Correlates of vigorous physical activity in adolescents in five secondary schools in Trinidad

OBJECTIVE: To determine the correlates of vigorous physical activity in adolescents in Trinidad. DESIGN AND METHODS: Adolescents (n = 344) between 11-15 years from five secondary schools in North-central Trinidad were cross-sectionally surveyed. Behavioural risk factors: alcohol and smoking use, physical activity and diet were obtained by a pilot tested interviewer administered questionnaire. In addition, anthropometric measures were obtained on site at school. Multivariate logistical regression was used to analyze correlates of vigorous physical activity by sex. RESULTS: Fruit and vegetable intake (p < 0.001) and religion (p = 0.034) were correlated with vigorous physical activity in females. Lower waist circumference (p = 0.014), age (p = 0.046) and diastolic blood pressure (p < 0.01) were correlated with vigorous physical activity in males. Body mass index (BMI) for age data indicated that 41.3% of the children were overweight or obese. However, vigorous physical activity did not correlate with BMI for age in either sex. In the final logistic regression models, higher vigorous physical activity was associated with lower diastolic blood pressure in males (p < 0.05) and an increased daily intake of fruit and vegetables in females (p < 0.001). CONCLUSION: Increased dietary intake of fruits and vegetables in females and lower diastolic blood pressure in males were associated with higher vigorous physical activity. Prospective studies are required to determine and clarify the relative importance of diet and physical activity in overweight adolescents and their risk of chronic metabolic disease.

Individual and school-level influences on moderate and vigorous physical activity in Grenada adolescents

OBJECTIVE: The effect of school level policies on the physical activity of Grenadian children had not been studied. The present study tested the hypothesis that schools with physical activity (PA)-promoting policies would positively impact student’s levels of moderate and vigorous physical activity in Grenada. DESIGN AND METHODS: Multilevel analysis of a nationally representative sample of first year students (i.e. Form 1) (n = 138) from the twenty-three secondary schools in Grenada were assessed as part of the Grenada School Nutrition Study (GSNS). At the individual level physical activity was measured using Actigraph GT3X accelerometers. In addition to socio-demographic measures, height, weight and waist circumference (WC) were collected using standard anthropometric procedures. School-level measures were self-reported by school administrators. The school PA policy index included: student to teacher ratio in physical education (PE) classes, minutes of PE per week, number of PE facilities/equipment, having at least one policy to address PE participation, having ≥1 policy for access to sports teams or activities, having a school board or council to address PE policies. RESULTS: No school-level variables were significantly related to student Moderate and Vigorous Physical Activity (MVPA). Waist circumference was the only variable that significantly predicted MVPA in both boys (p=0.03) and girls (p=0.005). In girls, overweight/obesity was significantly associated with decreased MVPA (p=0.004). CONCLUSIONS: Contrary to findings in United States children, Grenada school-level policies and environments were not related to student’s physical activity levels. Further research was needed to understand the variation in physical activity levels by schools in both male and female Grenada students.

Barriers and facilitators to physical activity amongst overweight and obese women in the Caribbean: a qualitative study

OBJECTIVE: To identify modifiable barriers to physical activity and to explore factors that facilitate physical activity among overweight and obese women in Barbados. DESIGN AND METHODS: Seventeen women aged 25 to 35 years with a body mass index (BMI) ≥25, purposefully sampled from a population-based cross-sectional study, were recruited to participate in in-depth semi-structured interviews. Twelve women participated in one or more additional ethnographic sessions in which the researcher joined and observed a routine activity chosen by the participant. More than 50 hours of ethnographic data collection were accumulated and documented in field notes. Thematic content analysis was performed on transcribed interviews and field notes. RESULTS: Social, health-related, and structural barriers to physical activity were identified. Social factors related to gender norms and expectations. Women tended to be active with their female friends rather than partners or male peers, and reported peer support but also alienation. Being active also competed with family responsibilities and expectations. Health-related barriers included perceptions about chronic disease and competing strategies for weight loss. Structural barriers included few opportunities for active commuting, limited indoor space for exercise in the home, and low perceived access to convenient and affordable exercise classes. Several successful strategies associated with sustained activity were observed, including walking and highly social, low-cost exercise groups. CONCLUSIONS: This study highlights the role that gender norms and health beliefs play in shaping experiences of physical activity. Affordable and accessible group exercise classes are feasible within a Caribbean context and successful models have the potential to be replicated.

Physical activity and health

In this final issue of Nayam News in this physical activity series we attempt to collate the main evidence for the various health indicators. Clearly, physical activity is positively related to health. However to reap maximum benefits from physical activity, individuals (2yrs and older) are recommended to participate in a minimum of 30 minutes or more on most or all the days of the week. Health can be defined as a state of physical, emotional, social and psychological well-being. In promoting health, one must take into consideration the importance of psychological well-being. It can therefore be assumed that , in an effort to improve health and wellness, physical activity is of major imortance.

Physical activity and cardiovascular disease

Cardiovascular disease accounts for most deaths in the Caribbean. Man of these diseases are preventeable by actions of major risk factors including unhealthy diet, physical inactivity and smoking. The major cardiovascular diseases include: (1) Coronary (or ischemic) heart disease (heart attack); (2) Cerebrovascualar disease (stroke); (3) Hypertension (high blood pressure); (4) Heart failure; ( Rheumatic heart disease. High blood presure, which affects both children and adults, is a major contributor to heart disease. The favorable effects of physical activity on cardiovascular diseases reflects positively on atherosclerosis, plasma lipid/lipo-protein profile, blood pressure, availability of oyxgenated blood for the heart muscle needs (ischemia), blood clotting (thrombosis) and heart rhythm disturbances (arrhythmias). Other effects of physical activity that may be associated with modification of cardiovascular disease risk include reduced incidence of obesity, healthier distribution of body fat and reduced incidents of Type 2 diabetes.

Physical activity and diabetes

The incidence of diabetes continues to increase in the Caribbean due to many contributing factors, but the most significant factors are directly linked to prevalence of sedentry lifestyle, diet and obesity. In this issue of Nayam News we will explore why it is so important to practise a healthy lifestyle through physical activity to prevent or control diabetes. The benefits of physical activity are greates in the early stages of the disease. In fact, studies have shown that exercise and healthy diet can prevent the development of type 2 diabetes in people with Impaired Glucose Tolerance (IGT). IGT, often referred to as pre-diabetes is a condition that is developed prior to type 2 diabetes. The problem with IGT and type 2 diabetes is that many people display on symptoms, and are therefore unaware that they are living with the condition. Large population-based studies in several developed countries suggest that moderate reduction in weight and walking wach day for half an hour, reduces the incidence of diabetes more than half in overweight individuals. Thus, regular physical activity is a primary prevention measure for individuals who may be susceptible to the condition.

Physical activity and cancer

Cancer is one of the leading causes of death in the Caribbean. There are many kinds of cancer: in fact cancer is the general name given to a group of more than 100 diseases which all develop as a result of abnormal cell-growth. The abnormal cells usually form into a tumour (a lump or mass) but there are some cancers, like leukaemia, which do not form tumours, and it must be noted that not all tumours are cancerous. Some of the well-known types of cancer in the Caribbean include breast cancer, prostate cancer, cancers of the colon, cervix, stomach, rectum and lung cancer. Less frequently are ovarian and endometrial cancers, as well as leukaemia and cancer found in the thyroid, bladder, kidney and pancreas. Physical activity is said to reduce the chance of developing certain types of cancers, so in this issue of Nayam News, we will be taking a look at the evidence for relationships between physical activity and some types of the disease.

Physical activity and obesity

Obesity has become one of the major public health problems in the Caribbean. It affects more than a quater of the adult population, particularly our women. Obesity is one of the easiest medical conditions to recognize but most difficult to treat. It can be defined as a condition in which the body stores excess fat in such a way that health is negatively affected. When an individual becomes obese or has excess body fat this can be a serious health hazard as the person becomes prone to other chronic diseases such as diabetes mellitus type 2, cardiovascular disease, osteoarthritis, sleep apnea, stroke and certain types of cancer.

Promoting physical activity

As a follow up to the first issue on physical activity, Nayam News continues this series by showing how physical activity can be promoted. First, a historical perspective. In addition to healthy eating, scientists and physicians of many ancient cultures recognised the role of physical activity in promoting the health of mind and body. In China and India, concepts of health and disease prevention were developed as early as 3000 B.C. and both cultures upheld philosophies that emphasized the importance of exercise in preserving good health. This recognition of the relationship between medicine and physical activity is reflected in the writings of Greek physicians such as Herodicus (480BC), Hippocrates (377BC) and Galen (129AD). Today educators, philosophers, scientists and physicians still believe that physical activity is one of the most significant contributors to health and longevity.

Understanding physical activity

Although NAYAM News focuses on food, we frequently mention that diet and physical activity are the twin pillars of a healthy lifestyle. In response to reader's requests, NAYAM News therefore presents some perspectives of physical activity in a series of issues. Physical activity is a broad term that emcompasses all forms of muscle movements - bodily movements that are produced by the contraction of the skeletal muscle that increases expenditure above the normal basal level. Physical activity therefore contributes to the movement of the body in such a way that it uses up energy and therefore can be a means by which individuals practice healthy lifestyles. It includes aerobics, strengthening and flexibility activities and ranges from moderate to (walking briskly, hiking, dancing etc.) to vigorous (running/jogging, aerobics, weight lifting etc.). Physical activity can be classified by either its mechanical or metabolic property as muscle contraction is associated with both processes. The physical activities in which individuals participate can be placed in several categories. Such categories include occupational, household, leisure time and transportation. Leisure activity can be further divided into three groups: competitive sports (physical activity that is governed by a set of rules), recreation activities (such as: hiking, swimming) and exercise training.

Rapid changes in lifestyle make increased physical activity a priority for the Americas

The health benefits of regular participation in sports and aerobic fitness have been well recognized for more than 30 years. However, over the past decade new scientific evidence has shown that physical activity need not be strenuous to be beneficial to health. In fact, 30 minutes of moderate-intensity physical activity every day or on most days of the week provides important health benefits. This modest but regular amount of activity can greatly reduce or prevent the risk of cardiovascular disease, type 2 diabetes, osteoporosis, colon cancer, and breast cancer. Regular, moderate phyical activity, including daily activities such as climbing stairs, brisk walking, and biking, can reduce stress, alleviate depression and anxiety, enhance self-esteem, and increase mental alertness. Moreover, school-age children who are regularly active demonstrate enhanced school performance and a better sense of personal and social responsibility than those who are more sedentary (AU)

Activity and behavioral development in stunted and nonstunted children and response to nutritional supplementation

It is frequently assumed that undernutrition in young children leads to poor development through reduced activity. Three groups of 26 1-year-old stunted children were studied: nutritional supplementation, supplementation with psychosocial stimulation, and controls. 26 nonstunted comparison children were also studied. Activity levels were measured by extensive observations in the homes, and development using 4 subscales of the Griffith's Mental Development Scales. Initially, stunted children were less active than nonstunted ones (p<.01), but after 6 months they caught up regardless of treatment. The mental ages of the stunted children were lower than those of the nonstunted children initially, and improved with either treatment. Initially activity levels made a significant contribution to the variance in the locomotor subscale only, but not 6 months later. Activity did not predict change in development over 6 or 12 months, nor did change in activity over 6 months predict change in development over 12 months (AU)

The relationship between undernutrition, activity levels and development in young children

We examine the evidence that, in undernourished children, low levels of exploration and activity lead to poor development. In one study, children in the acute stage of severe undernutrition had reduced activity and exploration levels which readily improved with nutritional rehabilitation. Their developmental levels (i.e., developmental quotients = DQs) were low and remained so for several years. No association was found between activity and exploration levels and DQs. Mildly to moderately undernourished children generally have low DQs. In both severely and moderately undernourished children, DQs and school achievement levels are more often associated with height-for-age than weight-for-height. In two studies in clinical settings, when energy intake was reduced, children's activity levels or energy expenditure were also reduced. There is only limited evidence of reduced activity and exploration from studies of young undernourished children in their own homes. Undernourished school children were studied only once, and no evidence of reduced energy expenditure was found. DQs and activity have not been examined together often. In one Asian study low exploration and DQs were found in undernourished children. In three studies of nutritional supplementation some evidence of increased activity and exploration and of improved development was found. However, there were problems in study design in two of them. No evidence was found linking low activity to poor development in a causal relationship. We present preliminary findings from a Jamaican study of nutritional supplementation in 129 stunted children aged, 9-24 months. They were compared with 32 non-stunted children from the same neighborhoods. The stunted group had lower scores on every subscale of the Griffiths Mental Development Scale. Using time-motion observation methods, they were also found to be less active than the non-stunted group. However, the stunted children had higher energy intakes per kilogram body weight. Activity levels were related to the children's locomotor quotients. When we controlled for locomotor quotients, no group differences remained (AU)

Interaction of dopamine agonists with disrupted mesolimbic pathways implications for mental health

This work was designed to evaluate, in conjunction with certain dopamine agonists, the effects of disruption of the mesolimbic system on spontaneous motor activity and stereotype. The results indicated that lesions to the nucleus accumbens produced increments in motor activity that were exacerbated by amphetamine (5.0 mg/kg). Administration of apomorphine (1.0 mg.kg) produced similar results but was not as effective as amphetamine in inducing motor dysfunction. The relevance of these findings to psychopathology and motor disorders is discussed, with implications for public health policy (AU)

Effects of interruption of pallidal function on striatal-mediated motor activity: relevance to concepts in neurology and psychiatry

This work was conducted to evaluate the effects of bilateral lesion of the globus pallidus on spontaneous motor behaviour and drug-induced stereotypy. The evidence suggests that the pallidus is necessary for the expression of normal motor behaviour. Bilateral lesioned rats manifested hypoactivity. This hypoactivity or response depression was counteracted by low and high doses of amphetamine. Apomorphime (1.0 mg/kg) induced a normalizing effect on spontaneous motor activity in lesioned rats. However this higher dose of apomorphine induced marked stereotypic activity in lesioned rats. The results of this work raise important implications for certain motor disorders and the psychoses. (AU)

The effect of atropine and physostigmine sulphates on behavioural arousal in the developing rat

The purpose of this study was to observe the effect of atropine and physostigmine sulphates on the behavioural arousal of the developing rat with the aim of determining the exact age at which these drugs became effective. The spontaneous motor activity of the rats aged 15 - 28 days was measured using photocell activity cage, motor activity was measured for sixty minutes while the observation period in the Y maze was 3 minutes, subsequent to the administration of atropine, physostigmine or saline. The drugs were administered intraperitoneally. Control studies revealed that the 15 - 18 day old rats habituate slowly while the 20 - 28 day olds show a more precipitous decline in motor activity as time progressed. This age-related ability to habituate resulted over a period of 60 minutes, in higher activity scores in younger rats. This decrease in motor activity has been attributed to a gradually developed acetyl-choline inhibitory system. In contrast, in the Y maze, there were increases in the activity scores as the rats aged. It has been suggested that the age-related increase in activity is a result of an increased ability to explore. The intraperitoneal administration of atropine resulted in decreases in the spontaneous motor activity of the 15 - 18 day olds. At 19 days however, atropine had no effect on the activity recorded. These increases continued until day 25, after which atropine had virtually no effect on activity. The decrease in the motor activity of the drug-treated 15 - 18 day olds may be a result of drug blockade of cholinoreactive elements of the reticular activating system. In addition, the increase in activity observed between 21 - 25 day olds may be related to (i) an alteration in the cholinergic/dopaminergic balance of the brain in favour of the dopaminergic system (ii) the development of a cholinergic inhibitory system after day 20 of life. Compared with saline controls, the administration of physostigmine (0.2 mg/kg) to rats aged 15 - 21, 25 and 28 days resulted in significant decreases in the activity of the 15 - 20 day olds only. Increases in the locomotor activity of the 21, 25 and 28 day old rats were observed. Physostigmine (0.05 mg/kg) was administered to 16, 18, 21, 25 and 28 day old rats. At this dosage, a depressant effect was noted in the 16 day olds only. By day 18, however, a tendency towards an increase in motor activity developed. By 21 days, a definitely significant increase in motor activity was detected. The decrease in the activity of the younger rats (15 - 20 days) is possibly due to a combination of drug action at the neuromuscular junction and on response inhibition. Increases observed after day 20 are a result of physostigmine-induced increase in bothcortical and behavioral arousal in the intact animal. The changing pattern of the rat's response to the effects of atropine and physostigmine may be correlated with the gradual maturation of forebrain inhibitory structures (frontal neocortex and hippocampus) responsible for the modulation of reticular excitability (AU)

Relationship between separation-age of offspring and level of arousal as an indication of behavioural disturbance

Forty Sprague-Dawley rats were separated from their mothers at 2, 3, and 4 weeks respectively and were either reared in groups or in isolation for four weeks. Spontaneous motor activity was determined in activity cages. Results showed that rats separated at 4 weeks and reared in isolation showed the highest level of motor activity. This would imply that the longer the pup spent with the mother prior to separation the greater the impact of the separation experience (AU)

Central cholinergic involvement in the mediation of spontaneous motor activity in rats

Spontaneous motor activity of preweanling rats (14-day-old) was examined in an activity cage following the administration of atropine at 1.0, 2.5, 5.0, and 10.0 mg/kg respectively. Compared with saline-control animals, atropine at these dosages, did not significantly affect the activity level of the 14-day-old rat. The motor activity of 14-20-day-old rats was also measured following the administration of atropine (10mg/kg) in the Y-maze and the activity cage. The activity level was significantly decreased in (a) all ages in Y-maze and (b) the 18-day-old animals only in the activity cage. In contrast, amphetamine (2.0, 4.0, and 10.0 mg/kg) induced significant increments in spontaneous motor activity. It is suggested that a cholinergic mechanism concerned with the modulation of central nervous system arousability becomes functional at 18 days of age, that is, subsequent to a more caudal arousal inducing mechanism, which seems to be mediated by a catecholaminergic system (AU)

Effects of reserpine, tranylcypromine, haloperidol and Fla-63 on physostigmine - Induced hyperactivity in rats

The effects of bis (4-methyl-l-homopiperazinyltio - carbonyl) disulphide (FLA-63), haloperidol, reserpine and tranylcypromine on physostigmine-inducedhyperactivity in rats were studied using jiggle platforms to measure motor activity levels. Haloperidol (0.025 mg/kg). On the other hand FLA-63 (2.5 mg/kg) and tranylcypromine (20 mg/kg) attenuated the effect of physostigmine during the first thirty minutes of testing and caused a potentiation during the next thirty minutes. All drugs were administered intraperitoneally. These results support the hypothesis of an interaction between the cholinergic and catecholminergic systems in the central nervous system (AU)