Normative values for musculoskeletal- and neuromotor fitness in apparently healthy Norwegian adults and the association with obesity: a cross-sectional study

Background

Up-to-date research on musculoskeletal- and neuromotor fitness (MSMF) is lacking. The aims of the present paper were to a) establish normative values of MSMF by gender and age, and b) to assess how much of the variance in MSMF can be explained by obesity in adults.

Methods

A random selection of 726 Norwegians (20–65 years) participated in a national cross-sectional study. Muscular endurance, muscular strength, explosive power, flexibility and balance were assessed in addition to waist circumference (WC).

Results

Females displayed significantly higher scores compared to males on muscular endurance of the back extensors and on the flexibility tests (p < 0.001). Males displayed significantly higher scores than females (p < 0.001) on handgrip strength, modified push-ups, and explosive power. An inverse association was found between age and all MSMF scores for females (Beta:−0.06–(−0.92), p ≤ 0.044) and males (Beta:−0.15–(0.91), p ≤ 0.006), where younger participants displayed higher test scores on all MSMF tests, compared to older participants. Furthermore, participants showing higher scores on WC displayed lower scores on the following MSMF tests for both females and males: muscular endurance of the back extensors, balance, flexibility of the shoulder, and explosive power (p < 0.001). Additionally, male participants with higher WC scores showed lower scores on muscular endurance of the upper body and flexibility of the hamstrings compared to males with lower WC scores (p < 0.001).

Conclusions

The data provide normative values of MSMF for adults based on age and gender, and support an inverse relationship of MSMF to age and WC.

Electronic supplementary material

The online version of this article (doi:10.1186/s13102-016-0059-4) contains supplementary material, which is available to authorized users.

Reference values for and cross-validation of time to exhaustion on a modified Balke protocol in Norwegian men and women

The aims of the present study were to provide reference values for time to exhaustion (TTE) on a modified Balke treadmill protocol, and to perform a cross-validation of TTE as a measure of maximal oxygen consumption (VO_2max ), in Norwegian men and women 20-85 years of age. Reference values for TTE were derived from a national sample of 765 subjects. An additional sample of 119 subjects was included in the cross-validation (total n = 884), where prediction equations for VO_2max was established. A decline in TTE was seen with increased age. Prediction of VO_2max in an independent dataset (n = 319) resulted in a R²  = 0.78 and standard error of the estimate = 4.55 mL/kg/min. The observed-predicted bias was small (mean difference <1.24 mL/kg/min), whereas random error was considerable (95% limits of agreement ± 7.11-9.70 mL/kg/min) across age in both men and women. Despite limitations concerning the prediction of VO_2max on an individual level, TTE from the Balke protocol is a good measure of aerobic fitness in adults across a range of settings, and could be evaluated according to the suggested reference values.

Musculoskeletal fitness and balance in older individuals (65-85 years) and its association with steps per day: a cross sectional study

Background

There is limited normative, objective data combining musculoskeletal fitness (MSF), balance and physical activity (PA) among older adults. The aims were therefore to; 1) describe MSF and balance in older Norwegian adults focusing on age- and sex-related differences; 2) investigate the associations among MSF, balance and objectively-assessed PA levels.

Methods

This was part of a national multicenter study. Participants (65–85 years) were randomly selected from the national population registry. We used ActiGraph GT1M accelerometers to measure PA. Balance and MSF were assessed using: one leg standing (OLS), handgrip strength (HG), static back extension (SBE), sit and reach (SR), back scratch right, left arm over (BSR, BSL). Univariate analyses of variance were used to assess sex differences within the different MSF and balance tests and for comparisons among multiple age groups. Linear regression analysis was used to investigate how PA (expressed in 1000 steps increments) was associated with MSF and balance.

Results

85 women and 76 men were included. Mean age (standard deviation (SD)) was 73.2 (5.4) years for women and 72.3 (4.8) years for men. The youngest participants (65–69 years) had significantly better mean OLS- and SBE results compared with older participants. Women (65–85 years) had significantly better mean SR, BSR, BSL and SBE results compared with men (65–85 years). Men had significantly better mean HG results compared with women. No sex differences in mean OLS results were observed. A daily increment of 1000 steps was associated with better mean test scores for OLS- and SBE tests (b = 1.88, 95 % CI: 0.85 to 2.90 (p ≤ 0.001) and b = 4.63, 95 % CI: 1.98 to 7.29 (p = 0.001), respectively).

Conclusion

The youngest (65–69 years) had better static balance and muscular endurance in trunk extensors compared with older participants. Older women (65–85 years) had better joint flexibility than older men (65–85 years), whereas older men had better handgrip strength than older women. A higher PA level was associated with better static balance and muscular endurance in trunk extensors in older individuals. This study provides important normative data, and further investigation of trunk endurance and static balance as key foci for PA interventions in elderly is warranted.

Effects of reducing sedentary time on glucose metabolism in immigrant Pakistani men

Purpose

This study aimed to examine the association between changes in objectively measured overall physical activity (PA) and changes in fasting and postprandial plasma insulin, C-peptide, and glucose concentrations in type 2 diabetes-prone immigrant Pakistani men living in Norway and to examine whether this association is explained by changes in moderate and vigorous PA (MVPA) or changes in sedentary time.

Methods

The current study is a secondary cohort analysis on data collected from the Physical Activity and Minority Health study, a randomized controlled trial aimed at increasing the PA level, and not sedentary time per se, in a group of sedentary immigrant Pakistani men (n = 150). For the present analyses, the two groups were merged and a cohort analysis was performed. Overall PA (counts per minute) and its subcomponents, sedentary time and MVPA, were measured with accelerometry. Outcome variables were measured after a 2-h standardized glucose tolerance test.

Results

Change in overall PA was significantly associated with postprandial log-transformed plasma insulin (β = −0.002; 95% confidence interval (CI), −0.003 to 0.000; P = 0.008), C-peptide (β = −2.7; 95% CI, −4.9 to −0.5; P = 0.01), and glucose concentration (β = −0.006; 95% CI, −0.01 to −0.002; P = 0.002). Change in sedentary time was significantly and beneficially associated with changes in postprandial log-transformed plasma insulin (β = 0.002; 95% CI, 0.001–0.003; P = 0.001), C-peptide (β = 3.7; 95% CI, 1.5–6.0; P = 0.001), and glucose concentration (β = 0.006; 95% CI, 0.002–0.1; P = 0.002), independent of changes in MVPA, waist circumference, and other confounders.

Conclusions

Increasing overall PA by reducing sedentary time seems as important as increasing time spent at MVPA in relation to postprandial plasma insulin and glucose levels in diabetes-prone immigrant men.

Obesity prevalence in Norwegian adults assessed by body mass index, waist circumference and fat mass percentage

The prevalence of obesity presents serious public health challenges worldwide and is most commonly estimated by the categorization of body mass index (BMI). The purpose of this study was (i) to describe the sensitivity of BMI, waist circumference (WC) and fat mass percentage in the classification of overweight and obesity and (ii) to describe the prevalence of overweight and obesity using different measurement methods in a national sample of Norwegians. A total of 904 Norwegians (20-85 years) were randomly enrolled. Body weight, height, WC and skinfold thickness were measured; BMI and fat mass percentage (FP(skf) ) were calculated. The sensitivity and specificity varied from 77.0% to 86.9% and from 60.6% to 82.3%, respectively. Area under the curve was 0.837 (95% confidence interval [CI]: 0.801-0.872) for the ability of BMI to predict obesity by FP(skf) and 0.811 (95% CI: 0.770-0.852) for WC. A total of 12.7% (male: 12.1%, female: 13.4%) were obese based on BMI classifications, 29.1% (male: 36.5%, female: 20.0%) of the sample were obese based on FP(skf) and 24.3% of men and 37.8% of women were abdominally obese by WC. The agreement between selected measuring methods was fair to good, although the variation in obesity prevalence rates between the different assessments methods varied markedly.

Cardiorespiratory fitness in groups with different physical activity levels

The aim of the study was to determine how different categorizations of self-reported and objectively measured physical activity (PA) reflect variations in cardiorespiratory fitness (VO2max ). A total of 759 individuals (366 women) with a mean age of 48.5 years (SD 14.4) wore an accelerometer (ActiGraph GT1M) for seven consecutive days and answered the short International Physical Activity Questionnaire (IPAQ). VO2max was directly measured during a continuous graded exercise treadmill test until exhaustion. Men and women categorized as highly active by IPAQ had 9% and 13% higher VO2max , respectively, than those reporting a low PA level (P < 0.05). Men and women meeting the PA recommendation of 150 min/week of daily moderate intensity PA, measured by accelerometer, had 13% and 9% higher VO2max , respectively, than participants not meeting this recommendation (P < 0.01). No significant differences in average sedentary time, analyzed in total min/day and in bouts of 10 and 30 min, were found between participants with high or low cardiorespiratory fitness. However, women spent less time than men in bouts of sedentary behaviors. Self-reported PA by IPAQ and objectively measured PA by accelerometer were both useful instruments for detecting differences in VO2max .

A new approach to define and diagnose cardiometabolic disorder in children

The aim of the study was to test the performance of a new definition of metabolic syndrome (MetS), which better describes metabolic dysfunction in children. Methods. 15,794 youths aged 6-18 years participated. Mean z-score for CVD risk factors was calculated. Sensitivity analyses were performed to evaluate which parameters best described the metabolic dysfunction by analysing the score against independent variables not included in the score. Results. More youth had clustering of CVD risk factors (>6.2%) compared to the number selected by existing MetS definitions (International Diabetes Federation (IDF) < 1%). Waist circumference and BMI were interchangeable, but using insulin resistance homeostasis model assessment (HOMA) instead of fasting glucose increased the score. The continuous MetS score was increased when cardiorespiratory fitness (CRF) and leptin were included. A mean z-score of 0.40-0.85 indicated borderline and above 0.85 indicated clustering of risk factors. A noninvasive risk score based on adiposity and CRF showed sensitivity and specificity of 0.85 and an area under the curve of 0.92 against IDF definition of MetS. Conclusions. Diagnosis for MetS in youth can be improved by using continuous variables for risk factors and by including CRF and leptin.

Differences in fat loss in response to physical activity among severely obese men and women

BACKGROUND

Direct measurement of physical activity may be critical to revealing its relationship with the change in fat mass over time. The aim of this study was to determine the relationship between accelerometer-determined change in physical activity and change in fat mass in severely obese men and women.

METHODS

A total of 49 severely obese men (n = 12) and women (n = 37) (mean age 42.8 years (standard deviation (SD) 9.6); mean body mass index 42.0 kg/m2 (SD 5.9) participated in a 1-year lifestyle intervention with 4 measurements of physical activity (Actigraph GT1M accelerometer), energy intake (180-item food frequency questionnaire), and body composition. Associations were determined using linear regression analyses.

RESULTS

In the total group change in both duration and intensity of physical activity were independently related to change in fat mass (partial r = -0.38 to -0.31, p = 0.001-0.007) after adjustment for baseline body weight, gender and change in energy intake. A gender-specific effect of change in physical activity duration was found for change in fat mass (p for change in physical activity duration*gender < 0.001), where the association was significant in men (partial r = -0.53, p < 0.001), but not in women (partial r = -0.17, p = 0.149).

CONCLUSION

Increased intensity of physical activity was associated with loss of fat mass in severely obese men and women, whereas physical activity duration was associated with fat mass loss in men.

High-intensity training following lung cancer surgery: a randomised controlled trial

BACKGROUND

Many patients with lung cancer are deconditioned with poor physical fitness. Lung resection reduces physical fitness further, impairing the patient's ability to function in daily life.

METHODS

We conducted a single-blind randomised controlled trial of high-intensity endurance and strength training (60 min, three times a week, 20 weeks), starting 5-7 weeks after surgery. The control group received standard postoperative care. The primary outcome was the change in peak oxygen uptake measured directly during walking until exhaustion. Other outcomes included changes in pulmonary function, muscular strength by one-repetition maximum (1RM), total muscle mass measured by dual energy X-ray absorptiometry, daily physical functioning and quality of life (QoL).

RESULTS

The intention-to-treat analysis of the 61 randomised patients showed that the exercise group had a greater increase in peak oxygen uptake (3.4 mL/kg/min between-group difference, p=0.002), carbon monoxide transfer factor (Tlco) (5.2% predicted, p=0.007), 1RM leg press (29.5 kg, p<0.001), chair stand (2.1 times p<0.001), stair run (4.3 steps, p=0.002) and total muscle mass (1.36 kg, p=0.012) compared with the controls. The mean±SD QoL (SF-36) physical component summary score was 51.8±5.5 and 43.3±11.3 (p=0.006), and the mental component summary score was 55.5±5.3 and 46.6±14.0 (p=0.015) in the exercise and control groups, respectively.

CONCLUSIONS

In patients recently operated for lung cancer, high-intensity endurance and strength training was well tolerated and induced clinically significant improvements in peak oxygen uptake, Tlco, muscular strength, total muscle mass, functional fitness and QoL. This study may provide a basis for exercise therapy after lung cancer surgery.

TRIAL REGISTRATION NUMBER

NCT01748981.

Comparison of three generations of ActiGraph activity monitors under free-living conditions: do they provide comparable assessments of overall physical activity in 9-year old children?

Background

A recent review concludes that the agreement of data across ActiGraph accelerometer models for children and youth still is uncertain. The aim of this study was to evaluate the agreement of three generations of ActiGraph accelerometers in children in a free-living condition.

Methods

Sixteen 9-year-olds wore the ActiGraph AM7164, GT1M and GT3X+ simultaneously for three consecutive days. We compared mean counts per minute (mcpm) and time spent at different intensities from the three generations of monitors, and the agreement of outputs were evaluated by intra-class correlation coefficients (ICC) and Bland-Altman plots.

Results

The ICC for mcpm was 0.985 (95% CI = 0.898, 0.996). We found a relative difference of 11.6% and 9.8% between the AM7164 and the GT1M and AM7164 and the GT3X+, respectively. The relative difference between mcpm assessed by the GT1M and GT3X+ was 1.7%. The inter-generation differences varied in magnitude and direction across intensity levels, with the largest difference found in the highest intensities.

Conclusion

We found that the ActiGraph model AM7164 yields higher outputs of mean physical activity intensity (mcpm) than the models GT1M and GT3X+ in children in free-living conditions. The generations GT1M and GT3X+ provided comparable outputs. The differences between the old and the newer monitors were more complex when investigating time spent at different intensities. Comparisons of data assessed by the AM7164 with data assessed by newer generations ActiGraphs should be done with caution.

Physical activity and cardiovascular risk factors in a 40- to 42-year-old rural Norwegian population from 1975-2010: repeated cross-sectional surveys

Background

Geographical differences in cardiovascular diseases (CVD) have been observed among Norwegian counties. Better long-term health status and higher physical activity (PA) levels have been documented in the county of Sogn & Fjordane compared with other counties. However, recent trends in CVD risk factors have not been documented. The aim of this study was to investigate the secular trends in leisure time physical activity (LTPA) and other CVD risk factors over a 35-year period in a rural population of 40- to 42-year-olds in western Norway and to compare these trends with national trends.

Methods

Data from eight cross-sectional studies from 1975–2010 (n = 375,682) were obtained from questionnaires and physical examinations and were analyzed using mixed model regression analyses.

Results

Decreasing trends were observed for sedentary behavior (for women), moderate PA, smoking, systolic blood pressure (SBP), diastolic blood pressure (DBP), high-density lipoprotein (HDL-c) and total cholesterol (TC), whereas increasing trends were observed for body mass index (BMI), triglycerides (TG), light PA, vigorous PA and sedentary behavior for men. Compared to the national trends, the trends in the 40-42-year-olds from Sogn & Fjordane were more beneficial in terms of TG, HDL-c and BMI but less beneficial in terms of SBP and DBP.

Conclusions

Over a 35-year-period, this study indicates that the LTPA level has been relatively stable in the county of Sogn & Fjordane. Upward trends were observed in light and vigorous PA, whereas a downward trend was observed in moderate PA. For sedentary behavior, an upward trend was observed in men, whereas a downward trend was observed in women. For smoking, BP and cholesterol decreasing trends were found, but increasing trends were observed in BMI and TG. Compared with the national data, the trends in Sogn & Fjordane were more beneficial for TG, HDL-c and BMI but less beneficial for BP.

Impact of physical activity and diet on lipoprotein particle concentrations in severely obese women participating in a 1-year lifestyle intervention

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT

Physical activity and high aerobic fitness protects against cardiovascular disease and early death, besides having a very modest impact on lipoprotein-cholesterol in obese subjects. Physical activity has been shown to favourably alter lipoprotein particle concentrations and apolipoprotein B with minimal weight loss in overweight to moderately obese subjects.

WHAT THIS STUDY ADDS

We studied the impact of physical activity on lipoprotein subclass particle concentrations in women with severe obesity. Increased physical activity duration was associated with favourable changes, whereas increased PA intensity was associated with adverse changes in some lipoprotein particle subclasses in severely obese women. Severely obese women that manage to increase their physical activity level can improve their lipoprotein profile, whether or not they lose fat mass Physical activity (PA) and high aerobic fitness protects against cardiovascular disease and early death possibly among others because of an anti-atherogenic impact on lipoprotein particle concentrations. The objective of this study was to determine the impact of PA and diet on lipoprotein particle concentrations. Thirty-one severely obese women (age 43.6 ± 10.2 years; body mass index 43.0 ± 6.3 kg m(-2) ) participated in a 1-year lifestyle intervention with repeated measurements of lipoprotein particle subclass concentrations and size of very low density lipoprotein (VLDL), low density lipoprotein (LDL) and high density lipoprotein (HDL), as well as fat mass, PA and diet. Multiple regression was used to determine associations with change (Δ) in two principal components (PCs) describing lipoprotein distributions: ΔPC 1 LIPO (dominated by VLDL and LDL) and ΔPC 2 LIPO (dominated by large HDL and mean HDL particle size). ΔPA duration was the only variable that was significantly related to ΔPC 1 LIPO (partial r = -0.40, P = 0.008), while ΔPA intensity was the only variable that was significantly related to ΔPC 2 LIPO (partial r = -0.43, P = 0.003) in adjusted models. Increased PA duration was associated with favourable changes, whereas increased PA intensity was associated with adverse changes in some lipoprotein particle subclasses in severely obese women.

Reference values for cardiorespiratory response and fitness on the treadmill in a 20- to 85-year-old population

BACKGROUND

Existing reference values for clinical exercise testing have been derived from small nonrandom samples, lacking women and older individuals and some with poor or no maximal end criteria. The objective was to study the cardiorespiratory response during maximal exercise in a representative predominantly Caucasian sample of men and women.

METHODS

Nine hundred four randomly sampled men and women, 20 to 85 years old, exercised on a treadmill to exhaustion. Oxygen uptake (V.O2), heart rate (HR), BP, blood lactate concentration, and ventilatory variables were measured.

RESULTS

Seven hundred fifty-nine participants met the criteria for an acceptable maximal V.O2 (V.O2max) based on a respiratory exchange ratio≥1.10 or a Borg score≥17. In the 20- to 29-year-old age group, V.O2max (mL/kg/min) was 40.3 (±7.1) in women and 48.6 (±9.6) in men. A linear decline (8% per decade) was observed after age 30 years in both sexes. Maximal HR decreased with age by ±6.3 beats/min per decade. The maximal oxygen pulse was 33% lower in women and decreased significantly with age in both sexes by 5% and 3% per decade for women and men, respectively. Women's maximal ventilation was 66% that of men and decreased with age after 40 to 49 years in both sexes. Breathing reserve was higher and blood lactate was lower in women than in men.

CONCLUSIONS

This study establishes reference values for V.O2max (absolute, relative to body weight and fat-free weight), maximal HR, oxygen pulse, BP, ventilation, breathing reserve, respiratory exchange ratio, and blood lactate concentration during maximal exercise on treadmill in a large population.

Increased physical activity improves aerobic fitness, but not functional walking capacity, in severely obese subjects participating in a lifestyle intervention

OBJECTIVE

To determine the relationship between change in physical activity level and change in directly measured maximal aerobic fitness in severely obese subjects participating in a 1-year lifestyle intervention, and to determine whether change in 6-min walk test (6 MWT) could be used as an indicator of change in aerobic fitness.

METHODS

Complete data on aerobic fitness (maximal oxygen consumption (VO2max) and time to exhaustion on the VO2max test), 6 MWT, and physical activity (Actigraph GT1M accelerometer) were obtained for 21 subjects (mean age 42.6 years (standard deviation (SD) 11.0 years); mean body mass index 39.6 (SD 4.5) kg/m(2)). Multiple linear regression (controlling for change in body mass index) was used to analyse the relationships for: (i) changes in physical activity vs aerobic fitness and change in 6 MWT; and (ii) changes in aerobic fitness vs 6 MWT.

RESULTS

Change in physical activity level was related to VO2max and time to exhaustion (partial r > 0.63, p < 0.003). No significant relationships were found between changes in aerobic fitness and 6 MWT (partial r < 0.22, p > 0.351) or between changes in physical activity level and 6 MWT (partial r = 0.15, p = 0.531).

CONCLUSION

Increased physical activity level over 1 year resulted in increased aerobic fitness in severely obese subjects. Although the sample size was small, these results suggest that change in 6 MWT might not be a good indicator of maximal change in aerobic fitness in this population.

Effects of a 20-month cluster randomised controlled school-based intervention trial on BMI of school-aged boys and girls: the HEIA study

Background

School-based interventions that target prevention of overweight and obesity in children have been tested with mixed results. Thus, successful interventions are still called for. The aim of the present study was to investigate effects of a multicomponent school-based intervention programme targeting physical activity, sedentary and dietary behaviours on anthropometric outcomes.

Methods

A 20-month intervention was evaluated in a cluster randomised, controlled study of 1324 11-year-olds. Outcome variables were body mass index (BMI), BMI-for-age z-score (BMIz), waist circumference (WC), waist-to-height ratio (WTHR) and weight status (International Obesity Task Force's cut-offs). Weight, height and WC were measured objectively; pubertal status was self-reported and parental education was self-reported by the parents. Intervention effects were determined by one-way analysis of covariance and logistic regression, after checking for clustering effects of school, and moderating effects of gender, pubertal status and parental education.

Results

Beneficial effects were found for BMI (p=0.02) and BMIz (p=0.003) in girls, but not in boys. While a beneficial effect was found for BMI (p=0.03) in participants of parents reporting a high level of education, a negative effect was found for WTHR in participants with parents reporting a low level of education (p=0.003). There were no intervention effects for WC and weight status.

Conclusions

A multicomponent 20-month school-based intervention had a beneficial effect on BMI and BMIz in adolescent girls, but not in boys. Furthermore, children of higher educated parents seemed to benefit more from the intervention, and this needs attention in future interventions to avoid further increase in social inequalities in overweight and obesity.

[The effect of physical activity on weight loss]

BACKGROUND

Physical activity increases energy expenditure and may cause considerable negative energy balance and weight loss. The objective of this article is to review the evidence for the effect of physical activity on weight loss in overweight or obese subjects.

MATERIAL AND METHOD

A literature search was undertaken in Medline and Embase. The search was restricted to adults (> 18 years), review articles and meta-analyses published from 2000 to 2012, as well as recent randomised controlled trials (RCTs) that were not included in these meta-analyses (2009-2012).

RESULTS

Five meta-analyses based on RCT studies and 13 original studies were included. Physical activity caused a weight loss of 1 to 3 kg when physical activity was compared to a control situation, or when combined interventions including dieting and physical activity were compared to dieting alone.

INTERPRETATION

Physical activity appears to have little effect on weight loss in case of obesity. However, the results should be interpreted in light of the fact that many studies are fraught with methodological shortcomings associated with the design of the interventions and the measurement of actual completed physical activity. The effect of physical activity is therefore probably strongly underestimated in many studies.

Intervention effects on physical activity: the HEIA study - a cluster randomized controlled trial

Background

Although school-based interventions to promote physical activity in adolescents have been suggested in several recent reviews, questions have been raised regarding the effects of the strategies and the methodology applied and for whom the interventions are effective. The aim of the present study was to investigate effects of a school-based intervention program: the HEalth in Adolescents (HEIA) study, on change in physical activity, and furthermore, to explore whether potential effects varied by gender, weight status, initial physical activity level and parental education level.

Methods

This was a cluster randomized controlled 20 month intervention study which included 700 11-year-olds. Main outcome-variable was mean count per minute (cpm) derived from ActiGraph accelerometers (Model 7164/GT1M). Weight and height were measured objectively. Adolescents reported their pubertal status in a questionnaire and parents reported their education level on the consent form. Linear mixed models were used to test intervention effects and to account for the clustering effect of sampling by school.

Results

The present study showed an intervention effect on overall physical activity at the level of p = 0.05 with a net effect of 50 cpm increase from baseline to post intervention in favour of the intervention group (95% CI −0.4, 100). Subgroup analyses showed that the effect appeared to be more profound among girls (Est 65 cpm, CI 5, 124, p = 0.03) and among participants in the low-activity group (Est 92 cpm, CI 41, 142, p < 0.001), as compared to boys and participants in the high-activity group, respectively. Furthermore, the intervention affected physical activity among the normal weight group more positively than among the overweight, and participants with parents having 13–16 years of education more positively than participants with parents having either a lower or higher number of years of education. The intervention seemed to succeed in reducing time spent sedentary among girls but not among boys.

Conclusions

A comprehensive but feasible, multi-component school-based intervention can affect physical activity patterns in adolescents by increasing overall physical activity. This intervention effect seemed to be more profound in girls than boys, low-active adolescents compared to high-active adolescents, participants with normal weight compared to the overweight, and for participants with parents of middle education level as opposed to those with high and low education levels, respectively. An implementation of the HEIA intervention components in the school system may have a beneficial effect on public health by increasing overall physical activity among adolescents and possibly among girls and low-active adolescents in particular.

Patterns of objectively measured physical activity in normal weight, overweight, and obese individuals (20-85 years): a cross-sectional study

BACKGROUND

The magnitude of the association between physical activity (PA) and obesity has been difficult to establish using questionnaires. The aim of the study was to evaluate patterns of PA across BMI-defined weight categories and to examine the independent contribution of PA on weight status, using accelerometers.

METHODS

The study was a cross-sectional population-based study of 3,867 adults and older people aged 20-85 years, living in Norway. PA was assessed for seven consecutive days using the ActiGraph GT1M accelerometer. Anthropometrical data was self-reported and overweight and obesity was defined as having a body mass index (BMI) of 25-<30 and ≥30 kg/m(2), respectively.

RESULTS

Overweight and obese participants performed less overall PA and PA of at least moderate intensity and took fewer steps, compared to normal weight participants. Although overall PA did not differ between weekdays and weekends, an interaction between BMI category and type of day was present, indicating a larger difference in overall PA between BMI categories on weekends compared to weekdays. Obese participants displayed 19% and 25% lower overall physical activity compared to normal weight participants, on weekdays and weekends, respectively. Participants in the most active quintile of overall PA had a 53% lower risk (OR 0.47, 95% CI: 0.37 to 0.60) for having a BMI above or below 25 kg/m(2), and a 71% lower risk (OR: 0.29, 95% CI: 0.20 to 0.44) for having a BMI above or below 30 kg/m(2).

CONCLUSIONS

Overweight and obese participants engaged in less overall PA and moderate and vigorous PA compared with normal weight individuals. The weight related differences in overall PA were most pronounced on the weekend and the risk of being overweight or obese decreases across quintiles of PA.

Time spent in vigorous physical activity is associated with increased exhaled nitric oxide in non-asthmatic adolescents

INTRODUCTION

Physical activity (PA) is important in preventing disease, but endurance elite athletes have increased prevalence of asthma and airway inflammation.

OBJECTIVES

We aimed to determine if PA was associated with increased fractional exhaled nitric oxide (FENO ) in asthmatic and non-asthmatic adolescents.

METHODS

FENO was recorded (Niox Mino®, Aerocrine AB, Stockholm, Sweden) in 169 adolescents (13-14 years) in a nested case-control analysis from the Environment and Childhood Asthma study, Oslo, 92 adolescents with and 77 without asthma. They underwent clinical examination, lung function measurements and treadmill run measuring peak oxygen uptake, and objectively recorded PA for four consecutive days. PA was classified as moderate, vigorous and very vigorous, and total number of hours of each category was recorded for each subject. Associations between FENO and PA were tested using linear robust multiple regression analyses.

RESULTS

In non-asthmatic adolescents, FENO was associated with daily hours of vigorous to very vigorous (r=0.27, P=0.02) and very vigorous PAs (r=0.25, P=0.036) in bivariate analyses. In multivariate analyses, FENO was associated with vigorous to very vigorous PA [regression coefficients (95% confidence interval) 1.9 (0.6, 3.1); P=0.004] and more strongly with very vigorous PA [3.9 (1.5, 6.4); P=0.002] in non-asthmatic but not in asthmatic adolescents. Total daily PA was not associated with FENO in either group. Thus, 1 h of very vigorous PA per day increased FENO by 3.9ppb.

CONCLUSION

Vigorous to very vigorous PA, contrasting total daily PA, was significantly associated with increased FENO in non-asthmatic adolescents, suggesting that intensive PA may induce airway inflammation independent of asthma.

Treadmill Calibration of the Actigraph GT1M in Young-to-Middle-Aged Obese-to-Severely Obese Subjects

To understand the impact of physical activity (PA) on health, valid accelerometer count cut points must be applied to measure PA. Because cut points may be population specific, we aimed to establish accelerometer cut points for moderate PA (MPA) and vigorous PA (VPA) (defined as ≥3 and ≥6 metabolic equivalents, resp.) in young-to-middle-aged obese-to-severely obese subjects. Data from 42 subjects (11 men; body mass index 39.8 ± 5.7; age 43.2 ± 9.2 years) who performed a treadmill calibration using the Actigraph GT1M, were analyzed using ordinary linear regression (OLR), linear mixed model regression (MIX), and receiver operating characteristics curves (ROC 1; ROC 2). Cut points obtained from the models were quite different (612 to 1646 counts/min for MPA; 3061 to 7220 counts/min for VPA). We argue that the MIX approach, which resulted in cut points of 612 and 4980 counts/min for MPA and VPA, respectively, is the most appropriate method to establish accelerometer cut points in this setting. We conclude that accelerometer cut points are lower in young-to-middle-aged obese-to-severely obese subjects compared to young normal-weight subjects and that care should be taken when analyzing PA level in groups that vary in age and degree of obesity.

Level of physical activity, cardiorespiratory fitness and cardiovascular disease risk factors in a rural adult population in Sogn og Fjordane

<strong><em>Background</em>:</strong> Physical activity (PA) and high cardiorespiratory fitness (CRF) are associated with reduced risk of cardiovascular disease (CVD). Sogn og Fjordane County has the reputation of being the most healthy county in Norway. The level of PA and/or CRF may partly explain this health status. However, only one study with regional objectively measured PA data and one study with regional data on CRF currently exist. Thus, the aim of this study was to describe levels of PA, CRF and CVD risk factors in an adult population in the county of Sogn og Fjordane.<em><strong> Methods:</strong> </em>In total, 314 (♀:178 ♂:136) 40-42-year-olds and 308 (♀:175 ♂:133) 53-55-yearolds participated in this cross-sectional study. PA was measured objectively by accelerometry, while CRF was measured directly. <em><strong>Results:</strong></em> There were no sex differences in total PA level. For the 40-42-year-olds, women spent 6.0min/day [95% CI: –11.7 to –0.3] less participating in moderate PA compared to men. For the 53-55- year-olds, women were inactive for 36.0 min/day [95% CI: –55.2 to –16.8] less and they participated in light activity for 26.4 min/day [95% CI: 7.7 to 45.2] more than men. In total, 30.0% [95% CI: 24.8 to 35.2] of the 40-42-year-olds and 30.2% [95% CI: 25.0 to 35.4] of the 53-55-year-olds met the Norwegian recommendations<br />for PA. CRF was 49.0 ml·kg–1·min–1 for men and 41.6 ml·kg–1·min–1 for women for the 40-42-year-olds. For 53-55-year-olds CRF was 41.2 ml·kg–1·min–1 for men and 33.9 ml·kg–1·min–1 for women.<em><strong> Conclusions:</strong></em> These results suggest that the level of PA and CRF are higher compared to other available data. This might explain the advantageous health status in Sogn og Fjordane.

Low level of objectively measured physical activity and cardiorespiratory fitness, and high prevalence of metabolic syndrome among Pakistani male immigrants in Oslo, Norway

<em><strong>Background:</strong></em> The level of physical fitness in south Asian immigrants living in Norway is largely unknown, but the level of physical activity seems to be low, possibly in part explaining their high prevalence of diabetes and cardiovascular diseases. However, previous studies have used self-reported measures of physical activity, and it might be questioned whether the previous data reflect the true physical activity level.<br /><em><strong>Aim:</strong></em> To describe objectively measured physical activity level, cardiorespiratory fitness and diabetes risk in a group of Pakistani immigrant men living in Oslo, Norway.<br /><em><strong>Methods:</strong></em> One hundred and fifty Pakistani immigrant men in the age group 25-60 years were included. Physical activity level was assessed with an accelerometer. Cardiorespiratory fitness was measured until exhaustion on a treadmill, and diabetes risk was evaluated with an oral glucose tolerance test.<br /><em><strong>Results:</strong></em> Mean age was 37.3 years (SD=7.7). Total physical activity level was 308 counts/min (SD=131), and peak oxygen uptake was 34.2 ml·kg-1·min-1 (SD=5.6). Fifty percent of the participants had the metabolic syndrome, and 76% were obese. Physical activity level and cardiorespiratory fitness level were lower, and prevalence of the metabolic syndrome higher in a subgroup of taxi drivers as compared with those in<br />other occupations (P&lt;0.05).<br /><em><strong>Conclusions:</strong></em> Physical activity and cardiorespiratory fitness levels are low and diabetes risk high among Pakistani immigrant men living in Oslo, especially in taxi drivers

Effects of a 2-year school-based daily physical activity intervention on cardiovascular disease risk factors: the Sogndal school-intervention study

The aim of this study was to investigate the effect of a 2-year school-based physical activity (PA) intervention in 9-year-old children on cardiovascular disease (CVD) risk factors. One intervention school (I-school) (n=125) and one control school (C-school) (n=131) were included. The children at the I-school carried out 60 min of PA daily. The PA lessons were planned, organized and led by expert physical education (PE) teachers. In the C-school, children were offered the normal 45 min of PE twice weekly. The intervention resulted in a greater beneficial development in systolic (P=0.003) and diastolic (P=0.002) blood pressure, total cholesterol-to-high-density lipoprotein cholesterol ratio (P=0.011), triglyceride (P=0.030) and peak oxygen uptake (P<0.001) in I-school children than in C-school children. No significant differences were observed in waist circumference, body mass index and the homeostasis model assessment for insulin resistance between the two groups. Furthermore, the intervention, primarily carried out at moderate intensity, had the strongest impact in children with the least favorable starting point. In conclusion, a daily school-based PA intervention can beneficially modify children's CVD risk profile if the intervention has sufficient duration and includes a substantial amount of daily PA, and if the PA is implemented by expert PE teachers.

Asthma symptoms in rural living Tanzanian children; prevalence and the relation to aerobic fitness and body fat

OBJECTIVE

To determine the prevalence of asthma symptoms in children from a rural district in North-Tanzania, and their relationship to aerobic fitness and body fat.

METHODS

In Manyara region in Tanzania, children (aged 9-10 years) were randomly selected to participate in the present cross-sectional study. Hundred and seventy two participants completed a video questionnaire showing the symptoms and signs of asthma. Lung function was measured by maximum forced expiratory flow-volume curves. Aerobic fitness was estimated from a standardized indirect maximal cycle ergometer test and sum of three skinfolds reflected body fat.

RESULTS

Twenty four per cent reported asthma symptoms last year. Severe wheezing attacks last year were reported in 5% of the participants. Thirty seven per cent of the participants were underweight. Underweight children had significantly lower (P < 0.02) lung function (per cent of predicted). Lower body fat was associated with higher occurrence of asthma symptoms (odds ratio and 95% CI; 0.45 (0.22-0.95; P = 0.04). Aerobic fitness was not associated with asthma symptoms.

CONCLUSIONS

More than every fifth 9-10 year old child from a rural district in North-Tanzania reported asthma symptoms. Lower body fat was associated with higher occurrence of asthma symptoms, but aerobic fitness was not associated with asthma symptoms.

Cardiovascular disease risk factors in a population-based sample of Norwegian children and adolescents

OBJECTIVE

The objective of the study was to describe the distribution of cardiovascular disease (CVD) risk factors, and to evaluate the extent of clustering of CVD risk factors in Norwegian children and adolescents.

MATERIAL AND METHODS

A randomly selected cohort of 9-year-olds and 15-year-olds from all regions of the country was sampled. Of 2,818 subjects invited to participate, 2,299 accepted, giving an overall participation rate of 82%.

RESULTS

Mean (SD) values for the main risk factors for 9-year-old and 15-year-old girls and boys were: total cholesterol (TC) (mmol/L) 4.49 (0.73), 4.37 (0.68), 4.19 (0.76) and 3.80 (0.69), respectively; triglycerides (TG) (mmol/L) 0.72 (0.33), 0.63 (0.32), 0.79 (0.32) and 0.82 (0.47), respectively; high density lipoprotein cholesterol (HDL-c) (mmol/L) 1.70 (0.35), 1.79 (0.40), 1.61 (0.34) and 1.42 (0.30), respectively; systolic blood pressure (mmHg) 102.6 (7.7), 103.3 (7.7), 109.0 (8.8) and 115.3 (9.0), respectively; and homeostasis model assessment score (HOMA) 1.29 (0.83), 1.19 (0.78), 2.10 (1.37) and 2.14 (1.49), respectively. At least five risk factors were found in 11.1 (95% confidence interval (CI) 8.76 to 13.44) times as many participants as expected. A significant degree of clustering of CVD risk factors was found in 11.4% (95% CI, 9.8 to 13.0) of the study population, and these had mean Z scores of 1.24 (0.06) and 1.04 (0.08) for the 9-year-olds and 15-year-olds, respectively.

CONCLUSION

This study presents national reference data on selected CVD risk factors in children and adolescents.

Objectively assessed physical activity and aerobic fitness in a population-based sample of Norwegian 9- and 15-year-olds

The present study described current physical activity, determined compliance with physical activity guidelines and assessed aerobic fitness in a nationally representative sample of 9- and 15-year-olds in Norway. In 2005-2006, 2299 children and adolescents were randomly recruited. The participation rate was 89% and 74% among the 9- and 15-year-olds, respectively. Physical activity was assessed objectively by accelerometry, and aerobic fitness was measured directly as peak oxygen uptake during a cycle ergometry test. Boys were more physically active than girls, and 9-year-olds were substantially more active than 15-year-olds. Physical activity was higher during weekdays than weekends, and 9-year-olds were most active during spring. While four out of five children met current physical activity guidelines, only half of the adolescents did. The mean (SD) values for peak VO2 were: 9-year-old boys, 48.2 (7.1) mL/min/kg; 9-year-old girls, 42.9 (6.7) mL/min/kg; and 15-year-old girls 41.1 (6.0) mL/min/kg and 15-year-old boys 51.9 (8.0) mL/min/kg. Because of the high participation rate, this study provides a good description of the physical activity and aerobic fitness in the young population. Finally, girls and adolescents seem appropriate targets when promoting physical activity in order to increase the proportion meeting the recommendations.

Cardiorespiratory fitness and body mass index values in 9-year-old rural Norwegian children

AIM

To describe cardiorespiratory fitness and body mass index (BMI) values in a representative population of 9-year-old Norwegian children in two rural communities and compare present values with previous findings.

METHODS

Two hundred and fifty-nine 9-year-old children were invited, and 256 participated in this study. Maximal oxygen uptake was directly measured during a continuous progressive treadmill protocol. Body mass and height were also measured.

RESULTS

The mean +/- SD relative maximal oxygen uptake was 52.8 +/- 6.5 for boys and 46.9 +/- 7.2 mL/kg/min for girls. Eight percent of the boys and 16.8% of the girls were classified as overweight, and 1.6% of the boys and 6.9% of the girls as obese. Mean age, body mass, height and Ponderal index were not significantly different between sexes. Girls had a higher BMI than boys (p = 0.05).

CONCLUSION

Compared to earlier Norwegian studies, children's BMI values seem to have increased substantially. This increase is most pronounced in girls. When assessing these differences using the PI, this increase is less marked. Comparing maximal oxygen uptake data with that in earlier Nordic studies, there is no evidence that fitness has declined among 9-year olds. However, the limitations of the few earlier studies make reliable comparisons difficult.

Norwegian adolescents with asthma are physical active and fit

BACKGROUND

Evidence regarding habitual physical activity levels and aerobic fitness of asthmatic compared to nonasthmatic children and adolescents is contradictory, and it is unclear if low physical activity levels can contribute to asthma development. The present study therefore aimed to determine whether adolescents with asthma have reduced physical activity levels and aerobic fitness, or increased energy intake and body fat compared to controls.

METHODS

From the environment and childhood asthma study in Oslo, 174 (13- to 14-year old) adolescents, 95 (66 boys) with and 79 (41 boys) without asthma performed maximal running on a treadmill with oxygen consumption measurement (aerobic fitness) and had the sum of four skinfolds and waist circumference recorded (body fat), followed by wearing an activity monitor and registering diet for four consecutive days. Asthma was defined by at least two of the following three criteria fulfilled: (1) dyspnoea, chest tightness and/or wheezing; (2) a doctor's diagnosis of asthma; (3) use of asthma medication. Participants with asthma used their regular medications.

RESULTS

Neither aerobic fitness, total energy expenditure nor hours in moderate to very vigorous intensity physical activity during week and weekend differed between adolescents with and without asthma. Energy intake and body fat was similar in both groups.

CONCLUSIONS

Total energy expenditure, aerobic fitness and hours in moderate to very vigorous intensity physical activity were not reduced and energy intake and body fat measured with skinfolds not increased among Norwegian adolescents with asthma.

An intermittent running test to estimate maximal oxygen uptake: the Andersen test

AIM

Monitoring of height and weight in children in schools has been discussed to get data on trends in obesity. Physical fitness may be just as important to monitor and a simple reliable test will therefore be important. The aim of this paper was to analyze the association between VO2max measured during maximal work on a treadmill and running distance in an intermittent running test.

METHODS

Three different groups conducted an intermittent running test VO2max was measured directly during treadmill running. The groups were 27 physical education students (age 20.0-27.0 years), 57 children (age 9.9-11.0 years), and 14 male elite soccer players (age 14.2-15.0 years).

RESULTS

The reproducibility of the Andersen test was good (r=0.84). Subjects ran 15 m (SD 61 m) longer the second time, but this difference was not significant (P=0.102). The association between running distance in the Andersen test and VO2max measured on the treadmill showed a correlation coefficient of 0.87 in university students, 0.68 in children, and 0.60 in soccer players. For the whole group: VO2max= 18.38 + (0.03301*distance) - (5.92*sex) (boys=0;girls=1) (r=0.84).

CONCLUSION

The test may provide teachers and health care professionals with an important tool to estimate physical fitness in children and adolescents in a fast, non-expensive and reliable way.

Changes in physical activity behavior and the development of body mass index during the last 30 years in Norway

Body mass index (BMI; kg/m(2)) has increased markedly in the last decades. We hypothesized that highly physically active persons both at work and at leisure would be resistant to weight gain. The hypothesis was tested by analyzing Norwegian cross-sectional data collected in the period 1972-2002. Participants were 214,449 men and 206,136 women (aged 20-70 years). During the last 30 years in men and the last 15 years in women, a systematic larger BMI increase per year was observed in the sedentary [regression coefficients (SE) in men 0.060 (0.004) kg/m(2) and women 0.137 (0.012) kg/m(2)] compared with highly physically active groups [regression coefficients (SE) in men 0.036 (0.00 4) kg/m(2), and in women -0.001 (0.039) kg/m(2)]. Analyses were robust to adjustments for age, smoking and education. There was a larger absolute net increase in the prevalence of obesity among the sedentary compared with persons performing light, moderate or heavy physical activity (PA) at leisure. PA level in women both at work and in leisure was not associated with weight gain during the last decades. This association was less evident among men. Men and women who were lightly, moderately or highly active at leisure were less likely to be obese compared with those who were sedentary.

Between- and within-day variability in physical activity and inactivity in 9- and 15-year-old European children

To examine differences in levels of physical activity (PA), time spent at moderate-to-vigorous intensity PA (MVPA) and time spent sedentary between and within days in children from four European countries, 1954 9 - and 15-year-olds were included. PA was measured during 2 weekdays and 2 weekend days using the manufacturing technology-incorporated (MTI) accelerometer. Average count per minute, time spent sedentary, time spent at MVPA and the proportion of children accumulating > or =60 min of MVPA were calculated. Data were compared between weekdays and weekend days and between school time and leisure-time. Although not entirely consistent across countries, overall PA, time spent sedentary and the proportion of children accumulating > or =60 min of MVPA were higher during weekdays compared with weekend days. Differences in overall PA between school time and leisure-time were highly inconsistent between countries. Few children (4-31%) accumulated > or =60 min of MVPA either during school time or during leisure-time. Differences in activity patterns between weekdays and weekend days are explained by less accumulated time in MVPA during weekend days. Weekend days and leisure-time during weekdays seem appropriate targets when promoting PA in order to increase the proportion of children achieving current recommendations on health-enhancing PA.

Comparison of equations for predicting energy expenditure from accelerometer counts in children

Several prediction equations developed to convert body movement measured by accelerometry into energy expenditure have been published. The aim of this study was to examine the degree of agreement between three different prediction equations, when applied to data on physical activity in a large sample of children. We examined 1321 children (663 boys, 658 girls; mean age 9.6+/-0.4 years) from four different countries. Physical activity was measured by the MTI accelerometer. One equation, derived from doubly labeled water (DLW) measurements, was compared with one treadmill-based (TM) and one room calorimeter-based (CAL) equation (mixture of activities). Predicted physical activity energy expenditure (PAEE) was the main outcome variable. In comparison with DLW-predicted PAEE, both laboratory-derived equations significantly (P<0.001) overestimated PAEE by 17% and 83%, respectively, when based on a 24-h prediction, while the TM equation significantly (P<0.001) underestimated PAEE by 46%, when based on awake time only. In contrast, the CAL equation agreed better with the DLW equation under the awake time assumption. Predicted PAEE differ substantially between equations, depending on time-frame assumptions, and interpretations of average levels of PAEE in children from available equations should be made with caution. Further development of equations applicable to free-living scenarios is needed.

Independent associations of physical activity and cardiorespiratory fitness with metabolic risk factors in children: the European youth heart study

AIMS/HYPOTHESIS

High levels of cardiorespiratory fitness (CRF) and physical activity (PA) are associated with a favourable metabolic risk profile. However, there has been no thorough exploration of the independent contributions of cardiorespiratory fitness and subcomponents of activity (total PA, time spent sedentary, and time spent in light, moderate and vigorous intensity PA) to metabolic risk factors in children and the relative importance of these factors.

METHODS

We performed a population-based, cross-sectional study in 9- to 10- and 15- to 16-year-old boys and girls from three regions of Europe (n = 1709). We examined the independent associations of subcomponents of PA and CRF with metabolic risk factors (waist circumference, BP, fasting glucose, insulin, triacylglycerol and HDL-cholesterol levels). Clustered metabolic risk was expressed as a continuously distributed score calculated as the average of the standardised values of the six subcomponents.

RESULTS

CRF (standardised beta = -0.09, 95% CI -0.12, -0.06), total PA (standardised beta = -0.08, 95% CI -0.10, -0.05) and all other subcomponents of PA were significantly associated with clustered metabolic risk. After excluding waist circumference from the summary score and further adjustment for waist circumference as a confounding factor, the magnitude of the association between CRF and clustered metabolic risk was attenuated (standardised beta = -0.05, 95% CI -0.08, -0.02), whereas the association with total PA was unchanged (standardised beta = -0.08 95% CI -0.10, -0.05).

CONCLUSIONS/INTERPRETATION

PA and CRF are separately and independently associated with individual and clustered metabolic risk factors in children. The association between CRF and clustered risk is partly mediated or confounded by adiposity, whereas the association between activity and clustered risk is independent of adiposity. Our results suggest that fitness and activity affect metabolic risk through different pathways.

ApoB but not LDL-cholesterol is reduced by exercise training in overweight healthy men. Results from the 1-year randomized Oslo Diet and Exercise Study

OBJECTIVES

(i) To estimate changes in apoB and apoB/apoA-I, reflecting the balance between atherogenic and anti-atherogenic lipoprotein particles, by exercise training and compare with changes in LDL-C and TC/HDL-C ratio, and (ii) To compare strengths of relationships between physical fitness and various lipoprotein variables.

DESIGN, SETTING, AND SUBJECTS

The study was a 1-year open randomized trial comprising 219 healthy middle-aged subjects aged 40-49 years who were allocated to exercise or no exercise, dietary advice or no advice in a 2 x 2 factorial design. This study includes 188 men who completed the trial, 45 to diet, 48 to exercise, 58 to diet + exercise and 37 to control.

INTERVENTIONS

Exercise; supervised endurance exercise three times a week. Diet; reduce weight, increase intake of fish and reduce total fat intake.

MAIN OUTCOME MEASURE

One-year change in apoB and apoB/apoA-I ratio.

RESULTS

Exercisers decreased their ApoB and ApoB/ApoA-I values significantly compared to non-exercisers. LDL-C was not, but LDL-C/HDL-C was marginally but statistically significantly reduced by exercise. One-year change in ApoB and ApoB/ApoA-I correlated more strongly to 1-year changes in physical fitness than LDL-C or LDL-C/HDL-C. Adjusting for changes in LDL-C or LDL-C/HDL-C did not influence the correlation between changes in fitness and ApoB or ApoB/ApoA-I. However, adjusting for changes in ApoB or ApoB/ApoA-I wiped out the correlation between change in fitness and LDL-C or LDL-C/HDL-C. Relationships weakened when adjusting for changes in waist circumference, but Apo B or ApoB/ApoA-I still correlated significantly to changes in fitness.

CONCLUSION

Physical exercise reduced the atherogenic burden as experienced by the reduction in apoB or apoB/apoA-I levels, but not by LDL-C in healthy middle-aged men. Possibly, regular physical activity might increase the LDL-C particle size, thereby making LDL less atherogenic. Monitoring of apolipoproteins rather than the cholesterol moiety of lipoproteins might improve the assessment of lipoprotein changes after exercise training.

Combined diet and exercise intervention reverses the metabolic syndrome in middle-aged males: results from the Oslo Diet and Exercise Study

We examined the single and combined effects of a 1-year diet and exercise intervention on the International Diabetes Federation (IDF) metabolic syndrome among middle-aged males. The study was a randomized, controlled, 2 x 2 factorial intervention study. Participants included 137 men with metabolic syndrome according to the IDF criteria aged 40-49 years randomly allocated to four intervention groups: diet alone (n=34), exercise alone (n=34), the combination of the diet and exercise intervention (n=43) or control (n=26). The main outcome measure was metabolic syndrome as defined by IDF criteria (2005). In the combined diet and exercise group, 14 participants (32.6%) (P<0.0001 as compared with control) had the metabolic syndrome after 1-year intervention. In the diet-only group, 22 participants (64.7%) (P=0.023 vs control) and in the exercise-only group 26 participants (76.5%) (P=0.23 vs control) had the metabolic syndrome following the intervention. Utilizing the factorial design, both dietary and exercise intervention had significant effects (P<0.005) on the resolution of the metabolic syndrome. Both exercise and dietary intervention reduced metabolic syndrome prevalence compared with control after 1 year of intervention. However, the combined diet and exercise intervention was significantly more effective than diet or exercise alone in the treatment of the metabolic syndrome.

Physical activity and clustered cardiovascular risk in children: a cross-sectional study (The European Youth Heart Study)

BACKGROUND

Atherosclerosis develops from early childhood; physical activity could positively affect this process. This study's aim was to assess the associations of objectively measured physical activity with clustering of cardiovascular disease risk factors in children and derive guidelines on the basis of this analysis.

METHODS

We did a cross-sectional study of 1732 randomly selected 9-year-old and 15-year-old school children from Denmark, Estonia, and Portugal. Risk factors included in the composite risk factor score (mean of Z scores) were systolic blood pressure, triglyceride, total cholesterol/HDL ratio, insulin resistance, sum of four skinfolds, and aerobic fitness. Individuals with a risk score above 1 SD of the composite variable were defined as being at risk. Physical activity was assessed by accelerometry.

FINDINGS

Odds ratios for having clustered risk for ascending quintiles of physical activity (counts per min; cpm) were 3.29 (95% CI 1.96-5.52), 3.13 (1.87-5.25), 2.51 (1.47-4.26), and 2.03 (1.18-3.50), respectively, compared with the most active quintile. The first to the third quintile of physical activity had a raised risk in all analyses. The mean time spent above 2000 cpm in the fourth quintile was 116 min per day in 9-year-old and 88 min per day in 15-year-old children.

INTERPRETATION

Physical activity levels should be higher than the current international guidelines of at least 1 h per day of physical activity of at least moderate intensity to prevent clustering of cardiovascular disease risk factors.

A comparison of estimated maximal oxygen uptake in 9 and 10 year old schoolchildren in Tanzania and Norway

OBJECTIVE

To compare estimated maximal oxygen uptake (VO2max) in Tanzanian and Norwegian children, by using the same bicycle protocol in both samples.

METHODS

Maximal oxygen uptake was estimated from an indirect maximal watt cycle ergometer test in 156 rural boys and girls in Tanzania. Similarly aged urban Norwegian boys and girls (n = 379) who underwent the same test were used for comparison. The Tanzanian children also participated in a 20 metre shuttle run test and a test of bicycle skill. The Tanzanian children were tested at altitude (approximately 1800 metres), while the Norwegian children were tested at sea level.

RESULTS

In the cycle ergometer test, estimated relative VO2max was similar in Tanzanian and Norwegian boys, while Tanzanian girls had 8% lower estimated VO2max compared with Norwegian girls (p<0.001). Only one third of the Tanzanian children were able to ride a conventional bicycle. Excluding subjects not able to ride a bicycle, there was no difference in estimated VO2max between Norwegian and Tanzanian children. The Tanzanian boys and girls reached significantly higher estimated VO2max in the shuttle run test compared with the cycle ergometer test (p<0.001).

CONCLUSIONS

Tanzanian and Norwegian children attained similar relative VO2max in the cycle ergometer test. However, the comparison was hampered by differences in altitude and the poor cycle ergometer skills in the Tanzanian children, both of which probably underestimated their VO2max.