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Biomedical subjects

B Marti

Publications and source records attributed to B Marti.

At least 37 records · Page 2Linked to original sources
PubMed1995

Ultrastructural modification of human skeletal muscle tissue with 6-month moderate-intensity exercise training.

The study was aimed at investigating if endurance training of moderate intensity and longer duration, intended to promote health rather than performance, evokes ultrastructural changes in skeletal muscle tissue comparable to those observed after high-intensity protocols. Twenty healthy, middle-aged men enrolled in a 6-month, home-based jogging program of 120 min/wk at 75% VO2max. Only 12 men showed a sufficient exercise adherence over the 6 months (> or = 60 min/wk on average) and were included into statistical analysis. Their average training activity was 105 +/- 31 min/wk. The results revealed significant increases in VO2max (+8.4%, p < 0.01) and submaximal power output (+18.1%, p < 0.01). Total mitochondrial volume density in M. vastus lateralis increased by 20% (p < 0.05) with a larger increase in subsarcolemmal volume compared to central volume (50% vs 15%). No changes in volume of intracellular lipid droplets, capillary density, capillary per fiber ratio, fiber mean cross-sectional area and muscle fiber type could be observed. Body composition analysis showed a decrease in trunk fat mass (-7.3%, p < 0.05) and an increase in trunk lean mass (+1.7%, p < 0.05), while changes in the legs were not significant. It can be concluded that a moderate-intensity, health oriented endurance training beneficially affected cardiovascular and muscle oxidation capacity as well as body composition in the trunk area. No adaptations in capillaries or lipid metabolism could be demonstrated. The results support the hypothesis of thresholds for induction of adaptation processes in muscle skeletal tissue depending on the intensity of the exercise stimulus.

Adipose Tissue↗
PubMed1994

Jogging or walking--comparison of health effects.

The present study compared the different health effects of 6 months' endurance training at two exercise intensities. Seventy-five nonsmoking, sedentary men were randomly assigned to either a home-based, unsupervised exercise program of 4 x 30 min/wk jogging at an intensity of 75% VO2max (n = 28), or of 6 x 30 min/wk walking at an intensity of 50% VO2max (n = 28), or to an inactive control group (n = 19). Exercise adherence and injuries related to exercise training as well as changes in endurance capacity, body fat, and serum lipids were assessed. After 6 months, joggers and walkers showed a similar increase in VO2max as measured by a maximal bicycle ergometer test (2.9 +/- 4.1 ml/kg min, P < 0.01 and 2.5 +/- 5.7 ml/kg min, P < 0.5, respectively). There were no significant changes in blood lipids in either group, although results revealed a significant association between the amount of training (i.e., kilometers exercised) and the increase in high-density lipoprotein-cholesterol (HDL-C) in joggers (Pearson's r = 0.42, P < 0.05). In walkers, a significant association between the amount of exercise and the decrease in sum of skinfolds and the waist-hip ratio was observed (Pearson's r = -0.48 and -0.45, P < 0.05 for both). The adherence rate was similar for both training groups with respect to the prescribed intervention goal with an average of 90 +/- 41 min/wk (joggers) and 121 +/- 72 min/wk (walkers) spent on endurance training.(ABSTRACT TRUNCATED AT 250 WORDS)

Adipose Tissue↗
PubMed1993

[Significance of after care by family practitioner following myocardial infarct from the patient's viewpoint].

In this study a questionnaire has been sent to 118 male patients about 21 months after the first myocardial infarction. The patients in question have suffered a first acute myocardial infarction in the second half-year of 1987 and have been hospitalized in ten different clinics around Zurich. 80 (72%) of the patients not older than 62 years have answered; 4 patients died. The results indicate that the treatment by the general practitioner has been assessed mostly positively; 63.7% of the patients were very content with the care provided by their general practitioner, 32.5% were rather content and only 3.8% were rather discontent. Only 5% changed to another general practitioner out of discontentment within the mentioned period. 91.2% of the patients taxed the expended time by the general practitioner as just about sufficient. Results concern the influence of the general practitioner on modification of habits after the myocardial infarction: former smokers indicated more often, that the advice of the general practitioner has helped them (p < 0.01), those patients who changed their eating habits talked more often with their physician about this subject (p < 0.05), respective counselling by the general practitioner had an evident influence on the sportive activities of the patients (p < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Aftercare↗
PubMed1993

[Body fat distribution: independent factor affecting the blood lipid profile].

The association of life style factors with profiles of blood lipids is described in a cohort of 75 middle aged (41.2 +/- 7.8 years) physically inactive, nonsmoking employees. The importance of body fat distribution in relation to relative body weight and the lipid profiles was also studied. The strongest possible predictor for an atherogenic lipid fraction was the quotient of abdominal and hip circumferences indicating an abdominal fat accumulation. In the group with the lowest quotient (< 0.84) the triglyceride and cholesterol values were lower by 43% and 13% respectively than in that with the highest quotient (< 0.88). The body mass index (BMI) gave the best inverse correlation with HDL-c and Apo A-I: Men with a BMI < 23.7 kg/m2 had in the average a HDL-c concentration 0.2 mmol/l higher than slightly overweighted men (BMI > 25 kg/m2). Physical inactivity and a reduced physical endurance were both associated with significantly higher total cholesterol and Apo B values. In a multivariate analysis the quotient of abdominal and hip circumferences, physical activity and endurance together with adherence to recommended nutritional behaviour explained approximately one third of the variations in LDL and Apo-B concentrations. This study thus confirms in a cohort of non smoking middle aged employees the predictive character of unfavorable life style for an atherogenic lipid profile. The assessment of body fat distribution added further information on the lipid profile that could not be detected by body size and weight determination alone.(ABSTRACT TRUNCATED AT 250 WORDS)

Adipose Tissue↗
PubMed1993

[Effect of occupation on health behavior and biological cardiovascular risk factors].

Within the framework of the second survey of MONICA-Switzerland (cantons of Vaud and Fribourg; canton of Tessin), the data of 683 working men were analysed to examine the relation between occupation and cardiovascular risk factors. For this purpose, lifestyle factors (smoking, nutritional habits, physical activity, alcohol intake) as well as blood pressure and serum lipoprotein concentrations were compared among 17 different occupational groups. Furthermore, every occupational group was ranked, based on the medians of the mentioned dependent variables. A strong relationship between socioeconomic status (recorded as number of years of schooling completed) and an index for healthy lifestyle was found. However, in some occupational groups a major discrepancy between socioeconomic status respectively lifestyle and measured cardiovascular risk factors (blood pressure, lipoprotein concentrations) was observed. It is therefore hypothesized that unknown occupational factors adversely affect blood pressure and serum lipoproteins for example in physicians, managers and executives whereas the contrary--beneficial effect of unknown occupational factors--is true for example for drivers and bricklayers.

Adult↗
PubMed1993

[Significance of life style factors for the blood lipids profile in bank employees].

In a study sample of 75 sedentary, non-smoking male bank employees (mean age 41.2 +/- 7.8 years) the relationship between lifestyle characteristics and serum lipid concentrations were examined. According to the mortality statistics of the canton of Zurich, this population is at increased risk for coronary heart disease. Statistical analyses confirmed the predictive character of physical activity for serum lipid levels. A low level of physical activity was associated with significantly higher concentrations of apolipoprotein B and LDL-C (Pearson coefficient of correlation r = -0.38, p < 0.001 and r = -0.35, p < 0.01, respectively). Accumulation of upper body fat (estimated by the waist to hip ratio) revealed to be a better predictor of lipid levels than body mass index and showed highly significant positive correlations with atherogenic lipid fractions. The most pronounced differences were seen for triglyceride levels, where the subgroup of subjects in the lowest tertile of waist-hip ratio showed about 40% lower triglyceride values compared to the highest waist-hip ratio tertile. In a study population of self-selected, non-smoking men, high levels of LDL-C and apolipoprotein B could partially be explained by unfavourable life style characteristics, particularly physical inactivity. The waist-hip ratio, characterizing abdominal fat accumulation, proved to be a good indicator of an atherogenic lipid profile. Measuring waist-hip ratio in medical routine examinations should thus be considered.

Adult↗
PubMed1993

Hip fracture mortality and morbidity in Switzerland and Japan: a cross-cultural comparison.

Based on national mortality data, the frequency of hip fractures in elderly people was compared between Switzerland and Japan. Age-adjusted annual incidence rates per 100,000 population estimated for Swiss persons over 60 years were around 150 and 200 in males and around 450 in females, while for the Japanese they were only 132 in males and 285 in females. Age-adjusted death rates from hip fracture for the Swiss over 60 were 20.0 in males and 28.9 in females, while for the Japanese they were only 1.6 in males and 2.7 in females. The inclination of the age-dependent slope in hip fracture mortality rates was substantially the same in both countries, but there was a "lag time" of approximately 10 years in Japan. Remarkably, the proportion of deaths due to falls among all accidental deaths was several times greater in both sexes for the Swiss than for the Japanese. This differential might be an important underlying reason for the observed difference between death rates of hip fracture in Switzerland and Japan. Other known behavioral risk factors for hip fracture such as diet, exercise, estrogen use etc. are unlikely to explain the observed difference in hip fracture mortality and morbidity between Switzerland and Japan. However, given the doubts on the reliability and thus comparability of the available data on mortality and morbidity, the present findings should be regarded as preliminary. In conclusion, we believe that the unexplained and large difference in the burden of hip fracture between Switzerland and Japan merits further studies, including new aetiological hypotheses.

Aged↗
PubMed1992

[Exercise and cancer. An epidemiologic short review of the effects of physical activity on carcinoma risk].

It is only during the past decade that occupational and leisure-time physical activity--whose importance for the prevention of cardiovascular diseases is well documented--has become a focus of research in cancer epidemiology. The most consistent observation of more than 15 epidemiological studies published in the 1980s is an average increase in the risk of colon cancer of 75 to 80% for physically inactive men and women, as compared to their more active counterparts. No study at all found a direct relationship between physical activity and colon cancer risk. A hypothetical explanation for this likely but unproven protective effect of regular exercise against colon cancer is that physical activity stimulates colon peristalsis, hereby reducing enteral transit time and diminishing exposure of the intestinal mucosa to fecal carcinogens. The epidemiologic evidence for a protective effect of exercise against rectal cancer and other cancers, however, is not sufficient. Isolated observations of a direct relationship between physical activity and the risk of cancer (e.g. prostate) have even been reported. For women, there is preliminary evidence of a protective effect of athletic activity against cancers of the breast and the reproductive system for which hormonal factors may be responsible. The cancer-protective effect of exercise per se is apparently too modest to serve as a justification for a general recommendation to take regular exercise.(ABSTRACT TRUNCATED AT 250 WORDS)

Carcinogens↗
PubMed1992

[Physical activity and blood pressure. An epidemiological brief review of primary preventive effects of physical exercise activities].

The relation between physical exercise and blood pressure as well as the risk of hypertension has been investigated extensively during recent years. Cross-sectional studies on exercising and physically fit subjects have shown that endurance capacity (i. e. maximum aerobic capacity) is inversely related to resting blood pressure. However, not all physical activities are associated with lower blood pressure levels; e.g. swimming, weight lifting and competitive cross-country skiing were found to be related to elevated blood pressure values in some studies. Population-based investigations reveal a trend towards lower blood pressure values in physically habitually active persons, with the difference between active and inactive subjects not exceeding 5 mmHg. Three epidemiological cohort studies have consistently demonstrated that sedentary, unfit persons have a 20 to 50% higher prospective risk of hypertension, as compared to exercising, physically fit persons. Some intervention studies with normotensive subjects show a reduction in resting blood pressure of 5 to 10 mmHg at best after several months of aerobic training, while other studies show no effect. At least two factors could be responsible for these somewhat inconsistent observations: 1. exercise intensity may act as an 'effect modifier', since vigorous to maximally hard exercise rather increases than lowers resting blood pressure, 2. in statistical analysis on the effect of physical training on blood pressure, it is crucial whether concomitant changes in body weight and body composition are taken into account: any adjustment for changes in body composition will substantially reduce the magnitude of 'exercise-induced' reductions in blood pressure.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Pressure↗
PubMed1992

Little effect of long-term, self-monitored exercise on serum lipid levels in middle-aged women.

To study the effect of long-term, self-monitored exercise on physical fitness and serum lipid levels of middle-aged, nonsmoking females, a controlled study was conducted in 33 sedentary Swiss women. Seventeen women were randomly allocated to jog 2h/wk for 4 months on an individually prescribed and heart rate controlled base, whereas 16 women served as controls. Although leisure-time physical activity increased significantly in exercisers compared to controls, the average running distance of 10.9 km/wk was somewhat less than expected. The "net decrease" (4-month change in exercisers minus 4-month change in controls) in the sum of four skin-folds was -4.85 mm (p < 0.05). Four-month changes in serum lipids were generally small and nonsignificant. For example, the net decrease in total triglycerides was -0.2 mmol/l (p = 0.13). Correlational analyses revealed significant associations between changes in the waist-hip ratio and changes in total cholesterol (total-C) or the HDL/total-C ratio (r = 0.44, p < 0.01 and r = -0.29, p < 0.05, respectively). An increase in endurance capacity was associated with an increase in the HDL2-subfraction and in the ratio of HDL/total-C (r = 0.46, p < 0.05 and r = 0.52, p < 0.01). Multivariate linear regression analyses confirmed a change in endurance capacity as the statistically strongest positive predictor of changes in HDL, HDL2 and the HDL/total-C ratio. However, women who used oral contraceptives did not show any favourable lipid changes despite a considerable improvement in endurance capacity. The present training study in healthy, habitually sedentary middle-aged women was not able to show the same beneficial changes in serum HDL concentration as seen in male counterparts, when analyzed according to the principle of intention-to-treat. Exploratory analyses revealed that a too low jogging activity as well as a confounding effect of oral contraceptive use may partially account for the lack of significant changes in serum lipid levels after training.

Adult↗
PubMed1992

On the epidemiology of sports injuries in Switzerland.

A review of the current literature and of insurance data sources on sports injuries in Switzerland during the latest decade is presented. Epidemiological denominator data to determine the population-at-risk and the exposure time are scarce and it is therefore recommended that both the quantity and the quality of Swiss research in this field will be enhanced. It is also proposed that at least one academic institution in Switzerland would assemble systematically all available data of standard format on sports and recreational injuries to ensure a continuous analysis of these data.

Accident Prevention↗
PubMed1992

[Cardiac and humoral mechanisms of the preventive effect of physical activity on cardiovascular diseases].

Many recent studies on the effects of regular exercise on the heart, coronary arteries and the balance between haemostasis and fibrinolysis suggest several mechanisms that are able to explain the epidemiologically well-documented association of habitual physical activity with a reduced risk of cardiovascular disease. Based on a review of current evidence, it is proposed that i) the haemodynamic adaptation of an aerobically-trained heart is an important cardioprotective mechanism, ii) the importance of exercise-induced effects on the coronary vessels may currently be somewhat underestimated, and iii) the importance of training-related changes in the haemostatic-fibrinolytic balance is equivocal at present, since the relative intensity of exercise seems to be a modifying factor that has not been taken into account appropriately so far. Further biomedical research into the cardiac and humoral effect of physical training is, thus, needed to corroborate the recent epidemiological observation that moderate-intensity exercise is just as--or even more--cardioprotective than high-intensity sports activity.

Cardiomegaly↗
PubMed1991

[Effects of jogging on mental well-being and seasonal mood variations: a randomized study with healthy women and men].

The long-term effect of jogging on mental well-being and seasonal mood variation was examined in a randomized, controlled intervention study with healthy, middle-aged, sedentary, non-smoking, white collar subjects. 17 women and 39 men were allocated to jog 2 h/week for 4 months, whereas 16 women and 22 men served as controls. After 4 months, there was a partial cross-over with the controls now taking up jogging. After 8 study months, all 38 subjects of the second jogging intervention as well as 10 women and 30 men of the first 4-month jogging period were re-examined for the second time. All participants in the second re-examination were mailed a survey questionnaire one year after beginning of the study (response rate 83%). Despite varying adherence for the exercise regimen, the 4-month "net effects" (i.e. effect in exercise group minus effect in control group) showed a significant improvement in physical fitness (endurance capacity, resting heart rate) in men, but not in women. Among the mood scales assessed, "anger" showed a marginally significant effect in men (relative decrease; p = 0.05) and "calmness" a significant effect in women (relative increase; p = 0.02); after exclusion of 4 non-compliers from analysis in women, also "vigor" (relative increase; p = 0.03) and "depressiveness" (relative decrease; p = 0.02) were significantly improved after jogging. In women, the number of kilometers run was significantly correlated with an improvement in mental well-being (Pearson's r = 0.32 with change in 4 "positive" mood scales and r = 0.57 with change in 4 "negative" mood scales). Changes in endurance capacity were not significantly related to changes in mental well-being. However, in both women and men these mental effects of jogging were superposed by clear seasonal variations in mood, i.e. by a deterioration of mental well-being during the winter months and by a slow "remission" during summer. Taking jogging-induced and seasonal effects on mood together, the magnitude of the 1-year variability in mental well-being was somewhat attenuated in those study groups jogging, with this "buffering" effect reaching statistical significance in women (p = 0.050). We conclude from this training study with normal subjects that regular jogging of approximately 10 to 15 km/week may help to diminish the deterioration of mood observed during winter months (e.g. increase in depressiveness), especially in women. Hereby, a training-induced increase in endurance capacity is apparently not a prerequisite for this long-term mental effect of jogging.

Adult↗
PubMed1991

[Cardiovascular risk factors of visitors to a mass-screening booth].

The attitude towards mass screening of serum cholesterol is controversial. In order to characterize the volunteers of such screenings and to test the representativity of its findings, we compared the data of 1686 adult health-screening participants collected during a trade fair in the city of Basel, Switzerland, with the results of two population-based studies, the Basel City Risk Factor Survey and the MONICA Project in Western Switzerland. Among those screened, there was an over-representation of women and older persons. The age-specific medians of blood cholesterol and proportions of hypercholesterolemic persons were consistently higher in female screenees--and marginally so in males--than in the reference populations, whereas higher proportions of persons with ideal cholesterol level in those screened were also observed, especially in younger males. Higher systolic blood pressure, lower relative body weight and less regular smoking were found consistently among the screenees. This cross-sectional study shows that the participants of such mass screening actions are a selective group of older, more frequently female health-conscious persons with a specific risk-factor pattern. Mass screenings of self-selected volunteers can, therefore, not be used for a reliable prediction of risk-factor distributions in the general population. Moreover, suggested further steps for those screenees with both health-conscious behavior and elevated biological risk-factor levels, such as second measurement, medical consultation and counselling, cannot be assured in the setting of a trade fair. The objectives and intentions of such mass screening activities should be reconsidered and discussed.

Adult↗