Fitness centre membership is related to healthy behaviours.

AIM: Maximizing the health benefits associated with reducing inactivity levels requires an understanding of the individual and environmental determinants of physical activity. Membership in a fitness facility promotes physical activity, yet little is known of its relationship to health. The purpose of this study was to compare physical activity levels, and health status, behaviours, and beliefs, in members of a fitness centre, and non-member community residents. METHODS: Using a cross-sectional design, fitness centre members (n=236) and non-members (n=302) were compared with respect to perceived health status, use of health care services, fitness status, physical activity level, perceived control over health, and the likelihood of engaging in health promoting behaviours, using The Health-Promoting Lifestyle Profile. Questionnaires were mailed to adult members of a fitness centre, and a stratified (age, sex) sample of non-members randomly selected from the local community. RESULTS: Fitness centre members were more likely than the comparison group to have visited a general physician, dentist, athletic therapist, optometrist, or nutritionist during the previous year (p<0.05), to exercise regularly, and to rate their physical fitness as very fit. They scored significantly higher on the overall health promoting lifestyle score (p=0.0353) as well as on health responsibility (p=0.0053), exercise (p=0.0001), and nutrition (p=0.0166) subscales, even after adjusting for differences in activity levels between groups. CONCLUSIONS: Fitness centre membership is associated with increased health responsibility and health promoting behaviours. This finding appears to be related to membership in the fitness centre, and not to increased participation in physical activity.

Cardiac structure and exercise blood pressure in urban and rural Canadian men of Icelandic descent.

The objective of the study was to determine the relationship between exercise systolic blood pressure (ESBP), during bicycle ergometry, and echocardiographically determined left ventricular structure in rural and urban Canadian men of Icelandic descent. The study was cross-sectional in design. The settings were urban Winnipeg and the rural Interlake District in the province of Manitoba, Canada. Subjects were adult male volunteers from families of wholly Icelandic descent. The subjects were 30 to 60 years of age and had supine blood pressure < 160/95 mm Hg. Anthropomorphic measurements, echocardiography and sphygmomanometry, at rest and during bicycle ergometry, were performed on all subjects. Prevalence of exaggerated ESBP (> or = 200 mm Hg) and left ventricular hypertrophy (LVH) was not significantly different in the two groups. In all but one individual LVH was classified as eccentric hypertrophy. In both urban and rural subjects with exaggerated ESBP, left ventricular mass index (LVMI) was greater than in those subjects without exaggerated ESBP. The LVMI correlated with ESBP at the highest workloads (> or = 150 W). Multivariate analysis of all subjects showed that cardiac index, ESBP, body mass index, and low exercise heart rate were predictive of LVMI. There was no significant difference in prevalence of ESBP or LVH between urban and rural Manitobans of Icelandic descent. However, LVMI levels were lower, and values for ESBP greater, in the rural group compared with the urban group. Within each of the two groups there was a positive association between ESBP and LVMI; hence, the study supports findings of our previous investigation showing evidence of early target organ effects in normotensive men with an exaggerated ESBP.

Characteristics and mechanisms of tachyphylaxis of cardiac contractile response to insulin.

Although insulin is known to cause internalization of its own receptors, the physiological significance of this phenomenon is not clear. In the isolated rat heart we observed that the positive inotropic effect of 25 munits/ml insulin was completely abolished if the heart was preperfused with insulin for 10 min. This tachyphylactic response to insulin began to appear 3-4 min after starting preperfusion with insulin and was partially reversible after 30 min of washing. Preperfusion with insulin did not affect the action of vanadate, which has insulin-like effect on glucose transport, or the actions of the other positive inotropic agents, isoproterenol and ouabain. The presence of propranolol in the perfusion medium, unlike atenolol, phenoxybenzamine, guanethidine, verapamil or quinidine, modified the inotropic as well as tachyphylactic responses to insulin. The positive inotropic and tachyphylactic responses to insulin were not altered in hearts from reserpine-treated animals. Perfusion of heart with glucose-free solution abolished the tachyphylaxis due to insulin. Likewise, no tachyphylactic response to insulin was evident when iodoacetate, but not sodium fluoride, was added in medium containing glucose. These results suggest that ATP formed during glycolysis may play an important role in insulin-induced tachyphylaxis with respect to cardiac contractile activity.

Exercise blood pressure and echocardiographic abnormalities in genetically comparable populations.

OBJECTIVE: To determine the relationship between the systolic blood pressure response to exercise and the echocardiographic dimensions of the left atrium and ventricle in two geographically separate, but genetically comparable, populations. DESIGN AND SETTING: The study was cross-sectional. The settings were two semirural communities, one in Iceland and one in Manitoba. SUBJECTS: Individuals from families where there had been no intermarriage with non-Icelandic individuals were eligible. Of the 200 eligible men in Manitoba and the 150 men in Iceland, 157 and 121 men, respectively, agreed to participate. In the majority of cases, those who chose not to participate stated that work commitments prevented them from taking part. The subjects were aged 25 to 63 years and had blood pressure less than 160/95 mmHg at rest. INTERVENTIONS: Blood pressure was taken at rest and during standardized bicycle ergometry. Left ventricular and atrial echocardiography was performed on a selected number of subjects. MAIN RESULTS: The Canadians of 'pure' Icelandic descent had a higher prevalence of exaggerated exercise systolic blood pressure (ESBP), left atrial enlargement (LAE) and left ventricular hypertrophy (LVH) than native Icelanders. Given their genetic similarity, it is suggested that the difference between the two groups is due to environmental factors. Within each group, subjects with exaggerated ESBP had a significantly greater left atrial dimension index and left ventricular mass index than subjects without an exaggerated ESBP. The relationship of ESBP with left atrial dimension index and left ventricular mass index was independent of age, body mass index and resting blood pressure. LVH was of the eccentric type and was absent in the majority of cases with LAE; however, LAE was present in nearly all LVH cases. CONCLUSIONS: This study demonstrates that an exaggerated ESBP in individuals with resting blood pressure less than 160/95 mmHg is not an innocuous finding it is associated with demonstrable cardiac abnormalities (LAE and LVH). Furthermore, it is proposed that the presence of LAE, with or without LVH, may add to the value of an exaggerated ESBP in identifying individuals at increased risk of developing sustained resting essential hypertension.

The association between exercise blood pressure and the prevalence of ECG abnormalities.

The relationship between atrial and ventricular electrocardiographic abnormalities and exercise systolic blood pressure was studied in 246 male and 183 female subjects, of whom 199 males and 158 females were normotensive (resting blood pressure below 140/90 mmHg) and 47 males and 25 females were borderline hypertensive (resting systolic blood pressure 140 to 159 and/or diastolic blood pressure 90 to 99 mmHg). Subjects were classified into three groups according to systolic blood pressure during treadmill exercise (less than or equal to 180 mmHg, 180 to 199 mmHg and greater than or equal to 200 mmHg). With respect to atrial electrocardiographic abnormalities, the prevalence of abnormal values of the P-terminal force in lead V1 increased significantly with increased levels of resting exercise systolic blood pressure in males and females. The prevalence of electrocardiographic left ventricular hypertrophy, as reflected in abnormal values of one or more RS voltage indices, increased significantly with exercise systolic blood pressure in males but not in females. Males did not show a trend of increasing electrocardiographic left ventricular hypertrophy with increased resting systolic blood pressure means. In females, the significant difference between resting systolic blood pressure means and electrocardiographic left ventricular hypertrophy did not reflect a linear progression across resting systolic blood pressure categories. The significant association of the P-terminal force in lead V1 with exercise systolic blood pressure has not previously been reported. Although an association between left ventricular hypertrophy and exercise systolic blood pressure in hypertensives has been reported by others, the association seen in normotensive and borderline hypertensive males has not been reported previously.(ABSTRACT TRUNCATED AT 250 WORDS)

Serum ferritin and heart disease: the effect of moderate exercise on stored iron levels in postmenopausal women.

OBJECTIVE: To determine the effect of a moderate exercise regimen on stored iron as measured by serum ferritin in previously sedentary postmenopausal women. DESIGN: Randomized assignment to one of three groups: a five day/week walking group (five-day group, n = 27); a three day/week walking group (three-day group, n = 27) or a sedentary group (control group, n = 25). SETTING: Community-based intervention. PARTICIPANTS: Women who were postmenopausal, over 50 years old, sedentary, not on hormone replacement therapy, nonsmokers, physically capable of exercising, without clinical signs of cardiovascular, pulmonary or metabolic disease, and not on medication that would affect iron metabolism. In addition, they had neither donated blood nor been transfused within the previous 12 months. All participants were screened volunteers who had responded to media advertisements. Seventy-nine participants met these criteria. Results are reported for 56 subjects (five-day group, n = 17; three-day group, n = 19; control group, n = 20) who completed the study. Their mean age was 61.3 +/- 5.8 years. INTERVENTION: The five-day group and the three-day group walked an average of 279 +/- 20 and 171 +/- 7 mins/week, respectively. Participants were counselled not to change their dietary intake. MAIN RESULTS: Following 24 weeks of walking, mean serum ferritin decreased significantly in the five-day group (P < 0.03), but not in the three-day group (P < 0.09) compared with controls. CONCLUSIONS: The extent of physical activity required to elicit a decrease in stored iron in postmenopausal women was determined. This may be clinically significant because stored iron increases significantly following menopause and excess stored iron have been cited as risk factors for coronary artery disease.

Comparison of a standard neurological tool with a stroke scale for detecting symptomatic cerebral vasospasm.

The purpose of this study was to critically analyze the effectiveness of two tools used by nurses to assess neurological status of individuals at risk of developing cerebral vasospasm following aneurysmal subarachnoid hemorrhage due to aneurysm rupture. Early detection of vasospasm provides an opportunity for prompt treatment so that further ischemia or infarction can be prevented. We hypothesized that the National Institutes of Health Stroke Scale would detect symptomatic vasospasm earlier than the standard neurological record currently used in the practice setting of a tertiary care teaching hospital. Thirty participants were entered into the study, and a differential diagnostic process identified 15 with symptomatic vasospasm. Quantitative prospective and retrospective analysis showed that there was no statistical difference between the two scales in early detection of vasospasm. This finding may partially be explained by the clinical similarities between the vasospasm and nonvasospasm groups and by the challenges experienced by nurses in administering the stroke scale. Clinically relevant observations suggested the stroke scale was more effective in the assessment of focal symptoms. Qualitative content analysis of nursing notes also provided insight into clinical findings not captured on either scale regarding generalized changes such as restlessness, impulsiveness, and unusual behavior. This study demonstrates the need to develop a more appropriate tool for early detection of vasospasm.

Analysis of nursing assessments in a cohort patients with ruptured cerebral aneurysms.

Patients admitted with subarachnoid hemorrhage are monitored for symptoms of vasospasm. A prospective study was designed to compare two monitoring instruments: a standard neurological tool (SNR) and the National Institutes of Health Stroke Scale (NIHSS). The two assessment tools were compared to evaluate their concordance and to identify areas where efficiency in recording assessments might be improved. We found no statistical difference between the two tools in detecting symptomatic cerebral vasospasm. Substantial discrepancies in the documentation of observations were noted, particularly in the assessment of limb drift. Avoidance of these discrepancies may require further definition in the SNR tool. A qualitative component consisting of a review of the nurses' notes regarding neurological status in the patients' charts was conducted. It was demonstrated that nurses commonly document information in the progress notes that is already captured in the SNR. Further education of nurses in the use of assessment tools is therefore recommended to avoid redundancies and increase efficiency in recording clinical observations.