The results showed significant differences in oxygen requirement and heart rates between stages (F [4, 172] = 803.522; p &lt; 0.001) and gender (p &lt; 0.01). The HR-VO2relationship for the test was r = 0.94; n = 3336; p &lt; 0.001 and the SEE was ± 4.506. Reliability of the DAFT was calculated by determining the coefficient of variation (CV) expressed as a percentage and the percentage change in the mean between trials (% mean). CV ranged between 1.4 and 6.0 and % Amean between 0.2 and 6.3 for the stages. The use of dance specific moves and specific levels of the test equating to the mean oxygen demands of class and performance confirmed that logical validity had been achieved. Possible applications to the dance world are the monitoring of heart rate at each of the stages during the year; setting of a target stage attainment for an individuals readiness to undertake class or performance after injury and/or, setting specific aerobic capabilities for dancers post-holiday or for guest artists (below a specific mean heart rate during a designated stage).

Cardiorespiratory responses to underwater treadmill walking in healthy females.

This study compared the cardiorespiratory responses of eight healthy women (mean age 30.25 years) to submaximal exercise on land (LTm) and water treadmills (WTm) in chest-deep water (Aquaciser). In addition, the effects of two different water temperatures were examined (28 and 36 degrees C). Each exercise test consisted of three consecutive 5-min bouts at 3.5, 4.5 and 5.5 km x h(-1). Oxygen consumption (VO2) and heart rate (HR), measured using open-circuit spirometry and telemetry, respectively, increased linearly with increasing speed both in water and on land. At 3.5 km x h(-1) VO2 was similar across procedures [chi = 0.6 (0.05) l x min(-1)]. At 4.5 and 5.5 km x h(-1) VO2 was significantly higher in water than on land, but there was no temperature effect (WTm: 0.9 and 1.4, respectively; LTm: 0.8 and 0.9 l x min(-1), respectively). HR was significantly higher in WTm at 36 degrees C compared to WTm at 28 degrees C at all speeds, and compared to LTm at 4.5 and 5.5 km x h(-1) (P < or = 0.003). The HR-VO2 relationship showed that at a VO2 of 0.9 l x min(-1) x HR was higher in water at 36 degrees C (115 beats x min[-1]) than either on land (100 beats min[-1]) or in water at 28 degrees C (99 beats x min[-1]). The Borg scale of perceived exertion showed that walking in water at 4.5 and 5.5 km x h(-1) was significantly harder than on land (WTm: 11.4 and 14, respectively; LTm: 9.9 and 11, respectively; P < or = 0.001). These cardiorespiratory changes occurred despite a slower cadence in water (the mean difference at all speeds was 27 steps/min). Thus, walking in chest-deep water yields higher energy costs than walking at similar speeds on land. This data has implications for therapists working in hydrotherapy pools.

Energy expenditure and physiological responses during indoor rock climbing.

OBJECTIVES: To report the physiological responses of indoor rock climbing. METHODS: Fourteen experienced climbers (nine men, five women) performed three climbing trials on an indoor climbing wall. Subjects performed three...

The Pressor Response to Submaximal Cycle Ergometry While Using Aerodynamic Handlebars

This study hypothesized that changes in static shoulder loading while using aerobars during submaximal cycle ergometry would elicit a combined static and dynamic pressor response. Seven trained cyclists (mean +/- SD: 22 +/- 3 years, 77 +/- 12 kg, 1.8 +/- 1.1 m) rode a modified Monark cycle ergometer at three inclines (+5 degrees, 0 degree, -5 degrees) for five minutes each using aerobars at a power output (144 +/- 21 W) eliciting 60-65% of each subject's age-predicted HR maximum (120 +/- 4.9 bts.min-1). The positive to negative incline changes were designed to increase the static load experienced by the shoulder musculature. Mean HR, VE, VO2, and rectified EMG for the triceps brachii (TB), anterior (AD) and posterior deltoid muscles were computed over each minute of each condition. All variables exhibited steady-state responses at +5 degrees and 0 degree inclines and nonsteady-state responses at -5 degrees.HR, VO2, and VE correlated highly with EMG from AD (mean r = 0.75-0.79) and TB (mean r = 0.68-0.75) at -5', but only moderately correlated for HR at +5 degrees and 0 degree (mean r = 0.21-0.86). Y-intercepts for HR-VO2 and VE-VO2 relationships shifted positively with increased static load. Thus, static loading of AD and TB may disassociate the HR-VO2 relationship during submaximal cycle ergometry and may be responsible for torso positioning preferences by time-trial cyclists.

Relationship between heart rate and oxygen uptake during submaximal arm cranking in paraplegics and quadriplegics.

The purpose of this study was to clarify the effect of the level of spinal cord injury (SCI) and of daily exercise on the relationship between heart rate (HR) and oxygen uptake (VO2) in persons with SCI (PSCI) during an arm cranking exercise. Eighteen PSCI were divided into three groups according to the level of SCI; 4 quadriplegics (C6-C8), 7 high- level paraplegics (T3-T8), and 7 low-level paraplegics (T10-L2). In the relationship between HR and VO2, the higher the level of SCI, the smaller the slope of regression line, that means the HR at a given VO2 become larger as level of SCI was higher. Significant differences were found among these regression lines (P < 0.01). In addition, the regression lines between HR and VO2 in active persons tended to shift toward upper in comparison with those in inactive persons. The present investigation clearly shows that the HR-VO2 relationship in PSCI is remarkably influenced by the level SCI and physical training.

The influence of furosemide on heart rate and oxygen uptake in exercising man.

We recently observed that heart rate (HR) related methods for assessing physical fitness lead to an overestimation of endurance capacity in subjects treated with furosemide. To gain a more detailed description of this effect, the relationships between work load (WL), oxygen uptake (VO2), and HR were determined in the present study. To this end, nine healthy male subjects performed two incremental exercise tests (10 W increase per 30 s) on a bicycle ergometer. In one test 40 mg furosemide (Lasix) was applied orally 90 min before exercise started. Compared with control conditions, furosemide led to a change in mean blood volume of -4.5% (range: +7.8% to -11.5%). Neither the maximal VO2 (VO2max) nor the maximal work load (WLmax) were significantly altered after furosemide application. Though the WL-VO2 relationship was not significantly affected, the HR-VO2 relationship showed significant alterations which depended on both the loss of blood volume (BV) and work intensity: When the reduction in BV was less than approximately 5%, HR was found to be lowered at all workloads. When the BV reduction was greater than about 5% HR was significantly reduced only in the lower ranges of work load but significantly increased at the higher work intensities. Since BV reductions are known to increase HR during exercise, our findings suggest that, in addition to the blood volume induced changes in HR, furosemide exerts further direct or indirect effects on heart rate adjustment.