by Monica Mollica
Part 1 of 3 on the deleterious effects of too much sitting
Are you struggling to lose that extra flab and all those nasty calories that seem to be glued to your waistline? Do you ever wonder why, despite your hard training and dieting, you still have those annoying love handles? then maybe you should try to implement the NEAT way to fat loss…
NEAT – the ignored component of physical activity, metabolic regulation and total daily caloric expenditure
When it comes to fat loss, a key is to increase your energy expenditure. Therefore, the traditional prescription for fat loss has focused on exercise as a means of revving up your energy expenditure to burn off excess fat. While exercise (both cardio and weight lifting) is essential for fat loss, there is one other less known, albeit important, component of total daily energy expenditure that could be the missing link in your fat loss endeavor. enter NEAT…
NEAT stands for non-exercise activity thermogenesis (or non-exercise activity energy expenditure). NEAT is the energy expenditure induced by non-exercise bodily movements in daily life, i.e. lifestyle embedded physical activity [1].
The term “physical activity” represents the full continuum of movement, with “exercise” being a subcategory representing the higher end of this continuum [2]. The remainder that falls below the exercise threshold is “non-exercise physical activity”, and is illustrated in the graphic below [3].
Sedentary behaviors (typically in the contexts of television viewing, computer use, workplace sitting, and time spent commuting) are a new focus for research in the physical activity and health field [4-8]. As will be outlined below, emerging evidence is showing that there is a physiological distinction between too little exercise vs. too much sitting, i.e. exercise deficiency and sitting excess are each unique states with difference health consequences.
Sedentary behaviors include sitting during commuting, in the workplace and domestic environment, and during leisure time. Actually, the word “sedentary” comes from the Latin “sedere”, which means “to sit’. Sedentary behaviors, a.k.a inactivity, are defined by both posture (sitting or reclining) and low energy expenditure; they don’t elevate energy expenditure substantially above the resting level [4, 7-10]. In other words, sedentary “activities” incur an energy expenditure at the level close to 1 – 1.5 metabolic equivalent unit (METs) [11-13]. This can be compared to moderate/vigorous physical activity, or “exercise” such as brisk walking or running, which elevates energy expenditure 3-10 times resting metabolic rate, i.e. 3–10 METs [12, 13].
One met is the energy cost of resting quietly, often defined as 1 cal/kg/hour (or 1 cal per 2.2 lb per hour) [11, 13]. To find out your “resting hourly burn rate”, i.e. how many calories you burn resting per hour, just divide your weight in lb by 2.2. For ex. a person weighing 150 lb will burn 68 cal (150 lb / 2.2), another person weighing 220 lb will burn 100 cal (220 lb / 2.2). It’s a rough estimate (actually an over-estimate by some 20% [11]), but you get the idea.
Different activities elevate caloric expenditure over resting level as follows: [5]
Sitting still 3.7 %
Sitting while fidgeting 54 %
Standing still 13 %
Standing while fidgeting 94 %
Slow strolling 154 %
Fast strolling 202 %
Even though standing still doesn’t markedly elevate caloric expenditure over sitting still, it is not considered to be a sedentary activity because muscle activity in the legs during standing is 2.5 times higher than during sitting [14]. during standing, postural muscles (predominantly in the legs) are continually contracting to keep the body upright and maintain balance. This muscle activity during standing in turn stimulates an enzyme called muscle lipoprotein lipase (LPL) [10]. LPL is the rate-limiting enzyme for the breakdown of fats circulating in the blood stream, and uptake of free fatty acids into muscle for use as energy (that is, fat burning) [10, 15-18]. LPL has been studied heavily because this enzyme has a central role in several aspects of fat metabolism [17, 18]. LPL also has a major influence on the partitioning of fatty acids between different tissues, plasma cholesterol metabolism and the subsequent downstream intracellular effects related to fat availability [17, 18]. Thus, the differences between standing and sitting aren’t trivial. more on muscle LPL below.
NEAT vs. sitting Time
Inactivity and non-exercise activity have gained growing attention because the proportion of time spent doing purposeful exercises usually make up only a fraction of the day, leaving much time for sedentary activities [10]. assuming 8 hours of sleep, we have 16 hours per day at our disposal. Studies that objectively measured Camiseta AC Milan physical activity show that people in the us on average spend about 8 hours daily, i.e. half of their waking time, being sedentary[19]. Those employed in sedentary occupations are sedentary for approximately 11 hours per day [20]. The graphic below illustrates the major contexts for sedentary behavior and their distribution over a typical adult’s waking hours [3].
Therefore, it is no wonder that individual differences in light physical activity outside of intense exercise have greater influence on inactivity time than the time we spend exercising [14]. This was confirmed in another study where some individuals participated in substantial amounts of intense exercise but otherwise had a relatively low overall daily physical activity energy expenditure [21]. Thus, even when adhering to the exercise guidelines recommending at least 30 min/day of moderate-to-vigorous intensity activity at least 5 days per week [22], this does not automatically mean that people will not engage in excessive “baseline” sitting over the rest of the day. because of this large amount of time we have at our disposal outside of formal exercise time, whether you spend most of your non-exercising time sitting, reclining, or standing and moving around, is a significant issue. this is underscored by the finding that 1 hour of daily physical exercise cannot compensate the negative effects of inactivity on insulin level and blood lipids if the rest of the day is spent sitting [23]. and as outlined below, too much inactive sitting can be what’s missing in your fat loss equation…
NEAT – small things add up fast in favor of fat gain or fat loss
This is true for both credit cards and energy expenditure. energy expended during the day, outside of typical exercise (standing, fidgeting like movements while seated and while standing, ambulation) can vary by up to 2000 calories per day between individuals [21, 24, 25], and thus may substantially contribute to the daily energy expenditure [5, 21, 26]. This can be explained by the very large variability between people in total inactivity times, ranging from 40 to 91% [14].
It have been estimated that energy demands have dropped by over 400-500 cal/day due to occupational and domestic computerized environments, mechanization, and TV/media [27]. Therefore, even one hour of daily exercise might not be enough to achieve fat loss or fat gain prevention [28, 29].
What does research say about NEAT as a tool to keep body fat under control?
Caloric expenditure
To examine NEAT’s role in obesity, a study recruited 10 lean and 10 mildly obese sedentary people and measured their body postures and movements every half-second for 10 days [30]. The measurements were made using micro-sensors that subjects wore under their clothes and allowed body postures and movements to be accurately measured. It was found that obese individuals were seated 2.7 hours more per day than lean individuals. It was concluded that if obese individuals adopted the NEAT-enhanced behaviors of their lean peers, they might expend an additional 350 calories per day [30], as illustrated in the following diagram [31].
This finding was confirmed in a later study which compared activity energy expenditure and daily activity patterns (using accelerometers) in lean and obese people [32]. It was found that obese women sat 2.6 h more each day (12.7 h vs. 10.1), stood 2 h less (2.7 h vs. 4.7 h) and spent half as much time in moving around activity than lean women (2.6 h vs. 5.4 h) [32]. After controlling for differences in fat-free mass, the lean subjects expended 400 calories more per day than the less active and more sedentary obese subjects [32].
It is interesting to note that this difference in magnitude of caloric expenditure between NEATers and non-NEATers is about the same as the formal exercise prescription dose that obese people are urged to adopt in order to induce a negative energy balance and fat loss (2500 cal/wk or 360 cal/day, corresponding to 75 min of brisk walking/d) [33, 34]. Thus, NEATing like standing/ambulating/fidgeting is of substantial importance for controlling body fat.
Interesting Statistics
Another study found that time spent watching TV is associated with risk of obesity and type 2 diabetes [35]. After adjusting for age, smoking, exercise levels and dietary factors, the following risk percentages were documented:
Each 2 hours/d increment in TV watching is associated with:
– 23% increase in obesity and a 14% increase in risk of diabetes.
Each 2 hours/d increment in sitting at work is associated with:
– 5% increase in obesity and a 7% increase in diabetes.
In contrast, standing or walking around at home (2 hr/d) is associated with:
– 9% reduced risk for obesity and a 12% reduced risk for diabetes.
Each 1 hour per day of brisk walking is associated with:
24% reduced risk for obesity and a 34% reduced risk for diabetes.
In this study population, it was estimated that 30% of new cases of obesity and 43% (95% CI, 32%-52%) of new cases of diabetes during a 6 year follow up could be prevented by adopting a relatively active lifestyle (less than 10hr/wk of TV watching and at least 30 min/day of Camiseta Selección de fútbol de Estados Unidos brisk walking) [35]. many other studies support the association between sitting time and body fat gain [29, 36-43].
Waistline
Sitting time is also deleteriously associated with a number of cardiovascular risk factors, including waist circumference, blood glucose, and blood fats [44-46]. Each 10% increase in sitting time has been associated with a 1.2 inch (3.1cm) larger waist circumference [44]. The association between sedentary time and waist circumference is largely independent of exercise participation [46].waist-measuring-man
Not just total sitting time, but also breaks in sitting time are important. compared to those who during the day have fewest breaks per hour of sitting, those with the breaks per hour of sitting have been found to have1.6 – 2.34 inches (4.1 – 5.95 cm) smaller waist circumferences [45, 47]. Of importance to note is that a break could be as short as 1 min and doesn’t have to be intense type “exercise”, suggesting that regular breaks from sitting time can be easily implemented both during the working day and at home. A walk to the kitchen to take a sip of water, or walking around while drinking your Camiseta SSC Napoli coffee/tee, might be enough.Thus, patterns of sedentary time accumulation are important in addition to total amount of sedentary time.
NEAT – your weapon against vacation and holiday fat gain
We all know about those lucky folks who magically appear to resist fat gain with overeating. These subjective observations have been confirmed in studies that documented a several-fold inter-individual variation in fat accumulation with overeating [48-50]. but what is it that makes those people resistant to fat gain?
To answer this question, a study was designed to find out if there is a component of energy expenditure that shows enough variability to account for the variability in resistance to fat gain during overfeeding [51]. Non-obese volunteers were fed 1000 calories per day in excess of weight-maintenance requirements for 8 weeks. It was found that fat gain varied over 10-fold, ranging from a gain of only 0.8 lb (0.36 kg) to a gain of 9.3 lb (4.23 kg), and that it was changes in NEAT that accounted for this enormous difference. The maximum increase in NEAT was close to 700 kcal/day, and could be accounted for by an increase in strolling-equivalent activity by about 15 min/hour during waking hours.
It could be argued that it is the obese state that causes declines in NEAT. In order to find out whether differences in NEAT are a cause or consequence of obesity, the same obese subjects were put on a diet for 2 months which caused a weight loss of 17.6 lb (8 kg) [51]. However, despite the weight loss, the original NEAT activities were maintained. This indicates that NEAT can be an inherent trait that causes some people to be more spontaneously active than others, and that a low NEAT that contributes to obesity.
The fact that NEAT is a mediator of the resistance to fat gain with overfeeding underscores its power. When people overeat, activation of NEAT dissipates a large part of the excess energy to preserve leanness, while failure to activate NEAT results in fat gain. Those who with overfeeding increase their NEAT the most, gain the least fat. Those who with overfeeding do not increase their NEAT gain the most fat and are predisposed to become obese.
Because the human genetic code has not changed during the past 50 years while obesity has become epidemic, obesity may in part be a consequence of enhanced responsiveness to environmental cues to be seated. but just because you don’t have an innate NEAT drive doesn’t mean you’re lost. knowing the importance of NEAT as an anti-fat gain weapon, you can cognitively override your gravitation to the chair and consciously decide to simply move around more in your daily life.
Sitting – not just simply the opposite of exercising
Intuitively, sitting might be interpreted a