Physical fitness, muscle morphology, and insulin-stimulated limb blood flow in normal subjects

1996 ◽  
Vol 270 (5) ◽  
pp. E905-E911 ◽  
Author(s):  
T. Utriainen ◽  
A. Holmang ◽  
P. Bjorntorp ◽  
S. Makimattila ◽  
A. Sovijarvi ◽  
...  
Keyword(s):  
Blood Flow ◽  
Physical Fitness ◽  
Muscle Fiber ◽  
Aerobic Power ◽  
Normal Subjects ◽  
Maximal Aerobic Power ◽  
Whole Body ◽  
Limb Blood Flow ◽  
Muscle Morphology ◽  
Fiber Composition

The response of limb blood flow to insulin is highly variable even in normal subjects. We examined whether physical fitness or differences in muscle morphology contribute to this variation. Maximal aerobic power, muscle fiber composition and capillarization, and the response of forearm glucose extraction and blood flow to a sequential hyperinsulinemic euglycemic clamp (serum insulin 374 +/- 10, 816 +/- 23, and 2,768 +/- 78 pmol/l) were determined in 16 normal males (age 25 +/- 1 yr, body mass index 24 +/- 1 kg/m2). Maximal aerobic power correlated positively with the proportion of type I fibers (r = 0.67, P < 0.01) and negatively with the proportion of type IIb fibers (r = -0.73, P < 0.01). Fiber composition but not blood flow correlated significantly with forearm and whole body glucose uptake. All doses of insulin significantly increased forearm blood flow, maximally by 123 +/- 21%. The ratio of capillaries per fiber was significantly correlated with basal and insulin-stimulated blood flow (0.58∑ 0.76, P < 0.05∑0.01). Mean arterial blood pressure and the insulin∑induced increase in blood flow were inversely correlated (r = ∑0.59, P < 0.05). We conclude that variation in glucose extraction is significantly determined by muscle fiber composition, whereas variation in insulin-stimulated blood flow is closely associated with muscle capillarization.

Does Cerebral Blood Flow Limit Maximal Aerobic Power Output?

2011 ◽  
Vol 43 (Suppl 1) ◽  
pp. 82
Author(s):  
Andrew W. Subudhi ◽  
J Tod Olin ◽  
Andrew C. Dimmen ◽  
Bengt Kayser ◽  
Robert C. Roach
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Power Output ◽  
Aerobic Power ◽  
Maximal Aerobic Power ◽  
Flow Limit ◽  
Aerobic Power Output

Effect of salt-loading on blood pressure, insulin sensitivity and limb blood flow in normal subjects

1998 ◽  
Vol 95 (2) ◽  
pp. 157 ◽  
Author(s):  
M. FOO ◽  
A.E. DENVER ◽  
S.W. COPPACK ◽  
J.S. YUDKIN
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Insulin Sensitivity ◽  
Normal Subjects ◽  
Limb Blood Flow ◽  
Salt Loading

O2 extraction by canine hindlimb during alpha-adrenergic blockade and hypoxic hypoxia

1980 ◽  
Vol 48 (4) ◽  
pp. 630-635 ◽  
Author(s):  
S. M. Cain ◽  
C. K. Chapler
Keyword(s):  
Blood Flow ◽  
Femoral Vein ◽  
Recovery Period ◽  
Whole Body ◽  
Adrenergic Blockade ◽  
Limb Blood Flow ◽  
O2 Uptake ◽  
Total Blood ◽  
O2 Extraction ◽  
Total Blood Flow

Hindlimb and total blood flow and O2 uptake were measured in anesthetized paralyzed dogs in which venous outflow from the left hindlimb (less paw) was directed through the femoral vein. After ventilation on room air, 10 dogs were given 3 mg/kg phenoxybenzamine + 10 ml/kg dextran and 10 other dogs were isovolemically exchanged with 10 ml/kg dextran without alpha-block while continuing to be ventilated on room air. All animals were then ventilated with 9.1% O2 in N2, followed by a recovery period on room air. Total and limb peripheral resistances were lowered by alpha-block, but total and limb blood flow changed little from control levels. Both total and limb O2 uptake were decreased below control values during hypoxia. Cardiac output and limb blood flow increased during hypoxia in both groups. Although alpha-block caused O2 extraction by the whole body to be less during hypoxia than in unblocked dogs, the hindlimb in both groups extracted O2 equally well. We concluded that skeletal muscle was not overperfused relative to O2 demand when alpha-blocked during hypoxia.

Risk Factors for Injury in Subelite Rugby League Players

2005 ◽  
Vol 33 (3) ◽  
pp. 428-434 ◽  
Author(s):  
Tim J. Gabbett ◽  
Nathan Domrow
Keyword(s):  
Risk Factors ◽  
Physical Fitness ◽  
Aerobic Power ◽  
Vertical Jump ◽  
Rugby League ◽  
Maximal Aerobic Power ◽  
Level Of Evidence ◽  
Risk Of Injury ◽  
Increased Risk ◽  
Subsequent Injury

Background Although player fatigue and playing intensity have been suggested to contribute to injuries in rugby league players, no study has confirmed if the level of physical fitness is a risk factor for injury in rugby league players. The aim of this study was to identify risk factors for injury in subelite rugby league players. Hypothesis Low physical fitness levels are risk factors for injury in subelite rugby league players. Study Design Cohort study; Level of evidence, 2. Methods One hundred fifty-three players from a subelite rugby league club underwent preseason measurements of muscular power (vertical jump), speed (10- and 40-m sprint), and maximal aerobic power (multistage fitness test) over 4 competitive seasons. All injuries sustained by players were prospectively recorded over the 4 competitive seasons. Results The risk of injury was greater in players with low 10- and 40-m speed. Players with a low maximal aerobic power had a greater risk of sustaining a contact injury. In addition, players who completed less than 18 weeks of training before sustaining their initial injuries were at greater risk of sustaining a subsequent injury. Conclusions Subelite rugby league players with low speed and maximal aerobic power are at an increased risk of injury. In addition, players who complete less than 18 weeks of training before sustaining an initial injury are at greater risk of sustaining a subsequent injury. These findings highlight the importance of speed and endurance training to reduce the incidence of injury in subelite rugby league players.

scholarly journals Effects of Cilnidipine on Muscle Fiber Composition, Capillary Density and Muscle Blood Flow in Fructose-Fed Rats.

2001 ◽  
Vol 24 (5) ◽  
pp. 565-572 ◽  
Author(s):  
Mikio TAKADA ◽  
Nobuyuki URA ◽  
Katsuhiro HIGASHIURA ◽  
Hideyuki MURAKAMI ◽  
Nobuhiko TOGASHI ◽  
...  
Keyword(s):  
Blood Flow ◽  
Muscle Fiber ◽  
Muscle Blood Flow ◽  
Capillary Density ◽  
Fiber Composition

Cardiac output and skin blood flow in lean and obese individuals during exercise in the heat

1983 ◽  
Vol 55 (1) ◽  
pp. 69-74 ◽  
Author(s):  
N. B. Vroman ◽  
E. R. Buskirk ◽  
J. L. Hodgson
Keyword(s):  
Blood Flow ◽  
Cardiac Output ◽  
Body Fat ◽  
Forearm Blood Flow ◽  
Aerobic Power ◽  
Venous Occlusion ◽  
Cycle Ergometer ◽  
Maximal Aerobic Power ◽  
Ambient Environment ◽  
Free Weight

Five obese (% body fat greater than or equal to 27%) and five relatively lean (% body fat less than 20%) men performed upright exercise on a cycle ergometer at intensities of 30, 50, and 70% of their maximal aerobic power [VO2max (ml X kg fat-free wt-1 X min-1)] in both a thermoneutral [dry bulb temperature (Tdb) = 22 degrees C, wet bulb temperature (Twb) = 14 degrees C] and a hot (Tdb = 38 degrees C, Twb = 20 degrees C) ambient environment. Cardiac output (Q) was measured by CO2 rebreathing and forearm blood flow (FBF) was measured by venous occlusion plethysmography. Esophageal temperature (Tes) was measured by a thermocouple placed in the esophagus at approximately heart level, and mean skin temperature (Tsk) was calculated from the average of thermocouple readings from six skin sites. When the exercise intensity was normalized for metabolic body mass by dividing by fat-free weight, Q was similar between lean and obese at all exercise intensities and in both ambient environments. No differences between the two groups were found in Tes and Tsk under all conditions. The obese had significantly lower FBF compared with the lean during the higher exercise intensities in the hot ambient environment. In both ambient environments, the slope of the FBF-Tes relationship was significantly less in the obese group. It was concluded that body composition may alter the balance between the two opposing sets of cutaneous vascular reflexes (baroreceptor-induced vasoconstriction and thermoregulatory vasodilation) that regulate the competition for blood flow between the skin and working muscle during exercise in the heat.

Nocturnal lowering of thresholds for sweating and vasodilation

1976 ◽  
Vol 41 (1) ◽  
pp. 15-19 ◽  
Author(s):  
C. B. Wenger ◽  
M. F. Roberts ◽  
J. A. Stolwijk ◽  
E. R. Nadel
Keyword(s):  
Blood Flow ◽  
Skin Temperature ◽  
Forearm Blood Flow ◽  
Aerobic Power ◽  
Weighted Average ◽  
Bicycle Ergometer ◽  
Maximal Aerobic Power ◽  
Esophageal Temperature ◽  
Mean Skin Temperature ◽  
Sweating Rate

Six subjects exercised on a bicycle ergometer at 60–70% of maximal aerobic power in a 25 degrees C ambient. Experiments on each subject wereconducted at night (4:00–5:30 A.M.) and in daytime (noon-4:30 P.M.).Chest sweating rate (msw) was measured with resistance hygrometry. Forearm blood flow (BF), with an arm skin temperature of 35.5 +/- 1.2 degrees C (SD), was measured with electrocapacitance plethysmography. Esophageal temperature (Tes) was measured with a thermocouple at the level of the left atriumand mean skin temperature (Tsk) was calculated from a weighted average of temperatures at three sites. Tes was corrected to a skin temperature of 33 degrees C as follows: T'es = Tes + (Tsk - 33 degrees C)/8. This correction reflects the relative contributions of Tes and Tsk to control of msw:T'es and BF:T'es relations were not consistently changed. In any given subject, thresholds for sweating and vasodilation were shifted about equally. These shifts averaged 0.57 degrees C (range: 0.23–0.93 degrees C)for msw and 0.63 degrees C (range: 0.17–0.98 degrees C)for BF.

Hindlimb vascular responses to sympathetic augmentation during acute anemia

1985 ◽  
Vol 63 (7) ◽  
pp. 782-786 ◽  
Author(s):  
Stephen M. Cain ◽  
C. K. Chapler
Keyword(s):  
Skeletal Muscle ◽  
Blood Flow ◽  
Sympathetic Activity ◽  
Carotid Arteries ◽  
Muscle Blood Flow ◽  
Recovery Period ◽  
Control Period ◽  
Whole Body ◽  
Block Group ◽  
Limb Blood Flow

The effect of increased sympathetic activity on skeletal muscle blood flow during acute anemic hypoxia was studied in 16 anesthetized dogs. Sympathetic activity was altered by clamping the carotid arteries bilaterally below the carotid sinus. One group (n = 8) was beta blocked by administration of propranolol (1 mg/kg); a second group (n = 8) was untreated. Venous outflow from the left hindlimb was isolated for measurement of blood flow and O2 uptake [Formula: see text]. After a 20-min control period, both carotid arteries were clamped (CC) for 20 min followed by a 20-min recovery period. The sequence was repeated after hematocrit was lowered to about 15% by dextran exchange for blood. Prior to anemia, CC did not alter cardiac output or limb blood flow in either group. After induction of anemia, hindlimb resistance was higher with CC in the beta block than in the no block group. Both limb blood flow and [Formula: see text] fell in the β-block group with CC during anemia. Beta block also prevented the additive increases in whole body [Formula: see text] seen with CC and induction of anemia. The data showed that the increased vasoconstrictor tone that was obtained with beta block during anemia was successful in redistributing the lower viscosity blood away from resting skeletal muscle, even to the point that muscle [Formula: see text] was decreased.

Sign in / Sign up

Export Citation Format

Share Document