共查询到20条相似文献,搜索用时 31 毫秒
1.
Exercise training protects against contraction-induced lipid peroxidation in the diaphragm 总被引:1,自引:0,他引:1
Heather K. Vincent Scott K. Powers Haydar A. Demirel Jeff S. Coombes Hisashi Naito 《European journal of applied physiology》1999,79(3):268-273
Endurance exercise training promotes a small but significant increase in antioxidant enzyme activity in the costal diaphragm (DIA) of rodents. It is unclear if these training-induced improvements in muscle antioxidant capacity are large enough to reduce oxidative stress during prolonged contractile activity. To test the hypothesis that training-related increases in DIA antioxidant capacity reduces contraction-induced lipid peroxidation, we exercise trained adult female Sprague-Dawley (n?=?7) rats on a motor-driven treadmill for 12?weeks at ≈ 75% maximal O2 consumption (90?min/day). Control animals (n?=?8) remained sedentary during the same 12-week period. After training, DIA strips from animals in both experimental groups were excised and subjected to an in vitro fatigue contractile protocol in which the muscle was stimulated for 60?min at a frequency of 30?Hz, every 2?s, with a train duration of 330?m. Compared to the controls, endurance training resulted in an increase (P?0.05) in diaphragmatic non-protein thiols and in the activity of the antioxidant enzyme superoxide dismutase. Following the contractile protocol, lipid peroxidation was significantly lower (P?0.05) in the trained DIA compared to the controls. These data support the hypothesis that endurance exercise training-induced increases in DIA antioxidant capacity protect the muscle against contractile-related oxidative stress. 相似文献
2.
J. L. Mauriz B. Tabernero J. García-López F. Jorquera J. G. Villa J. González-Gallego 《European journal of applied physiology》2000,81(1-2):62-66
Drug metabolizing capacity is generally reduced in the elderly, and physical exercise has been reported to increase drug
oxidative metabolism. The purpose of this investigation was to study the effects of engagement in a program of regular physical
exercise on the clearance and metabolite excretion of antipyrine, a marker of oxidative metabolism, in elderly subjects. The
saliva clearance of antipyrine and the production clearances of antipyrine metabolites were studied in 37 elderly women (mean
age 66 years). Subjects attended 60-min sessions three times a week for 12 weeks. Each session consisted of both aerobic (training
of cardiorespiratory capacity) and nonaerobic (training of muscular strength/endurance and flexibility/coordination) exercises
performed at 50–75% of maximum oxygen uptake. Antipyrine was administered orally and pharmacokinetic parameters were obtained
from saliva and urine samples. After 3 months of participation in the exercise program, salivary antipyrine clearance was
significantly increased by 17% mean (SEM) 0.42 (0.02) vs 0.36 (0.02) ml/min/kg; P < 0.05) and the half-life of antipyrine was significantly reduced by 18% (17.9 (1.1) vs 22.3 (1.3) h; P < 0.05). No significant change with exercise was observed in the renal clearance of antipyrine or in the norantipyrine formation
clearance, but significant increases were found for hydroxymethylantipyrine [42 (5) vs 32 (4) μl/kg/min; P < 0.05; +31%] and 4-hydroxyantipyrine [243 (18) vs 194 (17) μl/kg/min; P < 0.05; +25%] formation clearances. These findings indicate that regular exercise leads to increased disposition of antipyrine
in the elderly and that the main metabolic pathways of the compound are changed differentially.
Accepted: 25 June 1999 相似文献
3.
Strenuous endurance training in humans reduces oxidative stress following exhausting exercise 总被引:12,自引:0,他引:12
Miyazaki H Oh-ishi S Ookawara T Kizaki T Toshinai K Ha S Haga S Ji LL Ohno H 《European journal of applied physiology》2001,84(1-2):1-6
The aim of this study was to evaluate whether high-intensity endurance training would alleviate exercise-induced oxidative
stress. Nine untrained male subjects (aged 19–21 years) participated in a 12-week training programme, and performed an acute
period of exhausting exercise on a cycle ergometer before and after training. The training programme consisted of running
at 80% maximal exercise heart rate for 60 min · day−1, 5 days · week−1 for 12 weeks. Blood samples were collected at rest and immediately after exhausting exercise for measurements of indices
of oxidative stress, and antioxidant enzyme activities [superoxide dismutase (SOD), glutathione peroxidase (GPX), and catalase
(CAT)] in the erythrocytes. Maximal oxygen uptake (V˙O2max) increased significantly (P < 0.001) after training, indicating an improvement in aerobic capacity. A period of exhausting exercise caused an increase
(P < 0.01) in the ability to produce neutrophil superoxide anion (O2
•−) both before and after endurance training, but the magnitude of the increase was smaller after training (P < 0.05). There was a significant increase in lipid peroxidation in the erythrocyte membrane, but not in oxidative protein,
after exhausting exercise, however training attenuated this effect. At rest, SOD and GPX activities were increased after training.
However, there was no evidence that exhausting exercise enhanced the levels of any antioxidant enzyme activity. The CAT activity
was unchanged either by training or by exhausting exercise. These results indicate that high-intensity endurance training
can elevate antioxidant enzyme activities in erythrocytes, and decrease neutrophil O2
•− production in response to exhausting exercise. Furthermore, this up-regulation in antioxidant defences was accompanied by
a reduction in exercise-induced lipid peroxidation in erythrocyte membrane.
Accepted: 26 September 2000 相似文献
4.
Zange J Beisteiner M Müller K Shushakov V Maassen N 《Pflügers Archiv : European journal of physiology》2008,455(6):1153-1163
We conducted non-invasive methods to investigate the mechanisms how an orthostasis improves fatigue resistance in human calf
muscle during intense exercise. Eleven healthy volunteers performed two series of ten intervals of maximum dynamic exercise
(15 s) and recovery (45 s) at almost horizontal body position under both, control conditions (CON) and lower body negative
pressure (LBNP, −40 mbar). As from the second work interval, LBNP significantly improved fatigue resistance shown as a lower
reduction in work and in contraction velocity (P < 0.01). During each work interval, EMG showed a small increase in amplitude (P < 0.01) and a steep drop by 20% in median frequency (P < 0.01). Under LBNP, both EMG parameters completely recovered during subsequent rest, whereas under CON recovery was incomplete
(P < 0.01). During the first work interval, consumption of phosphocreatine (PCr) was almost the same for both conditions. In
periods of recovery under LBNP, resynthesis of PCr and inorganic phosphate were significantly faster. PCr reached 10 to 20%
higher levels (P < 0.01). LBNP caused an initial increase in intracellular pH (0.08 U (P < 0.01)). The subsequent time courses of pH were similar for CON and LBNP. During work, pH steeply increased by about 0.3 U.
During subsequent recovery, pH dropped to values between 6.3 and 6.5. LBNP caused significantly higher levels of total haemoglobin
and oxy-haemoglobin (P < 0.05). A simulated orthostasis increased fatigue resistance during high intense interval exercise because of a faster PCr
resynthesis and may be because of improvements in the maintenance of motoneuronal activity. 相似文献
5.
To determine the effect of acute plasma volume (PV) expansion on substrate utilization, blood metabolites and catecholamines
to prolonged, moderate intensity cycle exercise, eight untrained men mean maximal oxygen uptake,O2max 4.10 (SEM 0.32) l · min−1 were infused (10 ml·kg−1) with a 6% dextran (DEX) solution. These responses were also compared to those elicited using a short-term training (TR)
protocol involving cycling for 90 to 120 min · day−1 at 60% O2max for 3 consecutive days. In general DEX, which resulted in a calculated expansion of PV by 23.9%, was without effect in modifying
exercise oxygen uptake or the reduction in the respiratory exchange ratio (R) observed during prolonged exercise. In addition,
the concentrations of blood glucose, glycerol, alanine and serum free fatty acids, although altered (P < 0.05) by exercise, were not altered by DEX. Blood lactate concentration was only higher (P < 0.05) at 30 min of exercise during DEX compared to the control. With the exception of blood lactate concentration, which
was reduced (P < 0.05), TR did not change R or the concentrations of other blood metabolites. The concentrations of nonadrenaline and adrenaline, were depressed (P < 0.05) by DEX and TR at 60 and 90 min of exercise. These results would suggest that mechanisms as yet undefined can compensate
for the estimated 10% reduction in arterial oxygen content mediated by acute PV expansion and enable prolonged exercise to
be performed without adjustments in substrate selection and substrate mobilization.
Accepted: 23 August 1996 相似文献
6.
We have examined the effect of male sex hormones on the myosin heavy chain (MHC) expression of the soleus and extensor digitorum
longus (EDL) muscles. Young male adult Wistar rats were treated over a 25-day period with either oil (CON, n = 8), nandrolone (nortestosterone decanoate, NAN, n = 8), nandrolone combined with endurance exercise (treadmill running, NAN+EXE, n = 8), or were castrated (CAS, n = 8). The MHC composition of the soleus and EDL muscles was measured by electrophoresis. Castration and treatment with nandrolone
had no effect (P > 0.05) on the relative levels of MHC in the soleus and EDL. In contrast, in NAN+EXE rats, the relative level of MHC-1 increased
[slow isoform; mean (SD) 97.6 (4.7)% in NAN+EXE rats, versus 86.5 (7.5)% in CON rats] and MHC-2a decreased [fast isoform;
2.4 (4.7)% in NAN+EXE, versus 13.5 (7.5)% in CON rats], only in the soleus (P < 0.05). In conclusion, it appears that endogenous anabolic/androgenic steroids are not essential for the maintenance of
the MHC expression of fast- and slow-twitch muscles in the young adult male rat. In addition, nandrolone combined with endurance
exercise induced a shift from a fast to a slower MHC phenotype of the slow-twitch muscle.
Accepted: 27 July 1999 相似文献
7.
Coombes JS Rowell B Dodd SL Demirel HA Naito H Shanely RA Powers SK 《European journal of applied physiology》2002,87(3):272-277
Radical-mediated oxidative damage of skeletal muscle membranes has been implicated in the fatigue process. Vitamin E (VE)
is a major chain breaking antioxidant that has been shown to reduce contraction-mediated oxidative damage. We hypothesized
that VE deficiency would adversely affect muscle contractile function, resulting in a more rapid development of muscular fatigue
during exercise. To test this postulate, rats were fed either a VE-deficient (EDEF) diet or a control (CON) diet containing
VE. Following a 12-week feeding period, animals were anesthetized and mechanically ventilated. Muscle endurance (fatigue)
and contractile properties were evaluated using an in situ preparation of the tibialis anterior (TA) muscle. Contractile properties
of the TA muscle were determined before and after a fatigue protocol. The muscle fatigue protocol consisted of 60 min of repetitive
contractions (250 ms trains at 15 Hz; duty cycle=11%) of the TA muscle. Prior to the fatigue protocol, no significant differences
existed in the force-frequency curves between EDEF and CON animals. At the completion of the fatigue protocol, muscular force
production was significantly (P<0.05) lower in the EDEF group (reduced by 69%) compared to CON group (reduced by 38%). Following the fatigue protocol, a
right shift existed in the force-frequency curve at low stimulation frequencies (≤40 Hz) in the EDEF animals compared to the
CON animals (P<0.05). The stimulated and the contralateral TA muscle from the EDEF animals had significantly higher markers of lipid peroxidation
compared to the same muscles in the CON animals (P<0.05). These data support the hypothesis that VE deficiency impairs muscular endurance and alters muscle contractile properties
following a prolonged series of contractions.
Electronic Publication 相似文献
8.
Skeletal muscle adaptation to chronic hypoxia includes loss of oxidative capacity and decrease in fiber size. However, the
diaphragm may adapt differently since its activity increases in response to hypoxia. Thus, we hypothesized that chronic hypoxia
would not affect endurance, mitochondrial function, or fiber size in the mouse diaphragm. Adult male mice were kept in normoxia
(control) or hypoxia (hypoxia, FIO2 = 10%) for 4 weeks. After that time, muscles were collected for histological, biochemical, and functional analyses. Hypoxia
soleus muscles fatigued faster (fatigue index higher in control, 21.5 ± 2.6% vs. 13.4 ± 2.4%, p < 0.05), but there was no difference between control and hypoxia diaphragm bundles. Mean fiber cross-sectional area was unchanged
in hypoxia limb muscles, but it was 25% smaller in diaphragm (p < 0.001). Ratio of capillary length contact to fiber perimeter was significantly higher in hypoxia diaphragm (28.6 ± 1.2
vs. 49.3 ± 1.4, control and hypoxia, p < 0.001). Mitochondrial respiration rates in hypoxia limb muscles were lower: state 2 decreased 19%, state 3 31%, and state
4 18% vs. control, p < 0.05 for all comparisons. There were similar changes in hypoxia diaphragm: state 3 decreased 29% and state 4 17%, p < 0.05. After 4 weeks of hypoxia, limb muscle mitochondria had lower content of complex IV (cytochrome c oxidase), while
diaphragm mitochondria had higher content of complexes IV and V (F
1/F
0 ATP synthase) and less uncoupling protein 3 (UCP-3). These data demonstrate that diaphragm retains its endurance during chronic
hypoxia, apparently due to a combination of morphometric changes and optimization of mitochondrial energy production. 相似文献
9.
Resistance exercise training attenuates exercise-induced lipid peroxidation in the elderly 总被引:2,自引:0,他引:2
Vincent KR Vincent HK Braith RW Lennon SL Lowenthal DT 《European journal of applied physiology》2002,87(4-5):416-423
This study examined the effects of 6 months of resistance exercise (RX) on basal and post-aerobic exercise lipid peroxidation
(LIPOX). Men and women [n=62, mean (SD) age 68.4 (6) years] were divided randomly into either a control (n=16, CON), low-intensity training [LEX n=24; 50% one-repetition maximum (1RM), 13 repetitions/exercise], or high-intensity training (HEX n=22, 80% 1RM, 8 repetitions/exercise) group. Pre- and post-training, subjects performed a graded aerobic exercise test (GXT).
Blood samples were collected prior to and 10 min following each GXT. Subjects trained 3 times per week for 6 months using
12 RX machines. LIPOX was determined by measuring levels of thiobarbituric reactive acid substances (TBARS) and lipid hydroperoxides
(PEROX). RX had no effect on resting LIPOX. Post-training, post-GXT TBARS were lower in the LEX and HEX groups by 14% and
18%, respectively, compared to CON (P<0.05). Post-GXT PEROX levels were lower (P<0.05) in LEX and HEX compared to CON [CON 3.51 (0.56) nmol/ml, LEX 2.89 (0.80) nmol/ml, HEX 2.99 (0.63) nmol/ml]. Serum total
and non-protein (glutathione) thiols were higher in the LEX and HEX groups following training compared to CON (P<0.05). These data suggest that RX can (1) reduce serum LIPOX, (2) provide protection against oxidizing agents in vitro, and
(3) provide a "cross-protection" against the oxidative stress generated by aerobic exercise, perhaps mediated by improvements
in the thiol portion of the antioxidant defense.
Electronic Publication 相似文献
10.
Kawakami Y Akima H Kubo K Muraoka Y Hasegawa H Kouzaki M Imai M Suzuki Y Gunji A Kanehisa H Fukunaga T 《European journal of applied physiology》2001,84(1-2):7-12
Nine healthy men carried out head-down bed rest (BR) for 20 days. Five subjects (TR) performed isometric, bilateral leg extension
exercise every day, while the other four (NT) did not. Before and after BR, maximal isometric knee extension force was measured.
Neural activation was assessed using a supramaximal twitch interpolated over voluntary contraction. From a series cross-sectional
magnetic resonance imaging scans of the thigh, physiological cross-sectional areas (PCSA) of the quadriceps muscles were estimated
(uncorrected PCSA, volume/estimated fibre length). Decrease in mean muscle force after BR was greater in NT [−10.9 (SD 6.9)%, P < 0.05] than in TR [0.5 (SD 7.9)%, not significant]. Neural activation did not differ between the two groups before BR, but
after BR NT showed smaller activation levels. Pennation angles of the vastus lateralis muscle, determined by ultrasonography,
showed no significant changes in either group. The PCSA decreased in NT by −7.8 (SD 0.8)% (P < 0.05) while in TR PCSA showed only an insignificant tendency to decrease [−3.8 (SD 3.8)%]. Changes in force were related
more to changes in neural activation levels than to those in PCSA. The results suggest that reduction of muscle strength by
BR is affected by a decreased ability to activate motor units, and that the exercise used in the present experiment is effective
as a countermeasure.
Accepted: 18 September 2000 相似文献
11.
Carbohydrate supplementation during prolonged cycling exercise spares muscle glycogen but does not affect intramyocellular lipid use 总被引:1,自引:0,他引:1
Stellingwerff T Boon H Gijsen AP Stegen JH Kuipers H van Loon LJ 《Pflügers Archiv : European journal of physiology》2007,454(4):635-647
Using contemporary stable-isotope methodology and fluorescence microscopy, we assessed the impact of carbohydrate supplementation
on whole-body and fiber-type-specific intramyocellular triacylglycerol (IMTG) and glycogen use during prolonged endurance
exercise. Ten endurance-trained male subjects were studied twice during 3 h of cycling at 63 ± 4% of maximal O2 uptake with either glucose ingestion (CHO trial; 0.7 g CHO kg−1 h−1) or without (CON placebo trial; water only). Continuous infusions with [U-13C] palmitate and [6,6-2H2] glucose were applied to quantify plasma free fatty acids (FFA) and glucose oxidation rates and to estimate intramyocellular
lipid and glycogen use. Before and after exercise, muscle biopsy samples were taken to quantify fiber-type-specific IMTG and
glycogen content. Plasma glucose rate of appearance (R
a) and carbohydrate oxidation rates were substantially greater in the CHO vs CON trial. Carbohydrate supplementation resulted
in a lower muscle glycogen use during the first hour of exercise in the CHO vs CON trial, resulting in a 38 ± 19 and 57 ± 22%
decreased utilization in type I and II muscle-fiber glycogen content, respectively. In the CHO trial, both plasma FFA R
a and subsequent plasma FFA concentrations were lower, resulting in a 34 ± 12% reduction in plasma FFA oxidation rates during
exercise (P < 0.05). Carbohydrate intake did not augment IMTG utilization, as fluorescence microscopy revealed a 76 ± 21 and 78 ± 22%
reduction in type I muscle-fiber lipid content in the CHO and CON trial, respectively. We conclude that carbohydrate supplementation
during prolonged cycling exercise does not modulate IMTG use but spares muscle glycogen use during the initial stages of exercise
in endurance-trained men. 相似文献
12.
Recovery from prolonged exercise involves both rehydration and replenishment of endogenous carbohydrate stores. This study
examined the influence of drinking a carbohydrate-electrolyte solution on short-term recovery and subsequent exercise capacity
in a warm environment. Thirteen healthy male volunteers completed two trials, at least 7 days apart. On each occasion subjects
performed an initial treadmill run at 60% of maximal oxygen uptake (VO2max), for 90 min or until volitional fatigue (T1), in a warm environment (35 °C, 40% relative humidity, RH). Volitional ingestion
of water was permitted during each of the exercise trials. During a subsequent 4-h recovery period (REC) subjects consumed
either a 6.9% carbohydrate-electrolyte solution (CES) or a sweetened placebo (P), in a volume equivalent to 140% of body mass
loss. Following REC, subjects ran to exhaustion at the same %VO2max in order to assess their endurance capacity (T2). Mean (SEM) run times during T1 did not differ between the CES [74.8 (4.6) min]
and P [72.5 (5.2) min] trials. Body mass was reduced (P < 0.01) by 1.9 (0.2)% (CES) and 1.7 (0.2)% (P), and plasma volume (P < 0.01) by 6.0 (0.9)% (CES) and 5.4 (1.0)% (P) during the T1 trials. During REC 2006 (176) ml and 1830 (165) ml of fluid was
ingested, providing 138 (12) g and 0 g of carbohydrate in the CES and P trials, respectively. Prior to T2, plasma volume and
net fluid balance were similarly restored [CES +58 (26) g; P −4 (68) g] in both trials. During T2 the exercise duration was
longer (P < 0.01) in the CES compared to the P trial [CES 60.9 (5.5) min; P 44.9 (3.0) min]. Thus, provided that an adequate hydration
status is maintained, inclusion of carbohydrate within an oral rehydration solution will delay the onset of fatigue during
a subsequent bout of prolonged submaximal running in a warm environment.
Accepted: 25 February 2000 相似文献
13.
Hunter AM St Clair Gibson A Derman WE Lambert M Dennis SC Noakes TD 《European journal of applied physiology》2002,88(3):275-281
This study analysed the effect of selective β1-blockade on neuromuscular recruitment characteristics during progressive endurance exercise. Ten healthy subjects ingested
a selective β1-blocker, acebutolol (200 mg b.d.), for 7 days (for one of two cycling trials), with a 10-day wash-out period between trials.
On the last day of acebutolol ingestion subjects performed three successive 15-min rides at 30%, 50% and 70% of their peak
power output and then cycled at increasing (15 W min–1) work rates to exhaustion. Force output, heart rate, submaximal V˙O2, rate of perceived exertion (RPE), electromyographic (EMG) data and blood lactate were captured during the cycling activity.
Peak work rate [270 (111) W vs 197 (75) W, CON vs BETA, P <0.01], time to exhaustion [49.7 (23.2) min vs 40.3 (23.7) min, CON vs BETA, P <0.05] and heart rate [mean, for the full ride 135.5 (38.3) beats min–1 vs 111.5 (30.0) beats min–1 CON vs BETA, P <0.05] were significantly lower for the group who ingested β1-blockade (BETA) compared to the control group (CON). Although not significant, submaximal V˙O2 was reduced in BETA during the ride, while RPE was significantly higher during the ride for BETA (P <0.01). Mean integrated electromyography was higher in the BETA group although these differences were not significant. Mean
power frequency values of the BETA group showed a significant (P <0.05) shift to the upper end of the spectrum in comparison to the control group. Lactate values [11.7 (3.5) mmol.l–1 vs 7.1 (4.1) mmol.l–1 CON vs BETA] were significantly lower (P <0.05) at exhaustion in BETA. Significant reductions in cycling performance were found when subjects ingested β1-blockers. This study has shown significant shifts to the upper end of the EMG frequency spectrum after β1-blocker ingestion, which could be caused by a change in neuromuscular recruitment strategy to compensate for the impaired
submaximal exercise performance.
Electronic Publication 相似文献
14.
Kim YJ Shin YO Bae JS Lee JB Ham JH Son YJ Kim JK Kim C Lee BK Oh JK Othman T Min YK Yang HM 《Pflügers Archiv : European journal of physiology》2008,455(6):1081-1088
Recent studies showed that tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6), as well as high-sensitive C-reactive
protein (hsCRP) levels are predictive factors of cardiovascular risk. However, the effect of cardiac rehabilitation (CR) intervention
in coronary artery disease (CAD) patients on these factors is not known. The aim of this study was to evaluate the effects
of CR and exercise on hsCRP and inflammatory cytokine levels in patients with CAD after percutaneous coronary intervention
(PCI). CAD patients who underwent PCI were divided into a CR and exercise group (CRE, n = 29) or a control group (CON, n = 10). CR and exercise consisted of 6 weeks supervised exercise training and 8 weeks home-based, self-managed exercise. Compared
to pre-experimental levels, TNF-α (by 20.4%; p = 0.006) and IL-6 (by 49.0%; p < 0.0001), as well as hsCRP (by 59.4%; p < 0.0001), were markedly decreased after CR and exercise in CAD patients but not in control group, except for IL-6 (by 41.6%;
p = 0.001). However, there was no significant alteration of adiposity-related variables such as BMI, percent body fat, and
waist circumferences, in both groups. We suggest that CR and exercise in CAD patients after PCI induce significant reduction
in hsCRP and inflammatory cytokines (TNF-α and IL-6), and marked increase in exercise tolerance and capacity. 相似文献
15.
Vitamin E is the major lipid-soluble antioxidant found in foods, and its bioavailability is affected by the presence of dietary
fats. Athletes often consume low-fat diets and may be more susceptible to the oxidative stress produced by exercise due to
the low availability of vitamin E. In this study, the effects of a low-fat diet on vitamin E intake and oxidative stress markers
were assessed in collegiate female rowers. All subjects habitually consumed either a low-fat (LF; <40 g fat · day−1) or a high-fat (HF; >60 g fat · day−1) diet. Subjects ran downhill for 45 min at 75% of their age-predicted maximal heart rate. Blood samples were collected immediately
pre- and post-exercise, and at 6, 24, and 48 h post-exercise. Subjects in the LF group consumed significantly less vitamin
E (2.9 mg vitamin E · day−1) than advised by the Recommended Dietary Allowance (RDA; 8.0 mg vitamin E · day−1) and than those in the HF group (9.8 mg vitamin E · day−1; P < 0.05). Plasma concentrations of vitamin E, malondialdehyde, and conjugated dienes were not significantly different between
LF and HF before or after exercise. Creatine kinase became significantly elevated above baseline at 6 h and 24 h post-exercise
in both groups (P < 0.05). We can conclude from these data that although the subjects in the LF group were not consuming the recommended amount
of vitamin E in their diets, their vitamin E intake appears to be sufficient to protect against the oxidative stress produced
by this moderate-intensity exercise.
Accepted: 28 April 2000 相似文献
16.
Akova B Sürmen-Gür E Gür H Dirican M Sarandöl E Küçükoglu S 《European journal of applied physiology》2001,84(1-2):141-147
The purpose of this study was to investigate the individual and combined antioxidant effects of menstrual cycle phase-related
alterations in blood serum oestradiol concentrations and of dietary vitamin E supplementation on exercise-induced oxidative
stress and muscle performance. A group of 18 sedentary women, aged 19–35 years, were given supplements of 300 mg α-tocopherol
(n=10) or placebo (n=8) daily during the course of two menstrual cycles. The subjects exercised the knee isokinetically to exhaustion after cycling
submaximally at 50% maximal oxygen uptake during the menstrual and preovulatory phases of their menstrual cycles. Blood samples
were taken before and after the exercise, to evaluate haematocrit, plasma lactic acid and malondialdehyde concentrations,
erythrocyte antioxidant enzymes superoxide dismutase (SOD) and glutathione peroxidase (GPx) activities and apolipoprotein
B containing lipoprotein (non-high density lipoprotein, HDL, fraction) oxidation. Serum vitamin E, follicle stimulating hormone,
luteinizing hormone and oestradiol concentrations were measured in pre-exercise blood samples. Neither vitamin E supplementation
nor oestradiol concentrations influenced SOD and GPx activities or the susceptibility of the non-HDL fraction to oxidation
while at rest. Plasma malondialdehyde concentration was unaffected by exercise, however significant reductions in erythrocyte
SOD and GPx activities and increased susceptibility of the non-HDL fraction to oxidation were noted after exercise. Exercise-induced
changes were reduced when oestradiol concentration was high in the preovulatory phase, independent of the serum vitamin E
concentrations. In addition, both pre- (r=0.58, P < 0.05) and post-exercise (r=0.73, P < 0.001) GPx activities in placebo administered subjects were positively correlated with oestradiol concentrations. In conclusion,
these findings suggest a better protective role of oestradiol against oxidative injury, compared to vitamin E. Exhausting
muscle performance was, however, not influenced by vitamin E supplementation and/or cycle-phase related changes in oestradiol
concentrations.
Accepted: 18 September 2000 相似文献
17.
Exercise training induces similar elevations in the activity of oxoglutarate dehydrogenase and peak oxygen uptake in the human quadriceps muscle 总被引:1,自引:0,他引:1
Blomstrand E Krustrup P Søndergaard H Rådegran G Calbet JA Saltin B 《Pflügers Archiv : European journal of physiology》2011,462(2):257-265
During exercise involving a small muscle mass, peak oxygen uptake is thought to be limited by peripheral factors, such as
the degree of oxygen extraction from the blood and/or mitochondrial oxidative capacity. Previously, the maximal activity of
the Krebs cycle enzyme oxoglutarate dehydrogenase has been shown to provide a quantitative measure of maximal oxidative metabolism,
but it is not known whether the increase in this activity after a period of training reflects the elevation in peak oxygen
consumption. Fourteen subjects performed one-legged knee extension exercise for 5–7 weeks, while the other leg remained untrained.
Thereafter, the peak oxygen uptake by the quadriceps muscle was determined for both legs, and muscle biopsies were taken for
assays of maximal enzyme activities (at 25°C). The peak oxygen uptake was 26% higher in the trained than in the untrained
muscle (395 vs. 315 ml min−1 kg−1, respectively; P < 0.01). The maximal activities of the Krebs cycle enzymes in the trained and untrained muscle were as follows: citrate synthase,
22.4 vs. 18.2 μmol min−1 g−1 (23%, P < 0.05); oxoglutarate dehydrogenase, 1.88 vs. 1.54 μmol min−1 g−1 (22%, P < 0.05); and succinate dehydrogenase, 3.88 vs. 3.28 μmol min−1 g−1 (18%, P < 0.05). The difference between the trained and untrained muscles with respect to peak oxygen uptake (80 ml min−1 kg−1) corresponded to a flux through the Krebs cycle of 1.05 μmol min−1 g−1, and the corresponding difference in oxoglutarate dehydrogenase activity (at 38°C) was 0.83 μmol min−1 g−1. These parallel increases suggest that there is no excess mitochondrial capacity during maximal exercise with a small muscle
mass. 相似文献
18.
LeMura LM von Duvillard SP Andreacci J Klebez JM Chelland SA Russo J 《European journal of applied physiology》2000,82(5-6):451-458
The purpose of this study was to evaluate the effects of various modes of training on the time-course of changes in lipoprotein-lipid
profiles in the blood, cardiovascular fitness, and body composition after 16 weeks of training and 6 weeks of detraining in
young women. A group of 48 sedentary but healthy women [mean age 20.4 (SD 1) years] were matched and randomly placed into
a control group (CG, n=12), an aerobic training group (ATG, n=12), a resistance training group (RTG, n=12), or a cross-training group that combined both aerobic and resistance training (XTG, n=12). The ATG, RTG and XTG trained for 16 weeks and were monitored for changes in blood concentrations of lipoprotein-lipids,
cardiovascular fitness, body composition, and dietary composition throughout a 16 week period of training and 6 weeks of detraining.
The ATG significantly reduced blood concentrations of triglycerides (TRI) (P < 0.05) and significantly increased blood concentrations of high-density lipoprotein-cholesterol (HDL-C) after 16 weeks of
training. The correlation between percentage fat and HDL-C was 0.63 (P < 0.05), which explained 40% of the variation in HDL-C, while the correlation between maximal oxygen uptake (V˙O2max) and HDL-C was 0.48 (P < 0.05), which explained 23% of the variation in HDL-C. The ATG increased V˙O2max by 25% (P < 0.001) and decreased percentage body fat by 13% (P < 0.05) after 16 weeks. Each of the alterations in the ATG had disappeared after the 6 week detraining period. The concentration
of total cholesterol (TC), TRI, HDL-C and low density lipoprotein-cholesterol in the blood did not change during the study
in RTG, XTG and CG. The RTG increased upper and lower body strength by 29% (P < 0.001) and 38%, respectively. The 6 week detraining strength values obtained in RTG were significantly greater than those
obtained at baseline. The XTG increased upper and lower body strength by 19% (P < 0.01) and 25% (P < 0.001), respectively. The 6 week detraining strength values obtained in XTG were significantly greater than those obtained
at baseline. The RTG, XTG and CG did not demonstrate any significant changes in either V˙O2max, or body composition during the training and detraining periods. The results of this study suggest that aerobic-type exercise
improves lipoprotein-lipid profiles, cardiorespiratory fitness and body composition in healthy, young women, while resistance
training significantly improved upper and lower body strength only.
Accepted: 9 April 2000 相似文献
19.
Previous findings of a narcosis-induced reduction in heat production during cold water immersion, as reflected in oxygen
uptake (V˙O2), have been attributed to the attenuation of the shivering response. The possibility of reduced oxygen utilization (V˙O2) by the muscles could not, however, be excluded. Accordingly, the present study tested the hypothesis that mild narcosis,
induced by inhalation of a normoxic gas mixture containing 30% nitrous oxide (N2O), would affect V˙O2. Nine male subjects participated in both maximal and submaximal exercise trials, inspiring either room air (AIR) or a normoxic
mixture containing 30% N2O. In the submaximal trials, the subjects exercised at 50% of maximal exercise intensity (W˙
max
) as determined in the maximal AIR trial. Though the subjects attained the same W˙
max
in the AIR and N2O trials, maximal V˙O2 was significantly higher (P < 0.05) during the N2O condition [58.9 (SEM 3.1) ml · kg−1 · min−l] compared to the AIR condition [55.0 (SEM 2.4) ml · kg−1 · min−l]. However, the V˙O2-relative exercise intensity relationship was similar during both maximal AIR and maximal N2O at submaximal exercise intensities. There were no significant differences in the responses of oesophageal temperature, sweating
rate, heart rate and ventilation between AIR and N2O in the maximal and submaximal tests. It was concluded that the previously reported narcosis-induced reductions in V˙O2 observed during cold water immersion can be attributed solely to a reduction in the shivering response rather than to decreased
oxygen utilization by the muscles.
Accepted: 6 February 2000 相似文献
20.
Joey C. Eisenmann Peter T. Katzmarzyk Germain Thériault Thomas M. K. Song Robert M. Malina Claude Bouchard 《European journal of applied physiology》2000,81(1-2):40-46
The relationships between cardiac dimensions and physical activity and submaximal working capacity were examined in 198 boys
and 154 girls, aged 9–18 years, who were participants in the first phase of the Québec Family Study. The sample was divided
into three age groups, 9–12 years, 13–15 years, and 16–18 years. Indicators of physical activity included estimated daily
energy expenditure (EE) and time spent in moderate-to-vigorous physical activity (median metabolic equivalents of energy expenditure
above resting metabolic rate ≥4.8). Submaximal physical working capacity (PWC150) was determined using a submaximal exercise test on a Monark cycle ergometer. Echocardiographically determined dimensions
included posterior wall thickness, septal wall thickness, and left ventricular mass (LVM). The analyses were based on partial
correlation and analysis of covariance, controlling for age and body surface area. Relationships between EE/physical activity
variables and cardiac dimensions were low and, at best, moderate (r < 0.45). With subjects grouped into tertiles by indicators of physical activity, LVM was significantly different only among
16- to 18-year-old girls (157 g vs 134 g in the highest and lowest quartiles, respectively; P < 0.05). Correlations between cardiac dimensions and PWC150 were also low (r < 0.30), with few significant relationships. In general, cardiac dimensions were not related to habitual physical activity
and PWC150 in young subjects aged 9–18 years. However, significant correlations were positive, as expected. LVM may be related to submaximal
power output in boys since it accounts for 3% of the variance, after adjusting for age and BSA.
Received: 4 January 1999 / Accepted: 8 June 1999 相似文献