| 61. |
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| 62. |
- Dencker, Magnus, et al.
(författare)
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Maximal oxygen uptake versus maximal power output in children
- 2008
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Ingår i: Journal of Sports Sciences. - : Informa UK Limited. - 0264-0414 .- 1466-447X. ; 26:13, s. 1397-1402
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Tidskriftsartikel (refereegranskat)abstract
- Maximal oxygen uptake ([Vdot]O2max) is considered the optimal method to assess aerobic fitness. The measurement of [Vdot]O2max, however, requires special equipment and training. Maximal exercise testing with determination of maximal power output offers a more simple approach. This study explores the relationship between [Vdot]O2max and maximal power output in 247 children (139 boys and 108 girls) aged 7.9-11.1 years. Maximal oxygen uptake was measured by indirect calorimetry during a maximal ergometer exercise test with an initial workload of 30W and 15Wmin-1 increments. Maximal power output was also measured. A sample (n=124) was used to calculate reference equations, which were then validated using another sample (n=123). The linear reference equation for both sexes combined was: [Vdot]O2max (mlmin-1)=96 + 10.6maximal power + 3.5body mass. Using this reference equation, estimated [Vdot]O2max per unit of body mass (mlmin-1kg-1) calculated from maximal power correlated closely with the direct measurement of [Vdot]O2max (r=0.91, P0.001). Bland-Altman analysis gave a mean limits of agreement of 0.22.9 (mlmin-1kg-1) (1s). Our results suggest that maximal power output serves as a good surrogate measurement for [Vdot]O2max in population studies of children aged 8-11 years.
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| 63. |
- Dencker, Magnus, et al.
(författare)
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Objectively measured daily physical activity related to cardiac size in young children.
- 2009
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Ingår i: Scandinavian Journal of Medicine & Science in Sports. - : Wiley. - 1600-0838 .- 0905-7188. ; Aug 5, s. 664-668
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Tidskriftsartikel (refereegranskat)abstract
- Training studies in children have suggested that endurance training can give enlargement of cardiac dimensions. This relationship has not been studied on a population-based level in young children with objective methods. A cross-sectional study was made of 248 children (140 boys and 108 girls), aged 8-11 years, from a population-based cohort. Left ventricular end-diastolic diameter (LVDD) and left atrial end-systolic diameter (LA) were measured with echocardiography and indexed for body surface area (BSA). Physical activity was assessed by accelerometry, and the duration of vigorous physical activity per day (VPA) was calculated. Acceptable accelerometer and echocardiography measurements were obtained in 228 children (boys=127, girls=101). Univariate correlations between VPA and LVDD were indexed for BSA in boys (r=0.27, P<0.05) and in girls (r=0.10, NS). Multiple regression analysis showed that independent factors for LVDD, indexed for BSA for boys, were age and VPA. LA indexed for BSA was not related to physical activity variables in either gender. No clear relationship exists between cardiac size and daily physical activity in children aged 8-11 years. This suggests that significant cardiac remodelling due to volume exposure secondary to a high amount of physical activity begins later in life.
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| 64. |
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| 65. |
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| 66. |
- Dencker, Magnus, et al.
(författare)
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Total body fat, abdominal fat, body fat distribution and surrogate markers for health related to adipocyte fatty acid-binding protein (FABP4) in children
- 2017
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Ingår i: Journal of Pediatric Endocrinology and Metabolism. - : Walter de Gruyter GmbH. - 0334-018X .- 2191-0251. ; 30:4, s. 375-382
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Tidskriftsartikel (refereegranskat)abstract
- The aim of the study was to assess possible relationships between adipocyte fatty acid-binding protein (FABP4) and total body fat (TBF), abdominal fat, body fat distribution, aerobic fitness, blood pressure, cardiac dimensions and the increase in body fat over 2 years in a community sample of children. A cross-sectional study was used in a community sample of 170 (92 boys and 78 girls) children aged 8-11 years. TBF and abdominal fat (AFM) were measured by dual-energy X-ray absorptiometry (DXA). TBF was also expressed as percentage of total body mass (BF%), and body fat distribution was calculated as AFM/TBF. Maximal oxygen uptake (VO2PEAK) was assessed by indirect calorimetry during a maximal exercise test and scaled to body mass. Systolic and diastolic blood pressure (SBP and DBP) and pulse pressure (PP) were measured. Echocardiography was performed. Left atrial (LA) size was measured, and left ventricular mass (LVM) was calculated. A follow-up DXA scan was available in 152 children (84 boys and 68 girls). Frozen serum samples were analyzed for FABP4. Partial correlations, with adjustment for sex, between FABP4 vs. ln TBF, ln BF%, ln AFM, AFM/TBF and VO2PEAK were (r=0.69, 0.68, 0.69, 0.49 and -0.39, p<0.05 for all). Moreover, SBP, PP, LVM and LA were also weakly correlated with FABP4 (r=0.23, 0.22, 0.28 and 0.21, p<0.05 for all). Correlations between FABP4 vs. increase in TBF and AFM over 2 years were 0.29 and 0.26, p<0.05, for both. (Increase in percent body fat or change in fat distribution were not correlated.) Findings from this community-based cohort of young children show that increased body fat and abdominal fat, more abdominal body fat distribution, low fitness, more LVM and increased LA, increased SBP and PP were all associated with increased levels of FABP4. Increase in TBF and abdominal fat over 2 years were also associated with increased levels of FABP4.
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| 67. |
- Dencker, Magnus, et al.
(författare)
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Tracking of Physical Activity with Accelerometers Over a Two-year Time Period.
- 2013
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Ingår i: Journal of Physical Activity & Health. - 1543-5474. ; 10:2, s. 241-248
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Limited data exists of tracking and changes in accelerometer measured physical activity in children. METHODS: Physical activity was assessed by accelerometers for four days in 167 children (boys n=90, girls n=77), aged 9.8±0.6 years. Follow-up measurement was made 2.0±0.1 yrs later (range 1.9-2.1 yrs). General physical activity (GPA) was defined as mean count/minute. Minutes of inactivity, light- moderate- and vigorous physical activity (LMVPA), moderate and vigorous physical activity (MVPA) and vigorous physical activity (VPA) per day were calculated both as absolute values and as percentage of total registration time. RESULTS: Spearman rank order correlation indicated low tracking of MVPA and VPA in girls (r=0.25-0.33, P<0.05), and low-moderate tracking of GPA, inactivity, LMVPA, MVPA and VPA in boys (r=0.23-0.40, P<0.05). Time in inactivity increased at follow-up by 5-14%. Most of the assessed physical activity variables were decreased at follow-up by 6-30%. CONCLUSIONS: Physical activity tracks at a low-moderate degree from age 10 to age 12 years, which confirm previous investigations that have used self-report assessments. The low-moderate tracking of physical activity variables indicate that those who were most active initially remained most active. Increasing inactive behaviour was observed and that several other physical activity variables were decreased at follow-up.
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| 68. |
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| 69. |
- Dobric, Julia, et al.
(författare)
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Physical activity changes the deposited fractions of particles in the respiratory tract of adults and children
- 2022
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Ingår i: ; , s. 45-45
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Konferensbidrag (refereegranskat)abstract
- Exposure to ambient air pollution can cause a numberof health problems and may be particularly dangerous to susceptible population groups such as children. Health effects caused by air pollution are criticallydependent on both the deposited fraction (DF) of the inhaled particles and in what region of the respiratory tract the deposition takes place. With increasing physical activity, the breathing pattern is altered and the airflow in the respiratory tract increase, this affects the DF and deposition site. In this study we investigated changes in DF at increasing physical activity for three population groups: ~5 and 10 year-old children, and adults.Our results indicate that the variation in total DF with physical activity is minor, but that the DF for the UFPs increase in the AI region at higher activity levels. This is important since the removal of particles in the AI region is not effective and UFPs are believed to pose a specific health risk. Therefore, activity patterns and DF of different population groups need to be considered when estimating particle dose and evaluating health risks.
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| 70. |
- Dobric, Julia, et al.
(författare)
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Preschool Children’s Inhalation Rates Estimated from Accelerometers—A Tool to Estimate Children’s Exposure to Air Pollution
- 2022
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Ingår i: Aerosol and Air Quality Research. - : AAGR Aerosol and Air Quality Research. - 1680-8584 .- 2071-1409. ; 22:8
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Tidskriftsartikel (refereegranskat)abstract
- Children are particularly sensitive to air pollution exposure, and their personal exposures may differ significantly from those of adults. One key factor for understanding the personal inhaled dose of air pollutants is the respiratory minute ventilation (Ve). To estimate the amount of particles circulated through the lungs, 24 h averages of Ve are often used. These averages poorly capture variations in Ve during the day, and between individuals. We here develop and implement a concept to assess individual Ve of children, with minimal impact on their natural activity and movement pattern by using ActiGraph GT3X+ accelerometers. Activity of 136 preschool children in the ages 3 to 5 years was logged using accelerometers while the children attended their preschools during a week. A linear regression equation is developed and used for estimating Ve from the accelerometer data retrieved for each individual child. The results show large variations in weekly average Ve between individuals, ranging from 0.33 to 0.48 L min–1 kg–1. Over the days the averages of the individuals’ 1st and 3rd quartiles were 0.28 and 0.48 L min–1 kg–1, respectively. Outdoor activities resulted in a 17% higher Ve than indoor activities, which may be important to consider when estimating the inhaled dose of air pollutants since pollution levels and particle toxicities can be different indoors and outdoors. The observations motivate the use of individual values of Ve in exposure assessments and suggest that accelerometers are a suitable tool for estimating children’s individual Ve in their natural environment. Combined with time resolved local air pollution monitoring, these measurements can provide the basis of a more precise estimate of children’s inhaled dose of air pollutants. © The Author(s).
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