- Evento: ACSM's 66th Annual Meeting
- Local: Orlando - EUA
- Ano: 2019
Pulse Wave Reflection Responses After Aerobic Exercise with Different Volumes in Normotensive and Hypertensive Men
Guilherme Fonseca MSc, Tainah de Paula MSc, Mario F. T. Neves MD/PhD, Felipe A. Cunha PhD State University of Rio de Janeiro, RJ, Brazil.
BACKGROUND
Although aerobic exercise (AE) has been established as effective for lowering blood pressure (BP), little is known about the alterations in aortic BP and pulse wave reflection (PWR) after exercise.
PURPOSE
To investigate the acute aortic BP and PWR responses after moderate AE with different volumes in normotensive and hypertensive men.
METHODS
A total of twenty-four participants were assigned into normotensive (n = 14) and hypertensive groups (n = 10). Participants visited the laboratory on five occasions to perform: a) a pre-participation questionnaire for assessment of cardiovascular risk, BP at-office and anthropometric profile, and then 24-h ambulatory BP monitoring (ABPM) to confirm or not the diagnosis of hypertension – normotensives were defined as those with 24-h SBP/DBP < 130/80 mmHg, and hypertensives as those with 24-h SBP/DBP ≥ 130/80 mmHg groups; b) resting and maximal oxygen uptake (VO2) assessments; c) a non-exercise control session (CTL), and two cycling bouts at 50% VO2 reserve (150 vs. 300 kcal) in a randomized order. Aortic SBP (aSBP), aortic pulse pressure [aPP (i.e. aSBP minus aDBP)], augmented pressure [AP (i.e. augmentation of aSBP induced by return of the reflected wave)], and augmentation index [AIx (ratio between AP vs. PP × 100 to give a percentage)] were determined using applanation tonometry 10 min before, and 30- and 70-min after CTL and the two exercise bouts in a supine position (SphygmoCor® system, AtCor Medical Pty Ltd, Sydney, Australia).
All statistical analyses were performed using Statistica 10 software (StatSoftTM, Tulsa, OK, USA). Descriptive sample statistics are reported as the mean and standard error of the mean (SEM). Changes in aortic BP and PWR were calculated as ∆ values [i.e. difference between post- and pre-intervention values]. The effects of condition and time on aortic BP and PWR responses were analyzed using a 2-way RM-ANOVA. LSD post hoc tests were applied to determine pair wise differences when significant F ratios were obtained. Two-tailed statistical significance for all tests was accepted as P ≤ 0.05.
RESULTS
In the normotensive group, AE 150 kcal decreased aSBP (mean diff: ∆ – 8.1 mmHg, P = 0.050) and AIx (mean diff: ∆ – 10.5 %, P = 0.036), in comparison with CTL, until 30 min of recovery. In addition, normotensive men showed a decrease in aPP after all AE bouts, without differences between conditions. In the hypertensive group, only AE 300 kcal was able to mitigate the aSBP increase observed between 30 and 70 min post-CTL (mean diff30-70min: Δ 7.0 mmHg, P = 0.017) and post-AE 150 kcal (mean diff30-70min: Δ 7.3 mmHg, P = 0.013). Like aSBP, post hoc pairwise comparisons showed a significant increase for aPP between 30 and 70 min post-CTL (mean diff30-70min: Δ 4.0 mmHg, P = 0.050), while both AE bouts attenuated the aPP increase observed in CTL .
Figure 1: Mean ± SE values for aortic BP and PWR responses in the normotensive and hypertensive groups following 30 and 70 min of recovery from CTL and each cycling bout. P values indicate significant differences between 30 and 70 min post-intervention. *: Significantly different from CTL at 30 min (P < 0.05).
KEY POINTS
- In terms of acute aortic BP and PWR responses, exercise volume is not a primary outcome of the exercise prescription in normotensive men, at least when training bouts are performed at moderate-intensity.
- Aerobic exercise performed with higher volume (e.g. 300 kcal) is recommended for individuals with hypertension. The present study provides evidence that this strategy may mitigate the increased BP responses observed after CTL and AE with lower volume (e.g. 150 kcal).
- Regardless of exercise-related energy expenditure, aerobic bouts performed at moderate-intensity do not affect the acute PWR responses among hypertensive men.
- These findings may have important implications within the context of aerobic exercise prescription for the initial management of hypertension.
CONCLUSIONS
In the normotensive group, lower AE volume was able to reduce aortic BP until 30 min of recovery. However, only the greater AE volume attenuated the increase in aortic BP, with no difference in PWR after any experimental protocol in the hypertensive group.
FUNDING
Supported by the Brazilian Council for the Technological and Research Development (CNPq) and Carlos Chagas Foundation for the Research Development in the State of Rio de Janeiro (FAPERJ).
Recovery pattern of cardiac autonomic control following aerobic exercise with different volumes in hypertensive men
André C. Michalski MSc, Guilherme Fonseca MSc, Victor Costa, Tainá Pryor, Paulo Junior Tainah Paula PhD, and Felipe A. Cunha PhD.
State University of Rio Janeiro, RJ, Brazil.
BACKGROUND
The recovery pattern of cardiac autonomic control acute aerobic (AE) is a robust index of individual ability to recruit tone and may provide further evidence of the risks and benefits of a typical AE bout to promote health. However, the extent to which autonomic control, as assessed by heart rate variability (HRV), depends on exercise volume remains unclear in hypertensive individuals.
PURPOSE
The present study investigated the acute effects of cycling bouts with different volumes and matched by on HRV markers in hypertensive men.
Ten men [age: 39.0 ± 7.0 yr; body mass index: 29.3 ± 1.0 kg/m2; maximal oxygen uptake (VO2max): 26.7 ± 0.8 mL∙kg-1∙min-1; 24-h ambulatory systolic/diastolic blood pressure (SBP/DBP): 139 ± 8 / 86 ± 7 visited the times to undertake the following procedures: a) assessment of resting and maximal VO2; b) perform a non-exercise control session (CTL) and two AE bouts expending 150 (AE150) and 300 (AE300) at 50% VO2 , order. The root mean square of successive R-R differences calculated for consecutive 30-s windows (rMSSD30s) was calculated to assess the reactivation during the first 5 min of recovery in a supine position via (RS800cx, PolarTM, Finland). Prolonged HRV analysis [i.e. – (LF), high-frequency band (HF), and sympathovagal balance (LFHF ratio)] was performed during the subsequent 21-h under ambulatory conditions using a three-channel Holter (CardioLight, Cardios Ltda, Brazil).
All statistical analyses were performed using IBM SPSS® version 23 (SPSSTM Inc., Chicago, IL USA). Marginal models were used to compare HRV changes between trials. Where main effects were statistically significant, post hoc pairwise comparisons with Sidak-adjusted P values were performed. Statistical significance was accepted as P ≤ 0.05.
RESULTS
These findings suggest that exercise volume is not a major determinant of exercise prescription when considering the recovery pattern of cardiac autonomic control in hypertensive men, at least when AE is performed at
FUNDING
Supported by the Brazilian Council for the Technological and Research Development (CNPq) and Carlos Chagas Foundation for the Research Development in the State of Rio de Janeiro (FAPERJ).
- Evento: ACSM's 64th Annual Meeting
- Local: Denver - EUA
- Ano: 2017
Standardized MET Overestimates Resting VO2 And Underestimates Energy Cost Of Running In Low Cardiorespiratory Fitness Men
Helouane M. Ázara, Paulo T.V. Farinatti PhD, Adrian W. Midgley PhD, Fabrício Vasconcellos PhD, Patrícia Vigário PhD, and Felipe A. Cunha PhD.
Augusto Motta University Center, RJ, Brazil. Rio de Janeiro State University, RJ, Brazil. Edge Hill University, Ormskirk, England.
PURPOSE
Multiples of the metabolic equivalent (MET) are widely used to prescribe exercise intensity and quantify the energy cost of physical activities. A growing body of empirical evidence, however, suggests the standardized 1-MET value, represented by a resting oxygen uptake (VO2) of 3.5 mL·kg-1·min-1, significantly overestimates observed resting VO2 in populations with lower cardiorespiratory fitness (CRF). Hence the main purpose of the present study was to compare the standardized MET and resting VO2 with respect to these two applications and explore the association between CRF and resting VO2.
METHODS
A heterogeneous cohort of 114 healthy men, aged 18 to 38 yr, volunteered to participate in two studies. First, 100 men [lower CRF: n = 48, VO2max < 50.0 mL∙kg-1∙min-1; higher CRF: n = 52, VO2max ≥ 50.0 mL∙kg-1∙min-1] visited the laboratory twice to explore the association between directly assessed VO2máx and resting VO2. Second, 14 men performed a 30-min bout of running at 8.0 km∙h-1 (8.3 METs according to the Compendium of Physical Activities) to investigate the use of the MET to quantify the energy cost of treadmill running.
All statistical analyses were performed using Statistica 10 software (StatSoftTM, Tulsa, OK, USA). Descriptive sample statistics are reported as the mean and standard deviation (SD). One-sample t tests were used to test the null hypotheses that there were no mean differences between the MET value and observed resting VO2, METmax, MET exercise intensity classification, and the energy cost of the running bout. The Pearson correlation was used to determine the relationship between VO2max and observed resting VO2. In addition, the median VO2max value was used as the criterion to categorize participants into low and high cardiorespiratory fitness groups to investigate the influence of cardiorespiratory fitness on the differences between the reference MET value and observed resting VO2.
RESULTS
The VO2max was strongly positively correlated with resting VO2 (R = 0.68, P < 0.001). The mean observed resting VO2 values of 3.28 (n = 100) and 3.07 (n = 14) mL·kg-1·min-1 were significantly lower than the standardized value of 3.5 mL·kg-1·min-1 (P < 0.001 and P = 0.005, respectively). When compared to the standardized value, groups with lower CRF demonstrated significantly lower mean observed resting VO2 values of 3.06 (1st part of the study: P < 0.001) and 2.67 (2nd part of the study, P < 0.001) mL·kg-1·min-1. However, no significant difference was observed between standardized and observed resting VO2 values for the groups with higher CRF (1st part of the study: P = 0.87; 2nd part of the study: P = 0.78). Hence the observed values for METmax intensity and the energy cost of treadmill running were significantly underestimated when calculated using the standardized resting VO2 value of 3.5 mL·kg-1·min-1 (P = 0.005 to P < 0.001) only for the groups with lower CRF.
FUNDING
Supported by the Brazilian Council for the Technological and Research Development (CNPq) and Carlos Chagas Foundation for the Research Development in the State of Rio de Janeiro (FAPERJ).
- Evento: ACSM's 62th Annual Meeting
- Local: San Diego- EUA
- Ano: 2015
Effect of heat stress on postexercise hypotension induced by isocaloric cycling bouts in healthy men
Felipe A. Cunha PhD, Paulo T.V. Farinatti PhD, Helen Jones PhD, Lars R. McNaughton, FACSM PhD, and Adrian W. Midgley PhD.
Rio de Janeiro State University, RJ, Brazil. Edge Hill University, Ormskirk, England. Liverpool John Moores University, Liverpool, England.
PURPOSE
Aerobic exercise has consistently been shown to induce postexercise hypotension (PEH). However, the underlying physiological mechanisms are still unclear, especially when exercise is performed in a hot environment. Therefore, the purpose of this study was to investigate the effect of heat stress on PEH induced by isocaloric cycling bouts.
Seven men, aged 21-33 yr, visited the laboratory on four occasions to perform: a) a maximal cardiopulmonary exercise test in a temperate environment; b) a non-exercise control session in a temperate environment (CON); and c) two bouts of isocaloric (300 kcal) continuous cycling at 60% VO2R in environmental temperatures of 21°C (TEMP) and 35°C (HOT) in a randomized, counter-balanced order. Systolic (SBP) and diastolic (DBP) blood pressure, cardiac output, systemic vascular resistance, mean skin temperature, rectal temperature, plasma volume, and cardiac autonomic function (spontaneous baroreflex sensitivity and heart rate variability) were determined for 60-min after the non-exercise control session and after the two exercise bouts. SBP and DBP also were determined during the subsequent 21-hr recovery period using an ambulatory BP monitor.
All statistical analyses were completed using SPSS Statistics 22 (SPSS Inc., Chicago, IL). All physiological responses during the 60-min postexercise period (using 6 x 10 min time bins) for each condition (CON, TEMP, and HOT) were investigated using linear mixed models. Random effects were included in models if they significantly improved model fit, as indicated by a likelihood ratio test. Separate models were used to investigate mean differences in baseline physiological values and 21-hr blood pressure responses between conditions. In the event of significant main effects or interaction effects post hoc pairwise comparisons, with Sidak-adjusted P values, were conducted. The relationship between delta plasma volume and delta mean blood pressure in the 60-min post-exercise recovery period in TEMP and HOT was investigated using the Pearson correlation coefficient. Statistical significance for all null hypothesis significance tests was regarded as P < 0.05.
RESULTS
Exercise in the heat increases the hypotensive effects following exercise for at least 22-hr. The underlying mechanisms (at least for the first 60-min recovery period) appears to be increased body temperature, reduced plasma volume, and decreased systemic vascular resistance.
FUNDING
Supported by the Brazilian Council for the Technological and Research Development (CNPq) and Carlos Chagas Foundation for the Research Development in the State of Rio de Janeiro (FAPERJ).
Effect of Heat Stress on the Relationship between Heart Rate Reserve & Oxygen Uptake Reserve
Adrian W. Midgley 1, Felipe A. Cunha 2, Helen Jones 3, Lars R.McNaughton 1, FACSM, Paulo T.V. 2
1 Edge Hill University, Ormskirk, England; 2 State University of Rio de Janeiro, Rio de Janeiro, Brazil; 3 Liverpool John Moores University, Liverpool, England.
INTRODUCTION
Excess post-exercise oxygen consumption (EPOC) is an important component of exercise-based weight management programs. The isolated effects of exercise intensity and duration on EPOC have been the focus of previous research; however, the effect of exercise modality and whether or not the exercise is performed continuously or intermittently are presently unknown.
The purpose of this study was to investigate the EPOC induced by bouts of continuous and intermittent running and cycling exercise.
METHODS
-Participants were seven apparently healthy men aged 21 to 33 years
-Participants visited the laboratory on three occasions to perform a maximal incremental cycling test in a temperate environment and two bouts of continuous cycling at 60% VO2R in environmental temperatures of 21°C (TEMP) and 35°C (HOT)
-Associations between physiological responses were investigated using linear mixed models.
- Evento: ACSM's 61th Annual Meeting
- Local: Orlando - EUA
- Ano: 2015
Effect of continuous and intermittent
Felipe A. Cunha M Sc, Adrian W. Midgley PhD, Lars R. McNaughton, FACSM PhD, and Paulo T.V.
Rio de Janeiro State University, RJ, Brazil. Edge Hill University, Ormskirk, England.
PURPOSE
Excess post-exercise oxygen consumption (EPOC) is an important component of exercise-based weight management programs. The isolated effects of exercise intensity and duration on EPOC have been the focus of previous research; however, the effect of exercise modality and whether or not the exercise is performed continuously or intermittently are presently unknown.
The purpose of this study was to investigate the EPOC induced by
METHODS
Ten healthy men, aged 23 to 34 yr, performed six bouts of exercise: a) two maximal cardiopulmonary exercise tests for running and cycling to determine exercise modality-specific HRpeak and VO2