Relationships between anthropometry, cardiorespiratory fitness indices and physical activity levels in different age and sex groups in rural Senegal (West Africa).

BACKGROUND: A high level of activity is commonplace in traditional subsistence societies. Physiological characteristics of individuals, including body composition and physical fitness, could be limiting factors when performing daily tasks. OBJECTIVES: The study investigated the relationships between cardiorespiratory fitness, nutritional status and physical activity patterns, so as to test the hypothesis that these relationships are less straightforward in children than in adults. STUDY DESIGN: Four different groups of individuals from rural Senegal were investigated: 99 10-13-year-old children of both sexes (11.1 +/- 1.5 years old) from two settings in Senegal (Lambaye and Podor), 43 adolescent girls (15.5 +/- 0.5 years), and 30 adult women (17-40 years). METHODS: Subjects undertook a step test, and anthropometric measurements were collected. Continuous heart rate (HR) monitoring was performed for 8-12 h. The flex-HR method was used to estimate levels of activity (per cent of time spent under or over the flex-HR). RESULTS: Ten to 13-year-old children and adolescent girls presented slight degrees of malnutrition. Adult women were apparently not nutritionally deprived. Differences in cardiorespiratory fitness were found among 10-13-year-old children, while adult women performed better than adolescent girls. Children from Lambaye had a higher level of activity than children from Podor. Similarly, adult women were more active than adolescent girls. No relationships were found between cardiorespiratory or anthropometric measurements and per cent of time spent above the flex-HR (> flex-HR) in 10-13-year-old children. In contrast, in adult women and adolescent girls, body composition and cardiorespiratory indices were significant predictors of activity levels. CONCLUSION: Our data support the hypothesis that activity levels are less dependent upon physiological characteristics in children than in adults in traditional subsistence societies

Nutritional status, growth and sleep habits among Senegalese adolescent girls.

OBJECTIVE: To study the relation between sleep habits, nutritional status, growth and maturation in a group of African adolescent girls. The main hypothesis to be tested was that sleep length could be an effective way to spare energy, and thus malnourished girls sleep longer than normal girls. DESIGN: Three repeated yearly surveys (1997-1999) on a subsample of girls drawn from a larger study cohort on growth at adolescence. SETTING: The Niakhar district in the central part of Senegal. SUBJECT: In total, 40 girls were initially drawn. Missing girls were replaced at each round by girls having the same characteristics and belonging to the same cohort. INTERVENTION: At each round, data on pubertal development (breast stages and occurrence of menarche), growth and nutritional status were collected. Adolescents wore an accelerometer for three or four consecutive nights and days at each round. RESULTS: At the beginning of the survey, girls were 13.3+/-0.5 y old. They were under international reference values in weight and height. Their mean sleep duration was 8.5+/-0.9 h. Their puberty status did not influence their sleep habits; however, they slept more in March than in June, which was related to the seasonal change in daylight. There was a significant relation between body mass index and sleep habits: thinner girls slept a longer time and more quietly than the more corpulent girls. CONCLUSION: The nutritional status of these girls influenced their sleep habits: this may have been either a direct causal relation or a consequence of a protective attitude on the part of the mothers towards the frailer girls

Fat and muscle mass in different groups of pre-pubertal and pubertal rural children. Cross-cultural comparisons between Sahelian (rural Senegal) and Amazonian (Beni River, Bolivia) children.

Background: An increase in fat accretion is essential for triggering the puberty spurt. Hence, nutritional constraints may influence puberty timing. Aim: To measure changes in fat and muscle mass in children living in natural environments but with different nutritional exposures. Methods: Cross-comparisons of children from rural Senegal and lowland (Amazonian) Bolivia were carried out. Anthropometric measurements of stature, weight, four subcutaneous skin-folds (triceps, biceps, subscapular, supra-iliac) and arm circumference were made. Children were divided into two age groups (5-9.9-year-olds or 'pre pubescents' (n = 381) and 10-15-year-olds or 'pubescents' (n = 692)). Results: Senegalese girls menstruated later than Bolivian girls and Senegalese boys also matured later than Bolivian boys. Bolivian children displayed more fat and muscle before puberty and during puberty than the Senegalese. They also had more fat deposited on the trunk. There were substantial differences in living conditions and nutritional patterns between both locations. In Senegal, nutritional stress is likely to appear early during in utero life and to persist throughout the growth period, including puberty. This leads to a deficit in fat accretion before and during puberty that is associated with a considerable delay in puberty occurrence. In Bolivia, such stress is far less severe. Conclusion: Variability in puberty should be analysed taking into account these differences