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PubMed2001

[Physical inactivity: a modifiable risk factor in primary prevention?].

BACKGROUND AND AIM: Physical inactivity is an important risk factor for cardiovascular disease and for increased cardiovascular mortality. The aim of this review article was to demonstrate whether increased physical activity can safely reduce the increased cardiovascular mortality due to physical inactivity. A further aim was to derive recommendations for physical activity. METHODS: The effect of physical activity on indirect and direct cardiovascular parameters and clinical endpoints was analyzed by means of an inquiry of the literature. RESULTS: Physical inactivity is an important risk factor for cardiovascular and overall mortality. Many epidemiologic studies could demonstrate with high consistency that regular physical activity is associated with a lower cardiovascular mortality and overall mortality. There is an inverse relationship between physical activity and mortality. Even moderate physical activity (30 min brisk walking or 15 min jogging) on most days of the week can increase the wellness and reduce the cardiovascular and overall mortality. CONCLUSIONS: Regular physical activity can contribute to an enormous health benefit in the general population. Therefore the promotion of adequate physical activity should be a major aim of the policy of health.

Cardiovascular Diseases↗
PubMed2001

Ergometry for estimation of mechanical power output in sprinting in humans using a newly developed self-driven treadmill.

An evaluation of mechanical power during walking and running in humans was undertaken after developing a specially designed running ergometer (RE) in which the subjects gripped the handlebar in front of them keeping both arms straight and in a horizontal position. Ten subjects participated in comparisons of the mean horizontal pushing force (MFam) on the handlebar with the mean horizontal ground reaction force (MFfp) recorded by force platform under the RE during five different constant speeds of walking or running and sprint running with maximal effort. Mechanical power developed during sprint running on the RE was compared with a 50 m sprint. Mean linear velocity (Mv) of the RE belt was recorded by the rotary encoder attached to the axis of the belt. Mean mechanical power calculated from the handlebar setting (MPam = MFam x Mv) was compared to that calculated from force platform recordings (MPfp = MFfp x Mv). A high test-retest reproducibility was observed for both MFfp (r = 0.889) and MFam (r = 0.783). Larger values for the coefficient of variation for MFam (11.3%-15.8%) were observed than for MFfp (3.3%-8.2%). The MPam, which were obtained from five different constant speeds of walking, running and sprint running were closely correlated to those of MPfp (y = 0.98x - 19.10, r = 0.982, P < 0.001). In sprint running, MPam was 521.7 W (7.67 W.kg-1) and was correlated to the 50 m sprint time (r = -0.683, P < 0.01). It is concluded that the newly developed RE was useful in the estimation of mechanical power output during human locomotion such as when walking, jogging and sprinting.

Adult↗
PubMed2000

Physiological and metabolic responses of female games and endurance athletes to prolonged, intermittent, high-intensity running at 30 degrees and 16 degrees C ambient temperatures.

Eight female games players (GP) and eight female endurance athletes (EA) ran intermittently at high-intensity and for prolonged periods in hot (30 degrees C) and moderate (16 degrees C) ambient temperatures. The subjects performed a two-part (A, B) test based on repeated 20-m shuttle runs. Part A comprised 60 m of walking, a maximal 15-m sprint, 60 m of cruising (90% maximal oxygen uptake, VO(2max)) and 60 m of jogging (45% VO(2max)) repeated for 75 min with a 3-min rest every 15 min. Part B involved an exercise and rest pattern of 60-s running at 100% VO(2max) and 60-s rest which was continued until fatigue. Although the GP and EA did not respond differently in terms of distances completed, performance was 25 (SEM 4)% less (main effect trial, P < 0.01) in the hot (HT) compared with the moderate trial (MT). Sprints of 15 m took longer to complete in the heat (main effect, trial, P < 0.01), and sprint performance declined during HT but not MT (interaction, trial x time, P < 0.01). A very high correlation was found between the rate of rise in rectal temperature in HT and the distance completed [GP, r =-0.94, P < 0. 01; EA (n = 7), r = -0.93, P < 0.01]. Blood lactate [La(-) ](b) and plasma ammonia [NH(3)](p1) concentrations were higher for GP than EA, but were similar in HT and MT [La(-) ](b), HT: GP vs EA, 8.0 (SEM 0. 9) vs 4.9 (SEM 1.1) mmol x l(-1); MT: GP vs EA, 8.0 (SEM 1.3) vs 4.4 (SEM 1.2) mmol x l(-1); interaction, group x time, P < 0.01; [NH(3)](p1), HT: GP vs EA, 70.1 (SEM 12.7) vs 43.2 (SEM 6.1) mmol x l(-1); MT: GP vs EA, 76.8 (SEM 8.8) vs 32.5 (SEM 3.8) micromol x l(-1); interaction, group x time, P < 0.01. Ad libitum water consumption was higher in HT [HT: GP vs EA, 18.9 (SEM 2.9) vs 13.5 (SEM 1.7) ml x kg(-1) x h(-1); MT: GP vs EA, 12.7 (SEM 3.7) vs 8.5 (SEM 1.5) ml x kg(-1) x h(-1); main effect, group, n.s.; main effect, trial, P < 0.01]. These results would suggest that elevated body temperature is probably the key factor limiting performance of prolonged, intermittent, high-intensity running when the ambient temperature is high, but not because of its effect on the metabolic responses to exercise.

Adult↗
PubMed2001

Superior short-term results with eccentric calf muscle training compared to concentric training in a randomized prospective multicenter study on patients with chronic Achilles tendinosis.

In a previous uncontrolled pilot study we demonstrated very good clinical results with eccentric calf muscle training on patients with painful chronic Achilles tendinosis located at the 2-6 cm level in the tendon. In the present prospective multicenter study (Sundsvall and Umeå) patients with painful chronic Achilles tendinosis at the 2-6 cm level in the tendon were randomized to treatment with either an eccentric or a concentric training regimen for the calf muscles. The study included 44 patients, with 22 patients (12 men, 10 women; mean age 48 years) in each treatment group. The amount of pain during activity (jogging or walking) was recorded by the patients on a visual analogue scale, and patient satisfaction was assessed before and after treatment. The patients were instructed to perform their eccentric or concentric training regimen on a daily basis for 12 weeks. In both types of treatment regimen the patients were told to do their exercises despite experiencing pain or discomfort in the tendon during exercise. The results showed that after the eccentric training regimen 82% of the patients (18/22) were satisfied and had resumed their previous activity level (before injury), compared to 36% of the patients (8/22) who were treated with the concentric training regimen. The results after treatment with eccentric training was significantly better (P<0.002) than after concentric training. The good clinical results previously demonstrated in the pilot study with eccentric calf muscle training on patients with chronic Achilles tendinosis, were thus reproduced in this multicenter, showing superior results to treatment with concentric training.

Achilles Tendon↗
PubMed2001

Dynamic stability in the anterior cruciate ligament deficient knee.

Some individuals can stabilize their knees following anterior cruciate ligament rupture even during activities involving cutting and pivoting (copers), others have instability with daily activities (non-copers). Movement and muscle activation patterns of 11 copers, ten non-copers and ten uninjured subjects were studied during walking and jogging. Results indicate that distinct gait adaptations appeared primarily in the non-copers. Copers used joint ranges of motion, moments and muscle activation patterns similar to uninjured subjects. Non-copers reduced their knee motion, and external knee flexion moments that correlated well with quadriceps strength. Non-copers also achieved peak hamstring activity later in the weight acceptance phase and used a strategy involving more generalized co-contraction. Both copers and non-copers had high levels of quadriceps femoris muscle activity. The reduced knee moment in the involved limbs of the non-copers did not represent "quadriceps avoidance" but rather represented a strategy of general co-contraction with a greater relative contribution from the hamstring muscles.

Adult↗
PubMed2000

Serum isoforms of bone alkaline phosphatase increase during physical exercise in women.

Physical activity is an important factor for maintaining and probably increasing bone mass in humans. However, the mechanism by which this takes place is not completely understood. The purpose of this study was to examine the influence of physical exercise on serum alkaline phosphatase (ALP) and in particular, the bone isoforms of ALP. Six ALP isoforms were quantified by high-performance liquid chromatography: three bone (B/I, B1, and B2), and three liver ALP isoforms. In addition, serum calcium, parathyroid hormone (PTH), and other markers of bone formation and degradation, as measured by osteocalcin and cross-linked carboxyterminal telopeptide of type I collagen (ICTP), were analyzed. The study groups comprised 15 women, 8 postmenopausal (range 51-62 years) and 7 near age of peak bone mass (range 21-27 years). When the postmenopausal women exercised on an ergometer cycle until exhaustion we found significant increases in serum of bone ALP isoforms B1 and B2, and phosphate, even considering the hemoconcentration that occurred during the exercise. When the young women jogged in a moderate tempo for 40-40 minutes the levels of serum B2 and PTH increased. All changes turned towards baseline within 20 minutes after exercise. In conclusion, exercise increased serum ALP bone isoforms B1 and B2, and their responses were differentiated. As B1 and B2 are known to represent specific bone compartments, cortical and trabecular bone, the present findings may indicate different effects on bone of weight- and nonweight-bearing exercise.

Adult↗
PubMed1997

Effects of moderate endurance exercise on calcium, parathyroid hormone, and markers of bone metabolism in young women.

We investigated the short-term (1 hour-3 days) effects of a 45 minute run on calcium, parathyroid hormone, the carboxyterminal propeptide of type I procollagen (PICP), and the immunoactive carboxyterminal telopeptide of type I collagen in serum (ICTP) in young females. Fourteen healthy young women, aged 25.2 +/- 0.6 years (mean +/- SEM) with regular menstruations, participated. The test was outdoor jogging for 45 minutes at an intensity of 50% of VO2 max. Blood samples were collected 15 minutes before the test and 1, 24, and 72 hours after the test. The measured values were adjusted for changes in plasma volume. A significant decrease of ionized calcium was observed at 1 hour (P < 0.001) and 72 hours (P < 0.05) and a significant increase of parathyroid hormone (PTH) was noted 24 (P < 0.01) and 72 hours (P < 0.05) after the test. A significant decrease of PICP at 1 hour (P < 0.05) was followed by an increase after 24 (P < 0.01) and 72 hours (P < 0.001) and a significant increase in ICTP was noted at 24 and 72 hours (P < 0.05). A strong positive correlation was found between serum levels of PICP and ICTP (r = 0. 55-0.84; P < 0.05) throughout the experiment. In conclusion, young females showed biochemical signs of increased bone collagen turnover and altered homeostasis of calcium and PTH after a single bout of moderate endurance exercise.

Adult↗
PubMed2002

[Effects of physical training and age-induced structural and functional changes in cardiovascular system and skeletal muscles].

Age-related morphological changes in the cardiovascular system refer to a thickening of the arterial wall as well as a diffuse increase in the wall thickness of the myocardium. In terms of function, this leads to a decrease of the myocardial contractility in systole and to a delay of the diastolic myocardial relaxation. At the arterial wall, an impairment of wall elasticity as well as a decrease of the vasoreagibility can be observed. The systolic blood pressure and the blood pressure amplitude rise; the blood flow-dependent vasodilatation mediated by endothelial cells decreases. The loss of cardiac pacemaker cells by approximately 90% from the 2nd to the 8th decade leads to a reduction of the heart rate variability and to a decrease of the maximum heart rate during exhaustive physical exercise. Hemodynamically these changes resulted in a continuous decline of the maximum cardiac output as well as the maximum oxygen transport capacity. Between the 3rd and 8th decade the peripheral skeletal muscle mass decreases as a result of a reduction of the size and the number of muscle fibers with an overproportional loss of 30-40% regarding the highly glycolytic type IIb fibers. Furthermore, the intramuscular capillarization declines so that, with a concomitant decrease in the number and size of the mitochondria, the supply with oxygen and energy sources and consecutively the aerobic muscular energy metabolism decreases by 8-10% per decade beginning with the 4th to 5th decade. Additionally, the maximum and explosive muscular strength decreases by 30-35% from the 4th decade onwards. In older, healthy men who perform a regular aerobic muscular training in endurance sport disciplines (e.g., walking, jogging or cycling), a decrease of the resting heart rate, a restoration of the primarily lowered heart rate variability, an improvement of the early diastolic left-ventricular filling as well as a significant increase in the VO2max could be proven. Other studies showed that regular endurance training on a cycle-ergometer resulted in a significant increase in capillarization within the exercising muscle groups. In older, trained individuals a reduced stiffness of the arterial vessel walls and an improved maximum exercise-induced muscular blood supply occurs. In other training studies performed with older subjects, a positive influence of regular endurance training on the carbohydrate metabolism along with an improvement of the primarily reduced insulin sensitivity could be demonstrated. In older men and women who regularly underwent muscular strength training, a significant increase in maximum strength with a significant increase in the proportion of type II muscle fibers was found.

Adult↗
PubMed2006

Effect of exercise on postprandial lipemia in men with hypertriglyceridemia.

We examined the effect of exercise on postprandial lipemia (PPL) and insulin resistance in individuals with metabolic syndrome. Subjects were 10 hypertriglyceridemia (HTG) males with insulin resistance [age = 40.1 +/- 2.2 years, body weight = 96.3 +/- 3.3 kg, fasting triglyceride (TG) = 263 +/- 25 mg/dl, VO(2)max = 37 +/- 1.1 ml/kg/min, and Homeostatic Model Assessment (HOMA-IR, an index of insulin resistance) = 3.05 +/- 0.40]. Each subject performed a control trial (Ctr, no exercise), and three exercise trials at 40% (40%T), 60% (60%T), and 70% (70%T) of their VO(2)max. The order of trials was randomized and there were 1-2 weeks wash-out period between the trials. All subjects had a fat-meal in each trial. In the exercise trials, subjects jogged on a treadmill for 1 h at a designated intensity 12 h prior to a fat-meal ingestion. Blood samples were taken at 0 h (before the meal), and 2, 4, 6, and 8 h after the meal. The plasma TG, area score under TG concentration curve for over an 8 h-period (TG AUC) after the meal, and HOMA-IR were analyzed. The TG AUC score in 40%T was 30% lower (P = 0.003), 60%T was 31% lower (P = 0.02), and 70%T was 39% lower (P = 0.02) than Ctr. There were no significant differences in the TG AUC scores among the exercise trials (P > 0.05). The insulin concentrations in both 60 and 70%T were lower than Ctr (P < 0.01) which did not differ from 40%T. HOMA-IR in both 60%T (P = 0.041) and 70%T (P = 0.002) were lower than Ctr, but not different from 40%T (HOMA-IR: Ctr = 3.05 +/- 0.40, 40%T = 2.67 +/- 0.35, 60%T = 2.49 +/- 0.31, 70%T = 2.21 +/- 0.27). The results suggest that for physically inactive individuals with metabolic syndrome, exercising at low to moderate intensity may be sufficient to attenuate PPL and increase insulin sensitivity, whereas higher intensity exercise may be needed to normalize blood glucose.

Adult↗
PubMed1999

Changes in exercise and post-exercise core temperature under different clothing conditions.

This study evaluates the effect of different levels of insulation on esophageal (Tes) and rectal (Tre) temperature responses during and following moderate exercise. Seven subjects completed three 18-min bouts of treadmill exercise (75% VO2max, 22 degrees C ambient temperature) followed by 30 min of recovery wearing either: (1) jogging shoes, T-shirt and shorts (athletic clothing); (2) single-knit commercial coveralls worn over the athletic clothing (coveralls); or (3) a Canadian Armed Forces nuclear, bacteriological and chemical warfare protective overgarment with hood, worn over the athletic clothing (NBCW overgarment). Tes was similar at the start of exercise for each condition and baseline Tre was approximately 0.4 degree C higher than Tes. The hourly equivalent rate of increase in Tes during the final 5 min of exercise was 1.8 degrees C, 3.0 degrees C and 4.2 degrees C for athletic clothing, coveralls and NBCW overgarment respectively (P < 0.05). End-exercise Tes was significantly different between conditions [37.7 degrees C (SEM 0.1 degree C), 38.2 degrees C (SEM 0.2 degree C and 38.5 degrees C (SEM 0.2 degree C) for athletic clothing, coveralls and NBCW overgarment respectively)] (P < 0.05). No comparable difference in the rate of temperature increase for Tre was demonstrated, except that end-exercise Tre for the NBCW overgarment condition was significantly greater (0.5 degree C) than that for the athletic clothing condition. There was a drop in Tes during the initial minutes of recovery to sustained plateaus which were significantly (P < 0.05) elevated above pre-exercise resting values by 0.6 degree C, 0.8 degree C and 1.0 degree C, for athletic clothing, coveralls, and NBCW overgarment, respectively. Post-exercise Tre decreased very gradually from end-exercise values during the 30-min recovery. Only the NBCW overgarment condition Tre was significantly elevated (0.3 degree C) above the athletic clothing condition (P < 0.05). In conclusion, Tes is far more sensitive in reflecting the heat stress of different levels of insulation during exercise and post-exercise than Tre. Physiological mechanisms are discussed as possible explanations for the differences in response.

Adult↗
PubMed2005

Exercise barrier and task self-efficacy in breast cancer patients during treatment.

Understanding exercise self-efficacy in breast cancer patients during treatment is important for enhancing physical activity adherence. Therefore, the primary study purpose was to determine, among breast cancer patients during treatment, the psychometric properties of scales to measure exercise barrier and task self-efficacy. The study also aimed to determine the following: (1) level of self-efficacy, (2) associations between barrier and task self-efficacy, and (3) associations between self-efficacy and patient age, race, and treatment type. Eighty-six female breast cancer patients recruited from a medical oncologist's office completed the scales once, and 46 repeated the scales 2 weeks later. The majority were Caucasian (95%), with 26% receiving chemotherapy, 64% hormonal therapy alone, and 5% radiation/other. The mean age was 59+/-14 years. The Cronbach's alpha for the nine-item barrier self-efficacy scale was 0.96, with a test-retest correlation of 0.89 (p<0.001). The Cronbach's alpha for the four-item task self-efficacy scale was 0.89, with a test-retest correlation of 0.83 (p<0.001). The mean barrier self-efficacy was slightly to moderately confident, with the lowest confidence reported in the ability to exercise when nauseated. The mean task self-efficacy was slightly to moderately confident, with the lowest confidence reported in the ability to jog for 10 min without stopping. Although no significant associations were found between self-efficacy and participant's race or treatment type, lower task self-efficacy was associated with older age (r=-0.36, p=0.001). Both self-efficacy scales demonstrated good internal consistency and test-retest reliability. Self-efficacy may be a useful target for physical activity interventions among breast cancer patients during treatment.

Activities of Daily Living↗
PubMed2004

OsiriX: an open-source software for navigating in multidimensional DICOM images.

A multidimensional image navigation and display software was designed for display and interpretation of large sets of multidimensional and multimodality images such as combined PET-CT studies. The software is developed in Objective-C on a Macintosh platform under the MacOS X operating system using the GNUstep development environment. It also benefits from the extremely fast and optimized 3D graphic capabilities of the OpenGL graphic standard widely used for computer games optimized for taking advantage of any hardware graphic accelerator boards available. In the design of the software special attention was given to adapt the user interface to the specific and complex tasks of navigating through large sets of image data. An interactive jog-wheel device widely used in the video and movie industry was implemented to allow users to navigate in the different dimensions of an image set much faster than with a traditional mouse or on-screen cursors and sliders. The program can easily be adapted for very specific tasks that require a limited number of functions, by adding and removing tools from the program's toolbar and avoiding an overwhelming number of unnecessary tools and functions. The processing and image rendering tools of the software are based on the open-source libraries ITK and VTK. This ensures that all new developments in image processing that could emerge from other academic institutions using these libraries can be directly ported to the OsiriX program. OsiriX is provided free of charge under the GNU open-source licensing agreement at http://homepage.mac.com/rossetantoine/osirix.

Computer Graphics↗
PubMed1989

Asymptomatic left main coronary artery disease and silent myocardial ischemia.

Gathering data on the prognosis, detection, and natural history of asymptomatic left main coronary artery disease with silent myocardial ischemia is difficult. Epidemiologic studies of unexpected death and postmortem studies on silent myocardial infarction suggest this entity to be common. We reviewed 89 consecutive patients with left main coronary artery disease (LMD), defined as 50% or greater reduction of luminal diameter. Of this group, 10 patients (11%) were asymptomatic (ALMD) and 79 patients (88%) were symptomatic (SLMD). All 10 ALMD patients were men, with a mean age of 53 years (range 40 to 65). Treadmill tests (TMT) were performed for: ECG abnormalities six; pre-jogging evaluation two; risk factor evaluation two. The TMT within 9 minutes showed 2 mm or greater ST depression in seven (70%) and 1 to 2 mm in three (30%). Similar TMT results were obtained in the SLMD group, although two patients had negative responses. The degree of stenosis of the left main coronary artery and the frequency of three-vessel disease were similar in both groups. The ejection fraction (EF) and contractile pattern of the left ventricle (LV) were normal in all 10 ALMD patients, but the left ventricular end-diastolic pressure (LVEDP) was abnormal in three (70%). In the SLMD group, 51 (64%) had an abnormal ejection fraction, 50 (65%) had wall motion abnormalities, and 25 (32%) had an abnormal LVEDP.

Adult↗
PubMed1976

Comparison of active participants and dropouts in CAPRI cardiopulmonary rehabilitation programs.

Of 547 men and 56 women enrolled up to April 1974 in Cardiopulmonary Research Institute (CAPRI) community programs for cardiopulmonary rehabilitatation, 84.5 percent had clinical manifestations of coronary heart disease. These medically supervised programs of physical training involved 30 to 60 minutes of graded levels of working, calisthenics and, if indicated, jogging for 3 mornings/week. Altogether 352 (58.4 percent) dropped out after an average of 8.6 months for men and 5.7 months for women. The remaining 230 men and 21 women remained active for 22 and 20 months, respectively. In retrospect, there were few minor differences between active participants and dropouts in physical characteristics, clinical diagnoses and responses to exercise testing on enrollment. Elapsed time to morbidity tended to be longer in active persons than in dropouts. Over one half of active men and about one third of dropouts were working. Of six early deaths, one occurred before training was instituted, and five within the first 2 weeks of training. Among men, the respective total mortality rates were 2.7 and 4.7/100 person-years for active participants and dropouts; among women, the rates were 0 and 3.8 respectively. Whereas 24 episodes of cardiac arrest occurred in 13 men, with three fatalities outside the training program, in 11 instances of exertional arrest during class training all defibrillations were successful. Without this benefit of medical supervision there would have been little difference in mortality experience.

Animals↗
PubMed1986

Active transient myocardial ischemia during daily life in asymptomatic patients with positive exercise tests and coronary artery disease.

The management of asymptomatic patients with coronary artery disease (CAD) is controversial, and the level of "activity" of their CAD during normal daily life remains largely unknown. To examine this question, ambulatory Holter monitoring of ST segments was performed out of the hospital in 7 asymptomatic subjects with CAD during normal daily activities. Their condition was detected because they all had a silent positive exercise test and angiographically proved CAD. During a total of 384 hours of monitoring, 37 asymptomatic episodes of ST depression (1 mm or greater and lasting at least 30 seconds) were recorded in 5 of the patients. Most episodes (68%) were 10 minutes or less in duration but ranged from 1 to 253 minutes, and most (70%) had a maximal ST depression of 1 to 2 mm. A small increase in heart rate, ranging from 1 to 34 beats/min, preceded 65% of the episodes, but 35% were associated with no change or even a decline before the onset of ischemia. Fifty-four percent of the episodes occurred during rest or usual light physical activity, 8% during sleep and only 38% during exercise, including 1 prolonged bout while jogging. During 78% of the episodes, the subjects rated their mental activity as usual and only 14% occurred during mental stress. In addition, a distinct diurnal variation was noted with 57% of the ischemia occurring between 0600 and 1200 hours (p = 0.008). Therefore, most asymptomatic subjects had active transient ischemia during daily life, with many of the characteristics already described in symptomatic subjects with CAD.

Activities of Daily Living↗
PubMed1987

Effects of activity on ascending aortic velocity in children with valvar aortic stenosis.

The peak velocity of aortic blood flow was measured in 12 normal children and 20 children with valvar aortic stenosis (AS) by continuous-wave Doppler ultrasound (CWD). Measurements were made at rest, after 2 forms of exercise and, in the 11 children who underwent cardiac catheterization, while under sedation. The exercise was both formal cycle ergometry and a 200-meter jog. The peak velocity in normal children was 1.5 +/- 0.2 m/s at rest, increasing to 2.1 +/- 0.4 m/s (p less than 0.01) after running and to 1.9 +/- 0.4 m/s (p less than 0.01) after cycling. Peak velocity in children with AS was 3.5 +/- 0.8 m/s at rest, increasing to 4.4 +/- 0.8 m/s (p less than 0.01) after running and to 4.5 +/- 0.5 m/s (p less than 0.01) after cycling. The increase in peak velocity was greater in children with AS than in normal children. Measurements of left ventricular (LV) aortic pressure differences by cardiac catheterization were compared to those made by CWD, using the modified Bernoulli equation. The best correlation of the CWD prediction of LV aortic pressure differences was achieved when the children were sedated. The peak velocity of blood flow in the ascending aorta varied with level of activity, and this variability must be considered when using the Bernoulli equation to predict LV aortic pressure differences. CWD prediction of the LV aortic pressure difference was best when the child was sedated (r = 0.98). It is therefore prudent to consider the velocity measurement proximal to the AS to calculate LV aortic pressure differences more accurately unless the child is sedated.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1990

Aerobic exercise reduces levels of cardiovascular and sympathoadrenal responses to mental stress in subjects without prior evidence of myocardial ischemia.

Thirty-seven healthy type A men (mean age 42 years) were randomly assigned to either an aerobic exercise training group or to a strength and flexibility training group. Before exercise, subjects underwent comprehensive physiologic and behavioral assessments, including graded exercise treadmill testing with direct measurement of oxygen consumption (VO2) and measurement of cardiovascular (heart rate, systolic and diastolic blood pressure and rate pressure product) and neuroendocrine (epinephrine and norepinephrine) responses to mental arithmetic. The aerobic exercise consisted of walking and jogging at an intensity of greater than or equal to 70% maximal heart rate reserve for 1 hour 3 times/week for 12 consecutive weeks. The strength training consisted of 1 hour of circuit Nautilus training 2 times/week for 12 weeks. At the completion of the exercise program, all subjects underwent repeat testing. For the aerobic group, peak VO2 increased significantly from 33.6 to 38.4 ml/kg/min (p less than 0.001), whereas the strength group only achieved a slight increase from 34.5 to 35.6 ml/kg/min (difference not significant). During the mental arithmetic, the aerobic group experienced a greater reduction in levels of heart rate, diastolic blood pressure and rate pressure product than the strength group (after completing the exercise training programs). The aerobic group also tended to secrete less epinephrine and to show a faster recovery than the strength group after the exercise program. In addition, the aerobic group tended to exhibit less cardiovascular reactivity to mental stress after exercise training. These data suggest that aerobic exercise reduces levels of cardiovascular and sympathoadrenal responses during and after mental stress.

Adrenal Medulla↗
PubMed1982

Prevalence of oligomenorrhea and amenorrhea in a college population.

Menstrual disorders in college students have been reported as higher than in the general population. Several reasons, among them calorie-restricted diets, strenuous exercise, and college-related stress, have been attributed to this increased prevalence. During the period November, 1979, to January, 1980, 991 of 1,420 college students completed questionnaires which inquired about their menstrual history. The prevalence of oligomenorrhea in this group was 11.3% and that of amenorrhea was 2.6%. Significant factors associated with oligomenorrhea or amenorrhea in this group were weight loss (greater than 20 pounds) and jogging. In most women with oligomenorrhea or amenorrhea, menstrual irregularity was present prior to college entry. With the use of self-administered questionnaires, we could not identify any specific college stress to account for the presence of menstrual abnormalities in a college population.

Adolescent↗