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What is the Optimal FIT of Sedentary Interruption Bouts to Improve Cardiometabolic Health?

INTRODUCTION

In the past decade, sedentary behavior has been recognized as one of the main factors that contribute to the overweight and obesity epidemic (6). Worldwide, 1.4 billion people above the age of 20 are overweight, while nearly 500 million are obese (18). The cause of overweight and obesity is multifactorial and may include energy imbalance, low activity levels, and sedentary behavior (11). Sedentary behavior is a significant health problem because it leads to increased risk of morbidity and mortality from chronic diseases (3,9,18,19). Diseases linked to sedentary behavior include dyslipidemia, hypertension, elevated blood glucose, metabolic syndrome (MetS), type 2 diabetes mellitus (T2DM), and cardiovascular disease (CVD) (4,6,13,16).

Diseases linked to sedentary behavior, like hypertension, CVD, and T2DM are large contributors to mortality. Almost one billion people worldwide have hypertension (8,17). As to the United States, CVD was the leading cause of death in the year 2010, resulting in one in three deaths in American adults that equates to nearly 2,150 deaths per day (8). Worldwide, an estimated 422 million individuals have T2DM, and over 1.5 million diabetes-related deaths occur each year (8). Therefore, as evidence mounts regarding the health risks associated with physical inactivity, the current paradigm for improving public health is to encourage a minimum of 150 cumulative min*[wk.sup.-1] of moderate-to-vigorous physical activity to improve health (7).

The current physical activity recommendations are supported by decades of convincing scientific research (11). However, there is also emerging research highlighting the important and independent health benefits to reduce the amount of time people spend being sedentary, such as time spent sitting at desks and in front of a TV (6). Indeed, developing research suggests that life expectancy in the U.S. would be as much as 2 yrs longer if adults watched less television and sat for fewer hours per day (7).

Nevertheless, despite the well-defined relationship between sedentary behavior and health outcomes, the concept that remains unclear is the specific frequency, intensity, and time (FIT) recommendations for decreasing sedentary behavior to maintain or to improve cardiometabolic health (2). That is, how often (i.e., frequency) should there be interruptions to prolonged sitting? With interrupting sedentary behavior, what should be the intensity of the bout of activity? Further, when interrupting sedentary behavior, what should be the length of the bout of the activity? Answers to these important questions will provide exercise physiology healthcare professionals with critical evidence to guide clients in effectively reducing sedentary behavior and its associated deleterious cardiometabolic health consequences.

Thus, the purpose of this study was to determine the optimal FIT for reducing sedentary behavior and improve cardiometabolic health in middle-age and older adults. It was hypothesized that more frequent, longer, and intense bouts of activity (in a dose response manner) to interrupt sedentary behavior would result in a superior cardiometabolic health.

METHODS

Subjects

A total of 14 subjects began the research study, while one subject dropped out prior to intervention. The data were collected from 13 middle age and older active adults (7 men and 6 women with a mean age of 74.2 [+ or -] 7.8 yrs, height 167.4 [+ or -] 8.2 cm, weight 91.6 [+ or -] 25.2 kg, and V[O.sub.2] max 23.0 [+ or -] 4.7 mL*[kg.sup.-1]*[min.sup.-1]; refer to Table 1). The subjects were recruited from the Wellness Elevated community exercise program at Western State Colorado University (WSCU) in Gunnison, Colorado (elevation 2,350 m). All of the subjects' cardiometabolic data were collected at the High Altitude Performance Laboratory on the WSCU's campus.

Inclusionary criteria included: (a) a minimum of 6 hrs*[d.sup.-1] of sedentary behaviour as confirmed by the Physician Assessment and Clinical Education Program questionnaire (PACE, University of California, San Diego); and (b) the presence of one or more of the following cardiometabolic disorders: dyslipidemia, high fasting blood glucose, and/or elevated blood pressure. The subjects needed to be comfortable and capable of performing a submaximal exercise test safely. Each subject completed a written informed consent, Physical Activity Readiness Questionnaire (PAR-Q), and a medical history questionnaire prior to participation in the study. All subjects were fully informed of the research procedures and associated risks before providing written informed consent. This study was approved by the Human Research Committee at WSCU.

Experimental Design

All subjects performed 4 separate FIT programs of sedentary interruption bouts (SIB), lasting 1 wk each, with equivalent duration of 1 wk washout periods. The SIB programs consisted of prescribed physical activity movements that equated to a certain MET (2 or 3 METs), for a specified duration (5 or 10 min), every 60 or 120 min. The SIB programs were aimed at interrupting prolonged sitting time with the performance of low intensity standing physical activities such as slow walking, laundry, washing dishes, taking out the trash, and brisk walking. The 1-wk long washout periods (i.e., resumption of sedentary lifestyle) occurred between each of the SIB programs. During the washout periods the subjects were instructed to carry on their regular lifestyle. At the end of each washout period, each subject satisfied the PACE sedentary questionnaire to verify that he or she had resumed the previous sedentary lifestyle (i.e., >6 hrs*[d.sup.-1]) performing sedentary behavior.

Meanwhile, during the SIB periods, the subjects were instructed to interrupt sedentary behavior solely when sedentary (sitting) for prolonged periods of time lasting greater than 1 or 2 hrs. Accelerometers were worn by each subject during the 4 SIB periods to ensure that they fulfilled the sitting interruption intervention requirements.

Measures were acquired at the same day and time (Friday morning prior to exercise) each week during the 8-wk intervention that included fasting plasma lipids, fasting blood glucose, and resting blood pressure to quantify the effect of each SIB program on cardiometabolic health. Resting metabolic rate and a submaximal aerobic exercise test were completed for each subject prior to the intervention.

The experimental design is depicted in Figure 1. Throughout the study, the subjects performed a consistent regular exercise training program, while prior to the study the subjects were primarily sedentary. Since all subjects were involved in a weekly exercise training regimen for the total 8 wks at Wellness Elevated, WSCU, the study design permitted insight into the independent effect of sedentary behavior alone and the various SIB programs on cardiometabolic health:

* Frequency of SIB

To quantify whether frequency of SIB had an effect on cardiometabolic health, subjects completed two SIB programs of different frequencies (every 60 min and every 120 min) while holding the intensity (2 METs) and time (5 min) of the SIB constant. The standing METs activities are as represented in Table 2.

* Intensity of SIB

To quantify whether intensity of SIB had an effect on cardiometabolic health, subjects completed two SIB programs of different intensities (2 METs and 3 METs) while holding the frequency (every 120 min) and time (5 min) of the SIB constant.

* Time of SIB

To quantify whether time of SIB had an effect on cardiometabolic health, subjects completed two SIB programs of different times (5 min and 10 min) while holding the intensity (2 METs) and frequency (every 120 min) of the SIB constant.

Protocols

Resting Metabolic Rate

Prior to each resting metabolic rate assessment, the equipment was calibrated according to manufacture standards, also pre-test instructions were explained to each subject. After being connected to the Parvo Metabolic System (TrueOne 2400, Parvo Medics, Sandy, UT), participants rested quietly for 5 min in a seated position. The last minute of breath-by-breath and heart rate data was averaged and considered to be resting metabolic rate (V[O.sub.2]) and resting HR.

Submaximal Exercise Test

A modified graded exercise test was performed on the Recumbent Bike (Lifecycle 95RS, Life Fitness, Rosemont, IL) as identified elsewhere (1). The incremental test was performed to ~80% predicted heart rate reserve (i.e., [((220 - age) - [HR.sub.rest]) (0.80) + [HR.sub.rest]]) or an RPE on the 1-10 intensity scale of ~7 (i.e., "hard"). At a consistent speed (identified prior to test) the cycle test consisted of a 2-min warm-up at ~15 W followed by 1 -min stages (cycling at ~6 to 7 mi*[hr.sup.-1]). Based on consultation information, the starting load of 30 to 40 W was applied and increased by ~10 to 20 W for each stage. Blood pressure, heart rate, and RPE were recorded each stage and interpretation of symptom limits were used to optimize safe increments. The criteria for attainment of V[O.sub.2]submax (submaximal oxygen consumption) was to meet one of the following: (a) heart rate reached 80% heart rate reserve; or (b) a ~7 was achieved on the RPE scale. Data obtained from the last stage of the graded exercise test was used to predict V[O.sub.2] max.

Resting Blood Pressure

Subjects were seated quietly for 5 min in a chair with a back support with feet on the floor and arm supported at heart level. The left arm brachial artery blood pressure was measured using a sphygmomanometer (American Diagnostic Corp., Hauppauge, NY) and Littmann classic III stethoscope (3M Company, St. Paul, MN) in duplicate and separated by 1 min. The mean of the two measurements were reported and analyzed.

Fasting Plasma Lipids and Blood Glucose

Every Friday at the same time of day, all fasting lipid and blood glucose analyses were collected and performed at room temperature weekly for the 8-wk research program. Subjects' hands were washed with soap and rinsed thoroughly with water, then cleaned with alcohol swabs and allowed to dry. Skin was punctured using a lancet and a fingerstick sample was collected into a heparin-coated 40 [micro]l capillary tube. Blood was allowed to flow freely from the fingerstick into the capillary tube without milking the finger. Samples were then dispensed immediately onto commercially available test cassettes for analysis in a Cholestech LDX System (Alere Inc., Waltham, MA) according to strict standardized operating procedures. The LDX Cholestech measures total cholesterol, HDL cholesterol, LDL cholesterol, triglycerides, and blood glucose in fingerstick blood. A daily optics check was performed on the LDX Cholestech analyzer used for the study.

Measurement of Sedentary Behavior and Physical Activity Levels

Self-reported sedentary behavior assessments were incorporated using the sedentary behavior questionnaire by PACE, which were reported by the subjects after each use of the accelerometer to compare the objective sedentary time data to the subjective sedentary time data. The sedentary behavior questionnaire assesses the sedentary time across five different domains covering adults' daily life activities including meals, transportation, occupation, leisure screen time and time spent sedentary in other activities.

The questionnaire enabled calculation of domain-specific and total sedentary time. A triaxial commercial accelerometer (ActiGraph, Fort Walton Beach, FL) was used to objectively assess sedentary behavior. Subjects were instructed to wear the accelerometer on their dominant wrist during each SIB program, data was collected for 24 hrs*[d.sup.-1] for 5 d except while bathing and/or swimming. Data were analyzed according to published guidelines. A researcher instructed the subjects on how and where to wear the monitor.

Statistical Analyses

The primary outcome measures included change in cardiometabolic risk factors (fasting plasma lipids, fasting blood glucose, and resting blood pressure). To compare sedentary washout weeks to SIB, all washout/control periods were averaged for each subject and compiled together to create a strong pool of individualistic sedentary cardiometabolic measures. Measures of centrality and spread are presented as mean [+ or -] SD. Repeated measures ANOVA was used to compare cardiometabolic risk factors across the four SIB programs. If a significant F ratio was obtained, Tukey's post hoc test was used to locate differences between means. Level of significance was set at P<0.05. The Statistical Package for the Social Sciences, Version 24.0 (IBM Corporation, Armonk, NY) was used for the statistical analysis.

RESULTS

Accelerometer Verification of 2 and 3 MET Activities

Accelerometer data was used to verify that the subjects performed the physical activity recommendations for each SIB as depicted in Figure 2. The accelerometers showed actual METs the subjects performed during prescribed 2 METs activities with intensities greater than 2 METs for SIB1 (Figure 2A), SIB2 (Figure 2B), and SIB4 (Figure 2D). The accelerometers also displayed actual METs the subjects performed during prescribed 3 METs activities with actual intensities at ~3 METs for SIB3 (Figure 2C). There was no difference between prescribed and actual METs intensities of SIB, P>0.05.

Subject Pre and Post Physiological Characteristics

Thirteen subjects (7 men; 6 women) completed pre/post intervention measurements of weight, V[O.sub.2] max, and resting metabolic rate. The changes in pre/post subject descriptive statistics are presented in Table 3. There was no difference between baseline and post intervention assessment in weight, V[O.sub.2] max, and resting metabolic rate, P>0.05.

Factors with No Effect from Sedentary Interruption Bouts

All subjects fulfilled weekly measures of resting blood pressure and fasting blood concentration measurements of LDL, HDL, total cholesterol, triglycerides, and glucose when comparing control to SIB. All measurements of participant cardiometabolic risk factors for each SIB condition are presented in Table 4.

Comparing control and all four SIB treatments, one-way repeated measures ANOVA identified no difference in plasma LDL and total cholesterol concentration, as well as systolic and diastolic blood pressure; P>0.05. There was no significant difference between control and SIB2/SIB3 in HDL, triglyceride, and blood glucose concentrations; P>0.05.

Effect of Sedentary Interruption Bouts on HDL Cholesterol

The main effects across the four SIB treatments are shown in Figure 4. One week of SIB1 (frequency = 60 min, intensity= 2 METs, time = duration of 5 min) caused an increase in plasma HDL concentration by 21.2% compared to control, P<0.05. One week of SIB4 (frequency = 120 min, intensity = 2 METs, time = duration of 10 min) caused an increase in plasma HDL concentration by 18.4% compared to control, P<0.05.

The main effect on plasma HDL concentration (see Figure 3A) was statistically significant in SIB1 and SIB4 compared to control [F=4.615; P<0.05]. Post hoc testing showed plasma HDL concentration levels were significantly higher in SIB1 and SIB4 trials compared to control (49.5 [+ or -] 9.2 for control vs. 60.0 [+ or -] 12.1, SIB1; 58.6 [+ or -] 6.8 mg*[dL.sup.-1], SIB4; P<0.05). The coefficient of determination (Partial [Eta.sup.2] = 0.70) indicates a large effect between the two variables, therefore SIB had a larger effect on HDL production than control in most instances.

Effect of Sedentary Interruption Bouts on Triglyceride Cholesterol

One week of SIB1 (frequency = 60 min, intensity = 2 METs, time = duration of 5 min) caused a decrease in plasma triglyceride concentration by 24.6% compared to control, P<0.05. One week of SIB4 (frequency = 120 min, intensity= 2 METs, time = duration of 10 min) caused a decrease in plasma triglyceride concentration by 23.0% compared to control, P<0.05.

The main effect on plasma triglyceride concentration (see Figure 3B) was statistically significant in SIB1 and SIB4 compared to control [F=6.236; P<0.05]. Post hoc testing showed plasma triglyceride concentration levels were significantly higher in SIB1 and SIB4 trials compared to control (160.1 [+ or -] 15.5, control vs. 120.7 [+ or -] 24.8, SIB1; 123.3 [+ or -] 16.0 mg*[dL.sup.-1], SIB4; P<0.05). The coefficient of determination (Partial [Eta.sup.2] = 0.81) indicates a large effect between the two variables, therefore SIB had a larger effect on triglyceride reduction than control in most instances.

Effect of Sedentary Interruption Bouts on Blood Glucose

One week of SIB1 (frequency= 60 min, intensity= 2 METs, time = duration of 5 min) caused a decrease in blood glucose concentration by 6.1% compared to control, P<0.05. One week of SIB4 (frequency = 120 min, intensity = 2 METs, time = duration of 10 min) caused a decrease in blood glucose concentration by 7.8% compared to control, P<0.05.

The main effect on blood glucose concentration (see Figure 3C) was statistically significant in SIB1 and SIB4 compared to control [F=4.318; P<0.05]. Post hoc testing showed blood glucose concentration levels were significantly lower in SIB1 and SIB4 trials compared to control (110.5 [+ or -] 7.5, control vs. 103.8 [+ or -] 6.7, SIB1; 101.9 [+ or -] 4.7 mg*[dL.sup.-1], SIB4; P<0.05). The coefficient of determination (Partial [Eta.sup.2] = 0.32) indicates a medium effect between the two variables, therefore SIB had a moderate effect on blood glucose reduction compared to control in most instances.

DISCUSSION

This preliminary study examined the differences in cardiometabolic risk factors with different frequency, intensity, and time (i.e., FIT) parameters. The novel findings with this study are SIB1 and SIB4 were successful at increasing plasma HDL particle concentration, as well as decreasing plasma triglyceride and blood glucose concentration. SIB1 identified more frequent interruptions (every 60 min) in sedentary behavior are more beneficial to cardiometabolic health than every 120 min. SIB4 demonstrated that if the frequency of SIB is greater than 60 min, then longer duration (10 min) activities are more beneficial than 5 min SIB. After only 1 wk of sedentary behavior change, there was an improvement in cardiometabolic risk factors that occurred after SIB1 and SIB4. These results are suggestive evidence that SIB interventions have the potential to improve cardiometabolic health with more frequent (60 or 120 min) and longer durations (5 or 10 min, respectively) of SIB. The results also show there is no ideal intensity for SIB; any standing activities (2 or 3 METs) were sufficient to elicit a response with the proper dose (i.e., frequency and time) of SIB.

For past decades, health and fitness scientists have promoted the current recommendations of physical activity, and the health benefits of moderate-to-vigorous physical activities most recently (6). Meanwhile, a worldwide sedentary epidemic subsist, epidemiological research has recognized excessive amounts of sedentary behavior to be linked to overweight/obesity, morbidity, and mortality (6). Individuals can meet the weekly physical activity requirements, but also sit for a large portion of the day, this active couch potato phenomenon largely contributes to deleterious health outcomes (10). Katzmarzyk (6) identifies, with respect to sedentary behavior and health, a need for a prescription of optimal daily movement patterns. The SIB activities during anticipated prolonged sitting, might promote a healthy cardiometabolic cascade to obtain/maintain optimal health, alongside a routine exercise program. The results from this study suggest more frequent and longer bouts of activity (in a dose response manner) to interrupt sedentary behavior will likely improve primary cardiometabolic risk factors such as HDL, triglyceride, and blood glucose concentration.

It is well known that too much sedentary behavior can cause deleterious effects to cardiometabolic health, which can be partially explained by the need for ATP (2). The findings of improved plasma lipids and blood glucose profile might be because of an increased demand for ATP. ATP is required to maintain muscle contraction, while the two main fuel sources to be used are blood glucose (carbohydrate) and plasma triglycerides (fat) (2). Regular SIB creates the need for ATP resynthesis, thereby increasing the demand for ATP (2). Lipoprotein lipase is the rate limiting enzyme that is responsible for breaking down triglycerides into free fatty acids, uptake of free fatty acids into skeletal muscle and adipose tissue, and HDL cholesterol production (2,13,14). Therefore, high levels of lipoprotein lipase can lead to decreased circulating triglycerides and increased levels of HDL cholesterol (14).

In terms of sedentary behavior and carbohydrate metabolism, the GLUT-4 transporter protein activity decreases, therefore downregulating the uptake of blood glucose into the cell (2). Reduced muscle contractile activity lowers the skeletal muscle demand for ATP, which in return minimizes the need to utilize blood glucose and plasma triglycerides (2). Collection of intramuscular fatty acids has been known to interfere with insulin sensitivity. Hence, fatty acids restrict insulin stimulation with GLUT-4 transporter activity (12). Increased levels of glucose, triglycerides, and free fatty acids in the circulatory system can lead to a biochemical cascade of inflammation, endothelial dysfunction, hypercoagulability, and increased sympathetic activity (13). If sedentary behavior is prolonged for a significant amount of time, these manifestations can be detrimental to cardiometabolic health and increase the risk or development of CVD or T2DM (2,13). Past research has suggested that exercise stimulated alterations in fatty acid oxidation plays a critical role in insulin sensitivity regulation, and high mitochondrial oxidative capacity might be the key determinant in the improvement of insulin sensitivity (5). Therefore, the increase in mitochondrial oxidative stress, stimulated through SIB, may cause similar advances in insulin sensitivity.

Exercise physiologists should use this preliminary evidence to assist their clients with understanding the detrimental effects of sedentary behavior on cardiometabolic health, as well as the related cardiometabolic health benefits of sedentary interruption behaviors in conjunction with a cardiovascular based, exercise training program, as found in this study. The rapid significant change in cardiometabolic health, in a short period of one week, shows how important it is to reduce sedentary behavior on regular basis. Also, all the notable benefits from 1 wk of SIB were quickly reversed after one week of normal sedentary behavior habits. These findings provide important preliminary evidence that suggests active, yet highly sedentary individuals (sedentary for >6 hrs*[d.sup.-1]), are expected to improve their plasma lipid and blood glucose profile with minimal SIB activity (i.e., standing) at a frequency of 60 or 120 min, lasting 5 or 10 min respectively (SIB recommendations presented in Table 5).

Limitations of this Study

Future research should explore the effect of reducing sedentary behavior with a frequency of every 30 min, with the intention to improve cardiometabolic health in individuals who are less sedentary (sitting <6 hrs*[d.sup.-1]). This study is not without limitations. One limitation of this study was convenience sampling and therefore these findings may not be generalizable to a wider population. Another limitation was that other lifestyle factors could have influenced the results, such as nutrition, medication, and sleep variability. Lastly, the 2 and 3 METs intensities for SIB activities were identified from past evidence-based research, meanwhile the activities could have been individualized for a greater quality in specificity per participant; this may explain the differences in prescribed and actual METs (see Figure 2A, B, & D).

CONCLUSIONS

In conclusion, these findings indicate that more frequent bouts of SIB (every 60 min) are beneficial to cardiometabolic health. If the SIB is less frequent (>60 min), a longer duration of interruption bout activities (i.e., 10 min) is more likely to be favorable to cardiometabolic health. Findings from this study provide exercise physiologists with a preliminary guide for their clients in effectively reducing sedentary behavior and its associated deleterious cardiometabolic effects.

ACKNOWLEDGMENTS

This investigation was supported financially by the American Council on Exercise (ACE). The American Council on Exercise (ACE) was not involved in development of the study design, data collection and analysis, or preparation of the manuscript. There are no other potential conflicts of interest related to this article.

Address for correspondence: Lance C. Dalleck, PhD, High Altitude Exercise Physiology Program, Western State Colorado University, Gunnison, CO, USA, 81231, Email: ldalleck@western.edu

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Shawn M. Keeling, Christina A. Buchanan, Lance C. Dalleck

High Altitude Exercise Physiology Program, Western State Colorado University, Gunnison, CO USA
Table 1. Baseline Participant Characteristics (N = 13).

Demographics                                 Mean [+ or -] SD or %

Sex (men, %)                                  53.85 %
Age (yrs)                                     74.2 [+ or -] 7.8
Height (cm)                                  167.4 [+ or -] 8.2
Weight (kg)                                   91.6 [+ or -] 25.2
V[O.sub.2] max                                23.0 [+ or -] 4.7
(mL*[kg.sup.-1]*[min.sup.-1])
BMI (kg*[m.sup.-2])                           32.6 [+ or -] 8.2
Overweight & Obese                            84.62 %
(BMI [greater than or equal to] 25
kg*[m.sup.-2], %)
Sedentary Time (hr*[d.sup.-1])                 9.3 [+ or -] 3.8
Prevalence of Cardiometabolic
Risk Factor
 Prehypertension/Hypertension                 46.15 %
 Hyperglycemia                                76.92 %
 Dyslipidemia                                 84.62 %

The data are presented as mean [+ or -] SD or as percentage of
occurrences within the group.

Table 2. Standing 2 and 3 MET SIB Activities.

~2 MET Activities            ~3 MET Activities

Standing                     Walking 2.5 mi*[hr.sup.-1],
                             slowly walking and carrying
                             light objects under 25 lbs
Walking less than 2.0        Walking 3.0 mi*[hr.sup.-1],
mi*[hr.sup.-1], level        moderate speed not
ground, very slow            carrying anything
Standing- cooking or         Walking the dog
food preparation
Standing-laundry,            Standing- caring for
folding laundry              children (dressing, bathing,
                             grooming, feeding, occasional
                             lifting)
Standing- change a           Standing- carrying a small
light bulb                   child, playing with
                             children
Standing- hand sewing        Standing- playing with
                             animals (walking and
                             light running)
Standing- singing            Standing- stretching, yoga
Standing- washing dishes     Standing- arts and crafts
                             moderate effort
Standing- desk work,         Standing- baking preparation
computer work, typing
Standing- talking (in        Standing- sweeping,
person or phone)             vacuuming, or mopping
                             the floor
Standing- filing,            Standing- dusting
assembling light work         furniture
Standing- eating             Standing- cleaning
                             the sink or toilet
Standing- reading            Standing- taking
                             out the trash
Standing- getting dressed    Standing- washing
                             windows, clean garage,
                             clean car
Standing- beauty/hygiene     Standing- loading/unloading
maintenance                  the car
(hair, teeth, skin, nails)
Standing- shower/bathing     Standing- slow dancing
                             Standing- change bed linens
                             Standing- putting away
                             household items
                             Standing- painting, drawing
                             Standing- playing the guitar

METs = metabolic equivalence of task; SIB = sedentary interruption
bouts. All subjects were instructed to perform as many 2 to 3 METs
activities as they desired during their weekly specific SIB.

Table 3. Pre/Post Participant Descriptive Statistics.

Variable                        Pre                  Post
                                (N=13)               (N=13)

Age (yrs)                        74.2 [+ or -] 7.8   -
Height (cm)                     167.4 [+ or -] 8.2   -
Weight (kg)                      91.6 [+ or -] 25.2  91.6 [+ or -] 21.4
V[O.sub.2] max                   23.0 [+ or -] 4.7   22.2 [+ or -] 4.2
(mL*[kg.sup.-1]*[min.sup.-1])
RMR                               2.4 [+ or -] 0.4    2.4 [+ or -] 0.4
(mL*[kg.sup.-1]*[min.sup.-1])

Data are presented as mean [+ or -] SD. V[O.sub.2] max = Maximal oxygen
consumption. RMR = Resting metabolic rate.

Table 4. Subject Cardiometabolic Risk Factors Across Treatment Groups.

Variable               Control               [DELTA] in Control to
                                             SIB1
                                             (95% CI)

LDL (mg*[dL.sup.-1])   113.4 [+ or -] 50.2    -8.0 (-26.5 to 10.5)
(N=8)
HDL (mg*[dL.sup.-1])    49.5 [+ or -] 9.2     10.5 (2.2 to 18.7) (*)
(N=12)
TC (mg*[dL.sup.-1])    194.3 [+ or -] 54.5    10.6 (-9.0 to 30.2)
(N=9)
TRI (mg*[dL.sup.-1])   160.1 [+ or -] 15.5   -39.4 (-71.2 to -7.6) (*)
(N=10)
BG (mg*[dL.sup.-1])    110.5 [+ or -] 7.5     -6.8 (-13.5 to -0.1) (*)
(N=12)
SBP (mmHg)             126.4 [+ or -] 13.4    -3.0 (-12.4 to 6.4)
(N=13)
DBP (mmHg)              74.3 [+ or -] 13.1     0.1 (-6.5 to 6.7)
(N=13)

Variable                [DELTA] in Control to   [DELTA] in Control to
                        SIB2                    SIB3
                        (95% CI)                (95% CI)

LDL (mg*[dL.sup.-1])    -2.6 (-28.1 to 22.9)     -2.4 (-29.5 to 24.7)
(N=8)
HDL (mg*[dL.sup.-1])     3.1 (-3.4 to 9.6)        1.9 (-4.1 to 7.9)
(N=12)
TC (mg*[dL.sup.-1])      0.7 (-36.0 to 37.5)      7.6 (-12.5 to 27.7)
(N=9)
TRI (mg*[dL.sup.-1])    -5.1 (-33.4 to 23.2)    -18.6 (-46.6 to 9.4)
(N=10)
BG (mg*[dL.sup.-1])     -4.7 (-12.6 to 3.2)      -2.6 (-9.8 to 4.6)
(N=12)
SBP (mmHg)               0.8 (-9.9 to 11.5)       1.2 (-16.7 to 19.0)
(N=13)
DBP (mmHg)               0.3 (-3.4 to 4.0)        0.6 (-5.7 to 4.5)
(N=13)

Variable               [DELTA] in Control to
                       SIB4
                       (95% CI)

LDL (mg*[dL.sup.-1])    -7.1 (-40.1 to 25.9)
(N=8)
HDL (mg*[dL.sup.-1])     9.1 (0.3 to 17.8) (*)
(N=12)
TC (mg*[dL.sup.-1])      7.7 (-15.5 to 30.9)
(N=9)
TRI (mg*[dL.sup.-1])   -36.8 (-62.8 to -10.8) (*)
(N=10)
BG (mg*[dL.sup.-1])     -8.6 (-17.0 to -0.3) (*)
(N=12)
SBP (mmHg)              -1.6 (-9.8 to 6.6)
(N=13)
DBP (mmHg)               2.0 (-4.5 to 8.4)
(N=13)

Data are presented as control mean [+ or -] SD, and mean change (95%
CI) across all four treatment groups.
SIB1 = Sedentary interruption bout intervention week 1. LDL =
Low-density lipoprotein cholesterol plasma concentration. HDL=
High-density lipoprotein cholesterol plasma concentration. TC = Total
cholesterol plasma concentration. TRI = Triglycerides plasma
concentration. BG = Blood glucose concentration. SBP = Systolic blood
pressure. DBP = Diastolic blood pressure. (*)(P<0.05) different from
control.

Table 5. FIT Recommendations to Reduce Sedentary Behavior.

Component   Component Recommendation(s)

Frequency   SIB every 60 min of sitting
Intensity   Standing 2 to 3 METs activities
Time        Duration of 5 min for every 60 min
            of sitting, if seated for 2 hrs
            perform standing activities for 10
                               min. Duration of SIB should occur
            in accumulation of 5 min per
            each 60 min of sitting.

FIT = Frequency, Intensity, and Time; SIB = Sedentary Interruption
Bout; METs = Metabolic Equivalence of Task
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Title Annotation:frequency, intensity and time
Author:Keeling, Shawn M.; Buchanan, Christina A.; Dalleck, Lance C.
Publication:Journal of Exercise Physiology Online
Article Type:Report
Date:Apr 1, 2018
Words:5451
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