The aim of this study was to investigate if endurance training during juvenile life 'reprogrammes' the heart and leads to sustained improvements in the structure, function, and morphology of the adult heart. Male Wistar Kyoto rats were exercise trained 5 days week for 4 weeks in either juvenile (5-9 weeks of age), adolescent (11-15 weeks of age) or adult life (20-24 weeks of age). Juvenile exercise training, when compared to 24-week-old sedentary rats, led to sustained increases in left ventricle (LV) mass (+18%; P < 0.05), wall thickness (+11%; P < 0.05), the longitudinal area of binucleated cardiomyocytes (P < 0.05), cardiomyocyte number (+36%; P < 0.05), and doubled the proportion of mononucleated cardiomyocytes (P < 0.05), with a less pronounced effect of exercise during adolescent life. Adult exercise training also increased LV mass (+11%; P < 0.05), wall thickness (+6%; P < 0.05) and the longitudinal area of binucleated cardiomyocytes (P < 0.05), despite no change in cardiomyocyte number or the proportion of mono- and binucleated cardiomyocytes. Resting cardiac function, LV chamber dimensions and fibrosis levels were not altered by juvenile or adult exercise training. At 9 weeks of age, juvenile exercise significantly reduced the expression of microRNA-208b, which is a known regulator of cardiac growth, but this was not sustained to 24 weeks of age. In conclusion, juvenile exercise leads to physiological cardiac hypertrophy that is sustained into adulthood long after exercise training has ceased. Furthermore, this cardiac reprogramming is largely due to a 36% increase in cardiomyocyte number, which results in an additional 20 million cardiomyocytes in adulthood.

Background/Objectives: A community-based study was conducted to compare the nutritional status between smokers and non-smokers in association with dietary, biochemical and socioeconomic characteristics. Methods: A convenient sampling method was used to enroll 100 smokers and 99 non-smokers aged between 46 and 78 years from the urban and semi-urban areas of district Peshawar, Pakistan. Weight, height, waist and hip circumferences of the subjects were taken while body composition was determined by employing a Bodystat Analyzer. A blood sample was taken from each subject for the determination of serum vitamin A and zinc levels. Subjects were interviewed for a 24-hr dietary recall and demographic and socio-economic characteristics. Student's t-test and bivariate analysis were conducted to compare the mean differences and examine the association between different variables of smoker and non-smoker groups. Results: The results revealed that there was no significant (p>0.05) difference between the mean age, weight, height and body mass index of smokers and non smokers. However, the mean body fat, waist and hip circumference of the smokers were significantly (p<0.05) lower than the non-smokers. Conversely, the mean serum vitamin A (32.30±15.99 µg/dl) of smokers was significantly (p<0.05) higher than non-smokers (26.50±20.44 µg/dl) but the mean serum zinc concentration of smokers (99.76±27.42 µg/dl) was significantly lower than the non-smokers (108.25±32.20 µg/dl). Conclusions: The study concludes that anthropometric (body mass index), biochemical (vitamin A and zinc status), dietary (energy intake) and socio-economic (income, profession) characteristics failed to establish an association with smoking as most of the indicators of smokers are comparable to non-smokers.

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