Search PubMed⌕ Search

Biomedical subjects

N H Secher

Publications and source records attributed to N H Secher.

At least 91 records · Page 5Linked to original sources
PubMed1997

Middle cerebral artery blood velocity during rowing.

Dynamic exercise increases the transcranial Doppler determined mean blood velocity in basal cerebral arteries corresponding to the cortical representation of the active limb(s) and independent of the concomitant rise in the mean arterial pressure. In 12 rowers we evaluated the middle cerebral artery blood velocity response to ergometer rowing when regulation of the cerebral perfusion is challenged by stroke synchronous fluctuation in arterial pressure. Rowing increased mean cerebral blood velocity (57 +/- 3 to 67 +/- 5 cm s-1; mean +/- SE) and mean arterial (86 +/- 6 to 97 +/- 6 mmHg) and central venous pressures (0 +/- 2 to 8 +/- 2 mmHg; P < 0.05). The force on the oar triggered an averaging procedure that demonstrated stroke synchronous sinusoidal oscillations in the cerebral velocity with a 12 +/- 2% amplitude upon the average exercise value. During the catch phase of the stroke, the mean velocity increased to a peak of 88 +/- 7 cm s-1 and it was in phase with the highest mean arterial pressure (125 +/- 14 mmHg), while the central venous pressure was highest after the stroke (20 +/- 3 mmHg). The results suggest that during rowing cerebral perfusion is influenced significantly by the rapid fluctuations in the perfusion pressure.

Adult↗
PubMed1997

Mechanisms of cutaneous vasoconstriction during upright posture.

The cutaneous circulation is thought to participate in the neurocirculatory adjustments during orthostatic stress, but the underlying mechanisms mediating such reflex cutaneous vasoconstriction are poorly understood. The aim of this study was to assess the relative importance of baroreceptor (cardiopulmonary and arterial) and positional (vestibular, exercise, veno-arteriolar and myogenic) reflexes in triggering cutaneous vasoconstriction during upright posture. First, hypotensive lower body negative pressure (LBNP) was compared with actual postural changes to assess the relative contributions of baroreceptor reflexes and positional reflexes. Then changes in body position were compared with changes in limb position in the absence or presence of proximal (axillary) or distal (local cutaneous) nerve blocks, to assess the relative contributions of vestibular, exercise, veno-arteriolar and myogenic reflexes. Skin sympathetic nerve activity was determined by microneurography, and skin blood flow was determined by laser Doppler velocimetry. LBNP of -50 mm Hg cardiopulmonary + arterial baroreceptors) had no effect on skin sympathetic nerve activity or skin vascular resistance. In contrast, an upright posture with the arms dependent (baroreceptor + vestibular + exercise + veno-arteriolar reflexes) caused a two- to threefold increase in skin vascular resistance. In the supine position passive movement of the arm into a dependent position to activate veno-arteriolar reflexes alone evoked an increase in skin vascular resistance which approximated the response to normal upright posture. Blocking central sympathetic nerve impulses by application of an axillary blockade did not influence the cutaneous vasoconstrictor response to an upright posture or changes in limb position. In contrast, application of a distal nerve block by local cutaneous surface anaesthesia completely blocked vasoconstrictor responses evoked by these manoeuvres. In conclusion, these experiments in human subjects identify a primary role for veno-arteriolar reflexes in triggering vasoconstriction in the cutaneous circulation during upright posture.

Adult↗
PubMed1997

Muscle oxygen saturation during surgery in the lithotomy position.

Surgery in the lithotomy position can provoke ischaemic lesions in the lower leg. We assessed lower leg oxygen saturation using near-infrared spectroscopy (NIRS) in 42 patients undergoing urinary tract surgery. Lower leg perfusion pressure was calculated as the difference of mean arterial pressure to pressure in an air bag supporting the lower leg and the hydrostatic pressure difference from the level of the lower leg to the heart. During elevation of the lower leg for 25 (3-65) min (median and range), mean arterial pressure decreased from 100 (73-125) to 77 (53-112) mmHg and the lower leg perfusion pressure dropped from 103 (80-122) to 21 (-6-65) mmHg, corresponding to a reduction in oxygen saturation of the medial gastrocnemius muscle from 68% (40-100%) to 58% (20-96%) (P < 0.01). The results demonstrate significant desaturation of the calf muscles during surgery in the lithomy position.

Adult↗
PubMed1997

Mesenteric artery response to head-up tilt-induced central hypovolaemia and hypotension.

Superior mesenteric artery (SMA) blood flow and impedance were evaluated by duplex ultrasound during head-up tilt (HUT)-induced central hypovolaemia and hypotension in eight healthy volunteers. HUT induced a reduction in cardiac stroke volume from 88.8 +/- 6.3 to 64.7 +/- 6.3 ml (mean +/- SEM; P < 0.01) and an increase in thoracic electric impedance from 38.6 +/- 2.1 to 42.6 +/- 2.1 omega (P < 0.01) reflecting a reduced central blood volume. Maintained tilt provoked a 30% reduction in mean arterial pressure (from 87.1 +/- 3.3 to 63.4 +/- 3.6 mmHg: P < 0.01) and the appearance of presyncopal symptoms. During both the normotensive and the hypotensive phase of HUT, the SMA diameter (5.7 +/- 0.03 mm) and blood flow (514 +/- 75 ml min-1) did not change significantly, although the end-diastolic velocity increased from 9.7 +/- 4.8 to 39.7 +/- 4.0 cm s-1 (P < 0.01). The increase in diastolic velocity, despite a maintained or reduced arterial pressure, supports a reduction in the SMA impedance as it was reproduced during a meal test when a moderate reduction in mean arterial pressure (87 +/- 4 to 80 +/- 4 mm Hg; P = 0.04) was accompanied by a ninefold increase in the end-diastolic velocity (P < 0.01). The results indicate a reduction in the mesenteric vascular impedance to the extent that superior mesenteric artery blood flow is maintained during HUT-induced central hypovolaemia and hypotension.

Adult↗
PubMed1997

Cerebral oxygen saturation and blood flow during liver transplantation.

After reperfusion of a liver graft, transcranial Doppler determined middle cerebral artery flow velocity, increases more than expected from the arterial carbon dioxide tension (PaCO2). We evaluated if this indication of cerebral hyperperfusion is reflected in the jugular oxygen saturation (SjO2) (n = 31) and oxygen saturation (ScO2) (near-infrared spectrophotometry, n = 22). From the dissection phase to the anhepatic phase SjO2 71.0% (range 62.3%-78.5%), ScO2 70% (range 65%-77%), and PaCO2 34.9 mm Hg (range 30.8-38.3) remained statistically unchanged. In contrast, during the early reperfusion phase, SjO2 increased to 77.0% (71.4%-83.0%) (P < 0.01) and the ScO2 to 75% (68%-80%) (P < 0.05) as PaCO2 increased to 37.5 mm Hg (34.8-41.9) (P < 0.001). Notably, SjO2 also increased at reperfusion from 71.6% (66.5%-78.0% mm Hg) to 80.0% (76.8%-84.8%) in the four patients in whom PaCO2 decreased at reperfusion from 37.6 mm Hg (36.8-39.5) to 34.0 mm Hg (32.3-36.8). If the changes in SjO2 after reperfusion of the grafted liver should be explained as a reflection of changes in cerebral blood flow, in response to PaCO2, it would indicate a highly accentuated CO2 reactivity of 13%/mm Hg. The results support that cerebral blood flow and, in turn, oxygenation increase after reperfusion because the grafted liver liberates a vasodilating substance(s).

Adolescent↗
PubMed1997

Central cardiovascular and oxygen variables during haemorrhage in the pig.

BACKGROUND: We evaluated the ability of the standards issued by the Danish Society of Anaesthesiologists to reflect a blood loss. METHODS: In 9 pigs bled (0-24 ml kg-1 and retransfused (to 28 ml kg-1) during halothane anaesthesia central cardiovascular, thoracic electrical impedance (TI), oxygen, acid-base and temperature variables were recorded. RESULTS: With the recommendation for minor surgery (mean arterial pressure (MAP) and heart rate (HR)), the correlation to the blood loss was 0.74 (P < 0.001) and with that for major surgery (MAP, HR, central venous pressure (CVP) and rectal temperature (Tempr)) it was 0.79 (P < 0.001). With the recommendation for extensive surgery (MAP, HR, CVP, pulmonary artery catheter variables and the central-peripheral temperature difference (delta Tempr-t)), the correlation was 0.84 (P < 0.001). Non-invasive monitoring (MAP, HR, delta Tempr-t, TI and near-infrared spectroscopy of the brain (SinvosO2)) was only slightly better than basal monitoring (r = 0.76, P < 0.001). However, adding arterial base excess (BE), TI, and peripheral temperature (Tempt) to the recommendation for major surgery resulted in a correlation of 0.87 (P < 0.001), while adding BE and TI to the recommendation for extensive surgery raised correlation to only 0.88 (P < 0.001). CONCLUSION: When the recommendations were followed the correlation to the blood loss ranged from 0.74-0.84. However, with the recording of MAP, HR, CVP, delta Tempr-t, BE and TI a correlation of 0.87 was achieved, indicating that a pulmonary artery catheter may not be in need for patients undergoing surgical procedures with expected haemorrhage.

Animals↗
PubMed1997

Splenectomy impairs lymphocytosis during maximal exercise.

To evaluate the role of the spleen for the exercise-induced lymphocytosis, six splenectomized subjects and six matched control subjects cycled for 12 min at two submaximal work rates corresponding to 50 and 75% of their maximal work capacity, followed by a supramaximal intensity maintained until exhaustion (16 +/- 1 min; mean +/- SE). Venous blood samples were taken before, during, and 2 h after the maximal load. In both groups, the concentration of lymphocytes became elevated during exercise, but the increase from the level at rest was impaired in the splenectomized subjects compared with that of the controls (118 +/- 34 vs. 238 +/- 38%; P < 0.05). This was reflected in several lymphocyte subsets: cluster designation (CD) 3+ cells (pan T lymphocytes), 69 +/- 19 vs. 204 +/- 37%; CD8+ cells (T lymphocyte subset), 164 +/- 41 vs. 467 +/- 68%; CD16+ cells [natural killer (NK) cells], 291 +/- 88 vs. 870 +/- 177%; CD56+ cells (NK cells), 301 +/- 108 vs. 753 +/- 187%. Also, the specific NK cell lysis of target cells (NK cell activity) during exercise was lower for the splenectomized subjects (30 +/- 7%) than that of the control subjects (52 +/- 10%), but evaluation of lytic units indicates that this was due to a reduced number of NK cells in the assay rather than insufficient cell lysis. Plasma catecholamines reached the same level in the splenectomized subjects and control subjects, which was taken to reflect that the activity of the sympathetic nervous system was similar in the two groups of subjects. Thus the major finding of this study is that the spleen is important for lymphocytosis during exercise, accounting for two-thirds of the increase in T lymphocytes and NK cells.

Adult↗
PubMed1997

Restricted postexercise pulmonary diffusion capacity and central blood volume depletion.

Pulmonary diffusion capacity for carbon monoxide (DLCO), regional electrical impedance (Z0), and the distribution of technetium-99m-labeled erythrocytes together with concentration of plasma atrial natriuretic peptide (ANP) were determined before and after a 6-min "all-out" row in nine oarsmen and in six control subjects. Two and one-half hours after exercise in the upright seated position, DLCO was reduced by 6 (-2 to 21; median and range) %, the thoracic-to-thigh electrical impedance ratio (Z0 thorax/Z0 thigh) rose by 14 (-1 to 29) %, paralleled by a 7 (-3 to 11) % decrease and a 3 (-5 to 12) % increase in the thoracic and thigh blood volume, respectively. These responses were associated with a decrease in the plasma ANP concentration from 15 (13-31) to 12 (9-27) pmol/l (P < 0.05). Similarly, in the supine position, Z0 thorax/Z0 thigh increased by 10 (-5 to 28) % when DLCO was reduced 12 (6-26) % (P < 0.05), whereas DLCO remained stable in the control group. The increase in Z0 thorax/Z0 thigh and the corresponding redistribution of the blood volume in both body positions show that approximately one-half of the postexercise reduction of DLCO is explained by a decrease in the pulmonary blood volume. The role of a reduced postexercise central blood volume is underscored by the lower plasma ANP, which aids in upregulating the blood volume after exercise in athletes.

Adult↗
PubMed1997

Adrenergic beta 1- and beta 1 + 2-receptor blockade suppress the natural killer cell response to head-up tilt in humans.

To evaluate stress-induced changes in blood leukocytes with emphasis on the natural killer (NK) cells, eight male volunteers were followed during three trials of head-up tilt with adrenergic beta 1- (metoprolol) and beta 1 + 2- (propranolol) blockade and with saline (control) infusions. The beta 1- and beta 1 + 2-receptor blockade did not affect the appearance of presyncopal symptoms, but the head-up tilt induced a transient lymphocytosis that was abolished by beta 1 + 2-receptor blockade but not by beta 1-receptor blockade. Head-up tilt also resulted in delayed neutrophilia, which was insensitive to beta-receptor blockade. Lymphocyte subset analysis revealed that the head-up tilt resulted in a twofold increase in the percentage and absolute number of CD3-/CD16+ and CD3-/CD56+ NK cells in peripheral blood and that this increase was partially blocked by metoprolol and abolished by propranolol. The NK cell activity on a per NK cell basis did not change during head-up tilt, indicating that the cytotoxic capability of NK cells recruited to circulation is unchanged. The data suggest that the head-up tilt-induced lymphocytosis was due mainly to CD16+ and CD56+ NK cells and that their recruitment to the blood was inhibited by beta 1- and especially beta 1 + 2-receptor blockade. Thus stress-induced recruitment of lymphocytes, and of NK cells in particular, is mediated by epinephrine through activation of beta-receptors on the lymphocytes.

Adrenergic beta-1 Receptor Antagonists↗
PubMed1996

[Thoracic electric impedance and fluid balance during aortic surgery].

Indices of fluid balance were evaluated during and after aortic surgery in 16 consecutive patients. Thoracic electrical impedance (TI), heart rate (HR), central venous (CVP), pulmonary artery mean (PAMP), pulmonary wedge (PWP) and mean arterial (MAP) pressures as well as fourteen arterial and venous blood gas variables were followed. Consistent with a reduction of TI during the operation, fluid balance was in excess, and it remained elevated on the first postoperative morning. The HR, MAP and PWP remained stable, while CVP and PAMP decreased. Of the determined variables only TI revealed a meaningful correlation to fluid balance (rho = -0.41; p < 0.01). The results indicate that while central venous and pulmonary artery mean pressures gave the impression of a volume deficit, the positive fluid balance was mirrored by thoracic electrical impedance.

Aged↗
PubMed1996

Pharmacological manipulation of cardiovascular responses to lower body negative pressure.

To evaluate influences on blood volume distribution, atrial natriuretic peptide concentrations (ANP) and thoracic and leg electrical impedance at 2.5 (TI2.5 and LI2.5, respectively) and 100 kHz (TI100 and LI100, respectively) were monitored during administration of ketanserin, noradrenaline and trimetaphan combined with lower body negative pressure (LBNP) in 12 subjects. Administration of clinically relevant doses of ketanserin alone did not induce changes in mean arterial pressure (MAP) or in the central blood volume, as electrical impedance and ANP concentrations did not change. During continued infusion of ketanserin an increase in MAP from a mean of 90 (range 83-108) to 113 (range 98-138) mmHg was induced by noradrenaline, but TI2.5 [mean 45.6 (range 39.3-54.2)] and TI100 [mean 33.8 (range 27.5-38.5) omega] remainded stable until ganglionic blockade and LBNP were applied, when they increased by a mean of 3.1 (range 2.0-6.1) and 2.7 (range 1.1-4.2) omega, respectively (P < 0.05). Conversely, LI2.5 [mean 79.6 (range 74.1-89.4)] and LI100 [mean 56.7 (range 52.4-63.3) omega] decreased by a mean of 3.2 (range 1.2-8.0) and 2.3 (range 0.9-3.9) omega, ANP from a mean of 27.7 (range 10.2-62.7) to 12.7 (range 7.1-27.5) pmol.l-1 and MAP fell to a mean of 62 (range 42-70) mmHg (P < 0.05). The heart rate was a mean of 75 (range 69-77) beats.min-1 and did not change until LBNP, when it increased to a mean of 102 (range 78-104) beats.min-1, as presyncopal symptoms appeared. The data indicated that serotonergic blockade by ketanserin and alpha-sympathetic stimulation by noradrenaline did not affect blood volume distribution in normal humans, but that ganglionic blockade combined with LBNP reduced the central blood volume as leg volume increased; during central hypovolaemia tachycardia induced by ganglionic blockade did not prevent the fall in MAP, and thereby the appearance of presyncopal symptoms.

Adrenergic alpha-Agonists↗
PubMed1996

Changes in superior mesenteric artery Doppler waveform during reduction of cardiac stroke volume and hypotension.

Influence of stroke volume reduction and hypotension on the superior mesenteric artery (SMA) Doppler waveform was evaluated during head-up tilt-induced central hypovolemia in 11 healthy volunteers. During normotensive reduction in stroke volume, peak systolic velocity (pV), mean velocity, pulsatility and resistivity indices decreased, while diastolic velocities increased. During hypotension, a further decrease in pV was accompanied by maintained elevation of diastolic velocities and reduction in pulsatility and resistivity indices. Power of backscattered Doppler wave was elevated throughout the hypovolemia. Alterations in pV and pulsatility indices were closely related to changes in stroke volume, and a negative correlation was found between diastolic velocities and stroke volume. regression analysis showed no significant relation between variations in velocity parameters and blood pressure. Results of the study indicate that alterations in stroke volume induce consequential changes in the SMA Doppler waveform. These changes originate from both direct influence of stroke volume and/or pressure on blood flow velocity, and alterations in SMA peripheral resistance that follow variations in stroke volume. Presented interdependencies should be taken into consideration while studying mesenteric physiology with the use of Doppler technique and while interpreting the duplex results in patients suffering from diseases that may influence flow velocity and mimic or obscure Doppler effects of the SMA stenosis.

Adult↗
PubMed1996

Dissociated cerebral vasoparalysis in acute liver failure. A hypothesis of gradual cerebral hyperaemia.

BACKGROUND/AIMS: Normally, cerebral blood flow responds to changes in the arterial carbon dioxide tension (PaCO2) but not to changes in mean arterial pressure, commonly referred to as the cerebral CO2-reactivity and autoregulation. In patients with fulminant hepatic failure and in the rat with thioacetamide-induced liver failure, autoregulation is absent, presumably due to cerebral vasoparalysis. Since also CO2-reactivity may then be compromised, it was studied in patients with fulminant hepatic failure and rats with thioacetamide-induced liver failure. METHODS: In ten patients (median age 32 (range 20-48) years)) and in ten age-matched volunteers, cerebral perfusion was elevated by transcranial Doppler assessed mean flow velocity (V(mean)) in the middle cerebral artery during hypo- and hyper-capnia. In six rats with liver failure and in six control rats, cerebral blood flow was measured repeatedly by the intracarotid 133 Xenon injection technique. RESULTS: In the patients and volunteers, PaCO2 was lowered from 33 (23-44) to 28 (23-39) mmHg by hypocapnia and raised to 40 (34-48) mmHg by hypercapnia or 5% CO2 inhalation. During hypocapnia, the CO2-reactivity did not differ significantly between patients and volunteers, 4.0 (1.1-7.4) vs. 3.0 (1.7-5.0)% mmHg(-1), while it was reduced during hypercapnia in the patients, 2.2 (1.8-5.2) vs. 4.6 (3.0-8.0)% mmHg(-1) (p < 0.05). In the rats, PaCO2 was reduced from 39 (37-40) to 30 (29-31) mmHg and then raised to 51 (41-55) mmHg. During hypocapnia, CO2-reactivity was similar in rats with liver failure and in control rats, 2.3 vs 2.7% mmhg(21), respectively. In all rats with liver failure CO2-reactivity was abolished during hypercapnia, while it was 1.5% mmHg(-1) in the control rats (p < 0.01). CONCLUSIONS: The finding that cerebral CO2 reactivity is reduced in hypercapnia, while it is preserved in hypocapnia, suggests that gradual dilation of the cerebral resistance vessels develops in fulminant hepatic failure and connects previous morphological studies with changes in the regulation of cerebral blood flow, i.e. impaired cerebral autoregulation and blunted CO2-reactivity.

Acute Disease↗
PubMed1996

Central command increases cardiac output during static exercise in humans.

Neural control of the circulation during static two-leg exercise was evaluated in 10 subjects. External compression of the legs was employed to assess muscle mechano-receptor influence by achieving the same intramuscular pressure (80 mmHg) as developed during exercise. The muscle metabo-reflex contribution was assessed by post-exercise muscle ischaemia, and the influence from higher centres in the central nervous system ('central command') was taken as the part of the response that could not be accounted for by the two reflex contributions. During static exercise, mean arterial pressure was higher (26 +/- 3 mmHg; P < 0.01) as compared with leg compression (10 +/- 2 mmHg) and with post-exercise muscle ischaemia (11 +/- 2 mmHg). Heart rate (25 +/- 4 b.p.m.) and cardiac output (0.8 +/- 0.3 L min-1) were increased only during static exercise (P < 0.05). Increase in total peripheral resistance were similar during static exercise, post-exercise muscle ischaemia and leg compression. The pressor response to static exercise with a large muscle group was equally attributable to mechanical and metabolic stimulation of afferent nerves; and the two influences were redundant in their effect on total peripheral resistance. In contrast, the influence from central command was directed to the heart with elevation of its rate and minute volume.

Adult↗
PubMed1996

Middle cerebral artery blood velocity and plasma catecholamines during exercise.

During dynamic exercise, mean blood velocity (Vmean) in the middle cerebral artery (MCA) demonstrates a graded increase to work rate and reflects regional cerebral blood flow. At a high work rate, however, vasoactive levels of plasma catecholamines could mediate vasoconstriction of the MCA and thereby elevate Vmean at a given volume flow. To evaluate transcranial Doppler-determined Vmean at high plasma catecholamine levels, seven elite cyclists performed a maximal performance test on a bicycle ergometer. Results were compared with those elicited during five incremental exercise bouts and during rhythmic handgrip when plasma catecholamines are low. During rhythmic handgrip the Vmean was elevated by 21 +/- 3% (mean +/- SE), which was not statistically different from that established during moderate cycling. However, at the highest submaximal and maximal work intensities on the bicycle ergometer. Vmean increased by 31 +/- 3% and 48 +/- 4%, respectively, and this was significantly higher compared to handgrip (P < 0.05). During maximal cycling, plasma adrenaline increased from 0.21 +/- 0.04 nmol L-1 at rest to 4.18 +/- 1.46 nmol L-1, and noradrenaline increased from 0.79 +/- 0.08 to 12.70 +/- 1.79 nmol L-1. These levels were 12- to 16-fold higher than those during rhythmic handgrip (adrenaline: 0.34 +/- 0.03 nmol L-1; noradrenaline: 0.78 +/- 0.05 nmol L-1). The increase in Vmean during intense ergometer cycling conforms to some middle cerebral artery constriction elicited by plasma catecholamines. Such an influence is unlikely during rhythmic handgrip compared with low intensity cycling.

Adult↗
PubMed1996

Lymphocyte, NK and LAK cell responses to maximal exercise.

To evaluate if exhaustion after maximal exercise suppresses the immune system; ten healthy male oarsmen (maximal oxygen uptake, 5.7 +/- 0.2 l.min-1; mean and SE) performed a six minute "all-out" bout on a rowing ergometer (394 +/- 12 watt). Rowing increased the blood leucocyte count as reflected in the concentrations of lymphocytes, monocytes, and neutrophils. Two hours after rowing the leucocyte and neutrophil numbers remained elevated, while the lymphocyte count decreased below the prevalue. The concentrations of cluster designation CD3+ (pan T), CD4+ (T subset), CD8+ (T subset), CD19+ (B cells), and CD16+ natural killer (NK) cells increased during rowing with the elevation in CD16+ cells being sevenfold. Only the concentration of CD3+ and CD8+ cells decreased below prevalues two hours after exercise. The lymphokine activated killer (LAK) cell activity of blood mononuclear cells (BMNC), and the NK cell activity of BMNC (%lysis per fixed number of BMNC), either unstimulated or stimulated with interleukin-2, interferon-alfa or indomethacin, also increased in response to rowing, and returned to the prevalues after two hours. In contrast, the BMNC proliferative responses did not change significantly. The evaluation of NK and LAK cell activities, and the proliferative responses of BMNC suggest that six minute maximal exercise does not suppress the immune response during recovery, even when a large muscle mass is involved.

Adult↗
PubMed1996

The heart of the senior oarsman: an echocardiographic evaluation.

We evaluated left ventricular mass and function in 15 oarsmen aged 78 (65-82) yr (median and range) and in 15 sedentary males aged 72 (65-81) yr by 2-D and M-mode echocardiography and cycle ergometry. The weekly time spent exercising among the oarsmen was 6 (2-18) h and two of the oarsmen were former national and international champions. The two groups of subjects had similar weight, height, and resting blood pressure. The oarsmen reached a maximal work rate of 142 (117-174) vs 113 (75-150) W for the sedentary group (P < 0.01). The internal diameters of the left ventricle were not significantly different, but the septum and posterior wall thicknesses were larger in the oarsmen (11 (8-20) vs 9 (7-11) mm, and 9 (8-13) vs 8 (7-19) mm, respectively, P < 0.023). Thus, the left ventricular mass index of the oarsmen was 19% larger (127 (101-284) vs 103 (74-134) g.m-2, P < 0.01). Also, the systolic function appeared to be superior in the oarsmen as the fractional shortening was 0.45 (0.28-0.55) vs 0.36 (0.18-0.49) in the controls (P < 0.05). In conclusion, we found that long-term rowing in the senior oarsman is associated with enlarged myocardial wall thickness, a normal systolic function, and a high work capacity.

Aged↗