Background Obesity results from an imbalance between energy intake and expenditure. In rodents and newborn humans, brown adipose tissue helps regulate energy expenditure by thermogenesis mediated by the expression of uncoupling protein 1 (UCP1), but brown adipose tissue has been considered to have no physiologic relevance in adult humans. Methods We analyzed 3640 consecutive 18F-fluorodeoxyglucose (18F-FDG) positron-emission tomographic and computed tomographic (PET–CT) scans performed for various diagnostic reasons in 1972 patients for the presence of substantial depots of putative brown adipose tissue. Such depots were defined as collections of tissue that were more than 4 mm in diameter, had the density of adipose tissue according to CT, and had maximal standardized uptake values of 18F-FDG of at least 2.0 g per milliliter, indicating high metabolic activity. Clinical indexes were recorded and compared with those of date-matched controls. Immunostaining for UCP1 was performed on biopsy specimens from t...

/pdf/identification-and-importance-of-brown-adipose-tissue-in-550n982569.pdf

Identification and Importance of Brown Adipose Tissue in Adult Humans

Guidelines and Expert Consensus Documents summarize and evaluate all currently available evidence on a particular issue with the aim to assist physicians in selecting the best management strategies for a typical patient, suffering from a given condition, taking into account the impact on outcome, as well as the risk–benefit ratio of particular diagnostic or therapeutic means. Guidelines are not substitutes for textbooks. The legal implications of medical guidelines have been discussed previously.

A great number of Guidelines and Expert Consensus Documents have been issued in recent years by the European Society of Cardiology (ESC) as well as by other societies and organizations. Because of the impact on clinical practice, quality criteria for development of guidelines have been established in order to make all decisions transparent to the user. The recommendations for formulating and issuing ESC Guidelines and Expert Consensus Documents can be found on the ESC web site (http://www.escardio.org/knowledge/guidelines/rules).

In brief, experts in the field are selected and undertake a comprehensive review of the published evidence for management and/or prevention of a given condition. A critical evaluation of diagnostic and therapeutic procedures is performed, including assessment of the risk–benefit ratio. Estimates of expected health outcomes for larger societies are included, where data exist. The level of evidence and the strength of recommendation of particular treatment options are weighed and graded according to predefined scales, as outlined in the tables below.

The experts of the writing panels have provided disclosure statements of all relationships they may have which might be perceived as real or potential sources of conflicts of interest. These disclosure forms are kept on file at the European Heart House, headquarters of the ESC. Any changes in conflict of interest that arise during the writing period must be notified to the ESC. The Task Force report was entirely …

/pdf/european-guidelines-on-cardiovascular-disease-prevention-in-17acj3uib4.pdf

European guidelines on cardiovascular disease prevention in clinical practice (version 2012) : the fifth joint task force of the European society of cardiology and other societies on cardiovascular disease prevention in clinical practice (constituted by representatives of nine societies and by invited experts).

Methods for assessment, e.g., anthropometric indicators and imaging techniques, of several phenotypes of human obesity, with special reference to abdominal fat content, have been evaluated. The correlation of fat distribution with age, gender, total body fat, energy balance, adipose tissue lipoprotein lipase and lipolytic activity, adipose tissue receptors, and genetic characteristics are discussed. Several secreted or expressed factors in the adipocyte are evaluated in the context of fat tissue localization. The body fat distribution and the metabolic profile in nonobese and obese individuals is discussed relative to lipolysis, antilypolysis and lipogenesis, insulin sensitivity, and glucose, lipid, and protein metabolism. Finally, the endocrine regulation of abdominal visceral fat in comparison with the adipose tissue localized in other areas is presented.

/pdf/subcutaneous-and-visceral-adipose-tissue-their-relation-to-5crse4rslq.pdf

Subcutaneous and visceral adipose tissue : Their relation to the metabolic syndrome

Measuring Health: A Guide to Rating Scales and Questionnaires

ATS/ACCP statement on cardiopulmonary exercise testing.

A maximal multistage 20 m shuttle run test was designed to determine the maximal aerobic power of schoolchildren, healthy adults attending fitness class and athletes performing in sports with frequent stops and starts (e.g. basketball, fencing and so on). Subjects run back and forth on a 20 m course and must touch the 20 m line; at the same time a sound signal is emitted from a prerecorded tape. Frequency of the sound signals is increased 0.5 km h‐1 each minute from a starting speed of 8.5 km h‐1. When the subject can no longer follow the pace, the last stage number announced is used to predict maximal oxygen uptake (VO2max) (Y, ml kg‐1 min‐1) from the speed (X, km h‐1) corresponding to that stage (speed = 8 + 0.5 stage no.) and age (A, year): Y=31.025 + 3.238 X ‐ 3.248A + 0.1536.AX, r = 0.71 with 188 boys and girls aged 8–19 years. To obtain this regression, the test was performed individually. Right upon termination VO2 was measured with four 20 s samples and VO2max was estimated by retroextrap...

The multistage 20 metre shuttle run test for aerobic fitness

In order to validate a maximal multistage 20-m shuttle run test for the prediction of 
$$\dot V$$

 O2 max, 91 adults (32 females and 59 males, aged 27.3±9.2 and 24.8±5.5 year respectively and with mean 
$$\dot V$$

 O2 max (± SD) of 39.3±8.3 and 51.6±7.8 ml·kg−1·min−1 respectively) performed the test and had 
$$\dot V$$

 O2 max estimated by the retroextrapolation method (extrapolation to time zero of recovery of the exponential least squares regression of the first four 20-s recovery 
$$\dot V$$

 O2 values). Starting at 8 km·h−1 and increasing by 0.5 km·h−1 every 2 min, the 20-m shuttle run test enabled prediction of the 
$$\dot V$$

 O2 max (y, ml·kg−1·min−1) from the maximal speed (x, km·h−1) by means of the following regression equation: y=5.857x — 19.458; r=0.84 and SEE=5.4. Later, the multistage protocol was slightly modified to its final version, in which the test started at stage 7 Met and continued with a 1 Met (3.5 ml O2·kg−1·min−1) increment every 2 min. Twenty-five of the 91 subjects performed the 20-m shuttle test twice, once on a hard, low-friction surface (vinyl-asbestos tiles) and another time on a rubber floor, as well as a walking maximal multistage test on an inclined treadmill. There was no difference between the means of these tests or between the slopes of the 
$$\dot V$$

 O2max — maximal speed regressions for the two types of surfaces. The 20-m shuttle run test and another maximal multistage field test involving continuous track running gave comparable results (r=0.92, SEE=2.6 ml O2·kg−1·min−1, n=70). Finally, test and retest of the 20-m shuttle run test also yielded comparable results (r=0.975, SEE=2.0 ml O2·kg−1·min−1, n=50). It is concluded that the 20-m shuttle run test is a valid and reliable test for the prediction of the 
$$\dot V$$

 O2 max of male and female adults, individually or in groups, on most gymnasium surfaces.

/pdf/a-maximal-multistage-20-m-shuttle-run-test-to-predict-vo2-3l1oukha3z.pdf

A maximal multistage 20-m shuttle run test to predict VO2 max

This study had two objectives: 1) to establish magnetic resonance imaging (MRI) as a tool for measuring total and regional adipose tissue (AT) distribution in humans and 2) to assess the relationship between selected anthropometric variables and MRI-measured AT. Twenty-seven healthy men varying in age [40.8 +/- 14.5 (SD) yr], body mass index (28.5 +/- 4.8), and waist-to-hip ratio (WHR, 0.96 +/- 0.07) participated in the study. Total AT volume was determined using a linear interpolation of AT areas obtained on consecutive slices (n = 41) taken from head to toe (10-mm thickness, 50-mm centers). The mean change for repeated measures of total AT volume was 2.9% (range 0.9-–4.3%). Large interindividual differences were observed for total AT volume (6.9–59.3 liters), subcutaneous AT (6.3–49.8 liters), and visceral AT (0.5–8.5 liters). Visceral AT represented 18.3% of the total AT. The single best predictor of total adiposity was waist circumference (R2 = 0.92). For visceral AT volume, WHR was the strongest anth...

Quantification of adipose tissue by MRI: relationship with anthropometric variables

It is widely believed that the performance of children and adolescents on aerobic fitness tests is declining. To test this hypothesis, this meta-analysis compared the results of 55 reports of the performance of children and adolescents aged 6–19 years who have used the 20m shuttle run test (20mSRT). All data were collected in the period 1981–2000. Following corrections for methodological variation, the results of all studies were expressed using the common metric of running speed (km/h) at the last completed stage. Raw data were combined with pseudodata generated from reported means and standard deviations using Monte Carlo simulation. Where data were available on children and adolescents from the same country of the same age and sex, but tested at different times, linear regression was used to calculate rates of change. This was possible for 11 (mainly developed) countries, representing a total of 129 882 children and adolescents in 151 age × sex × country slices. There has been a significant decline in performance in the 11 countries where data were available, and in most age × sex groups, with a sample-weighted mean decline of 0.43% of mean values per year. The decline was most marked in older age groups and the rate of decline was similar for boys and girls. There has been a very rapid secular decline in the 20mSRT performance of children and adolescents over the last 20 years, at least in developed countries. The rate of decline is not related to the change in the country’s relative wealth, as quantified by per capita gross domestic product (GDP).

Secular trends in the performance of children and adolescents (1980-2000): an analysis of 55 studies of the 20m shuttle run test in 11 countries.

The object of this study was to report on the validity and reliability of the Universite de Montreal Track Test (UM-TT). The UM-TT is a continuous maximal indirect multistage running field test based on the energy cost of running. The first stage is set at a walking speed that requires 5 Mets; thereafter the speed is increased by 1 Met every two minutes. In order to assess the validity of the UM-TT, 25 subjects, 24.4 +/- 2.8 years old (X +/- SD) had their VO2max predicted with the UM-TT and measured directly with a running multistage treadmill test. Averages (+/- SD) were not significantly different (61.5 +/- 10.6 and 61.4 +/- 10.9 ml O2 . kg-1 . min-1, respectively), other statistics being r = 0.96, delta = 0.09 +/- 2.90 ml O2 . kg-1 . min-1 and Syx = 2.81 ml O2 . kg-1 . min-1. Seven males, 20.6 +/- 1.0 years old, had also their VO2max measured directly during the UM-TT. Comparison of predicted and directly measured VO2max yielded similar results: 70.0 +/- 4.5 and 70.7 +/- 6.0 ml O2 . kg-1 . min-1, respectively with r = 0.66, delta = 0.67 +/- 4.53 and Syx = 3.71. Reliability of the UM-TT was assessed by repeating the test twice on 60 subjects (49 males and 11 females; 39 subjects below 30 years old and 21, above; and 30 subjects below and above 15 Mets). Results were as follows: X +/- SD = 54.1 +/- 8.2 and 54.2 +/- 8.5, r = 0.97, delta 0.11 +/- 1.92, and Syx = 1.92. Similar reliability trends were observed for each one of the subgroups of subjects. It is concluded that the UM-TT is valid and reliable to estimate the VO2max of trained and untrained young and middle-age males and females.

Luc Léger

Papers

The multistage 20 metre shuttle run test for aerobic fitness

A maximal multistage 20-m shuttle run test to predict VO2 max

Quantification of adipose tissue by MRI: relationship with anthropometric variables

Secular trends in the performance of children and adolescents (1980-2000): an analysis of 55 studies of the 20m shuttle run test in 11 countries.

An indirect continuous running multistage field test: the Université de Montréal track test.