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At least 1,711 records · Page 95Linked to original sources
PubMed2003

Augmented leg vasoconstriction in dynamically exercising older men during acute sympathetic stimulation.

Vasoconstrictor responsiveness to acute sympathetic stimulation declines with advancing age in resting skeletal muscle. The purpose of the present study was to determine if age-related reductions in sympathetic vasoconstrictor responsiveness also occur in exercising skeletal muscle. Thirteen younger (20-30 years) and seven older (62-74 years) healthy non-endurance-trained men performed cycle ergometer exercise at ~60 % of peak oxygen uptake while leg blood flow (femoral vein thermodilution), mean arterial blood pressure (radial artery catheter), and plasma adrenaline and noradrenaline concentrations were measured. After steady state was reached (i.e. ~4 min), acute sympathetic stimulation was achieved by immersing a hand in ice water for 2-4 min (cold pressor test, CPT). CPT tended to cause a larger increase in mean arterial blood pressure in older men (older (O): 16 +/- 3 mmHg; younger (Y): 10 +/- 2 mmHg) during exercise, but increases in arterial noradrenaline were similar (O: 2.56 +/- 0.96 nM; Y: 1.98 +/- 0.40 nM). However, the older men demonstrated a larger percentage reduction in exercising leg vascular conductance (leg blood flow/mean arterial pressure) during CPT compared to younger men (O: -13.6 +/- 3.1 %; Y: -1.5 +/- 4.3 %; P = 0.04). Leg blood flow tended to increase in the younger men, but not in the older men (P = 0.10). These results suggest, in contrast to what has been observed in resting skeletal muscle, that vasoconstrictor responsiveness to sympathetic stimulation is not reduced, but may be augmented in exercising muscle of healthy older humans. This could reflect a reduced ability of local substances (e.g. nitric oxide) to impair vasoconstriction in response to sympathetic stimulation during exercise in older humans.

Adult↗
PubMed2005

[A case of nonclostridial gas gangrene of the leg complicated by severe pneumonia].

A 73-year-old man admitted for febrile left leg pain with dyspnea, who had poorly controlled diabetes was found on admission to have severe hypoxia and chest X-ray showed infiltrates in the middle to lower left lung. X-rays of the left leg showed gas around the knee joint. These findings suggested severe pneumonia with gas gangrene, necessitating immediate debridement of the gas gangrene lesion and hyperbaric oxygenation. Antibiotics were also administered intravenously (panipenem/betamipron 0.5 g x 3/day, clindamycin 600 mg x 2/day, and erythromycin 500 mg x 3/day). We conducted fiberoptic bronchoscope daily because consolidation of the whole left lung developed with purulent sputum expectoration. Both pneumonia and gas gangrene gradually ameliorated avoiding amputation of theleg. Gas gangrene was cured without leaving sequelae such as motor dysfunction. Staphylococcus aureus was detected in both pus from the leg and sputum collected by bronchoscopy. Microorganisms showed the same pattern of sensitivity to antibiotics, suggesting a causal relationship between pneumonia and gas gangrene through the blood stream. Gas gangrene was considered the primary infection followed by pneumonia, since pain and swelling of the left leg preceded the airway symptoms. The present case illustrates in compromised hosts including diabetics, gas gangrene may develop taking an opportunity of airway infection, and that in some cases, early debridement of the lesion and optimal use of antibiotics may help cure this disease without aggressive surgery. Hyperbaric oxygenation may also be useful, although its validity must be investigated further.

Aged↗
PubMed2004

The effect of 6 months training on leg power, balance, and functional mobility of independently living adults over 70 years old.

Where strength training has been used in conjunction with functional-task training in older people, not only have there been improvements in leg strength but also improved function has been measured (e.g., Skelton & McLaughlin, 1996). Many studies use participants from care homes rather than community dwellers. We investigated changes in leg power, balance, and functional mobility in community-dwelling sedentary men and women over 70 years of age (n = 6 for training group [TR]; n = 10 for control group [CN]). Progressive training took place over 24 weeks using seated and nonseated exercise. For TR, leg power increased 40%, from 108 +/- 40 to 141 +/- 53 W (p < .01); dynamic balance increased 48%, from 22.3 +/- 7.9 to 33.1 +/- 6.1 cm (p < .01; functional reach); and functional mobility increased 12%, from 7.46 +/- 1.32 to 6.54 +/- 1.41 s (p < .05; timed walk). CN showed no significant change. In conclusion, a community-based exercise program led to large improvements in leg-extensor power, dynamic balance, and functional mobility.

Adaptation, Physiological↗
PubMed1984

Haemoglobin saturation during incremental arm and leg exercise.

There are few reports concerning the alterations in the percent of haemoglobin saturated with oxygen (%SO2) during non-steady state incremental exercise. Further, no data exist to describe the %SO2 changes during arm exercise. Therefore, the purpose of this study was made to assess the dynamic changes in %SO2 during incremental arm and leg work. Nine trained subjects (7 males and 2 females) performed incremental arm and leg exercise to exhaustion on an arm crank ergometer and a cycle ergometer, respectively. Ventilation and gas exchange measurements were obtained minute by minute via open circuit spirometry and changes in %SO2 were recorded via an ear oximeter. No significant difference (p greater than 0.05) existed between arm and leg work in end-tidal oxygen (PETO2), end-tidal carbon dioxide (PETCO2), or %SO2 when compared as a function of percent VO2 max. These results provide evidence that arterial O2 desaturation occurs in a similar fashion in both incremental arm and leg work with the greatest changes in %SO2 occurring at work rates greater than 70% VO2 max.

Arm↗
PubMed1973

New radioisotope test for detection of deep venous thrombosis in the legs.

A radiopharmsceutical product, labelled macroaggregates of albumin (M.A.A.), which is in use as a lung scintiscanning agent has been noted to have an affinity for venous thrombi. With this material and an inexpensive portable scintillation detector we have attempted to diagnose and localize thrombi in leg veins. The procedure is performed at the bedside and the result is available in 30 minutes. Thirty-one patients with clinical evidence suggestive of deep venous thrombosis in the legs were studied by the radioisotope method and by phlebography. There was agreement in 18 of 21 legs shown to contain thrombus on phlebography and in 9 of 10 legs shown to be free of thrombosis on phlebography. There was, however, lesser agreement on the site of thrombosis between the two methods. The ease of performing the test combined with the rapidity of obtaining results and accuracy in diagnosis suggests that the test has a clinical application.

Adolescent↗
PubMed1995

Meta-analysis of efficacy of quinine for treatment of nocturnal leg cramps in elderly people.

OBJECTIVE: To assess quantitatively the efficacy of quinine (as quinine sulphate) compared with placebo in the treatment of nocturnal leg cramps. DESIGN: A meta-analysis of six randomised, double blind, crossover trials. SETTING: Randomised trials that were available as of April 1994. SUBJECTS: A total of 107 general ambulatory patients who suffered from regular nocturnal leg cramps from six clinical trials. RESULTS: Data from individual patients were used to calculate point estimates and 95% confidence intervals for each of the outcome measures reported by these studies. Treatment with quinine resulted in a significant reduction in the number of cramps for a four week period compared with placebo (8.83 fewer cramps; 95% confidence interval 4.16 to 13.49). Treatment with quinine reduced the number of nights with cramps by 27.4% (24.0% to 30.8%) compared with placebo. Treatment did not produce a significant change in the severity or duration of individual nocturnal leg cramps. Side effects were uncommon. CONCLUSIONS: The results indicate that quinine can prevent nocturnal leg cramps in general ambulatory populations. Given the possible serious side effects of treatment with quinine, the benefits and risks in patients taking this drug should be closely monitored.

Aged↗
PubMed1997

A systematic review of compression treatment for venous leg ulcers.

OBJECTIVE: To estimate the clinical and cost effectiveness of compression systems for treating venous leg ulcers. METHODS: Systematic review of research. Search of 19 electronic databases including Medline, CINAHL, and Embase. Relevant journals and conference proceedings were hand searched and experts were consulted. MAIN OUTCOME MEASURES: Rate of healing and proportion of ulcers healed within a time period. STUDY SELECTION: Randomised controlled trials, published or unpublished, with no restriction on date or language, that evaluated compression as a treatment for venous leg ulcers. RESULTS: 24 randomised controlled trials were included in the review. The research evidence was quite weak: many trials had inadequate sample size and generally poor methodology. Compression seems to increase healing rates. Various high compression regimens are more effective than low compression. Few trials have compared the effectiveness of different high compression systems. CONCLUSIONS: Compression systems improve the healing of venous leg ulcers and should be used routinely in uncomplicated venous ulcers. Insufficient reliable evidence exists to indicate which system is the most effective. More good quality randomised controlled trials in association with economic evaluations are needed, to ascertain the most cost effective system for treating venous leg ulcers.

Bandages↗
PubMed1998

Cost effectiveness of community leg ulcer clinics: randomised controlled trial.

OBJECTIVES: To establish the relative cost effectiveness of community leg ulcer clinics that use four layer compression bandaging versus usual care provided by district nurses. DESIGN: Randomised controlled trial with 1 year of follow up. SETTING: Eight community based research clinics in four trusts in Trent. SUBJECTS: 233 patients with venous leg ulcers allocated at random to intervention (120) or control (113) group. INTERVENTIONS: Weekly treatment with four layer bandaging in a leg ulcer clinic (clinic group) or usual care at home by the district nursing service (control group). MAIN OUTCOME MEASURES: Time to complete ulcer healing, patient health status, and recurrence of ulcers. Satisfaction with care, use of services, and personal costs were also monitored. RESULTS: The ulcers of patients in the clinic group tended to heal sooner than those in the control group over the whole 12 month follow up (log rank P=0.03). At 12 weeks, 34% of patients in the clinic group were healed compared with 24% in the control. The crude initial healing rate of ulcers in intervention compared with control patients was 1.45 (95% confidence interval 1.04 to 2. 03). No significant differences were found between the groups in health status. Mean total NHS costs were 878.06 pounds per year for the clinic group and 859.34 pounds for the control (P=0.89). CONCLUSIONS: Community based leg ulcer clinics with trained nurses using four layer bandaging is more effective than traditional home based treatment. This benefit is achieved at a small additional cost and could be delivered at reduced cost if certain service configurations were used.

Aged↗
PubMed1971

Prevention of early postoperative deep vein thrombosis by intermittent compression of the leg during surgery.

A clinical trial is described in which the effect of intermittent compression of the lower limb during surgery on the incidence of early postoperative deep vein thrombosis was assessed. Deep vein thromboses were diagnosed by the (125)I-fibrinogen uptake test. Peroperative intermittent compression was achieved by means of an inflatable plastic splint coupled to a pneumatic controller. By compressing only one leg of each patient, each patient acted as his own control.With a sequential statistical analysis, 39 patients were required to pass the 5% level of significance. Eleven thrombi were detected in the control (uncompressed) legs and two occurred in the compressed legs; one of the latter was bilateral. The investigation shows that increasing the pulsatility of the venous flow in the leg is a potent prophylactic against postoperative deep vein thrombosis.

Adult↗
PubMed1991

Chronic leg ulcers: an underestimated problem in primary health care among elderly patients.

STUDY OBJECTIVE: The aim was to establish leg ulcer point prevalence, basal patient characteristics, and level of caretaking. DESIGN: The study was a postal cross sectional survey. The validity was ensured by examining a randomly selected sample of reported patients. Responding health care officials were asked to report all patients with an open wound below knee (including foot ulcer) which did not heal or was supposed to heal within a six week period after onset of ulceration. Response rate was 92%. SETTING: Inpatient and outpatient care in hospitals, community health care, and private nursing homes within Skaraborg county, with a population of 270,800. PARTICIPANTS: 827 individual patients were found with active leg ulcers, 526 women and 301 men. MEASUREMENTS AND MAIN RESULTS: Age adjusted sex ratio of ulcer patients was 1:1.4 (M:F). The median age was 78 years for women and 76 for men; 700 patients (85%) were older than 64 years. The point prevalence for active leg ulcers was 3.0/1000 total population. District nurses provided care for 680 patients (82%), 106 (13%) were in hospital care, and 41 (5%) were managed by outpatient departments. CONCLUSIONS: There has been an underestimation of the leg ulcer problem among elderly patients, especially men. With an expected increasing number of elderly people it is important that this problem is recognised and measures taken to improve the primary care of these patients.

Adolescent↗
PubMed2003

Associations of height, leg length, and lung function with cardiovascular risk factors in the Midspan Family Study.

BACKGROUND: Taller people and those with better lung function are at reduced risk of coronary heart disease (CHD). Biological mechanisms for these associations are not well understood, but both measures may be markers for early life exposures. Some studies have shown that leg length, an indicator of pre-pubertal nutritional status, is the component of height most strongly associated with CHD risk. Other studies show that height-CHD associations are greatly attenuated when lung function is controlled for. This study examines (1) the association of height and the components of height (leg length and trunk length) with CHD risk factors and (2) the relative strength of the association of height and forced expiratory volume in one second (FEV(1)) with risk factors for CHD. SUBJECTS AND METHODS: Cross sectional analysis of data collected at detailed cardiovascular screening examinations of 1040 men and 1298 women aged 30-59 whose parents were screened in 1972-76. Subjects come from 1477 families and are members of the Midspan Family Study. SETTING: The towns of Renfrew and Paisley in the West of Scotland. RESULTS: Taller subjects and those with better lung function had more favourable cardiovascular risk factor profiles, associations were strongest in relation to FEV(1). Higher FEV(1) was associated with lower blood pressure, cholesterol, glucose, fibrinogen, white blood cell count, and body mass index. Similar, but generally weaker, associations were seen with height. These associations were not attenuated in models controlling for parental height. Longer leg length, but not trunk length, was associated with lower systolic and diastolic blood pressure. Longer leg length was also associated with more favourable levels of cholesterol and body mass index than trunk length. CONCLUSIONS: These findings provide indirect evidence that measures of lung development and pre-pubertal growth act as biomarkers for childhood exposures that may modify an individual's risk of developing CHD. Genetic influences do not seem to underlie height-CHD associations.

Adult↗
PubMed2005

Vascular mapping of the leg with multi-detector row CT angiography prior to free-flap transplantation.

PURPOSE: To retrospectively evaluate multi-detector row computed tomographic (CT) angiography in determining donor- and recipient-site arterial suitability for successful vascularized free-flap transplantation. MATERIALS AND METHODS: The institutional review board granted approval; informed consent was waived, and the study was HIPAA compliant. Lower extremities of 20 (12 male, eight female; mean age, 51 years; range, 10-84 years) patients undergoing vascularized free-flap procedures were examined at multi-detector row CT angiography. In five patients, legs were assessed as potential fibular free-flap donors for mandibular, maxillary, or radial reconstruction. In 15 patients, legs were assessed as recipient sites for free flaps. Vascular maps obtained with volume rendering, maximum intensity projections, and curved planar reformations were generated, and assessment was made in the depiction of calf vessels and presence of stenosis, occlusion, and anatomic anomaly. Findings of CT angiography, physical examination, and surgery were compared, where applicable, and successful CT-based prediction of the surgical intervention was assessed. Immediate and long-term (>70 days) viability of the graft was assessed in all patients. RESULTS: CT angiography depicted the entirety of all four major calf arteries in 29 of 32 legs scanned. In three legs, external-fixation hardware obscured some segments. There were no discrepancies between CT findings and those identified at the time of surgery. Arterial abnormalities, including stenosis, occlusion, and variant anatomy, were seen in 12 lower extremities in 10 patients. Only two were suspected on the basis of physical examination findings. In five of 20 patients, CT findings resulted in changes to the surgical plan. There was a 100% immediate viability of all grafts, which remained well vascularized between 70 days and 37 months after the procedure. CONCLUSION: Multi-detector row CT angiography provides a noninvasive means of preoperatively assessing lower extremity arteries for abnormalities, which could jeopardize graft viability or pedal arterial supply after free-flap procedures.

Aged↗
PubMed2002

Leg and arm lactate and substrate kinetics during exercise.

To study the role of muscle mass and muscle activity on lactate and energy kinetics during exercise, whole body and limb lactate, glucose, and fatty acid fluxes were determined in six elite cross-country skiers during roller-skiing for 40 min with the diagonal stride (Continuous Arm + Leg) followed by 10 min of double poling and diagonal stride at 72-76% maximal O(2) uptake. A high lactate appearance rate (R(a), 184 +/- 17 micromol x kg(-1) x min(-1)) but a low arterial lactate concentration ( approximately 2.5 mmol/l) were observed during Continuous Arm + Leg despite a substantial net lactate release by the arm of approximately 2.1 mmol/min, which was balanced by a similar net lactate uptake by the leg. Whole body and limb lactate oxidation during Continuous Arm + Leg was approximately 45% at rest and approximately 95% of disappearance rate and limb lactate uptake, respectively. Limb lactate kinetics changed multiple times when exercise mode was changed. Whole body glucose and glycerol turnover was unchanged during the different skiing modes; however, limb net glucose uptake changed severalfold. In conclusion, the arterial lactate concentration can be maintained at a relatively low level despite high lactate R(a) during exercise with a large muscle mass because of the large capacity of active skeletal muscle to take up lactate, which is tightly correlated with lactate delivery. The limb lactate uptake during exercise is oxidized at rates far above resting oxygen consumption, implying that lactate uptake and subsequent oxidation are also dependent on an elevated metabolic rate. The relative contribution of whole body and limb lactate oxidation is between 20 and 30% of total carbohydrate oxidation at rest and during exercise under the various conditions. Skeletal muscle can change its limb net glucose uptake severalfold within minutes, causing a redistribution of the available glucose because whole body glucose turnover was unchanged.

3-Hydroxyacyl CoA Dehydrogenases↗
PubMed1992

Effects of epinephrine on insulin-mediated glucose uptake in whole body and leg muscle in humans: role of blood flow.

In vivo insulin-mediated glucose uptake (IMGU) occurs chiefly in skeletal muscle, where it is determined by the product of arteriovenous glucose difference (delta AVG) and blood flow (BF) rate into muscle. Epinephrine (Epi) reduces the rate of IMGU in whole body. To examine whether this is due to a reduction in delta AVG across or BF into skeletal muscle we constructed insulin dose-response curves for whole body IMGU and leg muscle IMGU- using euglycemic clamp ((+)[3-3H]glucose infusion) and leg balance techniques during insulin infusions ranging from 10 to 1,200 mU.m-2.min-1. We studied six subjects [wt 70 +/- 2 (SE) kg] during an Epi infusion at a single rate of 0.002 mg.kg-1.min-1 and six subjects (70 +/- 3 kg) during a saline infusion alone. Maximum whole body glucose uptake (WBGU) was similar during Epi and saline infusions [71.4 vs. 73.6 mmol.kg-1.min-1, P = not significant (NS)]. Compared with saline, maximum delta AVG was decreased during Epi infusion (1.04 vs. 1.31 mM, P less than 0.01). Compared with saline alone maximum leg BF was increased (5.3 vs. 4.3 dl/min, P less than 0.01) during Epi infusion. Thus maximum leg glucose uptake (LGU) was similar (696 vs. 821 pmol.leg-1.min-1, P = NS) during infusion of Epi and saline, respectively. Half-maximal effective dose for insulin's effect to stimulate WBGU, delta AVG, BF, and LGU was increased two- to threefold during Epi vs. saline infusions (P less than 0.01 for all values).(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Circulation↗
PubMed1998

Poor relationship between arterial [lactate] and leg net release during exercise at 4,300 m altitude.

We evaluated the hypotheses that on acute exposure to hypobaric hypoxia, sympathetic stimulation leads to augmented muscle lactate production and circulating [lactate] through a beta-adrenergic mechanism and that beta-adrenergic adaptation to chronic hypoxia is responsible for the blunted exercise lactate response after acclimatization to altitude. Five control and 6 beta-blocked men were studied during rest and exercise at sea level (SL), on acute exposure to 4,300 m (A1), and after a 3-wk sojourn at altitude (A2). Exercise was by leg cycling at 49% of SL peak O2 consumption (VO2 peak) (65% of altitude VO2 peak or 87 +/- 2.6 W); beta-blockade was by propranolol (80 mg 3x daily), femoral arterial and venous blood was sampled; leg blood flow (Q) was measured by thermodilution, leg lactate net release [ = (2) (1-leg Q) venous-arterial concentrationL] was calculated, and vastus lateralis needle biopsies were obtained. Muscle [lactate] increased with exercise and acute altitude exposure but regressed to SL values with acclimatization; beta-blockade had no effect on muscle [lactate]. Arterial [lactate] rose during exercise at SL (0.9 +/- 0.1 to 1.5 +/- 0.3 mM); exercise at A1 produced the greatest arterial [lactate] (4.4 +/- 0.8 mM), and exercise at A2 an intermediate response (2.1 +/- 0.6 mM). beta-Blockade reduced circulating [lactate] approximately 45% during exercise under all altitude conditions. increased transiently at exercise onset but then declined over time under all conditions. Blood and muscle "lactate paradoxes" occurred independent of beta-adrenergic influences, and the hypotheses relating the blood lactate response at altitude to beta-adrenergic mechanisms are rejected. During exercise at altitude, arterial [lactate] is determined by factors in addition to hypoxemia, circulating epinephrine, and net lactate release from active muscle beds.

Acclimatization↗
PubMed1984

Comparison of motor unit activation during unilateral and bilateral leg extension.

Possible differences between the extent of muscle utilization during leg extensions performed bilaterally (BL, both legs acting together) and unilaterally were investigated in young males in college. Significantly less integrated electromyographic activity was recorded from the quadriceps muscles of the dominant leg during BL compared with UL maximal voluntary contractions (MVC). BL strength was significantly lower than the summed (UL; sum of 2 legs acting singly) UL value under isometric conditions [BL = 91 +/- 2.5% (mean +/- SE) of UL; P less than 0.01, n = 9]. By use of a modified isokinetic dynamometer, it was also shown that the effect of increasing the velocity of concentric contraction was significantly greater (P less than 0.001) on BL than UL force development; thus at 424 degrees/s mean BL MVC was only 51 +/- 3.5% of UL. Greater resistance to fatigue was shown in the BL condition in repeated concentric contractions (% decline over 100 MVC at 105 degrees/s was 28 +/- 2.7% for BL vs. 38 +/- 2.9% for UL, P less than 0.001). Results indicated that the extent of motor unit activation appeared to be reduced in BL relative to UL MVC. Compatible evidence from the strength-velocity and fatigability comparisons suggested that this reduction was due to a lesser utilization of the fast-twitch fatigable type of motor unit.

Adult↗
PubMed1986

Lactate extraction during net lactate release in legs of humans during exercise.

Lactate metabolism was studied in six normal males using a primed continuous infusion of lactate tracer during continuous graded supine cycle ergometer exercise. Subjects exercised at 49, 98, 147, and 196 W for 6 min at each work load. Blood was sampled from the brachial artery, the iliac vein, and the brachial vein. Arteriovenous differences were determined for chemical lactate concentration and L-[1-14C]-lactate. Tracer-measured lactate extraction was determined from the decrease in lactate radioactivity per volume of blood perfusing the tissue bed. Net lactate release was determined from the change in lactate concentration across the tissue bed. Total lactate release was taken as the sum of tracer-measured lactate extraction and net (chemical) release. At rest the arms and legs showed tracer-measured lactate extraction, as determined from the isotope extraction, despite net chemical release. Exercise elicited an increase in both net lactate release and tracer-measured lactate extraction by the legs. For the legs the total lactate release (net lactate release + tracer-measured lactate extraction) was roughly equal to twice the net lactate release under all conditions. The tracer-measured lactate extraction by the exercising legs was positively correlated to arterial lactate concentration (r = 0.81, P less than 0.001) at the lower two power outputs. The arms showed net lactate extraction during exercise, which was correlated to the arterial concentration (r = 0.86). The results demonstrate that exercising skeletal muscle extracts a significant amount of lactate during net lactate release and that the working skeletal muscle appears to be a major site of blood lactate removal during exercise.

Adult↗
PubMed1989

Differential control of forearm and calf vascular resistance during one-leg exercise.

The purpose of this study was to determine whether blood flow (BF) and vascular resistance (VR) are controlled differently in the nonactive arm and leg during submaximal rhythmic exercise. In eight healthy men we simultaneously measured BF to the forearm and calf (venous occlusion plethysmography) and arterial blood pressure (sphygmomanometry) and calculated whole limb VR before (control) and during 3 min of cycling with the contralateral leg at 38, 56, and 75% of peak one-leg O2 uptake (VO2). During the initial phase of exercise (0-1.5 min) at all work loads, BF increased and VR decreased in the forearm (P less than 0.05), whereas calf BF and VR remained at control levels. Thereafter, BF decreased and VR increased in parallel and progressive fashion in both limbs. At end exercise, forearm BF and VR were not different from control values (P greater than 0.05); however, in the calf, BF tended to be lower (P less than 0.05 at 75% peak VO2 only) and VR was higher (23 +/- 9, 44 +/- 14, and 88 +/- 23% above control at 38, 56, and 75% of peak VO2, respectively, all P less than 0.05). In a second series of studies, forearm and calf skin blood flow (laser-Doppler velocimetry) and arterial pressure were measured during the same levels of exercise in six of the subjects. Compared with control, skin BF was unchanged and VR was increased (P less than 0.05) in the forearm by end exercise at all work loads, whereas calf skin BF increased (P less than 0.05) and VR decreased (P less than 0.05). The present findings indicate that skeletal muscle and skin VR are controlled differently in the nonactive forearm and calf during the initial phase of rhythmic exercise with the contralateral leg. Skeletal muscle vasodilation occurs in the forearm but not in the calf; forearm skin vasoconstricts, whereas calf skin vasodilates. Finally, during exercise a time-dependent vasoconstriction occurs in the skeletal muscle of both limbs.

Adult↗