|
||||||
|
|
|
|
|||||||||||
|
|||||||||||||
| ||||||||||||||||||||||||||||||||||||
Walk, talk, fidget, shop, sweep the basement, hold a child. These are allforms of everyday low-key activities that scientists refer to as non-exerciseactivity thermogenesis, or NEAT.
While you probably won't break a sweat doing them, researchers at the MayoClinic have found that NEAT may be an even more powerful indicator than formalexercise in determining who is lean and who is obese.
In their recent study, James Levine, MD, and his team found that onaverage, obese people sit 2 hours more each day than their naturally leancounterparts.1 Thattranslates into a difference of about 350 calories burned per day betweenoverweight and lean people.
"Our patients have told us for years that they have low metabolism,and as caregivers, we have never quite understood what that means,"Levine says. "The answer is they have low NEAT, which means they have abiological need to sit more.... Our study shows that the calories that peopleburn in their everyday activities—their NEAT—are far, far moreimportant in obesity than we previously imagined."
NEAT RESEARCH
The researchers recruited 20 healthy but self-described "couchpotatoes" for this pilot study—10 who were lean (BMI
23) and10 who were mildly obese (BMI33). Each was outfitted with specialundergarments embedded with movement sensors and data-logging technology. Theywere instructed to go about their normal routines but were forbidden to swimor eat food not prepared by the research center. Movements were monitoredevery half-second during the 10-day study period.
Overall, the obese subjects sat an average 164 minutes more during the daythan their lean counterparts. Sleep (lying down) times were almost identicalin the two groups. Total body movement was negatively correlated with fatmass. There was also a 10-fold variation in how much energy participantsexpended in NEAT, Levine says.
In the study's second phase, the researchers investigated whether the lowerNEAT values in the obese subjects were a cause or a consequence of obesity.Seven of the original obese volunteers underwent supervised calorierestriction (1,000 fewer calories per day) over 8 weeks. Average weight losswas 8 kg (17.7 lb). Likewise, nine lean volunteers underwent supervisedoverfeeding (additional 1,000 calories per day) during the 8 weeks. Averageweight gain was 4 kg (8.8 lb).
After 10 more days of movement monitoring, members of both groupsmaintained their original NEAT values despite their significant weightchanges.
NEAT MOTIVATORS: BIOLOGY OR ENVIRONMENT?
Levine says his team's data support the theory that differences in NEAT arebiologically determined. Indeed, animal studies suggest certain brainchemicals—including the arousal neuropeptide, orexin—may beresponsible for driving spontaneous activitylevels.2
But environment and motivation also play a role, Levine says.
"As soon as the car and the computer became available, I think somepeople had a deep-seated genetic predisposition to go along with that moresedentary lifestyle," he says. "The rest found new outlets fortheir activity needs—like going to the gym."
But that doesn't mean people can't reverse predisposition, Levinesuggests.
"The idea that brain structure changes in light of environmentalstimuli is not new," he says. "In fact, there's some evidence thatif you motivate people in some way that makes them become more active, theyeventually want to be more active."
HELPING PATIENTS CONTROL WEIGHT WITH NEAT
"What Levine and colleagues clearly demonstrate is that small butsustained changes in the activities of daily living can profoundly affectenergy balance," notes Eric Rasmussin, PhD, chief of the Division ofHealth Performance and Enhancement at Louisiana State University's PenningtonBiomedical Research Center.
The implications are important, Rasmussin says. More than 60% of Americansare overweight and nearly half of that group is consideredobese.3 With that inmind, Levine suggests counseling patients on adding more NEAT activity totheir days by creatively rethinking their routines.
Find other ways to relax rather than sitting in front of the TV, hesuggests. Use part of your lunch break or conduct your weekly work meetingduring a walk. Play with your kids. Fire your cleaning person. Celebrate abirthday with an activity, not lots of treats.
"The whole point of being active should not be just to be healthy andprevent diabetes, but because it's really good fun," Levine says.
References
2. Sutcliffe JG, de Lecea L: Not asleep, not quite awake.Nat Med 10:673–674, 2004.[Medline]
3. National Center for Health Statistics. Overweight Prevalence:1999–2002. Available atwww.cdc.gov/nchs/products/pubs/pubd/hesptats/obese/obse99.htm.Accessed August 23, 2005.
CiteULike 
Del.icio.us 
Digg 
Reddit 
Technorati What's this?
| ||||||||||||||||||||||||||||||||||||
|
||||||
|
| DOC News | Diabetes | Diabetes Care | Clinical Diabetes | Diabetes Spectrum |
