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Biomedical subjects

M Kjaer

Publications and source records attributed to M Kjaer.

At least 127 records · Page 7Linked to original sources
PubMed1997

The effect of moderate exercise on postprandial glucose homeostasis in NIDDM patients.

The influence of exercise on glycaemia in the post-prandial state was studied for the first time in non-insulin-dependent diabetic (NIDDM) patients. Meal-induced glucose responses were followed for 8 h in 9 diet-treated patients with NIDDM. Subjects consumed a standardized breakfast and 4 h later a standardized lunch. They were studied in the resting state (control day (CD)) and on another day 45 min of bicycle exercise (53 +/- 2% VO2max (mean +/- SEM)) was performed 45 min after breakfast (exercise day (ED)). On day 3 (diet day (DD)), the breakfast meal was reduced corresponding to the extra energy expenditure during the exercise period on ED. Responses were calculated as areas under the plasma concentration curve (AUC) during 4 h after either breakfast (B-AUC) or lunch (L-AUC). B-AUC for glucose was identical on ED (215 +/- 63 mmol/l.240 min) and DD (219 +/- 60 mmol/l.240 min) and on these days lower (p < 0.05) than on CD (453 +/- 78 mmol/l.240 min). L-AUC for glucose on CD, ED and DD did not differ significantly. B-AUCs for both insulin and C-peptide were also significantly lower on ED and DD as compared to CD (Insulin: 31337 +/- 8682, 26092 +/- 6457 and 47649 +/- 15046 mmol/l.240 min, respectively. C-peptide: 99 +/- 19, 104 +/- 26 and 195 +/- 31 pmol/ml.240 min, respectively). Rate of appearance (Ra) for glucose was unaffected by exercise whereas rate of disappearance (Rd) increased significantly. No differences in Ra or Rd were observed after lunch. In conclusion, post-prandial exercise of moderate intensity decreases glycaemia and plasma insulin levels after breakfast in NIDDM patients, but this effect does not persist during and after the following lunch meal. Reduction of breakfast caloric intake has the same effect on post-prandial glycaemia and insulin secretion as an equivalent exercise-induced increase in caloric expenditure.

Analysis of Variance↗
PubMed1997

Increased bone mineral density after prolonged electrically induced cycle training of paralyzed limbs in spinal cord injured man.

Spinal cord injured (SCI) individuals have a substantial loss of bone mass in the lower limbs, equaling approximately 50% of normal values in the proximal tibia, and this has been associated with a high incidence of low impact fractures. To evaluate if this inactivity-associated condition in the SCI population can be reversed with prolonged physical training, ten SCI individuals [ages 35.3 +/- 2.3 years (mean +/- standard error [SE]); post injury time: 12.5 +/- 2.7 years, range 2-24 years; level of lesion: C6-Th4; weight: 78 +/- 3.8 kg] performed 12 months of Functional Electrical Stimulated (FES) upright cycling for 30 min per day, 3 days per week, followed by six months with only one weekly training session. Bone mineral density (BMD) was determined before training and 12 and 18 months later. BMD was measured in the lumbar spine, the femoral neck, and the proximal tibia by dual energy absorptiometry (DEXA, Nordland XR 26 MK1). Before training, BMD was in the proximal tibia (52%), as well as in the femoral neck, lower in SCI subjects than in controls of same age (P < 0.05). BMD of the lumbar spine did not differ between groups (P > 0.05). After 12 months of training, the BMD of the proximal tibia had increased 10%, from 0.49 +/- 0.04 to 0. 54 +/- 0.04 g/cm2 (P < 0.05). After a further 6 months with reduced training, the BMD in the proximal tibia no longer differed from the BMD before training (P > 0.05). No changes were observed in the lumbar spine or in the femoral neck in response to FES cycle training. It is concluded that in SCI, the loss of bone mass in the proximal tibia can be partially reversed by regular long-term FES cycle exercise. However, one exercise session per week is insufficient to maintain this increase.

Absorptiometry, Photon↗
PubMed1997

Long-term adaptation to electrically induced cycle training in severe spinal cord injured individuals.

Spinal cord injured (SCI) individuals most often contract their injury at a young age and are deemed to a life of more or less physical inactivity. In addition to the primary implications of the SCI, severe SCI individuals are stigmatized by conditions related to their physically inactive lifestyle. It is unknown if these inactivity related conditions are potentially reversible and the aim of the present study was, therefore, to examine the effect of exercise on SCI individuals. Ten such individuals (six with tetraplegia and four with paraplegia; age 27-45 years; time since injury 3-23 years) were exercise trained for 1 year using an electrically induced computerized feedback controlled cycle ergometer. They trained for up to three times a week (mean 2.3 times), 30 min on each occasion. The gluteal, hamstring and quadriceps muscles were stimulated via electrodes placed on the skin over their motor points. During the first training bouts, a substantial variation in performance was seen between the subjects. A majority of them were capable of performing 30 min of exercise in the first bout; however, two individuals were only able to perform a few minutes of exercise. After training for 1 year all of the subjects were able to perform 30 min of continuous training and the work output had increased from 4 +/- 1 (mean +/- SE) to 17 +/- 2 Kilo Joules per training bout (P < 0.05). The maximal oxygen uptake during electrically induced exercise increased from 1.20 +/- 0.08 litres per minute measured after a few weeks habituation to the exercise to 1.43 +/- 0.09 litres per minute after training for 1 year (P < 0.05). Magnetic resonance cross sectional images of the thigh were performed to estimate muscle mass and an increase of 12% (mean, P < 0.05) was seen in response to 1 year of training. In biopsies taken before exercise various degrees of atrophy were observed in the individual muscle fibres, a phenomenon that was partially normalized in all subjects after training. The fibre type distribution in skeletal muscles is known to shift towards type IIB fibres (fast twitch, fast fatiguable, glycolytic fibres) within the first 2 years after the spinal cord injury. The muscle in the present investigation contained of 63% myosin heavy chain (MHC) isoform IIB, 33% MHC isoform IIA (fast twitch, fatigue resistant) and less than 5% MHC isoform I (slow twitch) before training. A shift towards more fatigue resistant contractile proteins was found after 1 year of training. The percentage of MHC isoform IIA increased to 61% of all contractile protein and a corresponding decrease to 32% was seen in the fast fatiguable MHC isoform IIB, whereas MHC isoform I only comprised 7% of the total amount of MHC. This shift was accompanied by a doubling of the enzymatic activity of citrate synthase, as an indicator of mitochondrial oxidative capacity. It is concluded that inactivity-associated changes in exercise performance capacity and skeletal muscle occurring in SCI individuals after injury are reversible, even up to over 20 years after the injury. It follows that electrically induced exercise training of the paralysed limbs is an effective rehabilitation tool that should be offered to SCI individuals in the future.

Adaptation, Physiological↗
PubMed1997

Isokinetic muscle strength and capacity for muscular knee joint stabilization in elite sailors.

In the present study isokinetic dynamometry was used to evaluate the capacity for dynamic knee joint stabilization via muscle contraction in elite sailors (15 males, SM; 6 females, SF) compared to a group of matched controls (8 males, CM). Maximal concentric, eccentric and isometric moment of force (peak moment and moment at 50 degree knee flexion) was obtained for the knee extensors (quadriceps) and flexors (hamstrings) during isokinetic knee joint movement at angular velocities 0, 30, 120 and 180 degrees x s(-1). High levels of eccentric knee extension strength were observed for the elite sailors compared to the controls (p < 0.05). Based on peak moment and 50 degree moment, respectively, conventional hamstring/quadriceps (H/Q) strength ratio (+/-SD) ranged from 0.37+/-0.06 to 0.54+/-0.06 and from 0.42+/-0.07 to 0.57+/-0.10 across groups, speed and contraction mode. The female elite sailors displayed lower (p<0.05) concentric H/Q ratios at 120 and 180 degrees x s(-1) compared to the controls (0.41-0.45 vs. 0.51-0.56, respectively). The ratio of eccentric hamstring to concentric quadriceps strength (H/Q for extension) or concentric hamstring to eccentric quadriceps strength (H/Q for flexion) may provide a more functional estimate of the capacity for muscular knee joint stabilization (1). Based on peak moment and 50 degree moment, respectively, this "functional" H/Q ratio ranged from 0.24+/-0.03 and 0.25+/-0.02 for knee flexion at 180 degrees x s(-1) to 0.97+/-0.17 and 0.88+/-0.12 for knee extension at 180 degrees x s(-1) among the three groups. Comparable levels of "functional" H/Q ratio were observed (p>0.05) for fast knee extension in the elite sailors (SF:0.81-0.97, SM: 0.88-0.95) and the male controls (CM: 0.80-0.84). In conclusion, a "functional" H/Q ratio of 0.8-1.0 observed for all subjects indicated a significant functional capacity of the hamstring muscles for providing muscular stability at the knee joint in fast knee extension. A significant potential for muscular knee joint stabilization appeared for the elite sailors despite their high maximal quadriceps strength and partially lower (SF) conventional H/Q ratios.

Analysis of Variance↗
PubMed1997

The therapy of cancer pain and its integration into a comprehensive supportive care strategy.

By the beginning of the 21st century cancer will claim over nine million lives per year. Of these patients, 80%-90% will experience pain at some time during the course of their disease. The management of cancer and the associated pain syndromes is likely to cause a massive drain on resources, making it imperative that we use the resources available to maximum efficiency. In the past decade progress has been made in the understanding of cancer pain and how best to manage it. However, this area of cancer therapy continues to be surrounded by much controversy, particularly the availability and use of strong opioids. Additional measures are required to ensure that no patients are left to suffer the burden of cancer pain. These include: strongly improved education of all healthcare professionals in cancer pain and cancer pain therapy; academic affiliation--university chairs in palliative/supportive care securing education of the coming generations of medical doctors and nurses; improved legislation concerning opioids in many societies through systematic influence of politicians and healthcare decision makers; re-allocation of resources for cancer treatment programmes from the curative to the palliative/supportive treatment spectrum; re-defining myths concerning cancer, pain and opioid consumption, both among healthcare workers and in societies in general. The media will play a crucial role in this process. Revising the way in which our resources are allocated and providing all patients access to individually tailored treatment care packages are strategies that could be adopted for future supportive care of cancer patients.

Analgesics, Opioid↗
PubMed1997

Conservative treatment of a partial Achilles tendon rupture with an intratendinous lesion.

The Achilles tendon is a common site of acute and overuse injuries in runners. A case is described here in which the diagnosis of a post-traumatic intratendinous lesion was based on clinical examination and magnetic resonance imaging (MRI), and where conservative treatment was given. After a 6 months follow-up, symptoms as well as the MRI verified that intra-tendinous structural abnormalities had disappeared. This case report demonstrates that conservative treatment may be sufficient to cure Achilles injury with severe structural changes inside the tendon.

Achilles Tendon↗
PubMed1997

Determinants of musculoskeletal flexibility: viscoelastic properties, cross-sectional area, EMG and stretch tolerance.

Cross-sectional area, stiffness, viscoelastic stress relaxation, stretch tolerance and EMG activity of the human hamstring muscle group were examined in endurance-trained athletes with varying flexibility. Subjects were defined as tight (n = 10) or normal (n = 8) based on a clinical toe-touch test. Cross-sectional area was computed from magnetic resonance imagining (MRI) images. Torque (Nm) offered by the hamstring muscle group, electromyographic (EMG) activity, knee joint angle and velocity were continuously monitored during two standardized stretch protocols. Protocol 1 consisted of a slow stretch at 0.087 rad/s (dynamic phase) to a pre-determined final angle followed by a 90-s static phase. In the dynamic phase final angle and stiffness was lower in tight (28.0+/-2.9 Nm/rad) than normal subjects (54.9+/-6.5 Nm/rad), P<0.01. In the static phase tight subjects had lower peak (15.4+/-1.8 Nm) and final torque (10.8+/-1.6 Nm) than normal subjects (31.6+/-4.1 Nm, 24.1+/-3.7 Nm, respectively)(P<0.01), but torque decline was similar. Protocol 2 consisted of a slow stretch to the point of pain and here tight subjects reached a lower maximal angle, torque, stiffness and energy than normal subjects (P<0.01). On the other hand, stiffness was greater in tight subjects in the common range (P<0.01). Cross-sectional area of the hamstring muscles and EMG activity during the stretch did not differ between the groups. However, lateral hamstring cross-sectional area was positively related to mid-range stiffness (P<0.05), but inversely related to final stiffness, peak torque and the toe-touch test (P<0.01). Final angle and peak torque in protocol 1 combined to improve the predictability of the toe-touch test (R2=0.77, P<0.001). These data show that the toe-touch test is largely a measure of hamstring flexibility. Further, subjects with a restricted joint range of movement on a clinical toe-touch test have stiffer hamstring muscles and a lower stretch tolerance.

Biomechanical Phenomena↗
PubMed1996

[Bilateral Achilles tendon rupture in individuals with renal transplantation].

Increased incidence of tendinitis and tendon ruptures is reported in recipients of a kidney transplant. Two cases of bilateral achilles tendon rupture after minimal trauma are described. Tendon ruptures are more frequent in individuals with kidney disease in dialysis or after transplantation compared with patients receiving other organ transplantations. It is therefore more likely that tendon ruptures are related to metabolic changes associated with kidney disease rather than with transplantation or with glucocorticoid treatment per se. Clinical symptoms of achilles tendinitis should be considered as warning signs prior to tendon rupture and treated appropriately to avoid further morbidity. There is no contraindication towards surgical suturing of an achilles tendon rupture in patients receiving immunosuppressive treatment including glucocorticoids.

Achilles Tendon↗
PubMed1996

A mechanism for altered flexibility in human skeletal muscle.

1. We investigated the effect of a long-term stretching regimen on the tissue properties and stretch tolerance of human skeletal muscle. 2. Resistance to stretch was measured as torque (in N m) offered by the hamstring muscle group during passive knee extension while electromyographic (EMG) activity, knee joint angle and velocity were continuously monitored during a standardized stretch manoeuvre. Seven healthy subjects were tested before and after a 3 week training period using two separate protocols. Protocol 1 consisted of a slow stretch at 0.087 rad s-1 to a predetermined angle followed by a 90 s holding phase. Subjects were brought to the same angle before and after the training period. Protocol 2 was a similar stretch, but continued to the point of pain. 3. During protocol 1 the torque rose during the stretch and then declined during the holding phase. EMG activity was small and did not change significantly during the protocol. No significant differences in stiffness, energy and peak torque about the knee joint were seen as a result of the training. During protocol 2 the angle to which the knee could be extended was significantly increased as a result of the training. This was accompanied by a comparable increase in peak torque and energy. EMG activity was small and not affected by training. 4. It is concluded that reflex EMG activity does not limit the range of movement during slow stretches and that the increased range of motion achieved from training is a consequence of increased stretch tolerance on the part of the subject rather than a change in the mechanical or viscoelastic properties of the muscle.

Adult↗
PubMed1996

Myosin heavy chain isoform transformation in single fibres from m. vastus lateralis in spinal cord injured individuals: effects of long-term functional electrical stimulation (FES).

The myosin heavy chain (MHC) composition of single fibres from m. vastus lateralis of five spinal- cord-injured (SCI) individuals was analysed by Sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) before, and after 6 and 12 months of functional electrical stimulation (FES)-training, administrated for 30 min three times per week. Prior to FES training 37.2% of the fibres contained only MHC IIB, 21.2% only MHC IIA, and 40.7% co-expressed MHC IIA and MHC IIB. After 6 months of FES-training the number of fibres containing only MHC IIB was reduced to 2.6% (P < 0.05), the number of fibres containing only MHC IIA was increased to 44.3% (P < 0.05), and the number of fibres co-expressing MHC IIA and MHC IIB was 50.9% (ns). After 12 months almost all fibres (91.2%, P < 0.05) contained only MHC IIA. The number of fibres containing only MHC IIB was 2.3% and the fibres co-expressing MHC IIA and IIB had decreased to 4.6% (P < 0.05). The amount of fibres containing only MHC I never exceeded 0.5%. Likewise, the number of fibres co-expressing MHC I and MHC IIA was below 2% throughout the study period. In total, the MHC composition of 1596 single fibres was determined. This study shows that FES-training of paralysed human skeletal muscle administrated over a prolonged period of time, can lead to a marked switch in MHC expression from about equal amounts of MHC IIA and MHC IIB to an almost total dominance of MHC IIA.

Adult↗
PubMed1996

Mechanical and physical responses to stretching with and without preisometric contraction in human skeletal muscle.

OBJECTIVE: To examine electromyography (EMG) activity, passive torque, and stretch perception during static stretch and contract-relax stretch. DESIGN: Two separate randomized crossover protocols: (1) a constant angle protocol on the right side, and (2) a variable angle protocol on the left side. SUBJECTS: 10 male volunteers. INTERVENTION: Stretch-induced mechanical response in the hamstring muscles during passive knee extension was measured as knee flexion torque (Nm) while hamstring surface EMG was measured. Final position was determined by extending the knee to an angle that provoked a sensation similar to a stretch maneuver. Constant angle stretch: The knee was extended to 10 degree below final position, held 10sec, then extended to the final position and held for 80 sec. Variable angle stretch: The knee was extended from the starting position to 10 degrees below the final position, held 10sec, then extended to the onset of pain. Subjects produced a 6-sec isometric contraction with the hamstring muscles 10 degrees below the final position in the contract-relax stretch, but not in the static stretch. MAIN OUTCOME MEASURES: Passive torque, joint range of motion, velocity, and hamstring EMG were continuously recorded. RESULTS: Constant angle contract-relax and static stretch did not differ in passive torque or EMG response. In the final position, passive torque declined 18% to 21% in both contract-relax and static stretch (p<.001), while EMG activity was unchanged. In the variable angle protocol, maximal joint angle and corresponding passive torque were significantly greater in contract-relax compared with static stretch(p<.01), while EMG did not differ. CONCLUSION: At a constant angle the viscoelastic and EMG response was unaffected by the isometric contraction. The variable angle protocol demonstrated that PNF stretching altered stretch perception.

Adult↗
PubMed1996

Exercise performance in elite male and female sailors.

UNLABELLED: In order to evaluate the physiological profile of elite competitive sailors, and to determine if sailors revealed any seasonal variation in their exercise capacity over a 9 month period, results from female sailors (n = 6), and male sailors ("hikers" n = 8 and "non-hikers" n = 7) were compared with male physical education students (n = 8). Maximal oxygen uptake rate (VO2max) determined on treadmill did not differ between male sailors and control subjects (61.4 +/- 2.0 vs 64.9 +/- 1.4 ml O2/min.kg, mean +/- SE) and did not change with time in elite sailors (p > 0.05). Isometric endurance for abdominal and back muscles was similar for all groups. The isometric muscle endurance in a hiking bench was markedly greater in "hikers" [time: 218 sec (91-426) mean, range] compared to control subjects [time: 98 sec (48-188)], male "non-hikers", and female sailors (p < 0.05). Hiking endurance in "hikers" did not change over the 9 month observation period. Furthermore, dynamic arm performance ("all-out" in 60 sec) was higher in "hikers" compared to all other groups. IN CONCLUSION: Elite sailors who perform hiking activity ("hikers") show an enhanced performance in a functional arm test and higher endurance in a hiking-bench compared to "non-hiking" elite sailors and a control group matched for age, weight and fitness. Furthermore sailors did not show any seasonal variation in their VO2max or isometric endurance over a 9 month period.

Adult↗
PubMed1996

Combining 5-fluorouracil with interferon-alpha in the treatment of advanced colorectal cancer: optimism followed by disappointment.

Pre-clinical data have demonstrated synergy between 5-fluorouracil (5-FU) and interferon (IFN)-alpha in colon cancer cell lines. In 1989 the first small single-institution phase II study with this combination in advanced colorectal cancer showed a response of 81% with substantial toxicity, whereas IFN-alpha alone was virtually inactive. Ten published phase II studies including 175 evaluable patients have demonstrated a response rate of 2.3%. 5-FU alone has been used extensively and is moderately active with response rates of 10-11% in 1148 patients evaluated by the Advanced Colorectal Cancer Meta-analysis Project in 1992 and 1994. Eleven subsequent phase II studies with 5-FU + IFN-alpha published over the period of 1990-1994 on 548 patients showed a response rate of 28% with 2% toxic deaths. Recently, nine phase III clinical trials including 1727 randomized patients have compared 5-FU + IFN-alpha to some standard therapies, most often treatment regimens based on 5-FU + leucovorin. Except for one study involving 105 patients, the rest of the phase III studies have demonstrated either no difference (six studies) or significantly worse results (two studies showing substantial toxicity with IFN-alpha + 5-FU). Several studies are ongoing, but results are not likely to change. In conclusion, after a period of high hopes, the combination of 5-FU + IFN-alpha does not seem to fulfill the original expectations. It is costly, it is toxic and it is not effective. New treatment strategies must be developed if progress is to be obtained.

Antimetabolites, Antineoplastic↗
PubMed1996

Antiemetic treatment with two different doses of methylprednisolone in breast cancer patients: a double-blind randomized cross-over study with evaluation of efficacy parameters.

This randomized double-blind cross-over study followed a previous one which showed an antiemetic efficacy from methylprednisolone (MP) 250 mg superior to placebo. The present study compared MP 40 mg with 250 mg in breast cancer patients treated with non-cisplatin chemotherapy. Preference after course II was the determining parameter. Participation in two courses was compulsory for evaluation, participation in four courses was optional. Interim analyses were performed after each 12 patients to a maximum of 60 patients. As there was no significant difference in preference in 60 patients the study was closed. Patients treated with the CEF regimen, patients who requested rescue antiemetics and patients completing four study courses had a better effect from high-dose MP reflected in preference and other parameters. Global assessments, measurement of emetic volumes and the visual analog scale for nausea gave a fair coherence with patients' preference. The numbers of emetic episodes and observer registered nausea were of no value. The stability of preference and other parameters after course II and IV, respectively, was low. The present study did not prove superiority from high-dose MP. This hypothesis must be tested in patients more severely bothered by emesis after chemotherapy. These results show the complexity of evaluation of antiemetic effect and demonstrate the dependency of a given result on the parameter used.

Adult↗
PubMed1996

Viscoelastic stress relaxation during static stretch in human skeletal muscle in the absence of EMG activity.

The present study sought to investigate the role of EMG activity during passive static stretch. EMG and passive resistance were measured during static stretching of human skeletal muscle in eight neurologically intact control subjects and six spinal cord-injured (SCI) subjects with complete motor loss. Resistance to stretch offered by the hamstring muscles during passive knee extension was defined as passive torque (Nm). The knee was passively extended at 5 degrees/s to a predetermined final position, where it remained stationary for 90 s (static phase) while force and integrated EMG of the hamstring muscle were recorded. EMG was sampled for frequency domain analysis in a second stretch maneuver in five control and three SCI subjects. There was a decline in passive torque in the 90-s static phase for both control and SCI subjects, P < 0.05. Although peak passive torque was greater in control subjects, P < 0.05, there was no difference in time-dependent passive torque response between control (33%) and SCI (38%) subjects. Initial and final 5-s IEMG ranged from 1.8 to 3.4 microV.s and did not change during a stretch or differ between control and SCI subjects. Frequency domain analysis yielded similar results in both groups, with an equal energy distribution in all harmonics, indicative of 'white noise'. The present data demonstrate that no measurable EMG activity was detected in either group during the static stretch maneuver. Therefore, the decline in resistance to static stretch was a viscoelastic stress relaxation response.

Adolescent↗
PubMed1996

Regulation of glucose turnover and hormonal responses during electrical cycling in tetraplegic humans.

To examine the importance of blood-borne vs. neural mechanisms for hormonal responses and substrate mobilization during exercise, six spinal cord-injured tetraplegic (C5-T1) males (mean age: 35 yr, range: 24-55 yr) were recruited to perform involuntary, electrically induced cycling [functional electrical stimulation (FES)] to fatigue for 24.6 +/- 2.3 min (mean and SE), and heart rate rose from 67 +/- 7 (rest) to 107 +/- 5 (exercise) beats/min. Voluntary arm cranking in tetraplegics (ARM) and voluntary leg cycling in six matched, long-term immobilized (2-12 mo) males (Vol) served as control experiments. In FES, peripheral glucose uptake increased [12.4 +/- 1.1 (rest) to 19.5 +/- 4.3 (exercise) mumol.min-1.kg-1; P < 0.05], whereas hepatic glucose production did not change from basal values [12.4 +/- 1.4 (rest) vs. 13.0 +/- 3.4 (exercise) mumol.min-1.kg-1]. Accordingly, plasma glucose decreased [from 5.4 +/- 0.3 (rest) to 4.7 +/- 0.3 (exercise) mmol/l; P < 0.05]. Plasma glucose did not change in response to ARM or Vol. Plasma free fatty acids and beta-hydroxybutyrate decreased only in FES experiments (P < 0.05). During FES, increases in growth hormone (GH) and epinephrine and decreases in insulin concentrations were abolished. Although subnormal throughout the exercise period, norepinephrine concentrations increased during FES, and responses of heart rate, adrenocorticotropic hormone, beta-endorphin, renin, lactate, and potassium were marked. In conclusion, during exercise, activity in motor centers and afferent muscle nerves is important for normal responses of GH, catecholamines, insulin, glucose production, and lipolysis. Humoral feedback and spinal or simple autonomic nervous reflex mechanisms are not sufficient. However, such mechanisms are involved in redundant control of heart rate and neuroendocrine activity in exercise.

Adult↗