Leg Cycling Exercise Research Articles

Mood Responses to Passive and Active Motion Leg Cycling Exercise in Healthy Sedentary Young Adults.

Previous studies suggest that passive motion exercise (PME) may be useful for overcoming exercise limitations associated with a sedentary lifestyle, orthopedic disorders, and various other debilitating conditions. Negative mood response is one of the factors that limit a person's ability to exercise. Therefore, this study tests the hypothesis that the mood response associated with PME is not different than the mood response associated with active motion exercise (AME). Eight women and seven men participated in the study and were administrated the Profile of Mood States (POMS) during modes of PME and AME in a randomized order. Outcome of the POMS consisted of the total mood disturbance score [(feelings of tension + depression + fatigue + anger + confusion) − vigor]. ANOVA was used to determine significance of differences in total mood disturbance, oxygen uptake (V.O2), and middle cerebral blood flow velocity (MCAv) at baseline and immediately after 30-minute conditions of PME and AME. Postexercise total mood disturbance score was significantly decreased for both conditions (PME baseline 29.2 ± 5.2 vs. postexercise 16.4 ± 6.8, P < 0.05) and AME baseline 22.4 ± 4.4 vs. postexercise 13.1 ± 5.2, P < 0.05). These senses of changes in feelings were associated with significant physiological increases in V.O2 and MCAv during both PME and AME (P < 0.05). These results demonstrate that physiological and mood responses to passive and active motion cycling exercise are not different. Future studies should determine whether passive motion cycling exercise is a useful preventive medicine strategy for overcoming various disease-related exercise limitations and counteracting the adverse effects of sedentary lifestyles.

Impact of Dietary Nitrate Supplementation on Executive Function During Hypoxic Exercise.

We investigated the effects of 4-day dietary beetroot (BR) juice supplementation on executive function assessed by color-word Stroop task (CWST) in hypoxia (fraction of inspired oxygen [FiO2] = 0.1395). Eight healthy young men performed 25-minute leg cycling exercise (target heart rate, 140 bpm) randomly with placebo (PL) juice or BR supplementation. The CWST was evaluated at resting hypoxic condition (after 30 minutes of hypoxic exposure) and at 15 minutes during exercise. During exercise, the correct response time in the CWST was significantly shortened compared with those at rest with no differences between PL and BR. The response accuracy in the CWST with BR was marginally lower than that with PL during exercise (p = 0.066). There were no significant differences in all physiological values, including pulmonary ventilation, arterial oxygen saturation, partial pressure of end-tidal carbon dioxide output, and tissue oxygenation in the left frontal lobe, assessed by near-infrared spectroscopy during exercise conditions involving PL and BR supplementation. These results suggest that moderate exercise in hypoxia partially improved executive function; however, 4-day dietary BR supplementation did not improve executive function during hypoxic exercise.

Cardiorespiratory and Cerebrovascular Responses to Leg Cycling Exercise during Muscle Metaboreflex Activation with Blood Flow Restriction in Moderate Normobaric Hypoxia

Skeletal muscle blood flow restriction and normobaric hypoxia are strategies adopted during exercise training because the associated reductions in local or systemic oxygenation may enhance athletic performance. Both manoeuvres evoke cardiorespiratory and cerebrovascular responses but have not been studied in combination. Blood flow restriction during exercise activates metabolically sensitive group III and IV skeletal muscle afferents (i.e., muscle metaboreflex activation), while systemic hypoxia activates the peripheral chemoreflex. We sought to determine whether the cardiorespiratory and cerebrovascular response to muscle metaboreflex activation with blood flow restriction during leg cycling exercise is augmented in moderate normobaric hypoxia.Nine healthy men (age 23±2 years; mean±SE) participated in two experimental trials performed under normoxic (fraction of inspired O2 [FiO2] = 21 %) and hypoxic (FiO2 = 13.5 %; equivalent of altitude of 3500 m) conditions whilst seated in a semi‐recumbent position in an environmental chamber. Trials consisted of a resting baseline period (3 min), followed by low intensity leg cycling exercise (64±7 Watts) under free‐flow conditions (~3½ min), and then bilateral thigh cuff inflation to 100 mmHg to induce blood flow restriction and muscle metaboreflex activation (~3 ½ min). Peripheral capillary oxygen saturation (SpO2; finger pulse oximetry), mean arterial pressure (MAP; Finometer and SunTech), heart rate (HR; electrocardiogram), the partial pressure of end‐tidal carbon dioxide (PETCO2; capnography), minute ventilation (VE; pneumotachometer) and middle cerebral artery mean blood flow velocity (MCAV; transcranial Doppler) were recorded.At baseline, SpO2 was lower during hypoxia (87±1 %) than normoxia (97±1 %; P&lt;0.05), but MAP, HR, PETCO2, VE and MCAv were not different between trials (P&gt;0.05). Leg cycling under free‐flow conditions significantly increased MAP, HR, PETCO2, VE and MCAv (P&lt;0.05 vs. baseline), with no differences observed between hypoxic and normoxic trials (P&gt;0.05). MAP (Δ14±2 vs. Δ16±2 mmHg; P=0.215), HR (Δ10±2 vs. Δ8±3 b·min−1; P=0.251), PETCO2 (Δ−1.1±0.3 vs. Δ−3.4±1.8 mmHg; P=0.596), VE (Δ4±1 vs. Δ4±1 L·min−1; P=0.446) and MCAv (Δ4±2 vs. Δ4±1 cm·s−1; P=0.408) responses to blood flow restriction during leg cycling (i.e., muscle metaboreflex activation) were not different in the hypoxic and normoxic trials.These preliminary findings suggest that moderate normobaric hypoxia (FiO2 = 13.5 %) does not augment the cardiorespiratory and cerebrovascular responses to muscle metaboreflex activation with blood flow restriction during low intensity leg cycling.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Moderate-intensity Arm-cranking Exercise may not Improve Arterial Function in Healthy Adult Men.

Endurance exercises, such as cycling or running, are useful for improving arterial function. However, people suffering from partial paralysis or arthritis are unable to perform these kinds of lower-limb exercises. In the present study, we explored the acute effect of upper-arm exercise on arterial stiffness in healthy men. Fourteen healthy adult men performed two experimental trials. The order of experiments was randomized between a 30-min arm-cranking exercise at 50% V̇O2max (A-trial) and a 30-min leg-cycling exercise at 50% V̇O2max (C-trial). The brachial to ankle pulse wave velocity (baPWV), brachial systolic/diastolic blood pressure and heart rate were obtained with subjects in the supine position. The baseline hemodynamic values were not markedly different between the two trials. Compared with the baseline value, the baPWV was significantly reduced at 30 and 60 min after the C-trial. In the A-trial, however, there were no significant changes in the baPWV throughout the trial. These results indicate that acute 50% V̇O2max arm-cranking exercise induced relatively little change in the baPWV, which was the opposite of the finding observed with leg-cycling exercise. Therefore, in order to improve arterial function via aerobic upper-arm exercises, the exercise mode/intensity or other approaches should be considered.

Effect of In-Bed Leg Cycling and Electrical Stimulation of the Quadriceps on Global Muscle Strength in Critically Ill Adults

Early in-bed cycling and electrical muscle stimulation may improve the benefits of rehabilitation in patients in the intensive care unit (ICU). To investigate whether early in-bed leg cycling plus electrical stimulation of the quadriceps muscles added to standardized early rehabilitation would result in greater muscle strength at discharge from the ICU. Single-center, randomized clinical trial enrolling critically ill adult patients at 1 ICU within an 1100-bed hospital in France. Enrollment lasted from July 2014 to June 2016 and there was a 6-month follow-up, which ended on November 24, 2016. Patients were randomized to early in-bed leg cycling plus electrical stimulation of the quadriceps muscles added to standardized early rehabilitation (n = 159) or standardized early rehabilitation alone (usual care) (n = 155). The primary outcome was muscle strength at discharge from the ICU assessed by physiotherapists blinded to treatment group using the Medical Research Council grading system (score range, 0-60 points; a higher score reflects better muscle strength; minimal clinically important difference of 4 points). Secondary outcomes at ICU discharge included the number of ventilator-free days and ICU Mobility Scale score (range, 0-10; a higher score reflects better walking capability). Functional autonomy and health-related quality of life were assessed at 6 months. Among 314 randomized patients, 312 (mean age, 66 years; women, 36%; receiving mechanical ventilation at study inclusion, 78%) completed the study and were included in the analysis. The median global Medical Research Council score at ICU discharge was 48 (interquartile range [IQR], 29 to 58) in the intervention group and 51 (IQR, 37 to 58) in the usual care group (median difference, -3.0 [95% CI, -7.0 to 2.8]; P = .28). The ICU Mobility Scale score at ICU discharge was 6 (IQR, 3 to 9) in both groups (median difference, 0 [95% CI, -1 to 2]; P = .52). The median number of ventilator-free days at day 28 was 21 (IQR, 6 to 25) in the intervention group and 22 (IQR, 10 to 25) in the usual care group (median difference, 1 [95% CI, -2 to 3]; P = .24). Clinically significant events occurred during mobilization sessions in 7 patients (4.4%) in the intervention group and in 9 patients (5.8%) in the usual care group. There were no significant between-group differences in the outcomes assessed at 6 months. In this single-center randomized clinical trial involving patients admitted to the ICU, adding early in-bed leg cycling exercises and electrical stimulation of the quadriceps muscles to a standardized early rehabilitation program did not improve global muscle strength at discharge from the ICU. ClinicalTrials.gov Identifier: NCT02185989.

Intensive exercise program after spinal cord injury (SCIPA full-on): A randomized controlled trial

While upper body training is effective for improving aerobic fitness and muscle strength after spinal cord injury (SCI), activity-based therapies (ABT) intended to activate the paralysed extremities have been reported to promote neurological improvement. We investigated the effectiveness of intensive ABT compared with upper body training for people with SCI. One hundred and sixteen participants (C2-T12, AIS A-D) were recruited from six SCI units in Australia and New Zealand, and randomised to experimental or control groups. Experimental participants received a 12-week ABT program including locomotor training, functional electrical stimulation-assisted leg cycling, and trunk and lower extremity exercises, while control group participants undertook upper body strength and aerobic fitness training. The primary outcome measure was the ASIA motor scores for upper and lower extremities. One hundred and three participants completed the interventions and were included in the primary analysis. Mean (SD) upper extremity motor scores for experimental ( n = 49) and control ( n = 54) groups were 41.45 (12.11) and 39.39 (11.94), respectively, with an adjusted mean between-group difference of −0.039 (95% CI: −1.12 to 1.04). Mean (SD) lower extremity motor scores were 12.51 (17) and 10.24 (17.19) for experimental and control groups, with an adjusted mean between-group difference of 0.895 (95% CI: −0.48 to 2.27). There were 15 serious adverse events within each group, but only one of these was related to the experimental intervention (bilateral femoral condyle and tibial plateau subchondral fractures). Activity-based therapy did not lead to greater improvements in ASIA motor scores compared to upper body training.

Impact of acute dynamic exercise on radial artery low-flow mediated constriction in humans

PurposeA “low-flow mediated constriction” (L-FMC) is evoked in the radial artery by the inflation of an ipsilateral wrist cuff to a supra-systolic pressure. We sought to test the hypothesis that the radial artery L-FMC response is augmented immediately following acute dynamic leg exercise in young healthy individuals.MethodsTen healthy and recreationally active men (23 ± 4 years) undertook a 30-min trial of incremental dynamic leg cycling exercise (10 min at 50, 100 and 150 W) and a 30-min time control trial (seated rest). Trials were randomly assigned and performed on separate days. Radial artery characteristics (diameter, blood flow and shear rate) were assessed throughout each trial, with L-FMC and flow-mediated vasodilatation (FMD) assessments conducted prior to and immediately following (10 min) trials.ResultsDynamic leg cycling exercise increased radial artery blood flow, along with mean, retrograde and anterograde shear rate (P < 0.05). Blood flow profiles were unchanged during the time control trial (P > 0.05). Following exercise L-FMC was increased (mean [SD]; − 5.6 [3.3] vs. − 10.1 [3.8] %, P < 0.05), while it was not different in the time control condition (− 8.1 [3.2] vs. − 6.7 [3.4] %, P > 0.05). FMD was not different following either the exercise or time control trials (P > 0.05), but the composite end-point of L-FMC + FMD was enhanced post-exercise (P < 0.05).ConclusionsDynamic exercise with a large muscle mass acutely augments the vasoconstrictor response of the radial artery in response to a reduction in blood flow (L-FMC) in young healthy individuals. The time course of this post-exercise response and the underlying vasoregulatory mechanisms require elucidation.

SCIPA Full-On: A Randomized Controlled Trial Comparing Intensive Whole-Body Exercise and Upper Body Exercise After Spinal Cord Injury

Background. While upper body training has been effective for improving aerobic fitness and muscle strength after spinal cord injury (SCI), activity-based therapies intended to activate the paralyzed extremities have been reported to promote neurological improvement. Objective. To compare the effectiveness of intensive whole-body exercise compared with upper body exercise for people with chronic SCI. Methods. A parallel-group randomized controlled trial was conducted. Participants with a range of SCI levels and severity were randomized to either full-body exercise (FBE) or upper body exercise (UBE) groups (3 sessions per week over 12 weeks). FBE participants underwent locomotor training, functional electrical stimulation-assisted leg cycling, and trunk and lower extremity exercises, while UBE participants undertook upper body strength and aerobic fitness training only. The primary outcome measure was the American Spinal Injury Association (ASIA) motor score for upper and lower extremities. Adverse events were systematically recorded. Results. A total of 116 participants were enrolled and included in the primary analysis. The adjusted mean between-group difference was −0.04 (95% CI −1.12 to 1.04) for upper extremity motor scores, and 0.90 (95% CI −0.48 to 2.27) for lower extremity motor scores. There were 15 serious adverse events in UBE and 16 in FBE, but only one of these was definitely related to the experimental intervention (bilateral femoral condyle and tibial plateau subchondral fractures). No significant between-group difference was found for adverse events, or functional or behavioral variables. Conclusions. Full-body training did not lead to improved ASIA motor scores compared with upper body training in people with chronic SCI.

Blunted Sympathetic Vasomotor Outflow To Inspiratory Resistive Breathing During Exercise In Women Compared to Men

It has been reported that in young men high inspiratory muscle work at rest and during exercise reflexively increases muscle sympathetic nerve activity (MSNA), with corresponding increases in arterial blood pressure (ABP). This sympathoexcitation occurs through an inspiratory muscle-induced metaboreflex. Young women have attenuated inspiratory muscle metaboreflex-induced increases in ABP compared to age-matched men. One potential mechanism is less sympathetic vasomotor output in women compared to men. PURPOSE: We compared changes in MSNA and cardiovascular variables during leg cycle exercise with increased inspiratory muscle resistance in men and women. METHODS: Eight young women (19.5±0.2) and seven men (20.3±0.3) completed the study. The subjects performed two 10-min submaximal cycle ergometer exercises in a semirecumbent position. The first 5-min was spontaneous breathing, and latter 5-min half was voluntary hyperventilation with or without inspiratory resistive breathing. Mean arterial blood pressure (MAP) was measured using finger photoplethysmography and MSNA was recorded via microneurography of the arm at the elbow. RESULTS: During exercise with inspiratory resistive breathing, MSNA burst frequency was significantly increased accompanied by an increase (p<0.05) in MAP in both men and women. Women had significantly less of an increase in MSNA (Women: +9.6±1.0 vs. Men: +14.6±2.4 bursts/min) and MAP (Women: +22.8±5.7 vs. Men: +32.2±2.0 mmHg) as compared to men. CONCLUSION: These results suggest that lesser sympathetic vasomotor outflow partially contributes the attenuated inspiratory muscle-induced metaboreflex during exercise in young women. Supported by JSPS KAKENHI Grant Number 15H3079.

Elevated sympathetic vasomotor outflow in response to increased inspiratory muscle activity during exercise is less in young women compared with men.

What is the central question of this study? Premenopausal women have an attenuated inspiratory muscle metaboreflex-induced increase in arterial blood pressure compared with men. It is unclear whether sympathetic vasomotor outflow during dynamic exercise with increased inspiratory muscle activation is less in young women than in men. What is the main finding and its importance? The magnitude of increased sympathetic vasomotor outflow during leg cycling with inspiratory resistance was smaller in women than in men. Less sympathetic vasomotor outflow with inspiratory muscle metaboreflex activation could be one of the mechanisms for the attenuated inspiratory muscle-induced metaboreflex during exercise in young women. We compared changes in muscle sympathetic nerve activity (MSNA) and cardiovascular variables during leg cycle exercise with increased inspiratory muscle resistance in men and women. We hypothesized that sympathetic vasomotor outflow during exercise with increased inspiratory resistance would be attenuated in young women compared with age-matched men. Eight women and seven men completed the study. The subjects performed two 10min exercise bouts at 40% peak oxygen uptake using a cycle ergometer in a semirecumbent position [spontaneous breathing for 5min and voluntary hyperventilation with or without inspiratory resistive breathing for 5min (breathing frequency 50breathsmin-1 with a 50% duty cycle; inspiratory resistance 30% of maximal inspiratory pressure)]. Mean arterial blood pressure (MAP) was acquired using finger photoplethysmography. The MSNA was recorded via microneurography of the right median nerve at the cubital fossa. During leg cycle exercise with inspiratory resistive breathing, MSNA burst frequency was increased, accompanied by an increase in MAP in both men and women. Women, compared with men, had less of an increase in MAP (women +22.8±12.3mmHg versus men +32.2±5.4mmHg; P<0.05) and MSNA burst frequency (women +9.6±2.9burstsmin-1 versus men +14.6±6.4burstsmin-1 ; P<0.05). These results suggest that the attenuated inspiratory muscle-induced metaboreflex during exercise in young women is attributable, in part, to a lesser sympathetic vasomotor outflow compared with men.

Brachial artery blood flow dynamics during sinusoidal leg cycling exercise in humans

To explore the control of the peripheral circulation of a nonworking upper limb during leg cycling exercise, blood flow (BF) dynamics in the brachial artery (BA) were determined using a sinusoidal work rate (WR) exercise. Ten healthy subjects performed upright leg cycling exercise at a constant WR for 30 min, followed by 16 min of sinusoidal WR consisting of 4‐min periods of WR fluctuating between a minimum output of 20 W and a maximum output corresponding to ventilatory threshold (VT). Throughout the protocol, pulmonary gas exchange, heart rate (HR), mean arterial blood pressure (MAP), blood velocity (BV), and cross‐sectional area of the BA, forearm skin BF (SBF), and sweating rate (SR) were measured. Each variable was fitted to a sinusoidal model with phase shift (θ) and amplitude (A). Nearly all variables closely fit a sinusoidal model. Variables relating to oxygen transport, such as VO2 and HR, followed the sinusoidal WR pattern with certain delays (θ: VO2; 51.4 ± 4.0°, HR; 41.8 ± 5.4°, mean ± SD). Conversely, BF response in the BA was approximately in antiphase (175.1 ± 28.9°) with a relatively large A, whereas the phase of forearm SBF was dissimilar (65.8 ± 35.9°). Thus, the change of BF through a conduit artery to the nonworking upper limb appears to be the reverse when WR fluctuates during sinusoidal leg exercise, and it appears unlikely that this could be ascribed exclusively to altering the downstream circulation to forearm skin.

S186 Effect of reciprocal pedaling exercise on cortical reorganization and gait in stroke patients

Objectives Functional impairment of the lower limb is a major complication in stroke patients. The involvement of the cortex in pedaling has critical clinical implications to control of cyclical motor functions in patients with damaged cortical structures or cortical pathways.The study aimed at determining the effect of reciprocal pedaling exercise (RPE) on the gait and cortical reorganization in the stroke patients. Methods Forty patients suffering from stroke with hemiparesis will be included in this study. They were divided to Group I treated by training for lower limb muscles of the affected side. While Group II were treated by the same program as group I in addition to RPE. Quantitative EEG (QEEG) was carried for all patients before and after the treatment programs. The midline frontal, central and parietal regions (Fz, Cz and Pz) were studied for evidence of plasticity induced by RPE. Results Neuroplasticity was noticed among patients of group II in the midline frontal region (Fz) and to a lesser extent the midline central region (Cz). Discussion The rhythmic and reciprocal nature of cycling motion permits patients to generate timely symmetrical and reciprocal powers from both limbs required for locomotion. Conclusions Leg cycling exercise, and thus RPE, is a rehabilitation program that improves the function of ambulation in stroke patients. Significance Post stroke physical therapy can utilize RPE for better rehabilitation.

Effects of nitrate supplementation in trained and untrained muscle are modest with initial high plasma nitrite levels.

Nitrate (NO3-) supplementation resulting in higher plasma nitrite (NO2-) is reported to lower resting mean arterial blood pressure (MAP) and oxygen uptake (VO2 ) during submaximal exercise in non-athletic populations, whereas effects in general are absent in endurance-trained individuals. To test whether physiologic effects of NO3- supplementation depend on local muscular training status or cardiovascular fitness, male endurance-trained cyclists (CYC, n=9, VO2 -max: 64±3mL/min/kg; mean±SD) and recreational active subjects serving as a control group (CON, n=8, 46±3mL/min/kg), acutely consumed nitrate-rich beetroot juice ([NO3-] ~9mmol) (NIT) or placebo (PLA) with assessment of resting MAP and energy expenditure during moderate intensity (~50% VO2 -max) and incremental leg cycling (LEG-ex) and arm-cranking exercise (ARM-ex). NIT increased (P<.001) resting plasma NO3- by ~1200% relative to PLA. Plasma NO2- increased ~25% (P<.01) with a significant change only in CYC. LEG-ex VO2 (~2.60L/min), ARM-ex VO2 (~1.14L/min), and resting MAP (~87mm Hg) remained unchanged for CYC, and similarly for CON, no changes were observed for LEG-ex VO2 (~2.03L/min), ARM-ex VO2 (~1.06L/min), or resting MAP (~85mm Hg). VO2 -max was not affected by supplementation, but incremental test peak power was higher (P<.05) in LEG-ex for CYC in NIT relative to PLA (418±47 vs 407±46W). In both CYC and CON, high initial baseline values and small increases in plasma NO2- after NIT may have lowered the effect of the intervention implying that muscular and cardiovascular training status is likely not the only factors that influence the physiologic effects of NO3- supplementation.

Occlusion of blood flow attenuates exercise-induced hypoalgesia in the occluded limb of healthy adults.

Animal studies have demonstrated an important role of peripheral mechanisms as contributors to exercise-induced hypoalgesia (EIH). Whether these same mechanisms contribute to EIH in humans is not known. In the current study, pain thresholds were assessed in healthy volunteers (n = 36) before and after 5 min of high-intensity leg cycling exercise and an equivalent period of quiet rest. Pressure pain thresholds (PPTs) were assessed over the rectus femoris muscle of one leg and first dorsal interosseous muscles (FDIs) of both arms. Blood flow to one arm was occluded by a cuff throughout the 5-min period of exercise (or rest) and postexercise (or rest) assessments. Ratings of pain intensity and pain unpleasantness during occlusion were also measured. Pain ratings during occlusion increased over time (range, 1.5 to 3.5/10, all d > 0.63, P < 0.001) similarly in the rest and exercise conditions (d < 0.35, P > 0.4). PPTs at all sites were unchanged following rest (range, -1.3% to +0.9%, all d < 0.05, P > 0.51). Consistent with EIH, exercise significantly increased PPT at the leg (+29%, d = 0.69, P < 0.001) and the nonoccluded (+23%, d = 0.56, P < 0.001) and occluded (+8%, d = 0.19, P = 0.003) unexercised arms. However, the increase in the occluded arm was significantly smaller (d = -1.03, P < 0.001). These findings show that blocking blood flow to a limb during exercise attenuates EIH, suggesting that peripheral factors contribute to EIH in healthy adults.NEW & NOTEWORTHY This is the first demonstration in humans that a factor carried by the circulation and acting at the periphery is important for exercise-induced hypoalgesia. Further understanding of this mechanism may provide new insight to pain relief with exercise as well as potential interactions between analgesic medications and exercise.

Unilateral Arm Crank Exercise Test for Assessing Cardiorespiratory Fitness in Individuals with Hemiparetic Stroke.

Cardiorespiratory fitness assessment with leg cycle exercise testing may be influenced by motor impairments in the paretic lower extremity. Hence, this study examined the usefulness of a unilateral arm crank exercise test to assess cardiorespiratory fitness in individuals with stroke, including sixteen individuals with hemiparetic stroke (mean ± SD age, 56.4 ± 7.5 years) and 12 age- and sex-matched healthy controls. Participants performed the unilateral arm crank and leg cycle exercise tests to measure oxygen consumption (O2) and heart rate at peak exercise. The O2 at peak exercise during the unilateral arm crank exercise test was significantly lower in the stroke group than in the control group (p < 0.001). In the stroke group, the heart rate at peak exercise during the unilateral arm crank exercise test did not significantly correlate with the Brunnstrom recovery stages of the lower extremity (p = 0.137), whereas there was a significant correlation during the leg cycle exercise test (rho = 0.775, p < 0.001). The unilateral arm crank exercise test can detect the deterioration of cardiorespiratory fitness independently of lower extremity motor impairment severity in individuals with hemiparetic stroke. This study is registered with UMIN000014733.

Acute Exercise Improves Mood and Motivation in Young Men with ADHD Symptoms.

Little is known about whether acute exercise affects signs or symptoms of attention deficit/hyperactivity disorder (ADHD) in adults. This experiment sought to determine the effects of a single bout of moderate-intensity leg cycling exercise on measures of attention, hyperactivity, mood, and motivation to complete mental work in adult men reporting elevated ADHD symptoms. A repeated-measures crossover experiment was conducted with 32 adult men (18-33 yr) with symptoms consistent with adult ADHD assessed by the Adult Self-Report Scale V1.1. Measures of attention (continuous performance task and Bakan vigilance task), motivation to perform the mental work (visual analog scale), lower leg physical activity (accelerometry), and mood (Profile of Mood States and Addiction Research Center Inventory amphetamine scale) were measured before and twice after a 20-min seated rest control or exercise condition involving cycling at 65% V˙O2peak. Condition (exercise vs rest) × time (baseline, post 1, and post 2) ANOVA was used to test the hypothesized exercise-induced improvements in all outcomes. Statistically significant condition-time interactions were observed for vigor (P < 0.001), amphetamine (P < 0.001), motivation (P = 0.027), and Profile of Mood States depression (P = 0.027), fatigue (P = 0.030), and confusion (P = 0.046) scales. No significant interaction effects were observed for leg hyperactivity, simple reaction time, or vigilance task performance (accuracy, errors, or reaction time). In young men reporting elevated symptoms of ADHD, a 20-min bout of moderate-intensity cycle exercise transiently enhances motivation for cognitive tasks, increases feelings of energy, and reduces feelings of confusion, fatigue, and depression, but this has no effect on the behavioral measures of attention or hyperactivity used.

Hypoxia Attenuates Cardiopulmonary Reflex Control Of The Sympathetic Nerve Activity During Dynamic Leg Exercise

PURPOSE: The purpose of the present study was to test the hypothesis that cardiopulmonary baroreflex control of sympathetic vasomotor outflow is modulated by a powerful sympatho-excitatory drive from exercise pressor reflex, central command, and/or arterial chemoreflex. To test this hypothesis, under hypoxic conditions, muscle sympathetic nerve activity (MSNA) was recorded during leg cycling with an increase in central blood volume by increasing pedal frequency to increase the activity of cardiopulmonary baroreceptors. METHODS: Subjects performed mild leg cycle exercise at different pedal frequencies of 60 and 80 rpm (60EX and 80EX trials) while breathing a hypoxic gas mixture (inspired oxygen fraction = 0.12). The exercise workload of the 80EX trial was adjusted to get the same oxygen uptake as the 60EX trial. Stroke volume (SV) and cardiac output (CO) were measured non-invasively using impedance cardiology. MSNA was recorded via microneurography of the right median nerve at the elbow. RESULTS: Changes in thoracic impedance, SV, and CO in the 80EX trial were greater than those in the 60EX trial. MSNA burst frequency during hypoxic exercise in the 80EX trial (39±4 bursts/min) did not differ from that in the 60EX trial (39±3 bursts/min). CONCLUSIONS: These results suggest that a cardiopulmonary baroreflex of sympathetic vasomotor outflow during dynamic exercise is modulated by hypoxia-induced heightened sympathetic nerve activity.

Immediate Effects of Smoking on Cardiorespiratory Responses During Dynamic Exercise: Arm Vs. Leg Ergometry.

Purpose: This study compared the immediate effects of smoking on cardiorespiratory responses to dynamic arm and leg exercises.Methods:This randomized crossover study recruited 14 college students. Each participant underwent two sets of arm-cranking (AC) and leg-cycling (LC) exercise tests. The testing sequences of the control trial (participants refrained from smoking for 8 h before testing) and the experimental trial (participants smoked two cigarettes immediately before testing) were randomly chosen. We observed immediate changes in pulmonary function and heart rate variability after smoking and before the exercise test. The participants then underwent graded exercise tests of their arms and legs until reaching exhaustion. We compared the peak work achieved and time to exhaustion during the exercise tests with various cardiorespiratory indices [i.e., heart rate, oxygen consumption (VO2), minute ventilation (VE)]. The differences between the smoking and control trials were calculated using paired t-tests. For the exercise test periods, VO2, heart rate, and VE values were calculated at every 10% increment of the maximal effort time. The main effects of the time and trial, as well as their trial-by-time (4 × 10) interaction effects on the outcome measures, were investigated using repeated measure ANOVA with trend analysis.Results: 5 min after smoking, the participants exhibited reduced forced vital capacities and forced expiratory volumes in the first second (P < 0.05), in addition to elevated resting heart rates (P < 0.001). The high-frequency, low-frequency, and the total power of the heart rate variability were also reduced (P < 0.05) at rest. For the exercise test periods, smoking reduced the time to exhaustion (P = 0.005) and the ventilatory threshold (P < 0.05) in the LC tests, whereas no significant effects were observed in the AC tests. A trend analysis revealed a significant trial-by-time interaction effect for heart rate, VO2, and VE during the graded exercise test (all P < 0.001). Lower VO2 and VE levels were exhibited in the exercise response of the smoking trial than in those of the control LC trials, whereas no discernable inter-trial difference was observed in the AC trials. Moreover, the differences in heart rate and VE response between the LC and AC exercises were significantly smaller after the participants smoked.Conclusion: This study verified that smoking significantly decreased performance and cardiorespiratory responses to leg exercises. However, the negative effects of smoking on arm exercise performance were not as pronounced.

Exaggerated blood pressure response to dynamic exercise despite chronic refractory hypotension: results of a human case study

BackgroundChronic refractory hypotension is a rare but significant mortality risk in renal failure patients. Such aberrant physiology usually deems patient unfit for renal transplant surgery. Exercise stimulates the mechano-chemoreceptors in the skeletal muscle thereby modulating the sympathetic effects on blood pressure regulation. The haemodynamic response to dynamic exercise in such patients has not been previously investigated. We present a case with severe chronic hypotension who underwent exercise testing before and after renal transplantation, with marked differences in blood pressure response to exercise.Case PresentationA 40-year old haemodialysis-dependent patient with a 2 year history of refractory hypotension (≤80/50 mmHg) was referred for living donor renal transplantation at our tertiary centre. Each dialysis session was often less than 2 h and 30 min due to symptomatic hypotension. As part of the cardiovascular assessment, she underwent haemodynamic evaluation with cardiopulmonary exercise testing. Blood pressure normalized during unloaded pedalling but was exaggerated at maximal workload whereby it rose from 82/50 mmHg to a peak of 201/120 mmHg. Transthoracic echocardiography, tonometric measure of central vascular compliance and myocardial perfusion scan were normal. She subsequently underwent an antibody-incompatible renal transplantation and was vasopressor reliant for 14 days during the post-operative period. Eight weeks following transplant, resting blood pressure was normal and a physiological exercise-haemodynamic response was observed during a repeat cardiopulmonary exercise testing.ConclusionThis case highlights the potential therapeutic role of unloaded leg cycling exercise during dialysis session to correct chronic hypotension, allowing patients to have greater tolerance to fluid shift. It also adds to existing evidence that sympathetic dysfunction is reversible with renal transplant. Furthermore chronic hypotension with preserved exercise-haemodynamic response and cardiovascular reserve should not preclude these patients from renal transplant surgery.

Effects Of Exercise Training And Diet On Visceral And Subcutaneous Adipose Tissue In Overweight Adults

Studies have shown that elevated visceral adipose tissue (VAT) and intra-abdominal fat are important risk factors for obesity-related metabolic dysfunction (Fabbrini et al. 2009; Ross et al. 2000). It is the VAT many researchers considered an important biomarker of metabolic dysfunction that is linked to cardiovascular disease. PURPOSE: The purpose of this study was to examine the effect of a 12-week aerobic exercise plus American Heart Association Step-One (AHA-S1) diet intervention on VAT and subcutaneous adipose tissue (SAT) distribution, fasting insulin and lipid profiles, and cardiorespiratory fitness in overweight adults. METHODS: Thirty-six untrained overweight men and women were recruited as study subjects. Study outcome measurements include body mass index (BMI), magnetic resonance imaging (MRI) of VAT, SAT and total abdominal fat (TAF), VO2max, and fasting lipid and insulin (IN) concentration. Following randomized assignment to one of three groups, 1) exercise only (EX, n=12), 2) exercise plus AHA-S1 diet (ED, n=12), or 3) control group (CON, n=12), the ED performed a 45-min leg-cycling exercise at 70% of VO2max, 3 days/wk and consumed the AHA-S1 diet for 12 weeks while the EX performed the identical exercise routine 3 days/wk and consumed a preferred habitual-diet for the same time period. The non-exercise control (CON) group consumed a preferred habitual diet for 12 weeks. SUMMARY OF RESULTS: Results of repeated-measures ANCOVA showed significant reductions in weight (-4.8%), BMI (-4.6%), VAT (-18.5%), SAT (-10.4%), TAF (-12%) and fasting IN (-36.9%), and significant increase in high-density lipoprotein cholesterol (HDL-C)(6.4%) and VO2max (11%) (all p<0.05) in the ED group. These changes were not observed in the CON and EX. CONCLUSIONS: We conclude that the combination of a 12-week aerobic exercise and AHA-S1 diet is effective for reduction of VAT, SAT, body weight, and improvement of fasting insulin concentration, HDL-C and VO2max in untrained overweight adults.