EDITORIALS

ONE SMALL STEP FOR MAN. . .?

Researchers interested in the physiology of fat should bethankful. The obesity epidemic has created the impetusfor substantial basic and clinical work, and this work is

increasingly before the public. The recent dramatic increase inthe prevalence of insulin resistance and its feared consequence,type II diabetes mellitus, has allowed the understanding anddocumentation, in childhood, of a malignant progression fromthe accumulation of excess adiposity to the presence of targetorgan injury and disease morbidity. The journey encompassesthe development of cardiovascular risk, sleep and otherrespiratory disorders, orthopedic abnormalities, the discoverythat fat is an active metabolic tissue, new hormones (leptinand adponectin), the association with chronic low gradeinflammation, psychosocial morbidity, and the demonstrationof microvascular disease.1

In this issue of The Journal, Kelly et al have, in a smallcontrolled study, linked this new metabolic milieu of obesityto, surprise, exercise and physical fitness.2 In those participat-ing in a modest 8-week regular exercise program, statisticallysignificant improvements in fitness, HDL cholesterol, andvascular function were observed. For most other variablesstudied, exercise was associated with trends in a favorabledirection, although statistical significance was not achieved.

This study is an example of the ‘‘one small step.’’ There isnow developing, in many ‘‘small step’’ studies conducted in allage groups, a substantial body of work suggesting thatsustained regular exercise over a lifetime is critical for healthmaintenance. Observations in much larger adult studiesconducted with 15 or more years of follow-up provide ‘‘thegiant leap for mankind.’’ Regular exercise and physical fitnessprevent the development of hypertension, diabetes mellitus,and the metabolic syndrome; are more effective thanpharmacologic therapy in preventing future diabetes mellitus;and, independent of the aforementioned risk factors, lowercardiovascular mortality by as much as 50%.3-6 Most of thesmall step studies show the benefit from exercise in one or twoareas associated with the toxic milieu of obesity and insulinresistance. Well-conducted long-term clinical trials andepidemiologic observations show that these small steps arecumulative over time, that is, the long-term benefits ofsustained exercise and activity are a giant leap toward sustainedhealth. Because severely overweight persons are often bothunfit and insulin resistant, they may benefit the most fromincreased regular exercise.2-7

There are two important components to the work ofKelly et al and other researchers who have undertaken thedifficult task of getting a group of overweight persons to

Editorials

change their lifestyles and to exercise. The first is the researchthat demonstrates scientifically that exercise is healthful; thesecond is the exercise itself. It is common in editorials toapplaud the scientific work done by creative investigators andcall for more research to enhance our understanding of thedisease process under consideration. However, I would preferto call for more of the second part of the study. I think weought to do more exercise and exercise teaching than research.

One hour per day of moderate-intensity work willexpend about 300 kcal of energy or about 2000 calories perweek, enough to help maintain body weight and improveinsulin sensitivity.8 That hour must be scheduled into the dailygrind. How do you know you have done enough? You can usea treadmill or other exercise machine and count calories or youcan simply recognize that you have worked up a light sweat.Youcanwalk3miles, ride amountainbike10 to12miles,marchin a band, garden, swim laps, or dance. And, you can limit par-ticipation in sedentary activities such as television watching.9

It is too easy to get caught up in the excitement of thescience. In 1969, when man first set foot on the moon andthe people of the United States were gazing up at the sky, onthe earth the Viet Nam war was being fought and the streets ofUS cities were tinder boxes. In obesity research, we try to findthe pathologic mechanism. Is it endothelial injury? Is it insulinresistance secondary to low-grade vascular inflammation? IfI am overweight but my C reactive protein is normal, have Idodged the ‘‘obesity bullet’’? While looking up at the sciencewe are missing what is happening on the ground: we eat toomuch, are too sedentary, and do not go out and play.

Samuel S. Gidding, MDProfessor of Pediatrics

Jefferson Medical CollegeInterim Director of Outreach Services, Research, and Preventive Cardiology

Nemours Cardiac CenterA.I. duPont Hospital for Children

Wilmington, DE 19899

REFERENCES1. Gidding SS, Leibel RL, Dan-

iels S, Rosenbaum M, Van Horn L,

Marx GR. Understanding obesity in

youth. Circulation 1996;94:3383-7.

2. Kelly AS,Wetzsteon RJ, Kaiser

DR, Steinberger J, Bank AJ, Dengel

DR. Inflammation, insulin, and en-

dothelial function in overweight

children and adolescents: the role of

exercise. J Pediatr 2004;145:731-6.

Reprint requests: Dr Samuel S. Gid-ding, Nemours Cardiac Center, 1600Rockland Road, Wilmington, DE19899. E-mail: sgidding@nemours.org.

J Pediatr 2004;145:719-20.0022-3476/$ - see front matter.

Copyrightª 2004 Elsevier Inc. All rightsreserved.

10.1016/j.jpeds.2004.08.053

See related article, p 731.

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3. Carnethon MR, Gidding SS, Nehgme R, Sidney S, Jacobs DR, Liu K.

Low physical fitness in young adulthood predicts the development of

cardiovascular disease risk factors: the CARDIA study. JAMA 2003;290:

3092-100.

4. Knowler WC, Barrett-Connor E, Fowler SE, Hamman RF, Larchin

JM, Walker EA, et al. Reduction in the incidence of type 2 diabetes

mellitus with lifestyle intervention or metformin. N Engl J Med 2002;346:

393-403.

5. Katzmarzyk PT, Church TS, Blair SN. Cardiorespiratory fitness

attenuates the effects of the metabolic syndrome on all-cause and

cardiovascular disease mortality in men. Ach Intern Med 2004;164:

1092-7.

TO AVOID HEAT LOSS IN

Newborn infants of all gestational ages are at risk oflosing heat soon after birth. In the very pretermnewborn infant, there will be a serious drop in body

temperature after birth unless measures are taken to preventthis heat loss. The international guidelines1 recommendplacing the infant under a radiant heater, drying the skin,removing wet linen, and wrapping the infant in prewarmedblankets to reduce heat loss or, alternatively, placing the driedinfant skin-to skin on the mother’s chest to use her body asa heat source. Very preterm infants are still at risk of a lowbody temperature if they are not cared for under a prewarmedradiant heater, ideally with the infant placed on a heatedmattress or in a prewarmed incubator with a high air humidity,at an ambient temperature within the thermoneutral zone.2

The importance of thermal balance, especially in the mostpreterm infants, is illustrated by comparing data from theEPICure study3 with results of the study by Serenius et al.4 Inthe EPICure study,3 which concerned infants with a gesta-tional age (GA) of <26 weeks who were born in 276 maternityunits of different sizes and staffing in the United Kingdom,29.6% of the infants born at 25 weeks GA had a bodytemperature of <358C, and the corresponding proportions ofinfants born at 24 and 23 weeks with a body temperature<358C were 42.7 and 58.3%, respectively, indicating a highincidence of cold stress. In that study, the survival rates todischarge were 52.1%, 33.6%, and 19.9% in infants born atGAs of 25, 24, and 23 weeks, respectively. In the Sereniusstudy, carried out at two Swedish university hospital neonatalintensive care units (NICUs), the survival rates to dischargewere 77%, 63%, and 53% for infants born at 25, 24, and 23weeks, respectively. In that study, a senior neonatologistattended all deliveries. After the infant’s skin had been wiped,the infant was placed under a prewarmed radiant heater

BW Birth weightGA Gestational ageHcond Conduction heat exchangeHconv Convection heat exchangeHconv-r Respiratory tract convection heat exchangeHevap Evaporation heat exchangeHevap-r Respiratory tract evaporation heat exchangeHrad Radiation heat exchangeNICU Neonatal intensive care unit

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6. Gulati M, Pandey DK, Arnsdorf MF, Lauderdale DS, Thisted RA,

Wicklund RH, et al. Exercise capacity and the risk of death in women: the

St James Women Take Heart Project. Circulation 2003;108:1554-9.

7. Gidding SS, Nehgme R, Heise C, Muscar C, Linton A, Hassink S.

Severe obesity associated with cardiovascular deconditioning, high prevalence

of cardiovascular risk factors, diabetes mellitus/hyperinsulinemia, and

respiratory compromise. J Pediatr 2004;144:766-9.

8. US Department of Health and Human Services. Physical activity and

health: a report of the surgeon general. Washington, DC: National Center for

Chronic Disease Prevention and Health Promotion; 1996.

9. American Academy of Pediatrics.Children, adolescents, and television.

Pediatrics 107: 423-6.

VERY PRETERM INFANTS

and—after the necessary initial treatment—was placed ina prewarmed transport incubator for transfer to the NICU,where it was cared for in a prewarmed incubator with a high airhumidity andwithwarmed and humidified gas for ventilation.4

In this issue of The Journal, Vohra and co-workers5

present a randomized controlled trial undertaken to determinewhether the use of polyethylene occlusive skin wrapping in verypreterm infants born at GAs of <28 weeks prevents heat lossafter delivery better than conventional drying with a towel andto determine whether any benefit is sustained after wrapremoval. Both groups of preterm infants were cared for undera radiant warmer. The results showed that control infants whowere dried completely immediately after birth had a 0.98Clower rectal temperature on admission to the nursery thaninfants who were enclosed in the polyethylene material fromthe neck down. The compared groups were very similar as tobirth weight (BW), GA, sex, and umbilical arterial blood pH.One hour after admission to the NICU there was no differencein rectal temperature between the groups and there were nodifferences in secondary outcome measures. The rectaltemperature on NICU admission was below 36.58C in 2 ofthe 6 infants in the wrap group who died and in 7 infants in thecontrol group who died. In 1999, Vohra et al6 reported resultsfrom a similar study concerning a group of very preterm infantsborn at a GA of <28 weeks. In that study, infants in whom thepolyethylene wrap was used had a mean rectal temperature onadmission to the NICU that was significantly higher than thatin infants who were only dried soon after birth. Differences inBW, however, made the comparison less conclusive. In anobservational study of a very small number of preterm infantssimilar results were obtainedusing a polyvinyl chloridewrap.7

At birth the infant isexposed to a colder tempera-ture than it has experienced inutero. To avoid a rapid dropin body temperature the in-fant has to be placed in anenvironment where the heatproduction and the heat ex-change with the environment

Reprint requests: Dr Gunnar Sedin,Department of Women’s and Chil-dren’s Health, University Children’sHospital, SE-751 85 Uppsala, Sweden.E-mail: gunnar.sedin@kbh.uu.se

J Pediatr 2004;145:720-2.0022-3476/$ - see front matter.

Copyrightª 2004 Elsevier Inc. All rightsreserved.

10.1016/j.jpeds.2004.08.065

See related article, p 750.

The Journal of Pediatrics � December 2004