Exercise- and cold-induced changes in plasma beta-endorphin and beta-lipotropin in men and women

1987 ◽  
Vol 62 (2) ◽  
pp. 622-627 ◽  
Author(s):  
M. Viswanathan ◽  
J. P. Van Dijk ◽  
T. E. Graham ◽  
A. Bonen ◽  
J. C. George

The plasma beta-endorphin (beta-EP) and beta-lipotropin (beta-LPH) response of men, eumenorrheic women, and amenorrheic women (n = 6) to 1 h of rest or to a bicycle ergometer test [20 min at 30% maximum O2 uptake (VO2max), 20 min at 60% VO2max, and at 90% VO2max to exhaustion] was studied in both normal (22 degrees C) and cold (5 degrees C) environments. beta-EP and beta-LPH was measured by radioimmunoassay in venous samples collected every 20 min during rest or after each exercise bout. Exhaustive exercise at ambient temperature (Ta) 22 degrees C induced significant increases in plasma beta-EP and beta-LPH in all subjects as did work at 60% VO2max in amenorrheic and eumenorrheic women. During work at Ta 5 degrees C, the relative increase in beta-EP and beta-LPH was suppressed in eumenorrheic women and completely prevented in amenorrheic women. Although significant lowering of beta-EP and beta-LPH was observed in men and eumenorrheic women during rest at 5 degrees C, amenorrheic women maintained precold exposure levels. These findings suggest that plasma beta-EP and beta-LPH may reflect a thermoregulatory response to heat load. There appears to be a sexual dimorphism in exercise- and cold-induced release of beta-EP and beta-LPH and amenorrhea may be accompanied by alterations in these responses.

1979 ◽  
Vol 46 (4) ◽  
pp. 766-771 ◽  
Author(s):  
W. W. Winder ◽  
R. C. Hickson ◽  
J. M. Hagberg ◽  
A. A. Ehsani ◽  
J. A. McLane

Plasma glucagon and catecholamines increase during prolonged submaximal exercise, but the magnitude of the increase is less in endurance-trained individuals than in untrained subjects. We have studied the rapidity at which this adaptation occurs. Six initially untrained healthy subjects exercised vigorously (on bicycle ergometers and by running) 30–50 min/day, 6 days/wk, for 9 wk. Prior to the beginning of training and at 3-wk intervals thereafter, participants were subjected to 90-min bicycle ergometer test work loads that elicited 58 +/- 2% of the subjects' initial maximal oxygen consumption. The major proportion of the training-induced decrement in plasma glucagon and catecholamine responses to exercise was seen after 3 wk of training. We conclude that the hormonal component of the training adaptation occurs very early in the course of a vigorous endurance training program.


1962 ◽  
Vol 17 (1) ◽  
pp. 47-50 ◽  
Author(s):  
B. Issekutz ◽  
N. C. Birkhead ◽  
K. Rodahl

Oxygen uptake and carbon dioxide output were measured in 32 untrained subjects during exercise on the bicycle ergometer. It was shown that the work respiratory quotient (RQ) under standardized conditions can be used as a measure of physical fitness. ΔRQ (work RQ minus 0.75) increases logarithmically with the work load and maximal O2 uptake is reached at a ΔRQ value of 0.40. This observation offered the possibility of predicting the maximal O2 uptake of a person, based on the measurement of RQ during a single bicycle ergometer test at a submaximal load. For each work RQ between 0.95 and 1.15 a factor was presented, together with the aid of a simple equation, which gave a good approximation (generally better than ±10%) of the maximal O2 uptake.


2003 ◽  
Vol 10 (1) ◽  
pp. 21-23 ◽  
Author(s):  
A G Avtandilov ◽  
S T Vetrile ◽  
D I Nemanova ◽  
A A Kuleshov

Cardiorespiratory system was examined in 33 patients with thoracic scoliosis of degree IV (15 - nonsurgical, 18 - surgical treatment). Eighteen surgically treatment patients were operated using Cotrel-Dubousset instrumentation and were examined within 1-3 years after surgery. Examination included evaluation of external respiration function, echocardiography (ECG), bicycle ergometer test (BEMT). It was shown that postsurgically the function of external respiration was better than in nonsurgically treated patients. ECG showed reliably lower size and thickness of the right ventricular wall as well as considerably lower level of pulmonary hypertension. Tolerance to physical load at BEMT, level of working capacity and the term of restoration was reliably better in surgically treated patients.


1992 ◽  
Vol 17 (4) ◽  
pp. 259-271 ◽  
Author(s):  
Olavi Airaksinen ◽  
Arto Remes ◽  
Pertti J. Kolari ◽  
Teuvo Sihvonen ◽  
Osmo Hānninen ◽  
...  

2019 ◽  
Author(s):  
Chao Zhang ◽  
Mohamed Soliman-Hamad ◽  
Roxanne Robijns ◽  
Niels Verberkmoes ◽  
Frank Verstappen ◽  
...  

BACKGROUND Home-based cardiac rehabilitations (CRs) with digital technologies have been researched and implemented to replace, augment, and complement traditional center-based CR in recent years with considerable success. One problem that technology-enhanced home-based CR can potentially address is the gap between cardiac interventions and formal CR programs. In the Netherlands and some other countries (eg, Australia), patients after cardiac interventions stay at home for 3-4 weeks without much support from their physicians, and often engage in very little physical activity (PA). A home-based exercise program enabled by digital technologies may help patients to better prepare for the later center-based CR programs, potentially increasing the uptake rate of those programs. OBJECTIVE In a randomized controlled trial (RCT), we will evaluate the effectiveness of a home-based walking exercise program enhanced by self-tracking and mobile-based coaching (treatment condition), comparing it with a version of the same program without these technologies (control condition). The added value of the digital technologies is justified if patients in the treatment group walk more steps on average (primary outcome) and show better physical fitness in a bicycle ergometer test and higher self-efficacy toward PA (secondary outcomes). METHODS Based on a power analysis, we will recruit 100 cardiac patients and assign them evenly to the 2 parallel groups. Eligible patients are those who are scheduled in the postanesthesia care unit, know the Dutch language, have basic literacy of using smartphones, and are without medical conditions that may increase risks associated with PA. In a face-to-face meeting with a nurse practitioner, all patients are prescribed a 3-week exercise program at home (2 walking exercises per day with increasing duration), based on national and international guidelines and tailored to their physical conditions after cardiac intervention. Their physical activities (daily steps) will be measured by the Axivity AX3 accelerometer worn at hip position. Patients in the treatment group will also be supported by a Neo Health One self-tracking device and a mobile platform called Heart Angel, through which they are monitored and coached by their nurses. After the study, all patients will perform a bicycle ergometer test and return the devices within 1 week. In addition, 5 questionnaires will be sent to the patients by emails to assess their self-efficacy toward PA and other psychological states for exploratory analyses (at discharge, at the end of each monitoring week, and 1 week after the study). To minimize bias, the randomization procedure will be performed after introducing the exercise program, so the nurse practitioners are blind to the experimental conditions until that point. RESULTS The study protocol has been approved by the Medical Research Ethics Committees United on February 26, 2018 (NL 62142.100.17/R17.51). By the end of 2018, we completed a small pilot study with 8 patients and the results based on interviews and app usage data suggest that a larger clinical trial with the targeted population is feasible. We expect to complete the RCT by the end of 2021, and statistical analyses will follow. CONCLUSIONS Results of the RCT will help us to test the hypothesized benefits of self-tracking and mobile-based coaching for cardiac patients in home-based exercise programs during the discharge–rehabilitation gap. If the results are positive, cost-effectiveness analysis will be performed based on the insights of the study to inform the translation of the technology-enhanced program to clinical practice. We also note limitations of the trial in the discussion. CLINICALTRIAL Registered at Netherlands Trial Register NL8040; https://www.trialregister.nl/trial/8040 INTERNATIONAL REGISTERED REPORT PRR1-10.2196/16737


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