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Biomedical subjects

Roy J Shephard

Publications and source records attributed to Roy J Shephard.

At least 19 recordsLinked to original sources
PubMed2006

Yearlong physical activity and depressive symptoms in older Japanese adults: cross-sectional data from the Nakanojo study.

OBJECTIVE: The objective of this study was to investigate associations between accelerometer measurements of physical activity and psychosocial variables in older people. METHODS: Subjects were 184 Japanese aged 65-85 years. An accelerometer provided step count and physical activity intensity data throughout each 24-hour period for 1 year. At the end of the year, anxiety, depression, and cognitive function were assessed. RESULTS: Controlling for age, the daily number of steps, and the daily duration of moderate-intensity physical activity showed significant negative correlations with depressive mood. CONCLUSION: A depressive mood is associated with the quantity and quality of habitual physical activity.

Aged↗
PubMed2006

Yearlong physical activity and health-related quality of life in older Japanese adults: the Nakanojo Study.

We hypothesized that the health-related quality of life (HRQOL) would be poorer in physically inactive older adults. This was tested in a sample of 73 male and 108 female free-living healthy Japanese participants, age 65-85 years. We measured accelerometer step counts and their metabolic equivalents (METs) throughout each 24-hr period for 1 year. At the end of the year, HRQOL was assessed. Physical activity was grouped into quartiles. HRQOL was poorer in the lowest quartiles of participants with respect to both step count and duration of activity >3 METs; however, our sample showed no better HRQOL in those participants exceeding minimum standards of daily physical activity, corresponding to counts of around 5,500 and 4,500 steps/day and durations of around 13 and 14 min/day in men and women, respectively. Causation cannot be demonstrated from this cross-sectional study, but nevertheless we suggest that elderly individuals should be encouraged to meet such standards of habitual physical activity.

Age Factors↗
PubMed2006

Implementing national population-based action on physical activity--challenges for action and opportunities for international collaboration.

This paper summarises recent past and current international developments on physical activity looking at the challenges and opportunities they pose. Key elements of the WHO's Global Strategy on Diet, Physical Activity and Health (GSDPAH) are summarised, focusing specifically on the physical activity components, and by drawing upon recent fora (Atlanta, October 2002; Miami, December 2004; Cascais, February 2005; Beijing, October 2005; Bogotá, November 2005), we outline the barriers and areas of support required for successful development and implementation of national, population-based action on physical activity. These gatherings focused particularly on the needs of developing countries, where to date little has been done to augment physical activity at a population level. Unless swift action is taken, these countries will soon suffer significantly from an increased prevalence of non communicable diseases (NCD). Existing initiatives and opportunities for national and international action on physical activity are identified. Specific actions are proposed for advocacy, communication and dissemination, networks and partnerships, fundraising, policy development and implementation, programme implementation and evaluation, surveillance and capacity building. The development of the Global Alliance for Physical Activity (GAPA) provides a structure for international collaboration.

Developing Countries↗
PubMed2005

Meteorology and the physical activity of the elderly: the Nakanojo Study.

Seasonal changes in ambient temperature and day length are thought to modify habitual physical activity. However, relationships between such environmental factors and the daily physical activity of older populations remain unclear. The present study thus examined associations between meteorological variables and the number of steps taken per day by elderly Japanese. Continuous pedometer counts over a 450-day period were collected from 41 healthy subjects (age 71+/-4 years), none of whom engaged in any specific occupational activity or exercise programs. An electronic physical activity monitor was attached to a belt worn on the left side of the body throughout the day. Daily values for mean ambient temperature, duration of bright sunshine, mean wind speed, mean relative humidity, and precipitation were obtained from local meteorological stations. The day length was calculated from times of sunrise and sunset. Based on the entire group of 41 subjects (ensemble average), a subject's step count per day decreased exponentially with increasing precipitation (r2=0.19, P<0.05). On days when precipitation was <1 mm, the step count increased with the mean ambient temperature over the range of -2 to 17 degrees C, but decreased over the range 17-29 degrees C. The daily step count also tended to increase with day length, but the regression coefficient of determination attributable to step count and mean ambient temperature (r2=0.32, P<0.05) exceeded that linking the step count and day length (r2=0.13, P<0.05). The influence of other meteorological factors was small (r2<or=0.03) and of little practical significance. On days when precipitation is <1 mm, physical activity is associated more strongly with ambient temperature than with day length, duration of bright sunshine, wind speed, or relative humidity. Our findings have practical implications for health promotion efforts designed to increase the physical activity of elderly people consistently in the face of seasonal variations in environmental conditions.

Adult↗
PubMed2005

Contribution of school programmes to physical activity levels and attitudes in children and adults.

Although children and youth currently form the most active segments of the population in developed societies, there is a marked trend toward an increase in sedentary lifestyle among school-age children. The purpose of this review is to analyse the effects of school physical education (PE) programmes on: (i) the physical activity (PA) levels of participants as children and adults; and (ii) attitudes toward PE and PA in the same groups. Based on the literature analysed, it can be suggested that a sufficient quantity of a quality PE programme can contribute significantly to the overall amount of moderate-to-intense PA of the school-age child. Schools also have the potential to influence the habitual PA of children by encouraging increased participation in extracurricular sports activities, by favouring active commuting to school and by providing exercise equipment and supervision for youth in their neighbourhoods. Most young children have a very positive attitude towards PE. However, as they grow older, their perception of PE as a positive experience seems to become more ambiguous. From the few studies available, it seems likely that quality PE programmes help to maintain initial positive perceptions. Future research should address factors influencing the change of perceptions as a child matures. In addition to offering a quality PE programme, schools should ensure that the total weekly amount of PE is sufficient not only to maintain but also to enhance a child's physical fitness. More research is needed to determine the ability of school PE programmes to influence PA behaviour in adult life and to evaluate strategies that will make optimal use of the curricular time allocated to PE.

Adolescent↗
PubMed2004

Walking velocity measured over 5 m as a basis of exercise prescription for the elderly: preliminary data from the Nakanojo Study.

Moderate-intensity physical activity is recommended to promote health, and augment peak oxygen transport, thus reducing the risk of chronic disease, and delaying functional loss in the elderly. The optimal method of prescribing the recommended intensity of effort [approximately 50% of oxygen intake reserve ( V(.)O(2reserve)) or heart rate reserve (HR(reserve))] remains unclear for this age group. Our aim was to develop a new field-method of prescribing exercise for the elderly, based on walking velocity measured over a 5-m distance. Walking velocities were calculated from the time taken to move from the 3-m to the 8-m mark on an 11-m, straight, flat walkway. Interrelationships of preferred and maximal walking velocities with traditional laboratory measurements [peak isometric knee-extension strength and maximal oxygen intake ( V(.)O(2max))] were examined in 10 healthy male and 13 healthy female volunteers, aged 65-74 years. Percentages of oxygen intake reserve (% V(.)O(2reserve)) and heart rate reserve (%HR(reserve)) were also determined when walking at 30-70% of maximal velocity. Preferred and maximal walking velocities were significantly correlated ( r>0.60; P<0.05), the former corresponding to an average of 53-54% of the latter in both men and women. Maximal walking velocity was significantly correlated with both peak knee-extension torque ( r>0.90; P<0.05) and V(.)O(2max) ( r>0.80; P<0.05). As a result, the % V(.)O(2reserve) and %HR(reserve) showed a regular and linear relationship to various submaximal walking velocities. For both men and women, 40-60% of the maximal walking velocity corresponded to about 30-50% of V(.)O(2reserve) and HR(reserve). Approximately 60% of the maximal walking velocity (or 110-115% of the preferred walking velocity) represents an appropriate intensity of moderate exercise for the typical elderly person. Our preliminary data suggest that a prescription based on walking velocity over the 5-m distance allows the healthy elderly to exercise simply, safely, and effectively.

Aged↗
PubMed2004

Natural killer cell lytic activity and CD56(dim) and CD56(bright) cell distributions during and after intensive training.

The purpose of this study was to examine the impact of intensive training for competitive sports on natural killer (NK) cell lytic activity and subset distribution. Eight female college-level volleyball players undertook 1 mo of heavy preseason training. Volleyball drills were performed 5 h/day, 6 days/wk. Morning resting blood samples were collected before training (Pre), on the 10th day of training (During), 1 day before the end of training (End), and 1 wk after intensive training had ceased (Post). CD3(-)CD16(bright)CD56(dim) (CD56(dim) NK), CD3(-)CD16(dim/-)CD56(bright) NK (CD56(bright) NK), and CD3(+)CD16(-)CD56(dim) (CD56(dim) T) cells in peripheral blood were determined by flow cytometry. The circulating count of CD56(dim) NK cells (the predominant population, with a high cytotoxicity) did not change, nor did the counts for other leukocyte subsets. However, counts for CD56(bright) NK and CD56(dim) T cells (subsets with a lower cytotoxicity) increased significantly (P < 0.01) in response to the heavy training. Overall NK cell cytotoxicity decreased from Pre to End (P = 0.002), with a return to initial values at Post. Lytic units per NK cell followed a similar pattern (P = 0.008). Circulating levels of interleukin-6, interferon-gamma, and tumor necrosis factor-alpha remained unchanged. These results suggest that heavy training can decrease total NK cell cytotoxicity as well as lytic units per NK cell. Such effects may reflect in part an increase in the proportion of circulating NK cells with a low cytotoxicity.

Adult↗
PubMed2004

Role of the physician in childhood obesity.

OBJECTIVE: To suggest the role of the practicing physician in examining and treating childhood obesity. How should obesity be determined at clinical examination? Is there an obesity epidemic? What is the likely influence of obesity upon current and future health? What are the causes of obesity, and what does this imply for prevention and treatment? DATA SOURCES: Relevant articles in Medline and personal files. DATA SYNTHESIS: The 80th and 95th percentiles of body mass index and skinfold readings provide the most commonly accepted indices of overweight and obesity in the child. Over the last 20 years, the proportions of overweight and obese children have increased in both indigenous populations and most developed societies. Current methods of assessing physical activity and diet during childhood lack the precision to establish the primary cause of the obesity epidemic, but correlational analysis shows a close relationship between body fat content and a decline in daily energy expenditures. Immediate consequences of childhood obesity include an increased prevalence of atherosclerotic plaques, hypertension, and an adverse lipid profile, with a poor self-image that limits participation in physical activity. Tracking is such that many obese children become obese adults, and in consequence, the long-term risks of cardiovascular and all-cause deaths are increased. The prevention of obesity is easier than its cure. A combination of increased lifestyle activities, less sedentary behavior, and dietary modification seems the most effective approach. This should be supported by the use of behavioral modification techniques and changes in the urban environment that encourage an active lifestyle. CONCLUSIONS: The pediatric physician can contribute to the control of obesity by monitoring body mass index and skinfold thicknesses in all patients. Children above the 50th percentile of body fat need dietary modification and a greater amount of moderate physical activity. Physicians should also advocate quality daily physical education and an environment that encourages adoption of an active lifestyle.

Adolescent↗
PubMed2004

Tracking of physical activity from childhood to adulthood.

PURPOSE: To examine 1) relationships between adult PA at 35 yr and PA as a child, and 2) the influence of enhanced primary school physical education (physed+) and of parental PA upon the long-term tracking of PA in the offspring. METHODS: PA data from the 1970-1977 Trois-Rivieres Growth and Development Study, completed when the children were aged 10-12 yr, were compared with PA data collected on 166 of the same subjects in 1996-1998, when aged 34.9 +/- 1.1 yr. The weekly duration of total PA, intense PA, light PA, organized PA, and total sedentary behaviors other than sleep as a child were each correlated with a questionnaire assessment of total weekly PA as an adult. RESULTS: Considering males and females jointly, adult PA showed a significant but weak association with childhood PA, correlations for total PA, intense PA, light organized PA, and nonorganized PA amounting to r = 0.20, 0.18, 0.12, and 0.19, respectively. In males (N = 79), the total time spent during childhood in organized PA was associated with adult PA (r = 0.26, P < 0.05), due to students who received physed+ (r = 0.34). In females, also, a higher PA frequency as an adult was significantly associated with physed+. There was no association of PA patterns between children and their parents. CONCLUSION: Our results suggest a positive impact of early required physical education upon adult PA but provide little evidence of an overall association between time spent in other categories of PA during childhood and PA as an adult.

Adult↗
PubMed2003

Peak oxygen intake and cardiac mortality in women referred for cardiac rehabilitation.

OBJECTIVES: This study investigated the prognostic importance of measured peak oxygen intake (VO(2peak)) in women with known coronary heart disease referred for outpatient cardiac rehabilitation. BACKGROUND: Exercise capacity is a powerful predictor of prognosis in men with known or suspected coronary disease. Similar findings are described in women, but fewer studies have utilized measured VO(2peak), the most accurate measure of exercise capacity. METHODS: A single-center design took data from 2,380 women, age 59.7 +/- 9.5 years (1,052 myocardial infarctions, 620 coronary bypass procedures, and 708 with proven ischemic heart disease), who underwent cardiorespiratory exercise testing. They were followed for an average of 6.1 +/- 5 years (median 4.5 years, range 0.4 to 25 years) until cardiac and all-cause death. RESULTS: We recorded 95 cardiac deaths and 209 all-cause deaths. Measured VO(2peak) was an independent predictor of risk, values > or =13 ml/kg/min (3.7 multiples of resting metabolic rate) conferring a 50% reduction in cardiac mortality (hazard ratio [HR] 0.5, p = 0.001). Considered as a continuous variable, a 1 ml/kg/min advantage in initial VO(2peak) was associated with a 10% lower cardiac mortality. Adverse predictors were diabetes (HR 2.73, p = 0.0005) and antiarrhythmic therapy (HR 3.93, p = 0.0001). CONCLUSIONS: As in men, measured VO(2peak) is a strong independent predictor of cardiac mortality in women referred for cardiac rehabilitation.

Coronary Artery Bypass↗
PubMed2003

Long-term cardiorespiratory results of exercise training following cardiac transplantation.

The long-term influence of exercise training after heart transplantation remains unclear. Accordingly, we performed a 12-year follow-up study of 36 patients who underwent heart transplantation. Findings for survivors were compared with those of age-matched controls over the same period. Comparisons were also made between survivors and deceased patients. The sample comprised 36 men (aged 47 +/- 9 years) and a group of healthy age-matched controls. The patients received 16 months of outpatient exercise training; physiologic data were collected initially and at discharge. At 12 years, further data were collected on 20 of 23 survivors and their controls; 3 of the survivors were unavailable for final assessment, and 13 patients had died in the interim. The survivors' peak oxygen intake (V*O(2peak)) increased 26% after training and decreased 0.39 mlkg(-1)min(-1) per year (27.9 +/- 7 to 23.7 +/- 6), which was a similar rate as the controls (0.37 mlkg(-1)min(-1) per year; 33.7 +/- 7 to 29.2 +/- 7). Lean body mass (LBM) increased 3 kg by 16 months and a further 2.5 kg by 12 years, but ultimately was 3 kg below the controls. Although there was no difference in entry data between deceased patients and survivors, the latter attained greater gains in V*O(2peak) and LBM over the 16 months of training. Thus, in heart transplantation patients who undergo training, gains in exercise capacity are lost over 12 years at a rate commensurate with normal aging. A reduced training response in V*O(2peak) and LBM contributes to a poorer prognosis.

Adult↗
PubMed2003

Supervision of occupational fitness assessments.

Controversy continues regarding an appropriate level of supervision for occupational fitness assessments. A bout of vigorous physical activity can augment the immediate risk of a cardiac catastrophe by a factor of 5-100 depending on age, cardiac risk factors, and the physical and emotional circumstances of the participant. However, if a person engages regularly in such activity, the immediate risk is more than offset by an improvement in prognosis during intervening periods of rest. During demanding physical work, there is a small but measurable risk of sudden death (3 to 7 episodes per 100,000 personnel per year). The risk associated with a brief (< 15 min) but vigorous occupational fitness assessment is so low as to preclude attempts to reduce it still further by direct medical supervision. If testing encourages an increase in personal fitness, any immediate increase in risk is enormously offset by a reduction in the number of cardiac deaths while resting. Furthermore, evidence is unconvincing that the average medical practitioner can prevent or treat any emergencies that may arise better than a well-trained professional fitness and lifestyle consultant (PFLC), a person certified by the Canadian Society for Exercise Physiology who has had frequent opportunities to practice the necessary skills. Since occupational fitness assessments are not diagnostic procedures, they appear to fall outside the jurisdiction of medical licensing bodies. In the absence of a history of cardiovascular disease, supervision of such assessments is safely and appropriately undertaken by the PFLC. Unnecessary insistence on medical supervision could preclude annual evaluation of occupational fitness and a resulting enhancement of physical condition, thus increasing rather than diminishing the risk to the worker.

Cardiopulmonary Resuscitation↗
PubMed2003

Tracking of physical fitness from childhood to adulthood.

The purpose of the present study was to investigate the tracking of selected aspects of physical fitness (peak handgrip force, sit-ups, aerobic fitness, and blood pressure) from childhood to adulthood. The investigation studied a randomly selected subgroup from the original participants in the Trois-Rivières growth and development study, 95 women (57 experimental and 38 control) and 96 men (56 experimental and 40 control). During their primary-school education, the experimental group had received 5 hours of physical education each week whereas the control group had received 40 minutes per week. Data were gathered when subjects were 10-12 years old (baseline) and during follow-up around the age of 35 years. Tracking between 10, 11, 12, and 35 years of age was assessed by correlation analysis. In females the tracking of grip strength increased from the interval 10-35 to the intervals 11-35 and 12-35 years of age (r = 0.54 to 0.69 and 0.67, respectively, all p < 0.001). In males the tracking of grip strength was less consistent, but also increased over the same intervals to become significant for the correlation between 12 and 35 years of age (r = 0.32, p < 0.05). Tracking for sit-ups also increased, from 0.29 to 0.38 for females and from 0.23 to 0.54 for males. The tracking of PWC 170/kg between 11 and 35 years was significant but low in females (r = 0.24) as well as in males (r = 0.34). The ability of childhood blood pressure to predict adult values was low in females (r = 0.24 for diastolic, ns; and r = 0.26 for systolic, p < 0.05) and absent in males. Presumably because some of the influence of the added physical education was lost by adulthood, the tracking of PWC 170/kg and grip strength was weaker for experimental than for control subjects. In conclusion, data from the Trois-Rivières longitudinal study showed limited tracking of PWC170/kg and situps in both sexes. The tracking of grip strength was moderately high in females but less consistent in males. This may reflect the larger influence of sex hormones on the muscle strength of males at puberty.

Adult↗