Physiological responses and RPE during underwater treadmill walking in women of middle and advanced age

[Water aerobics training: selection and control of the exercise intensity using the Borg scale]

OBJECTIVE

To evaluate the opportunity of Borg scale using for applying and monitoring the aerobic training intensity in the pool as well as the relationship between the Borg scale and the heart rate (HR) in the aquatic environment.

MATERIAL AND METHODS

The study involved 11 healthy individuals (mean age 46.4±7.5 years). After a cardiopulmonary test on a treadmill and a probation lesson the training was conducted in the pool using a set of basic aerobic exercises lasting 45 minutes. During training the subjects had to maintain a load level corresponding to 12-14 points on the Borg scale. Every 10 minutes of the main training part the heart rate was calculated and the rating of perceived exertion (RPE) was determined according to the Borg scale.

RESULTS

The average heart rate in the main part of the training was 126.8±14.0 beats/min. The intensity of aerobic exercise was 82% of the maximum heart rate determined during the cardiopulmonary test and 68% of the reserve heart rate which corresponded to a high level of intensity. Between the heart rate and the Borg scale a significant correlation was found in the first period of training (r=0.67, p<0.02). At RPE 12-13 in almost ¹/₂ cases the subjects felt a subjectively lower intensity of the load than they actually performed (by heart rate) while at RPE 14 a high percentage of coincidences was observed between different measurement methods (p<0.05).

CONCLUSION

During water aerobics training the use of the Borg scale to prescribe and maintain a level of exercise allows to achieve a sufficient intensity level which is necessary to improve cardiorespiratory fitness and physical performance in order to influence risk factors for cardiovascular disease. The Borg Scale as a stand-alone method of controlling intensity when using water-based aerobic training, especially with high-intensity training should be used with caution. Further investigation is needed to determine the relation between subjective measures of exercise intensity and HR and validity of their use during water aerobics training.

Validity of differentiated ratings of perceived exertion for use during aquatic cycling

BACKGROUND

Although aquabiking has become widespread, the assessment of the intensity for aquatic cycling remains poorly defined.

METHODS

This study investigated the validity of differentiated ratings of perceived exertion (dRPE) recorded from the chest (RPE-chest) and legs (RPE-legs) during aquatic cycling and aimed to determine a simple and accurate estimate of dRPE to regulate aquabiking. Twelve active young subjects performed a pedaling task on an immersed ergocycle using randomly imposed cycling cadences ranging from 50 to 100 rpm in 3-minute steps interspersed by 3-minute active recovery periods. dRPE and cardiorespiratory responses (heart rate [HR]; percentage of heart rate peak value [%HR<inf>peak</inf>]; oxygen uptake [V̇O<inf>2</inf>]<inf>;</inf> and percentage of peak oxygen uptake [%V̇O<inf>2peak</inf>]) were measured during the last minute of each level.

RESULTS

The data described three-step relationships between dRPE and rpm. RPE-chest and RPE-legs increased linearly only for cadences between 60 and 90 rpm (r=0.81 and r=0.88, respectively; P<0.001). At these cadences, significant relationships were also observed between dRPE and all the physiological data (highest Pearson product moment for %V̇O<inf>2peak</inf>: 0.81 for RPE-chest and 0.88 for RPE-legs, P<0.0001). Last, the classic signal dominance from the legs was observed (RPE-legs>RPE-chest, P<0.0001) but was reduced compared with data obtained during dryland cycling, suggesting a modulating effect of the aquatic medium.

CONCLUSIONS

Cycling cadence was the better estimator of RPE-legs, which seemed to be the more appropriate dRPE to regulate the intensity of aquabiking in a safe range of pedaling rates.

Relationship between Oxygen Uptake, Heart Rate, and Perceived Effort in an Aquatic Incremental Test in Older Women

Different parameters can be used to control the intensity of aerobic exercises, a choice that should consider the population and exercise environment targeted. Therefore, our study aimed to verify the relationship between oxygen uptake (VO₂), heart rate (HR), rating of perceived exertion (RPE), and cadence during an aquatic incremental test in older women. Nine older women (64.3 ± 4.4 years) engaged in a water-based aerobic training performed an aquatic incremental test using the stationary running exercise (cadence increases of 15 b·min⁻¹ every 2 min) until participants’ volitional exhaustion. VO₂, HR, and RPE data were measured, and the percentage of peak VO₂ (%VO_2peak) and percentage of maximal HR (%HR_max) were calculated. Linear and polynomial regression analyses were performed (α = 0.05). Polynomial regressions revealed the best adjustments for all analyses. Data showed a significant relationship (p < 0.001) between %VO_2peak and %HR_max (r = 0.921), %VO_2peak and RPE (r = 0.870), and %HR_max and RPE (r = 0.878). Likewise, significant relationships between cadence (p < 0.001) and %VO_2peak (r = 0.873), %HR_max (r = 0.874), and RPE (r = 0.910) were also observed. In summary, the physiological, subjective, and mechanical variables investigated were highly associated during an aquatic incremental test to exhaustion in older women. Therefore, these different parameters can be employed to adequately prescribe water-based programs according to preference and availability.

Acute breathing patterns in healthy and heart disease participants during cycling at different levels of immersion

We aimed to determine the effect of aquatic cycling and different levels of immersion on respiratory responses in healthy and heart disease (HD) volunteers. Thirty-four age matched volunteers, 21 HD and 13 healthy controls (HC) took part in this study. The ventilatory pattern, phase 1V_E and steady-state ventilatory responses to progressive exercise from 40 to peak rpm, were measured while participants exercised on a water stationary bike (WSB) at different levels of immersion. No effect of immersion was observed on steady-state respiratory responses in the HD group, but immersion reduced V_E phase 1 by ∼79% at pedaling cadences of 40, 50 and 60rpm. In conclusion, immersion at hips and xiphoid process blunted the fast drive to breathe in the HD group. This transient effect on the respiratory response to immersed exercise cannot be considered a contraindication for exercise in HD individuals.

Rating of Perceived Exertion and Physiological Responses in Water-Based Exercise

The aim of the present study was to relate the overall rating of perceived exertion (RPE-overall) with cardiorespiratory and neuromuscular variables during stationary running with the elbow flexion/extension performed with water-floating equipment. The sample consisted of eleven women that performed the water-based exercise at submaximal cadences. The heart rate, oxygen uptake, ventilation, and electromyographic signal (EMG) from biceps brachii (%EMG BB), triceps brachii (%EMG TB), biceps femoris (%EMG BF) and rectus femoris (%EMG RF) muscles were measured during the exercise, and the overall RPE was measured immediately following its completion. The Pearson product-moment linear correlation was used to investigate associations between the variables analyzed in the present study. Significant relationships were observed between the RPE-overall and all the cardiorespiratory variables, with the r values ranging from 0.60 to 0.70 (p<0.05). In addition, the RPE-overall showed a significant (p<0.05) relationship with %EMG BB (r=0.55) and %EMG BF (r=0.50). These results suggest an association between the RPE-overall with all cardiorespiratory and two neuromuscular variables during the execution of a water-based aerobic exercise using water-floating equipment.

Comparison of cardiorespiratory responses during aquatic and land treadmill exercise in patients with coronary artery disease

PURPOSE

To investigate cardiorespiratory responses during exercise stress tests using an aquatic treadmill and a land-based treadmill in patients with coronary artery disease (CAD).

METHODS

Twenty-one stable CAD patients were enrolled. All patients participated in 2 symptom-limited incremental exercise tests, using both an aquatic and a land treadmill. For the aquatic treadmill protocol, patients were submerged to the upper waist in 28°C water. The treadmill speed started at 2.0 km/h and increased 0.5 km/h every minute thereafter. For the land treadmill protocol, the speed and gradient were started at 2.4 km/h and 1.5%, respectively. The speed was increased by 0.3 km/h and grade by 1% every minute thereafter. Oxygen consumption ((Equation is included in full-text article.)O2), heart rate (HR), and respiratory exchange ratio were measured continuously and peak values recorded. Rating of perceived exertion, percentage of age-predicted maximal HR, and total exercise duration were also recorded.

RESULTS

Peak cardiorespiratory responses during both protocols were compared. The peak (Equation is included in full-text article.)O2 and peak HR did not show any significant differences. The peak respiratory exchange ratio was significantly greater using the land treadmill than the aquatic treadmill protocol. Rating of perceived exertion, age-predicted maximal HR percentage, and total exercise duration were similar for both protocols. There was a significant linear relationship between HR and (Equation is included in full-text article.)O2 with both protocols.

CONCLUSIONS

This study demonstrated that aquatic treadmill exercise elicits similar peak cardiorespiratory responses compared with land treadmill exercise, suggesting that aquatic treadmill exercise may be effective for CAD patients in cardiac rehabilitation.

Metabolic and cardiovascular responses during aquatic exercise in water at different temperatures in older adults

PURPOSE

The aim of this study was to investigate the physiological responses during upper-body aquatic exercises in older adults with different pool temperatures.

METHOD

Eleven older men (aged 65 years and older) underwent 2 identical aquatic exercise sessions that consisted of 3 upper-body exercises using progressive intensities (30, 35, and 40 metronome beat · min(- 1)) on separate visits. Water temperatures for the visits were 28°C (cold water [CW]) and 36°C (hot water [HW]), and water depth ranged from 1.2 m to 1.4 m. Measurements for heart rate (HR), blood pressure (BP), oxygen consumption (VO2), and rate of perceived exertion (RPE) were compared between the CW and HW conditions.

RESULTS

The comparison between temperatures showed a higher HR response during exercise in HW, particularly when participants exercised at the highest intensities. During a 30-min postexercise period in resting conditions, HR was statistically significantly higher for the HW condition compared with the CW condition, with a large effect size (15.9%, d = 1.23). Systolic and diastolic BPs were found to be lower for the HW condition ( - 7.2%, d = - 0.60; - 10.1%, d = - 0.65), while VO2 and RPE showed no differences. The effect size between double products (HR · systolic BP) for the 2 conditions was small (CW = 8,649 ± 1,287, HW = 9,340 ± 1,672; d = 0.36), suggesting similar myocardial oxygen requirements.

CONCLUSION

This study showed that HR response was higher in an HW condition for older men. Warmer environments may add additional stressors to the body, which may impact training strategies and should be considered when estimating the effort of performing aquatic exercise.

The effects of landed and aquatic treadmill walking at moderate intensity on heart rate, energy expenditure and catecholamine

PURPOSE

The present study was to examine whether or not the appropriate exercise intensity of water-walking could be accurately prescribed by land-based walking speed.

METHODS

Using a crossover design, nine healthy male college students completed bouts of walking for thirty minutes at 100m/min, 50m/min, respectively, on land and water treadmills. Heart rate (HR), ratings of perceived exertion (RPE), energy expenditure, blood lactic acid and catecholamine concentration were measured. Two-way repeated measured ANOVA was used with the SPSS program for data analysis.

RESULTS

HR (P < 0.001), RPE (P < 0.001), energy expenditure (P < 0.001), blood lactic acid (P < 0.001) and epinephrine concentration (P < 0.05) were significantly increased during walking both in water and on land. The change of HR was significantly lower at 50min/m in water than 100min/m on land (P < 0.01). There were no significant interaction effects for RPE, energy expenditure, blood lactic acid and catecholamine concentration, but these variables were slightly lower in water than on land. These results indicated that the use of land walking speed-based prescriptive norms would underestimate the physiological cost in water walking at the moderate intensity.

CONCLUSION

Therefore, approximately two-half of the speed would be needed to walk in water in order to obtain the same level of physiological load as during treadmill walking at the moderate intensity.

Physiological and biomechanical responses to walking underwater on a non-motorised treadmill: effects of different exercise intensities and depths in middle-aged healthy women

Non-motorised underwater treadmills are commonly used in fitness activities. However, no studies have examined physiological and biomechanical responses of walking on non-motorised treadmills at different intensities and depths. Fifteen middle-aged healthy women underwent two underwater walking tests at two different depths, immersed either up to the xiphoid process (deep water) or the iliac crest (shallow water), at 100, 110, 120, 130 step-per-minute (spm). Oxygen consumption (VO2), heart rate (HR), blood lactate concentration, perceived exertion and step length were determined. Compared to deep water, walking in shallow water exhibited, at all intensities, significantly higher VO2 (+13.5%, on average) and HR (+8.1%, on average) responses. Water depth did not influence lactate concentration, whereas perceived exertion was higher in shallow compared to deep water, solely at 120 (+40%) and 130 (+39.4%) spm. Average step length was reduced as the intensity increased (from 100 to 130 spm), irrespective of water depth. Expressed as a percentage of maximum, average VO2 and HR were: 64-76% of peak VO2 and 71-90% of maximum HR, respectively at both water depths. Accordingly, this form of exercise can be included in the "vigorous" range of exercise intensity, at any of the step frequencies used in this study.

Consumo de oxigênio e índice de esforço percebido em diferentes ritmos de execução na hidroginástica

O objetivo do estudo foi correlacionar o consumo de oxigênio (VO2) e o percentual do VO2 máximo (%VO2máx) com o índice de esforço percebido (IEP) e comparar essas variáveis entre exercícios de hidroginástica executados no meio aquático em diferentes ritmos de execução. Seis mulheres realizaram quatro sessões de testes, uma no meio terrestre (teste de esforço máximo) e três no meio aquático, cada uma com a execução de um exercício de hidroginástica: corrida estacionária, deslize lateral e chute frontal até 45°. Cada exercício aquático foi realizado em três ritmos de execução, 80, 100 e 120bpm, durante 6 min (intervalo de 30 min). Para todas as variáveis, não foram observadas diferenças significativas entre os três exercícios, todavia, as mesmas apresentaram diferenças significativas entre os ritmos, indicando que com o aumento do ritmo, o esforço para executar os exercícios foi intensificado. Correlações significativas foram observadas entre VO2 e IEP e entre %VO2máx e IEP. Logo, baseado nessas associações, sugere-se que a prescrição da intensidade dos exercícios analisados possa ser feita através do IEP durante aulas de hidroginástica.

Comparison of physiological and perceptual responses between continuous and intermittent cycling

The present study tested the hypothesis that the exercise protocol (continuous vs. intermittent) would affect the physiological response and the perception of effort during aquatic cycling. Each protocol was divided on four stages. Heart rate, arterial blood pressure, blood lactate concentration, central and peripheral rate of perceived exertion were collected in both protocols in aquatic cycling in 10 women (values are mean ± SD): age=32.8 ± 4.8 years; height=1.62 ± 0.05 cm; body mass=61.60 ± 5.19 kg; estimated body fat=27.13 ± 4.92%. Protocols were compared through two way ANOVA with Scheffé’s post-hoc test and the test of Mann- Whitney for rate of perceived exertion with α=0.05. No systematic and consistent differences in heart rate, arterial blood pressure, double product and blood lactate concentration were found between protocols. On the other hand, central rate of perceived exertion was significantly higher at stage four during continuous protocol compared with intermittent protocol (p=0.01), while the peripheral rate of perceived exertion presented higher values at stages three (p=0.02) and four (p=0.00) in the continuous protocol when compared to the results found in intermittent protocol. These findings suggest that although the aquatic cycling induces similar physiologic demands in both protocols, the rate of perceived exertion may vary according to the continuous vs. intermittent nature of the exercise.

The relative cost of bent-hip bent-knee walking is reduced in water

The debate about how early hominids walked may be characterised as two competing hypotheses: They moved with a fully upright (FU) gait, like modern humans, or with a bent-hip, bent-knee (BK) gait, like apes. Both have assumed that this bipedalism was almost exclusively on land, in trees or a combination of the two. Recent findings favoured the FU hypothesis by showing that the BK gait is 50-60% more energetically costly than a FU human gait on land. We confirm these findings but show that in water this cost differential is markedly reduced, especially in deeper water, at slower speeds and with greater knee flexion. These data suggest that the controversy about australopithecine locomotion may be eased if it is assumed that wading was a component of their locomotor repertoire and supports the idea that shallow water might have been an environment favourable to the evolution of early forms of "non-optimal" hominid bipedalism.

Water Exercise in Patients With and Without Cardiovascular Disease: Benefits, Rationale, Safety, and Prescriptive Guidelines

Research regarding the benefits of exercise-based cardiac rehabilitation is extensive and well documented. Water exercise, in the form of stretching, walking, jogging, aerobics, strength and balance training, and swimming, provides an attractive alternative from traditional land-based exercise for achieving improved health and fitness. Patients with orthopedic or musculoskeletal limitations, pulmonary disease, excess adiposity, and other medical conditions may significantly benefit from a water-based exercise program. Although water exercise is beneficial for varied patient populations, the safety and appropriateness of higher intensity activities such as swimming should be considered. Because coronary patients have a reduced ability to identify ischemic symptoms in water, water exercise should be prescribed with caution in high-risk patients, individuals with limited swimming skills, and those with significant left ventricular dysfunction. Furthermore, the acute physiological responses during water submersion and exercise may vary considerably from land-based activity and require attention when prescribing a water-based exercise program for patients with and without coronary artery disease.

Caminhada em ambiente aquático e terrestre: revisão de literatura sobre a comparação das respostas neuromusculares e cardiorrespiratórias

O objetivo deste estudo foi realizar uma revisão de literatura sobre a comparação das respostas neuromusculares e cardiorrespiratórias durante a caminhada em meio aquático e em meio terrestre. As respostas foram apresentadas para a caminhada em piscina rasa e para a caminhada em piscina funda. Em relação à caminhada em piscina rasa, as respostas neuromusculares (sinal EMG) e cardiorrespiratórias (FC e VO2) são muito dependentes da velocidade do exercício. As respostas neuromusculares podem ser menores no meio aquático quando a velocidade da caminhada é menor nesse ambiente. Por outro lado, quando o exercício é realizado com velocidades similares, a atividade dos músculos propulsores pode ser superior durante a caminhada aquática. Da mesma forma, respostas cardiorrespiratórias maiores são registradas no exercício aquático quando velocidades similares de caminhada são utilizadas. Contudo, com velocidades menores, essas respostas são semelhantes ou menores que as encontradas em meio terrestre. No que diz respeito à caminhada em piscina funda, as respostas neuromusculares diferem daquelas encontradas durante a caminhada em meio terrestre devido à ausência das forças de reação com o solo. Essa característica possivelmente modifica os músculos envolvidos na produção de força propulsiva nesse exercício. Além do mais, durante a caminhada em piscina funda, as respostas cardiorrespiratórias parecem sempre mais baixas devido à grande redução no peso hidrostático e à menor atividade dos músculos posturais e pela utilização do cinturão flutuador nessa modalidade.

Respostas de freqüência cardíaca, consumo de oxigênio e sensação subjetiva ao esforço em um exercício de hidroginástica executado por mulheres em diferentes situações com e sem o equipamento aquafins

As aulas de hidroginástica estão cada vez mais diversificadas com o uso de materiais apropriados ao meio aquático. Entretanto, poucos estudos verificaram a influência da utilização de tais materiais nas respostas cardiorrespiratórias. O objetivo foi analisar as respostas de freqüência cardíaca, consumo de oxigênio e sensação subjetiva ao esforço em mulheres durante a execução de um exercício de hidroginástica em diferentes situações com e sem o equipamento resistivo Aquafins®. Onze mulheres realizaram o exercício deslize frontal com a flexão e extensão horizontal de ombros em quatro situações: sem equipamento resistivo (S-FINS), com Aquafins nos membros inferiores (FINS-MIs), com Aquafins nos membros superiores (FINS-MSs) e com Aquafins nos membros superiores e inferiores (FINS-MIs/MSs). Em todas as situações foi verificado a FC, o VO2 e a SSE. Utilizou-se ANOVA para medidas repetidas, com post-hoc de Bonferroni (p < 0,05). A FC foi significativamente mais elevada nas situações FINS-MIs/MSs (159 ± 12bpm) e FINS-MIs (147 ± 18bpm), comparando-as com as demais situações. No entanto, a situação FINS-MIs apresentou FC similar à FINS-MSs (148 ± 16 bpm). Por sua vez, as três situações com o Aquafins foram diferentes da situação S-FINS (131 ± 14bpm). Para o VO2 houve diferença significativa entre a situação FINS-MIs/MSs (22,77 ± 3,58ml.kg-1.min-1), comparando-a com as demais. As situações FINS-MSs (19,67 ± 4,29ml.kg-1.min-1) e FINS-MIs (20,38 ± 3,99ml.kg-1.min-1) apresentaram VO2 significativamente maior que S-FINS (15,18 ± 4,67ml.kg-1.min-1). A SSE foi significativamente maior na situação FINS-MIs/MSs (16 ± 1,55), comparando-a com FINS-MIs (14 ± 0,9) e S-FINS (13 ± 1,29), entretanto, não foi diferente da FINS-MSs (14 ± 1,57). Portanto, a utilização de equipamentos que promovam resistência ao movimento na hidroginástica é indicada para melhorias no sistema cardiorrespiratório.

Body temperature, oxygen uptake and heart rate during walking in water and on land at an exercise intensity based on RPE in elderly men

The purpose of this study was to clarify the characteristics of the physiological response that occurs while walking in water and on land at an exercise intensity based on the rating of perceived exertion (RPE) in elderly men. Nine elderly men ranging from 66-70 years of age participated in this study as subjects. The actual trials consisted of walking for 20 minutes in 31 degrees C and 35 degrees C water on an underwater treadmill. The water depth of the treadmill corresponded to the level of the xiphoid process in the subject. The same subjects performed on-land walking using a moving belt treadmill for 20 minutes at a room temperature of 27 degrees C. The exercise intensity during walking in the two water trials and the on-land trial was the same "somewhat hard" measured on the basis of the subject's RPE rating of 13. There was no significant difference between the subjects' rectal temperatures among the three trials. The mean skin temperature and mean body temperature while walking for 20 minutes in 35 degrees C water were significantly higher (P<0.01) than in 31 degrees C water and on land. There were no significant differences in oxygen uptake and heart rate among the two trials in water and the on-land trial. The above results suggest that the exercise intensity based on a subject's RPE may be an effective index for the prescription of thermoneutral water walking in the same way that it is for land walking in the elderly.

Cardiorespiratory response to low-intensity walking in water and on land in elderly women

The purpose of the present study was to determine whether or not the exercise intensity of water-walking for elderly women could be accurately prescribed by heart rate data obtained during treadmill exercise on land. Six healthy female volunteers, with a mean age of 62.2 +/- 4.2 years, took part in this study. Walking on land was performed on a treadmill. Each subject completed three consecutive 4-minute walks at a progressively increasing velocity (40, 60 and 80 m.min-1), with a 1-minute rest after both the first and second walks. The room temperature and relative humidity were 24.5 +/- 0.2 degrees C and 54.8 +/- 4.0%, respectively. Walking in water was performed in a Flowmill, which is a treadmill positioned at the base of a water flume. Each subject completed three consecutive 4-minute walks at a progressively increasing belt and water-flow velocity (20, 30 and 40 m.min-1), with a 1-minute rest after both the first and second walks. The water depth was at the level of the xiphoid process of each subject. The water temperature was 30.7 +/- 0.1 degrees C. The exercise intensity at the highest workrate was equivalent to 44.2 +/- 10.3% of the heart rate reserve (HRR) during water-walking and 38.4 +/- 4.7% of the HRR during land-walking. There was a highly significant linear relationship between heart rate (HR) and oxygen uptake (VO2) during both water-walking and land-walking. The relationship between HR and VO2 in both exercise modes was similar. Thus, the relationship of HR to VO2 derived from a treadmill-graded walking test on land may be used to prescribe exercise intensity for water-walking in thermoneutral water.

Physiological responses to water-walking in middle aged women

The purpose of the present study was to examine the physiological responses to water-walking using the Flowmill, which has a treadmill at the base of a water-flume, in two groups of women. In the first group, the women were known to regularly swim and exercise in water (group A), while in the second, they did not routinely participate in water-exercise (group B). In both groups, twelve healthy female volunteers in their fifties participated in the study. All of the subjects walked in water using the Flowmill for the first time. Subjects completed four consecutive bouts of 4-minute duration at progressively increasing speeds (20, 30, 40, and 50 m.min-1), with 1-minute rests between each bout. In addition, water-velocity was adjusted to the walking speed of each bout. The water-depth of the Flowmill was the level of the xiphoid process. The water and room temperatures were 30.3 +/- 0.1 degrees C and 24.9 +/- 0.4 degrees C, respectively. In both groups, the relationship between walking speed and oxygen uptake (VO2) as well as that between walking speed and heart rate (HR) changed exponentially as the walking speed increased, and the relationship between HR and VO2 was linear. The relationship between HR and VO2 was similar in both groups, and there was no significant difference between the predicted maximal oxygen uptake (VO2max) of the two groups. VO2 and HR of group B during water-walking, however, were significantly higher than those of group A at all walking speeds. The results of this study clearly showed that experience in moving through the water strongly affects physiological responses to water-exercise, even when fitness levels are equivalent.