Microneurographic characterization of sympathetic responses during 1-leg exercise in young and middle-aged humans

The aim of this study was to clarify the relationship between sympathetic outflow to skeletal muscle and oxygen uptake during dynamic exercise. Muscle sympathetic nerve activity (MSNA) was recorded from the right median nerve microneurographically in eight healthy volunteers during leg cycling at four different intensities in a seated position for a 16-min bout. Work loads selected were 20, 40, 60, and 75% of maximal oxygen uptake (VO2max). Heart rate and blood pressure were measured during each exercise test. MSNA burst frequency was suppressed by 28% during cycling at 20% VO2max (23 vs. 33 bursts/min for control). Thereafter, it increased in a linear fashion with increasing work rate, with a significantly higher burst frequency during 60% VO2max than the control value. Both heart rate and mean blood pressure rose significantly during 20% VO2max from the control value and increased linearly with increased exercise intensity. During light exercise, MSNA was suppressed by arterial and cardiopulmonary baroreceptors as a result of the hemodynamic changes associated with leg muscle pumping. The baroreflex inhibition may overcome the muscle metaboreflex excitation to induce MSNA suppression during light exercise. These results suggest that during light exercise MSNA is inhibited, perhaps due to loading of the cardiopulmonary and arterial baroreflexes, and that during heavier exercise the increase in MSNA occurs as muscle metaboreflexes are activated.

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Effects of caffeine on blood pressure, heart rate, and forearm blood flow during dynamic leg exercise

Journal of Applied Physiology ◽

10.1152/jappl.1998.85.1.154 ◽

1998 ◽

Vol 85 (1) ◽

pp. 154-159 ◽

Cited By ~ 66

Author(s):

Jason W. Daniels ◽

Paul A. Molé ◽

James D. Shaffrath ◽

Charles L. Stebbins

Keyword(s):

Blood Pressure ◽

Heart Rate ◽

Blood Flow ◽

Systolic Blood Pressure ◽

Skin Temperature ◽

Rectal Temperature ◽

Forearm Blood Flow ◽

Dynamic Exercise ◽

Ang Ii ◽

Leg Exercise

This study examined the acute effects of caffeine on the cardiovascular system during dynamic leg exercise. Ten trained, caffeine-naive cyclists (7 women and 3 men) were studied at rest and during bicycle ergometry before and after the ingestion of 6 mg/kg caffeine or 6 mg/kg fructose (placebo) with 250 ml of water. After consumption of caffeine or placebo, subjects either rested for 100 min (rest protocol) or rested for 45 min followed by 55 min of cycle ergometry at 65% of maximal oxygen consumption (exercise protocol). Measurement of mean arterial pressure (MAP), forearm blood flow (FBF), heart rate, skin temperature, and rectal temperature and calculation of forearm vascular conductance (FVC) were made at baseline and at 20-min intervals. Plasma ANG II was measured at baseline and at 60 min postingestion in the two exercise protocols. Before exercise, caffeine increased both systolic blood pressure (17%) and MAP (11%) without affecting FBF or FVC. During dynamic exercise, caffeine attenuated the increase in FBF (53%) and FVC (50%) and accentuated exercise-induced increases in ANG II (44%). Systolic blood pressure and MAP were also higher during exercise plus caffeine; however, these increases were secondary to the effects of caffeine on resting blood pressure. No significant differences were observed in heart rate, skin temperature, or rectal temperature. These findings indicate that caffeine can alter the cardiovascular response to dynamic exercise in a manner that may modify regional blood flow and conductance.

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Effect of short moderate intensity exercise bouts on cardiovascular function and maximal oxygen consumption in sedentary older adults

BMJ Open Sport & Exercise Medicine ◽

10.1136/bmjsem-2019-000672 ◽

2020 ◽

Vol 6 (1) ◽

pp. e000672 ◽

Cited By ~ 1

Author(s):

Karani Magutah ◽

Kihumbu Thairu ◽

Nilesh Patel

Keyword(s):

Blood Pressure ◽

Older Adults ◽

Heart Rate ◽

Oxygen Consumption ◽

Systolic Blood Pressure ◽

Maximal Oxygen Consumption ◽

Cardiovascular Function ◽

Moderate Intensity ◽

Group Differences ◽

Moderate Intensity Exercise

AimTo investigate effect of <10 min moderate intensity exercise on cardiovascular function and maximal oxygen consumption (V˙ O2max) among sedentary adults.MethodsWe studied 53 sedentary urbanites aged ≥50 years, randomised into: (1) male (MS) and (2) female (FS) undertaking three short-duration exercise (5–10 min) daily, and (3) male (ML) and (4) female (FL) exercising 30–60 min 3–5 days weekly. Resting systolic blood pressure (SBP), diastolic blood pressure (DBP), heart rate and V˙ O2max were measured at baseline and 8 weekly for 24 weeks.ResultsAt baseline, 50% MS, 61.5% ML, 53.8% FS and 53.8% FL had SBP ≥120 mm Hg, and 14.3% MS, 53.8% ML, 23.1% FS and 38.5% FL had DBP ≥80 mm Hg. At 24 weeks, where SBP remained ≥120 mm Hg, values decreased from 147±19.2 to 132.3±9.6 mm Hg (50% of MS), from 144±12.3 to 128±7.0 mm Hg (23.1% of ML), from 143.1±9.6 to 128.0±7.0 mm Hg (53.8% of FS) and from 152.3±23.7 to 129±3.7 mm Hg (30.8% of FL). For DBP ≥80 mm Hg, MS and FS percentages maintained, but values decreased from 101±15.6 to 84.5±0.7 mm Hg (MS) and 99.0±3.6 to 87.7±4.9 mm Hg (FS). In ML and FL, percentage with DBP ≥80 mm Hg dropped to 15.4% (86.1±6.5 to 82.5±3.5 mm Hg) and (91.4±5.3 to 83.5±0.71 mm Hg). V˙ O2max increased from 26.1±4.4 to 32.0±6.2 for MS, from 25.8±5.1 to 28.8±5.4 for ML (group differences p=0.02), from 20.2±1.8 to 22.7±2.0 for FS and from 21.2±1.9 to 24.2±2.7 for FL (groups differences p=0.38).ConclusionAccumulated moderate intensity exercise bouts of <10 min confer similar-to-better cardiovascular and V˙ O2max improvements compared with current recommendations among sedentary adults.

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Estimation of energy expenditure of Nordic walking: a crossover trial

BMC Sports Science Medicine and Rehabilitation ◽

10.1186/s13102-021-00240-0 ◽

2021 ◽

Vol 13 (1) ◽

Author(s):

Sora Baek ◽

Yuncheol Ha

Keyword(s):

Blood Pressure ◽

Heart Rate ◽

Energy Expenditure ◽

Oxygen Uptake ◽

Systolic Blood Pressure ◽

Lower Limb ◽

Surface Electromyography ◽

Minute Ventilation ◽

Lower Limb Muscles ◽

Limb Muscles

Abstract Background Nordic walking (NW) requires more energy compared with conventional walking (W). However, the metabolic equation for NW has not been reported. Therefore, this study aimed to characterize responses in oxygen uptake, minute ventilation, heart rate, systolic blood pressure, and surface electromyography of the upper and lower limb muscles during NW and W and develop a metabolic equation for energy expenditure (E, mL·kg− 1·min− 1) of NW. Methods This study was performed in a randomized, controlled, crossover design to test the energy expenditure during NW and W. Fifteen healthy young men were enrolled (aged 23.7 ± 3.0 years). All participants performed two randomly ordered walking tests (NW and W) on a treadmill at a predetermined stepwise incremental walking speed (3–5 km·h− 1) and grade (0–7%). The oxygen uptake, minute ventilation, heart rate, systolic blood pressure, and surface electromyography signals of the three upper limb muscles and three lower limb muscles in their right body were recorded and compared between NW and W using paired-t test. Multiple linear regression analysis was used to draw estimation of E during W and NW. Results Oxygen uptake (+ 15.8%), minute ventilation (+ 17.0%), heart rate (+ 8.4%), and systolic blood pressure (+ 7.7%) were higher in NW than in W (P < .05). NW resulted in increased muscle activity in all of the upper limb muscles (P < .05). In the lower limb, surface electromyography activities in two of the three lower limb muscles were increased in NW than in W only during level walking (P < .05). Energy expenditure during W and NW was estimated as follows: ENW = 6.1 + 0.09 × speed + 1.19 × speed × grade and EW = 4.4 + 0.09 × speed + 1.20 × speed × grade. Conclusion NW showed higher work intensity than W, with an oxygen consumption difference of 1.7 mL·kg− 1·min− 1. The coefficients were not different between the two walking methods. NW involved more muscles of the upper body than W.

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Estimation of Energy Expenditure of Nordic Walking: A Crossover Trial

10.21203/rs.3.rs-49475/v2 ◽

2020 ◽

Author(s):

Sora Baek ◽

Yuncheol Ha

Keyword(s):

Blood Pressure ◽

Heart Rate ◽

Energy Expenditure ◽

Oxygen Uptake ◽

Systolic Blood Pressure ◽

Lower Limb ◽

Surface Electromyography ◽

Minute Ventilation ◽

Lower Limb Muscles ◽

Limb Muscles

Abstract Background: Nordic walking (NW) requires more energy compared with conventional walking (W). However, the metabolic equation for NW has not been reported. Therefore, this study aimed to characterize responses in oxygen uptake, minute ventilation, heart rate, systolic blood pressure, and surface electromyography of the upper and lower limb muscles during NW and W and develop a metabolic equation for energy expenditure (E, mL·kg-1·min-1) of NW.Methods: This study was performed in a randomized, controlled, crossover design to test the energy expenditure during NW and W. Fifteen healthy young men were enrolled (aged 23.7 ± 3.0 years). All participants performed two randomly ordered walking tests (NW and W) on a treadmill at a predetermined stepwise incremental walking speed (3–5 km·h-1) and grade (0%–7%). The oxygen uptake, minute ventilation, heart rate, systolic blood pressure, and surface electromyography signals of the three upper limb muscles and three lower limb muscles in their right body were recorded and compared between NW and W using paired-t test. Multiple linear regression analysis was used to draw estimation of E during W and NW.Results: Oxygen uptake (+15.8%), minute ventilation (+17.0%), heart rate (+8.4%), and systolic blood pressure (+7.7%) were higher in NW than in W (P<.05). NW resulted in increased muscle activity in all of the upper limb muscles (P<.05). In the lower limb, surface electromyography activities in two of the three lower limb muscles were increased in NW than in W only during level walking (P<.05). Energy expenditure during W and NW was estimated as follows: ENW = 6.1 + 0.09 × speed + 1.19 × speed × grade and EW = 4.4 + 0.09 × speed + 1.20 × speed × grade.Conclusion: NW showed higher work intensity than W, with an oxygen consumption difference of 1.7 mL·kg-1·min-1. The coefficients were not different between the two walking methods. NW involved more muscles of the upper body than W.

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Estimation of Energy Expenditure of Nordic Walking: A Crossover Trial

10.21203/rs.3.rs-49475/v3 ◽

2021 ◽

Author(s):

Sora Baek ◽

Yuncheol Ha

Keyword(s):

Blood Pressure ◽

Heart Rate ◽

Energy Expenditure ◽

Oxygen Uptake ◽

Systolic Blood Pressure ◽

Lower Limb ◽

Surface Electromyography ◽

Minute Ventilation ◽

Lower Limb Muscles ◽

Limb Muscles

Abstract Background: Nordic walking (NW) requires more energy compared with conventional walking (W). However, the metabolic equation for NW has not been reported. Therefore, this study aimed to characterize responses in oxygen uptake, minute ventilation, heart rate, systolic blood pressure, and surface electromyography of the upper and lower limb muscles during NW and W and develop a metabolic equation for energy expenditure (E, mL·kg-1·min-1) of NW.Methods: This study was performed in a randomized, controlled, crossover design to test the energy expenditure during NW and W. Fifteen healthy young men were enrolled (aged 23.7 ± 3.0 years). All participants performed two randomly ordered walking tests (NW and W) on a treadmill at a predetermined stepwise incremental walking speed (3–5 km·h-1) and grade (0%–7%). The oxygen uptake, minute ventilation, heart rate, systolic blood pressure, and surface electromyography signals of the three upper limb muscles and three lower limb muscles in their right body were recorded and compared between NW and W using paired-t test. Multiple linear regression analysis was used to draw estimation of E during W and NW.Results: Oxygen uptake (+15.8%), minute ventilation (+17.0%), heart rate (+8.4%), and systolic blood pressure (+7.7%) were higher in NW than in W (P<.05). NW resulted in increased muscle activity in all of the upper limb muscles (P<.05). In the lower limb, surface electromyography activities in two of the three lower limb muscles were increased in NW than in W only during level walking (P<.05). Energy expenditure during W and NW was estimated as follows: ENW = 6.1 + 0.09 × speed + 1.19 × speed × grade and EW = 4.4 + 0.09 × speed + 1.20 × speed × grade.Conclusion: NW showed higher work intensity than W, with an oxygen consumption difference of 1.7 mL·kg-1·min-1. The coefficients were not different between the two walking methods. NW involved more muscles of the upper body than W.

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Hemodynamic response to converting enzyme inhibition at rest and exercise in humans

Journal of Applied Physiology ◽

10.1152/jappl.1982.53.3.576 ◽

1982 ◽

Vol 53 (3) ◽

pp. 576-581 ◽

Cited By ~ 9

Author(s):

R. Fagard ◽

P. Lijnen ◽

L. Vanhees ◽

A. Amery

Keyword(s):

Blood Pressure ◽

Heart Rate ◽

Oxygen Uptake ◽

Arterial Pressure ◽

Plasma Renin Activity ◽

Systemic Vascular Resistance ◽

Vascular Resistance ◽

Plasma Renin ◽

Peak Oxygen Uptake ◽

Converting Enzyme

The response of the systemic circulation to acute inhibition of the converting enzyme with 25 mg of oral Captopril (Squibb) was studied in six normal sodium-replete male volunteers at rest and during exercise, together with its effects on exercise capacity for graded uninterrupted exercise. In recumbent subjects at rest Captopril did not affect arterial pressure or heart rate, and plasma renin activity rose 2.5-fold (P less than 0.05). In subjects in the sitting position, at rest and during exercise until exhaustion, Captopril reduced mean brachial intra-arterial pressure by an average of 7 Torr in comparison to placebo (P less than 0.001). Captopril's hypotensive effect was caused by a reduction of systemic vascular resistance (P less than 0.01), without changes of cardiac output (measured by CO2 rebreathing), heart rate, or stroke volume. Plasma renin activity was significantly higher during Captopril (P less than 0.001). Peak oxygen uptake and exercise duration were the same after administration of Captopril or placebo. The data demonstrate that the renin-angiotensin system is not involved in the homeostasis of blood pressure in supine sodium-replete humans, but has a modest role in blood pressure regulation when posture is changed from supine to upright. The orthostatic effect of Captopril is maintained during upright exercise. Furthermore the reduction of systemic vascular resistance by Captopril does not affect peak oxygen uptake.

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Central and regional circulatory adaptations to one-leg training

Journal of Applied Physiology ◽

10.1152/jappl.1982.52.4.976 ◽

1982 ◽

Vol 52 (4) ◽

pp. 976-983 ◽

Cited By ~ 97

Author(s):

K. Klausen ◽

N. H. Secher ◽

J. P. Clausen ◽

O. Hartling ◽

J. Trap-Jensen

Keyword(s):

Blood Pressure ◽

Heart Rate ◽

Blood Flow ◽

Oxygen Uptake ◽

Maximal Exercise ◽

Exercise Heart Rate ◽

Leg Blood Flow ◽

Arterial Blood ◽

Before And After ◽

Leg Exercise

Six young healthy male subjects performed submaximal and maximal exercise on bicycle ergometers with one leg and two legs before and after 8 wk of one-leg training with each of both legs. The following variables were measured during one- and two-leg exercise: oxygen uptake, heart rate, mean arterial blood pressure, cardiac output, leg blood flow, and iliac arteriovenous differences for oxygen and lactate. After training the maximal oxygen uptake during one- and two-leg exercise was increased by 19 and 11%, respectively. The corresponding cardiac outputs increased by 16 and 11%, respectively. During submaximal one-leg exercise, heart rate decreased by 11%, whereas a decrease of only 2% was seen during submaximal two-leg exercise. Mean blood pressure decreased by about 10 Torr in both types of exercise and during both submaximal and maximal exercise. Maximal leg blood flow increased only by 1.2 l/min during one-leg exercise. Leg blood flow and leg oxygen uptake were smaller during two-leg exercise than during one-leg exercise and more so after training. These findings indicate that one-leg exercise, compared with two-leg exercise, involves circulatory adaptations that respond differently to one-leg training. The findings further imply that oxygen supply to one large muscle group of exercising muscles may be limited by vasoconstriction when another large group of muscles is exercising simultaneously.

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Acute Cardiometabolic Responses to Multi-Modal Integrative Neuromuscular Training in Children

Journal of Functional Morphology and Kinesiology ◽

10.3390/jfmk4020039 ◽

2019 ◽

Vol 4 (2) ◽

pp. 39 ◽

Cited By ~ 2

Author(s):

Avery D. Faigenbaum ◽

Jie Kang ◽

Nicholas A. Ratamess ◽

Anne C. Farrell ◽

Mina Belfert ◽

...

Keyword(s):

Heart Rate ◽

Oxygen Uptake ◽

Physical Fitness ◽

Peak Oxygen Uptake ◽

Moderate Intensity ◽

Neuromuscular Training ◽

Effective Strategy ◽

Rest Interval ◽

Peak Heart Rate ◽

Experimental Conditions

Integrative neuromuscular training (INT) has emerged as an effective strategy for improving health- and skill-related components of physical fitness, yet few studies have explored the cardiometabolic demands of this type of training in children. The aim of this study was to examine the acute cardiometabolic responses to a multi-modal INT protocol and to compare these responses to a bout of moderate-intensity treadmill (TM) walking in children. Participants (n = 14, age 10.7 ± 1.1 years) were tested for peak oxygen uptake (VO2) and peak heart rate (HR) on a maximal TM test and subsequently participated in two experimental conditions on nonconsecutive days: a 12-min INT protocol of six different exercises performed twice for 30 s with a 30 s rest interval between sets and exercises and a 12-min TM protocol of walking at 50% VO2peak. Throughout the INT protocol mean VO2 and HR increased significantly from 14.9 ± 3.6 mL∙kg−1∙min−1 (28.2% VO2 peak) to 34.0 ± 6.4 mL∙kg−1∙min−1 (64.3% VO2 peak) and from 121.1 ± 9.0 bpm (61.0% HR peak) to 183.5 ± 7.9 bpm (92.4% HR peak), respectively. While mean VO2 for the entire protocol did not differ between INT and TM, mean VO2 and HR during selected INT exercises and mean HR for the entire INT protocol were significantly higher than TM (all Ps ≤ 0.05). These findings suggest that INT can pose a moderate to vigorous cardiometabolic stimulus in children and selected INT exercises can be equal to or more metabolically challenging than TM walking.

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Atrial natriuretic polypeptide during exercise in healthy man

Acta Endocrinologica ◽

10.1530/acta.0.1160059 ◽

1987 ◽

Vol 116 (1) ◽

pp. 59-65 ◽

Cited By ~ 32

Author(s):

Yoshihiko Saito ◽

Kazuwa Nakao ◽

Akira Sugawara ◽

Kazunobu Nishimura ◽

Makoto Sakamoto ◽

...

Keyword(s):

Blood Pressure ◽

Heart Rate ◽

Plasma Concentration ◽

Oxygen Uptake ◽

Systolic Blood Pressure ◽

Exercise Test ◽

Maximal Oxygen Uptake ◽

Plasma Norepinephrine ◽

Atrial Natriuretic Polypeptide ◽

Atrial Natriuretic

Abstract. The plasma concentration of atrial natriuretic polypeptide was measured in eight healthy men during two grades of exercise performed in the supine position on a bicycle ergometer. The plasma concentration of atrial natriuretic polypeptide slightly increased during the first exercise test with 20% of the maximal oxygen uptake and it approximately doubled during the second exercise with 40% of the maximal oxygen uptake (from 15.5 ± 5.5 (mean ± sd) pmol/l to 31.8 ± 10.7 pmol/l). The increase in the plasma level of atrial natriuretic polypeptide in the second exercise was significantly greater than that in the first one. The plasma norepinephrine level and plasma renin activity showed significant increases during the second exercise test. Heart rate and systolic blood pressure also increased in response to the graded exercise. The increase in the plasma concentration of atrial natriuretic polypeptide during exercise was significantly correlated with the increase in heart rate, systolic blood pressure, and the plasma norepinephrine concentration (r = 0.75, r = 0.71 and r = 0.51, respectively). These results indicate that the plasma concentration of atrial natriuretic polypeptide increases in response to the intensity of a workload, and suggest that exercise is a useful test to evaluate the releasing function of atrial natriuretic polypeptide in the heart.

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