Effects of different levels of compression during sub-maximal and high-intensity exercise on erythrocyte deformability

The aim of the study was to test the hypothesis whether different levels of sock compression (0, 10, 20, and 40 mmHg) affect erythrocyte deformability and metabolic parameters during sub-maximal and maximal running. Nine well-trained, male endurance athletes (age 22.2 ± 1.3 years, peak oxygen uptake 57.7 ± 4.5 mL min(-1) kg(-1)) carried out four periods of sub-maximal running at 70% of peak oxygen uptake for 30 min followed by a ramp test until exhaustion with and without compression socks that applied different levels of pressure. Erythrocyte deformability, blood lactate, heart rate and arterial partial pressure of oxygen (pO(2)) were monitored before and during all of these tests. Erythrocyte deformability, heart rate, pO(2) and lactate concentration were unaffected by compression, whereas exercise itself significantly increased erythrocyte deformability. However, the increasing effects of exercise were attenuated when high compression was applied. This first evaluation of the potential effects of increasing levels of compression on erythrocyte deformability and metabolic parameters during (sub-) maximal exercise, revealed no effects whatsoever.     

Thoracoscopic sympathetic surgery for hyperhidrosis

Resectional surgery of sympathetic nerves has been known to be the most effective treatment for essential hyperhidrosis and the application of thoracoscopic electrocauterization has provided a minimally-invasive procedure with the least morbidity and a resultant higher satisfaction rate. This paper describes our experience on the 1,167 cases of thoracoscopic sympathetic surgery for the treatment of essential hyperhidrosis. A total of 1,167 patients (674 males (58%) and 493 females (42%), mean age of 26.4 years with palmar (930), craniofacial (190) or axillary (47) hyperhidrosis underwent thoracoscopic sympathetic surgery from July 1992 to March 1999. Since the T2-4 sympathectomy, first performed in July 1992 for a patient of palmar hyperhidrosis, the operative methods have been altered to achieve a higher satisfaction level with the least complication by adopting less invasive procedures. Our current standard procedures being performed are T3 and T2 clipping for palmar and craniofacial hyperhidrosis and T3,4 sympathicotomy for axillary hyperhidrosis, all using a 2 mm needle thoracoscope. As the surgical procedures have been transited to a less invasive method with limited resection using the newest endoscopic devices, the average operation time and complications such as Horner's syndrome and compensatory hyperhidrosis have gradually decreased and thus the long-term satisfaction rate has been raised up to 98% for palmar hyperhidrosis, 92% for craniofacial hyperhidrosis and 89% for axillary hyperhidrosis. The recurrent cases (14/1167) were treated successfully with reoperations of thoracoscopic sympathetic surgery. The optimal goal of therapy could be achieved by complete elimination of the hyperhidrotic symptom, by decreasing the incidence and degree of compensatory hyperhidrosis through a selective and limited resection, and by adopting the least invasive procedures. Sympathicotomy has provided the advantages of a limited extent of denervation and the resultant decrease of compensatory hyperhidrosis compared to sympathectomy. The reversible method of clipping may be an effective, provisionary means for cases of severe, intractable compensatory sweating. For craniofacial hyperhidrosis, T2 sympathicotomy or clipping has been proven to be superior to the T1 sympathectomy due to the decreased occurrence of Horner's syndrome and T3,4 sympathicotomy providing a satisfactory outcome with less compensatory hyperhidrosis for axillary hyperhidrosis.     

Objective evaluation of plantar hyperhidrosis after sympathectomy

OBJECTIVE:

The aim of the present study was to prospectively, randomly, blindly, and objectively investigate how surgery affects plantar sudoresis in patients with palmar and plantar hyperhidrosis over a one-year period using a sudorometer (VapoMeter).

METHODS:

From February 2007 to May 2009, 40 consecutive patients with combined palmar hyperhidrosis and plantar hyperhidrosis underwent video-assisted thoracic sympathectomy at the T3 or T4 ganglion level (15 women and 25 men, with a mean age of 25 years).

RESULTS:

Immediately after the operation and during the one-year follow-up, all of the patients were free from palmar hyperhidrosis episodes. Compensatory hyperhidrosis of varying degrees was observed in 35 (87.5%) patients after one year. Only two (2.5%) patients suffered from severe compensatory hyperhidrosis. There was a large initial improvement in plantar hyperhidrosis in 46.25% of the cases, followed by a progressive regression of that improvement, such that only 30% continued to show this improvement after one year. The proportion of patients whose condition worsened increased progressively (from 21.25% to 47.50%), and the proportion of stable patients decreased (32.5% to 22.50%). This was not related to resection level; however, a lower intensity of plantar hyperhidrosis prior to sympathectomy correlated with worse evolution.

CONCLUSION:

Patients with palmar hyperhidrosis and plantar hyperhidrosis who underwent video-assisted thoracic sympathectomy to treat their palmar hyperhidrosis exhibited good initial improvement in plantar hyperhidrosis, which then decreased to lesser degrees of improvement over a one-year period following the surgery. For this reason, video-assisted thoracic sympathectomy should not be performed when only plantar hyperhidrosis is present.     

Coronary circulation in acute hypoxia

Healthy young men were subjected to different degrees of hypoxia at rest and during increased levels of cardiac work induced by atrial pacing and physical exercise at submaximal and maximal loads. Coronary sinus (cs) blood flow was measured by thermodilution and a-cs differences of O2 and lactate were obtained. At low cardiac power output (rest, pacing) the reduction in arterial oxygen content was compensated for mainly by a more complete myocardial oxygen extraction producing lowered cs O2 saturation and tension, while at higher cardiac power (exercise) the compensatory mechanism was entirely an increased coronary blood flow. It was possible to compensate fully for a reduction in arterial O2 saturation of 9% even during maximal physical exercise. With a reduction in arterial oxygen content of more than 20-25% the flow increase was sufficient to supply the heart with enough O2 during submaximal (heart rate 157 beats min-1) but not maximal exercise, in which case anaerobic glycolysis contributed significantly to the myocardial energy metabolism. It is concluded that the normal heart has a 'coronary flow reserve' of about 33% above the flow prevailing during maximal physical exercise under air breathing.     

Time course of O2-pulse during various tests of aerobic power

Summary The purpose of this study was to test the hypothesis that oxygen pulse typically reaches a maximum before maximal oxygen consumption by observing the time course of oxygen pulse throughout exercise to maximal stress and to discern those physiologic variables which might predispose an individual to reach a peak in oxygen pulse before achieving maximal oxygen consumption. Thirty male volunteers ranging in age from 18–25 (¯X=20.5) years were recruited for this study. Maximal oxygen uptake was assessed on both bicycle ergometer and treadmill. Based upon the results of the exercise tests, subjects were classified into subgroups as a consequence of whether or not a maximal oxygen pulse or a plateau in oxygen pulse was demonstrated during submaximal exercise. The results indicate that submaximal peaking or at least the achieving of plateau values of oxygen pulse does in fact occur in some but not all individuals. It was observed that this phenomenon occurs at a relatively high percentage of maximal heart rate and maximal oxygen consumption. It appeared that individuals who demonstrate low heart rates at low-work intensities, high maximal heart rates, and a disproportionate increase in R for a given ventilation are most likely to reach a submaximal peak in oxygen pulse. Oxygen pulse during submaximal exercise appears to provide a good indication of cardiorespiratory fitness.     

Twenty Months of Evolution Following Sympathectomy on Patients with Palmar Hyperhidrosis: Sympathectomy at the T3 Level is Better than at the T2 Level

OBJECTIVE

To compare two surgical techniques (denervation levels) for sympathectomy using video-assisted thoracoscopy to treat palmar hyperhidrosis in the long-term.

METHODS

From May 2003 to June 2006, 60 patients with palmar hyperhidrosis were prospectively randomized for video-assisted thoracoscopic sympathectomy at the T2 or T3 ganglion level. They were followed for a mean of 20 months and were evaluated regarding their degree of improvement of palmar hyperhidrosis, incidence and severity of compensatory hyperhidrosis and its evolution over time, and quality of life.

RESULTS

Fifty-nine cases presented resolution of the palmar hyperhidrosis. One case of therapeutic failure occurred in the T3 group. Most of the patients presented an improvement in palmar hyperhidrosis, without any difference between the groups. Twenty months later, all patients in both groups presented some degree of compensatory hyperhidrosis but with less severity in the T3 group (p = 0.007). Compensatory hyperhidrosis developed in most patients during the first month after the operation, with incidence and severity that remained stable over time. An improvement in quality of life was seen starting from the first postoperative evaluation but without any difference between the groups. This improvement was maintained until the end of the follow-up.

CONCLUSION

Both techniques were effective for treating palmar hyperhidrosis. The most frequent complication was compensatory hyperhidrosis, which presented stable incidence and severity over the study period. Sympathectomy at the T3 level presented compensatory hyperhidrosis with less severity. Nevertheless, the improvement in quality of life was similar between the groups.     

Left ventricular volumes during exercise in endurance athletes assessed by contrast echocardiography

AIM: The objective was to assess left ventricular (LV) volumes at rest and during upright submaximal exercise in endurance athletes to see whether changes in heart volume could explain the large predicted increase in cardiac output in endurance athletes. METHOD: Contrast echocardiography was used to assess changes in LV volumes during upright bicycle exercise in 24 healthy male endurance athletes. Maximal oxygen uptake and oxygen pulse were measured by using cardiopulmonary exercise testing. RESULTS: From rest to exercise at a heart rate of 160 beats min(-1) end-diastolic volume increased by 18% (P < 0.001) and end-systolic volume decreased by 21% (P = 0.002). Stroke volume showed an almost linear increase during exercise (45% increase, P < 0.001). The increase in end-diastolic volume contributed to 73% of the increase in stroke volume. No significant differences were observed between stroke volume calculated from LV volumes with contrast echocardiography and stroke volume calculated from oxygen pulse at heart rates of 130 and 160 beats min(-1). Using the linear regression equation between oxygen uptake and cardiac output assessed by echocardiography during exercise (r=0.87, P=0.002), cardiac output at maximal exercise was estimated at 33 +/- 3 L min(-1), with an estimated increase in stroke volume by 69% from rest to maximal exercise. CONCLUSION: By using contrast echocardiography, a large increase in stroke volume in endurance athletes could be explained by an almost linear increase in end-diastolic volume and an initial small decrease in end-systolic volume during incremental upright exercise.     

Effect of digoxin on physical performance in healthy man

The effect of digoxin on the maximal oxygen uptake, the heart rate reaction during submaximal and maximal bicycle exercise and the isokinetic skeletal muscle strength in the thigh was investigated in nine well-trained healthy young men. A daily dose of digoxin of 0.50 mg for 2 weeks, giving a steady state serum digoxin concentration of 1.0 +/- 0.2 nmol/l, did not significantly change maximal oxygen uptake or isokinetic muscle strength. However, the heart rate at rest and during exercise, both at submaximal and maximal levels, decreased significantly during digoxin administration.     

Cardiac repolarization properties during standardized exercise test as studied by QT, QT peak and terminated T-wave intervals

Changes in QT, QT peak (QTp) and terminal T-wave, Tp-Te (QT-QTp) were studied in 11 apparently healthy subjects during and after a standardized exercise test. ECG was recorded at scalar lead positions. Averaged complexes were later analysed by computer for the different time intervals. QT and QTp decreased in parallel with increasing heart rate with a ratio QTp/QT of 0.80 +/- 0.02 at rest and 0.74 +/- 0.02 at maximal heart rate around 170. After exercise QT and QTp prolonged disproportionately slower than heart rate, reaching the relation observed during exercise only 9.5 min post exercise. Tp-Te was 75 +/- 10 ms at rest and 65 +/- 8 ms at maximal heart rate. The decrease was significant (P less than 0.001). The main part of the rate-associated shortening of the QT interval occurred in the QTp interval where it was about six to seven times larger than in the Tp-Te interval. In conclusion, QT and QTp decreased similarly with heart rate during exercise. Post exercise there was an initial slower return of these intervals to the resting state than for heart rate. Tp-Te changes were minimal.     

Methodological framework for heart rate variability analysis during exercise: application to running and cycling stress testing

Standard methodologies of heart rate variability analysis and physiological interpretation as a marker of autonomic nervous system condition have been largely published at rest, but not so much during exercise. A methodological framework for heart rate variability (HRV) analysis during exercise is proposed, which deals with the non-stationary nature of HRV during exercise, includes respiratory information, and identifies and corrects spectral components related to cardiolocomotor coupling (CC). This is applied to 23 male subjects who underwent different tests: maximal and submaximal, running and cycling; where the ECG, respiratory frequency and oxygen consumption were simultaneously recorded. High-frequency (HF) power results largely modified from estimations with the standard fixed band to those obtained with the proposed methodology. For medium and high levels of exercise and recovery, HF power results in a 20 to 40% increase. When cycling, HF power increases around 40% with respect to running, while CC power is around 20% stronger in running.     

Environmental tobacco smoke: Association with cardiovascular function at rest and during stress

Chronic exposure to environ mental tobacco smoke (ETS) contributes to cardiovascular disease morbidity and mortality, and ETS alters cardiovascular performance during exercise stress. However, no study has examined whether those with ETS exposure have altered cardiovascular functioning during psychological stress, relative to those with no substantial ETS exposure. Seventy-eight healthy, nonsmoking adult men with either high levels of current ETS exposure at home and work or no current or significant lifetime ETS exposure were tested in a stress reactivity protocol. Blood pressure and heart rate were monitored during rest and during two psychological stressors. Those with high ETS exposure had significantly elevated heart rate and blood pressure at baseline, relative to those with no exposure. The groups did not differ on their cardiovascular stress responses. These data suggest that chronic ETS exposure is associated with altered cardiovascular functioning at rest, but not during stress. Results are discussed with regard to the role of ETS on the development of heart disease among nonsmokers.     

Effect of low-dose endurance training on heart rate variability at rest and during an incremental maximal exercise test

We evaluated the effects of low-dose endurance training on autonomic HR control. We assessed the heart rate variability (HRV) of 11 untrained male subjects (36.8 +/- 7.2 years) at rest and during an incremental maximal aerobic exercise test prior to a 7-week preparatory period and prior to and following a 14-week endurance training period, including a low to high intensity exercise session twice a week. Total (0.04-1.2 Hz), low (0.04-0.15 Hz) and high (0.15-1.2 Hz) frequency power of HRV were computed by short-time Fourier transform. The preparatory period induced no change in aerobic power or HRV. The endurance training period increased peak aerobic power by 12% (P < 0.001), decreased the HR (P < 0.01) and increased all HRV indices (P < 0.05-0.01) at absolute submaximal exercise intensities, but not at rest. In conclusion, low-dose endurance training enhanced vagal control during exercise, but did not alter resting vagal HR control.     

Acute dietary nitrate supplementation improves dry static apnea performance

Acute dietary nitrate (NO??) supplementation has been reported to lower resting blood pressure, reduce the oxygen (O?) cost of sub-maximal exercise, and improve exercise tolerance. Given the proposed effects of NO?? on tissue oxygenation and metabolic rate, it is possible that NO?? supplementation might enhance the duration of resting apnea. If so, this might have important applications both in medicine and sport. We investigated the effects of acute NO?? supplementation on pre-apnea blood pressure, apneic duration, and the heart rate (HR) and arterial O? saturation (SaO?) responses to sub-maximal and maximal apneas in twelve well-trained apnea divers. Subjects were assigned in a randomized, double blind, crossover design to receive 70 ml of beetroot juice (BR; containing ～5.0 mmol of nitrate) and placebo juice (PL; ～0.003 mmol of nitrate) treatments. At 2.5 h post-ingestion, the subjects completed a series of two 2-min (sub-maximal) static apneas separated by 3 min of rest, followed by a maximal effort apnea. Relative to PL, BR reduced resting mean arterial pressure by 2% (PL: 86±7 vs. BR: 84 ± 6 mmHg; P=0.04). The mean nadir for SaO? after the two sub-maximal apneas was 97.2±1.6% in PL and 98.5±0.9% in BR (P=0.03) while the reduction in HR from baseline was not significantly different between PL and BR. Importantly, BR increased maximal apneic duration by 11% (PL: 250 ± 58 vs. BR: 278±64s; P=0.04). In the longer maximal apneas in BR, the magnitude of the reductions in HR and SaO? were greater than in PL (P ≤ 0.05). The results suggest that acute dietary NO?? supplementation may increase apneic duration by reducing metabolic costs.     

Cardiorespiratory and subjective responses to prolonged arm and leg exercise in healthy young and older men

Ten young (aged 23–30 years) and nine older (aged 54–59 years) healthy men with a similar size of limb muscle mass performed arm crank and leg cycle exercise for 30 min at relative exercise intensities of 50% and 75% of maximal oxygen uptake for the corresponding muscle group. In the tests, heart rate, blood pressure, gas exchange variables, rating of perceived exertion and blood lactate concentration were measured. The limb muscle mass was determined by anthropometric measurements. At the 75% target exercise level, four of the older men and two of the young men could not complete the arm-cranking test, and one of the older men and two of the young men could not complete the leg-cycle test. During arm-cranking the absolute exercise intensity was similar for the young and older men because of similar maximal values during arm-cranking. But during leg-cycling the absolute excercise intensity was higher for the young men than for the older men due to the difference in corresponding maximal values. During arm-cranking there were no significant differences in the physiological responses between the age groups except that a higher ventilatory response was noted among the older compared to the young men. During leg-cycling the heart rate values were higher among the young compared to the older men. But, when the heart rate values were expressed as a percentage of maximal heart rate in the corresponding maximal tests, no significant differences between the age groups were found. The results indicated that 30-min of arm or leg exercise at the same relative submaximal excercise intensity produces a similar degree of physiological strain in healthy older compared to young men. During arm-cranking, the young and the older men exercised at the same external intensity, indicating a similar ability to perform prolonged excercise using smaller muscle groups expressed both in absolute and relative terms.     

Characteristics of the carotid baroreflex in man during normal and flow-restricted exercise.

Eight subjects were studied in the supine position at rest, during normal dynamic leg exercise (control exercise) and with blood-flow restriction in the working legs (flow-restricted exercise). Graded muscle blood-flow restriction was accomplished by applying a supra-atmospheric pressure of 50 mmHg to the working legs. During incremental-load exercise, flow restriction reduced exercise performance and peak heart rate by 36% and 13%, respectively. The function of the cardiac branch of the carotid baroreflex was studied over its full operational range, at rest and during constant-load control and flow-restricted exercise, by measuring R-R intervals during application of pulse-synchronous graded pressures (40 to -65 mmHg) in a neck-chamber device. Heart rate and arterial pressure were higher during flow-restricted than control exercise, indicating that the flow restriction activated the muscle chemoreflex. Raising the carotid transmural pressure (systolic arterial pressure minus neck-chamber pressure) was accompanied by increasing R-R intervals in all conditions. The set point (point of baseline carotid transmural pressure and R-R interval) coincided with the midportion of the pressure-response curve at rest and with the threshold point of the curve during exercise. The maximal rate of change in relative R-R intervals and the corresponding carotid transmural pressure range were higher during control exercise than at rest and highest during flow-restricted exercise, indicating that exercise and especially flow-restricted exercise increased carotid baroflex sensitivity, and shifted the carotid baroreflex optimal buffering range to higher pressures. The results suggest that the carotid baroflex attenuates exercise heart rate increases mediated by the muscle chemoreflex and/or by central command.     

The influence of exercise intensity on the power spectrum of heart rate variability

Summary The power spectral analysis of R-R interval variability (RRV) has been estimated by means of an autoregressive method in seven sedentary males at rest, during steady-state cycle exercise at 21 percent maximal oxygen uptake. (% V _{O 2max}), SEM 2%, 49% V_{O 2max}, SEM 2% and 70% V_{O 2max}, SEM 2% and during recovery. The RRV, i.e. the absolute power of the spectrum, decreased 10, 100 and 500 times in the three exercise intensities, returning to resting value during recovery. In the RRV power spectrum three components have been identified: (1) high frequency peak (HF), central frequency about 0.24 Hz at rest and recovery, and 0.28 Hz, SEM 0.02, 0.37 Hz, SEM 0.03 and 0.48 Hz, SEM 0.06 during the three exercise intensities, respectively; (2) low frequency peak (LF), central frequency about 0.1 Hz independent of the metabolic state; (3) very low frequency component (VLF), <0.05 Hz, no peak observed. The HF peak power, as a percentage of the total power (HF%), averaged 16%, SEM 5% at rest and did not change during exercise, whereas during recovery it decreased to 5%–10%. The LF% and VLF% were about 50% and 35% at rest and during low exercise intensity, respectively. At higher intensities, LF% decreased to 16% and VLF% increased to 70%. During recovery a return to resting values occurred. The HF component may reflect the increased respiratory rate and the LF peak changes the resetting of the baroreceptor reflex with exercise. The hypothesis is made that VLF fluctuations in heart rate might be partially mediated by the sympathetic system.     

Myocardial blood flow and lactate metabolism at rest and during exercise with reduced arterial oxygen content

The effect of a reduction in arterial oxygen content, equivalent to acute exposure to an altitude of 2300 metres above sea level, on myocardial blood flow and oxygen and lactate exchange was studied by coronary sinus catheterization in 12 healthy men. Measurements were made at rest, during atrial pacing and during submaximal and maximal exercise both breathing air and breathing 15% oxygen (hypoxia). Coronary sinus blood flow was measured by thermodilution and the possibility of a simultaneous uptake and release of lactate by the heart was calculated using intravenous infusion of 14C lactate. At all levels of cardiac power output myocardial oxygen consumption was the same during hypoxia as during air breathing. At rest this was achieved entirely by a more complete extraction of oxygen from the coronary blood, during maximal exercise entirely by a greater coronary sinus blood flow, while at intermediate levels of cardiac power output a combination of these mechanisms prevailed. At rest and during submaximal work myocardial lactate extraction was lower with hypoxia than air breathing suggesting a change in myocardial redox state, while the 14C lactate data suggested no significant lactate release or possibly limited areas with some lactate production. During maximal exercise, however, there was no difference in myocardial lactate net extraction between hypoxia and air breathing, which together with the greater blood flow suggests that the heart has a 'coronary flow reserve' permitting maximal exercise at moderate altitude without anaerobic myocardial metabolism.     

Effects of pre-cooling procedures on intermittent-sprint exercise performance in warm conditions

The aim of this study was to determine whether pre-cooling procedures improve both maximal sprint and sub-maximal work during intermittent-sprint exercise. Nine male rugby players performed a familiarisation session and three testing sessions of a 2 × 30-min intermittent sprint protocol, which consisted of a 15-m sprint every min separated by free-paced hard-running, jogging and walking in 32°C and 30% humidity. The three sessions included a control condition, Ice-vest condition and Ice-bath/Ice-vest condition, with respective cooling interventions imposed for 15-min pre-exercise and 10-min at half-time. Performance measures of sprint time and % decline and distance covered during sub-maximal exercise were recorded, while physiological measures of core temperature (T _core), mean skin temperature (T _skin), heart rate, heat storage, nude mass, rate of perceived exertion, rate of thermal comfort and capillary blood measures of lactate [La⁻], pH, Sodium (Na⁺) and Potassium (K⁺) were recorded. Results for exercise performance indicated no significant differences between conditions for the time or % decline in 15-m sprint efforts or the distance covered during sub-maximal work bouts; however, large effect size data indicated a greater distance covered during hard running following Ice-bath cooling. Further, lowered T _core, T _skin, heart rate, sweat loss and thermal comfort following Ice-bath cooling than Ice-vest or Control conditions were present, with no differences present in capillary blood measures of [La⁻], pH, K⁺ or Na⁺. As such, the ergogenic benefits of effective pre-cooling procedures in warm conditions for team-sports may be predominantly evident during sub-maximal bouts of exercise.     

Effect of chemical sympathectomy on coronary flow and cardiovascular adjustment to exercise in dogs

Summary The exercise capacity and the increase of coronary and systemic hemodynamics under treadmill exercise were studied in 5 dogs, chemically sympathectomized with 6-hydroxy-dopamine.Completeness of adrenergic denervation was verified by stimulation of the right stellate ganglion, by intravenous administration of tyramine, and by demonstration of supersensitivity to exogenous norepinephrine.These dogs demonstrated a retarded adaptation of hemodynamics to a sudden start of exercise. A fall in mean arterial pressure below 45 mmHg within 10 to 15 sec lead to collapse. After a recovery period of 60–90 sec, moderate treadmill exercise could be continued; steady state attainment of hemodynamic parameters was considerably delayed.A steady state of exercise with an O₂-consumption (vO₂) of 29.6±2.6 ml/min · kg and a cardiac outupt (CO) of 307±16 ml/min · kg was tolerated for at least 20 min.An increase of vO₂ up to 42.0±1.7 ml/min · kg and of CO up to 357±13 ml/min · kg under exercise was tolerated for 5 min with steady state, maximal heart rate being 160±4 min^–1 at this level of exercise.Mean arterial pressure and total peripheral resistance were significantly reduced at rest and during steady state of exercise as compared to controls prior to sympathectomy identical vO₂, whereas CO remained unchanged.The significant fall in left circumflex coronary flow was proportional to the decline in external heart work due to sympathectomy both at rest and under exercise.Supported by Deutsche Forschungsgemeinschaft.