Pedro B. Júdice

Validity of GT3X and Actiheart to estimate sedentary time and breaks using ActivPAL as the reference in free-living conditions

Sedentary time, specifically sitting/reclining, is a risk factor for many non-communicable diseases and premature mortality. Inclinometers have been used as a valid measurement of sedentary time and its patterns; however, there is a lack of information regarding the validity of alternative accelerometry and heart rate methods. The validity of GT3X and Actiheart in estimating changes in daily sedentary time and breaks, during free-living settings, using ActivPAL as the reference was examined. A crossover randomized control trial of an intervention that aimed to reduce ∼3 h/day of sitting time included 10 overweight/obese adults (37-65 years). Participants had a total of 74 valid days for the three devices (29 controls; 45 interventions). For ActivPAL, sedentary time was measured directly based upon posture (sitting/reclining); Actiheart, the presumed MET cutpoint for sedentary time (<1.5 METs) based on accelerometry+heart rate; GT3X, the traditional <100countsmin(-1). A break in sedentary time was defined as when the participants were above the aforementioned cutoffs. GT3X overestimated and Actiheart underestimated sedentary time (bias=135min; bias=-156min, respectively) and both methods overestimated breaks in sedentary time (bias=78; bias=235 breaks, respectively). The GT3X method was in better agreement with the ActivPAL sedentary time (r2=0.70; concordance correlation coefficient (CCC)=0.56) than the Actiheart (r2=0.24; CCC=0.31). The present results highlight the magnitude of potential errors in estimating sedentary time and breaks from common alternative methods other than ActivPAL. Because misclassification errors from the commonly used surrogates are potentially large, this raises concern that alternative methods used in many epidemiological observations may have underestimated the true effects caused by too much sitting (ClinicalTrials.govID:NCT02007681).

Total body water and its compartments are not affected by ingesting a moderate dose of caffeine in healthy young adult males

Acute and chronic caffeine intakes have no impact on hydration status (R.J. Maughan and J. Griffin, J. Hum. Nutr. Diet. 16(6): 411-420, 2003), although no research has been conducted to analyze the effects using dilution techniques on total-body water (TBW) and its compartments. Therefore, the aim of this study was to investigate the effects of a moderate dose of caffeine on TBW, extracellular water (ECW), and intracellular water (ICW) during a 4-day period in active males. Thirty men, nonsmokers and low caffeine users (<100 mg·day(-1)), aged 20-39 years, participated in this double-blind, randomized, crossover trial (ClinicalTrials.gov: No. NCT01477294). The study included 2 conditions (5 mg·kg(-1)·day(-1) of caffeine and placebo (malt-dextrin)) of 4 days each, with a 3-day washout period. TBW and ECW were assessed by deuterium oxide and sodium bromide dilution, respectively, whereas ICW was calculated as TBW minus ECW. Body composition was assessed by dual-energy X-ray absorptiometry. Physical activity (PA) was assessed by accelerometry and water intake was assessed by dietary records. Repeated-measures analysis of variance (ANOVA) was used to test main effects. No changes in TBW, ECW, or ICW and no interaction between the randomly assigned order of treatment and time were observed (p > 0.05). TBW, ECW, and ICW were unrelated to fat-free mass, water ingestion, and PA (p > 0.05). These findings indicate that a moderate caffeine dose, equivalent to approximately 5 espresso cups of coffee or 7 servings of tea, does not alter TBW and fluid distribution in healthy men, regardless of body composition, PA, or daily water ingestion.

Caffeine Intake, Short Bouts of Physical Activity, and Energy Expenditure: A Double-Blind Randomized Crossover Trial

PA energy expenditure (PAEE) is the most variable component of Total Energy Expenditure (TEE) and largely due to the balance of sedentary time (SedT) and low intensity physical activity (LIPA). There has been an emergence for seeking an understanding of factors which determine variations in SedT, LIPA, and PAEE. Sedentary behavior and physical activity are relatively resistant to change by experimental dietary treatments and significant body weight changes. Although caffeine (Caf) is by far the most heavily used nutritional agent ingested to promote a sense of vigor/alertness, it is still unknown if Caf is effective in increasing PAEE and physical activity. The aim of the study was to test the hypothesis that 2 daily doses of Caf (as a capsule to blind the treatment and divided equally during breakfast and lunch) increase PAEE and TEE, and it would do so through increasing the frequent and brief bouts of physical activity (~1-5 min long) through the day as measured by accelerometry. In 21 low Caf users (<100 mg day-1), we used a double-blind crossover trial (ClinicalTrials.govID;NCT01477294) with two conditions (4-day each with a 3-day washout period) randomly ordered as 5 mg kg-1 day-1 of Caf and maltodextrin as placebo (Plc). Resting energy expenditure (REE) by indirect calorimetry, total energy expenditure (TEE) from doubly labeled water, PAEE calculated as TEE-(REE+0.1TEE), and accelerometry measurements of both LIPA and MVPA were not different between conditions. However, regardless of caffeine or placebo, there were several significant relationships between brief bouts of LIPA and MVPA with PAEE. In conclusion, this double-blind study found that low and moderate-vigorous activity as well as the total volume of PAEE in free-living conditions is resistant to dietary caffeine intake that was equivalent to 5 cups of espresso or 7 cups of tea. Trial Registration ClinicalTrials.gov NCT01477294

Accuracy of a combined heart rate and motion sensor for assessing energy expenditure in free-living adults during a double-blind crossover caffeine trial using doubly labeled water as the reference method.

Background/Objectives:A combined heart rate (HR) and motion sensor (Actiheart) has been proposed as an accurate method for assessing total energy expenditure (TEE) and physical activity energy expenditure (PAEE). However, the extent to which factors such as caffeine may affect the accuracy by which the estimated HR-related PAEE contribution will affect TEE and PAEE estimates is unknown. Therefore, we examined the validity of Actiheart in estimating TEE and PAEE in free-living adults under a caffeine trial compared with doubly labeled water (DLW) as reference criterion.Subjects/Methods:Using a double-blind crossover trial (Clinicaltrials.gov ID: #NCT01477294) with two conditions (4-day each with a 3-day-washout period), randomly ordered as caffeine (5 mg/kg per day) and placebo (malt-dextrine) intake, TEE was measured by DLW in 17 physically active men (20–38 years) who were non-caffeine users. In each condition, resting energy expenditure (REE) was assessed by indirect calorimetry and PAEE was calculated as (TEE−(REE+0.1 TEE)). Simultaneously, PAEE and TEE were estimated by Actiheart using an individual calibration (ACC+HRstep).Results:Under caffeine, ACC+HRstep explained 76 and 64% of TEE and PAEE from DLW, respectively; corresponding results for the placebo condition were 82 and 66%. No mean bias was found between ACC+HRstep and DLW for TEE (caffeine:-468 kJ per day; placebo:-407 kJ per day), although PAEE was slightly underestimated (caffeine:-856 kJ per day; placebo:-1147 kJ per day). Similar limits of agreement were observed in both conditions ranging from −2066 to 3002 and from −3488 to 1776 kJ per day for TEE and PAEE, respectively.Conclusions:Regardless of caffeine intake, the combined HR and motion sensor is valid for estimating free-living energy expenditure in a group of healthy men but is less accurate for an individual assessment.

Sedentary bout durations are associated with abdominal obesity in older adults

ObjectivesIn older adults, sedentary behavior has been positively associated with obesity and impaired metabolic health, additional to low moderate-to-vigorous physical activity (MVPA). Further to the total time spent in sedentary behavior, the manner in which it is accumulated — number of continuous sedentary bouts of different extends — may also be relevant. The association for objectively measured uninterrupted sedentary bouts and respective patterns with abdominal obesity in older adults was examined.DesignCross-sectional.SettingCommunity-based older people were recruited in each region of Portugal. Data collection was performed between September, 2007 and May, 2009.Participants351 older adults (230 women) mean age of 75-years.MeasurementsSedentary time was measured by an accelerometer (counts/minute <100), worn during waking hours for four consecutive days. Continuous sedentary bouts of 560 length were treated (counts/minute <100). Abdominal obesity was defined by waist circumference (men>102 cm; women>88 cm).ResultsThere were positive and escalating linear associations for the continuum of sedentary bouts’ lengths with waist circumference. Logistic regression showed that for each additional sedentary bout of 10< min<20 the odds of being abdominally obese increased by 6.8% (OR=1.07, 95% CI: 1.02 — 1.13) up to 48% (OR=1.48, 95% CI: 1.07 — 2.03) for each 1-hour sedentary bout increment, after controlling for age, gender, total sedentary time, MVPA time, total wear time, movement counts within the sedentary bouts, socio-demographic and other behavioral attributes, and medical history.ConclusionThese findings indicate positive graded associations for continuous sedentary bouts with abdominal obesity. Public health recommendations regarding breaking up sedentary time more often, potentially avoiding very prolonged bouts of sedentary time, are expected to be relevant for older adults.

Sedentary behaviour and adiposity in elite athletes

Abstract Overweight and obesity are defined as abnormal or excessive fat accumulation that presents a health risk. Even in athletes an increased adiposity affects health and performance. Sedentary behaviour has been associated with higher levels of adiposity, independent of moderate-to-vigorous physical activity. However, it is unclear whether this independent relationship still exists in highly trained athletes. The aim of this study was to examine the association of sedentary behaviour with body fatness in elite athletes. Cross-sectional data from 82 male athletes (mean age 22 years) were used. Total and regional body composition was measured by dual energy X-ray absorptiometry. Self-reported time spent in sedentary behaviour and weekly training time was assessed in all participants at one time point and multiple regression analyses were used. Sedentary behaviour predicted total fat mass (β = 0.77; 95% CI: 0.36–1.19, P < 0.001) and trunk fat mass (β = 0.25; 95% CI: 0.07–0.43, P = 0.007), independent of age, weekly training time, and residual mass (calculated as weight-dependent variable) but not abdominal fat. Also, no associations of sedentary behaviour with fat-free mass, appendicular lean soft tissue, and body mass index were found. These findings indicate that athletes with higher amounts of sedentary behaviour presented higher levels of total and trunk fatness, regardless of age, weekly training time, and residual mass. Therefore, even high moderate-to-vigorous physical activity levels do not mitigate the associations between sedentary behaviour and body fatness in highly trained athletes.

Suitability of Bioelectrical Based Methods to Assess Water Compartments in Recreational and Elite Athletes

Objective: It is important for highly active individuals to easily and accurately assess their hydration level. Bioelectrical impedance (BIA) can potentially meet these needs but its validity in active individuals is not well established. We aim to validate total body water (TBW), extracellular water (ECW), and intracellular water (ICW) estimates obtained from 50 kHz BIA, bioelectrical impedance spectroscopy (BIS), and BIA-based models against dilution techniques in 2 populations: active adults and elite athletes. Methods: Active males (N = 28, 20–39 years) involved in recreational sports and elite athletes (females: N = 57, 16–35 years; males: N = 127, 16–38 years) participated in this study. TBW and ECW were assessed with deuterium and bromide dilution, respectively. ICW was assessed as their difference. Body water compartments were also assessed by BIA (BIA-101), BIS (model 4200), and BIA-based equations. Results: Small but significant differences were observed between alternative methods and the criterion in all subsamples. In female athletes, r2 > 0.69, r2 > 0.57, and r2 > 0.65 were observed between methods in the TBW, ECW, and ICW estimates. In males, r2 > 0.75, r2 > 0.65, and r2 > 0.68 were found between alternative and reference methods in the TBW, ECW, and ICW estimates, respectively, whereas for male recreational exercisers, r2 > 0.58, r2 > 0.73, and r2 > 0.75 were observed. Pure errors ranged between 0.19 to 3.32 kg for TBW, 0.64 to 1.63 for ECW, and 1.98 to 2.64 in ICW. The highest limits of agreement (LoA) were observed in Van Loan and Mayclin equation and the BIA method, respectively, for TBW and ECW assessment and the lowest LoA were observed in BIS for both TBW and ECW estimates. Conclusions: The higher accuracy of BIS in predicting individual TBW, ECW, and ICW highlights its utility in water assessment of recreational and elite athletes.

Sedentary Patterns, Physical Activity, and Cardiorespiratory Fitness in Association to Glycemic Control in Type 2 Diabetes Patients

Background: Sedentary behavior has been considered an independent risk factor for type-2 diabetes (T2D), with a negative impact on several physiological outcomes, whereas breaks in sedentary time (BST) have been proposed as a viable solution to mitigate some of these effects. However, little is known about the independent associations of sedentary pursuits, physical activity, and cardiorespiratory fitness (CRF) variables with glycemic control. We investigated the independent associations of total sedentary time, BST, moderate-to-vigorous physical activity (MVPA), and CRF with glycemic outcomes in patients with T2D. Methods: Total sedentary time, BST, and MVPA were assessed in 66 participants (29 women) with T2D, using accelerometry. Glucose and insulin were measured during a mixed meal tolerance test, with the respective calculations of HOMA-IR and Matsuda index. Glycated hemoglobin (HbA1c) was also analyzed. CRF was measured in a maximal treadmill test with breath-by-breath gases analysis. Multiple regressions were used for data analysis. Results: Regardless of CRF, total sedentary time was positively associated with HbA1c (β = 0.25, p = 0.044). Adjusting for MVPA, total sedentary time was related to fasting glucose (β = 0.32, p = 0.037). No associations between total sedentary time and the remaining glycemic outcomes, after adjusting for MVPA. BST had favorable associations with HOMA-IR (β = −0.28, p = 0.047) and fasting glucose (β = −0.25, p = 0.046), when adjusted for MVPA, and with HOMA-IR (β = −0.25, p = 0.036), Matsuda index (β = 0.26, p = 0.036), and fasting glucose (β = −0.22, p = 0.038), following adjustment for CRF. When adjusting for total sedentary time, only CRF yielded favorable associations with HOMA-IR (β = −0.29, p = 0.039), fasting glucose (β = −0.32, p = 0.012), and glucose at 120-min (β = −0.26, p = 0.035), and no associations were found for MVPA with none of the metabolic outcomes. Conclusion: The results from this study suggest that sedentary time and patterns are relevant for the glycemic control in patients with T2D. Still, MVPA and CRF counteracted most of the associations for total sedentary time but not for the BST. MVPA was not associated with metabolic outcomes, and CRF lost some of the associations with glycemic indicators when adjusted for total sedentary time. Future interventions aiming to control/improve T2D must consider reducing and breaking up sedentary time as a viable strategy to improve glycemic control.

Patterns of accelerometer-derived sedentary time across the lifespan

ABSTRACT We aimed to describe ST and its patterns on a national level. A hip-worn accelerometer (ActiGraph GT1M) was used to collect data during waking hours from 4575 Portuguese’ participants from 2007–2009 (2683 females) aged 10–102 years old. Data was presented by sex, in 5-years age intervals, and by adolescents (n=2833), adults (n=1122), and older adults (n=620). Lambda-mu-sigma (LMS) smoothed percentile curves were estimated. Girls, women, and older women spent 61, 57, and 64% of wear time in ST, respectively. In males, ST represented 57, 60, and 62% of wear time respectively for boys, men, and older men. Comparing to other age groups, older adults spent a larger amount of ST in bouts ≥30-min (women: 33%, men: 39% of total ST). The number of breaks/ST hour were: 10.6 in girls, 11.7 in women, and 9.6 in older women. In males, the number of breaks/ST hour were: 11.2, 10.5, and 8.5 for boys, men, and older men. In conclusion, ST was not consistently higher at older ages. Instead, we found that the potential critical moments in which ST may be higher are during adolescence and in the transition from adulthood into older adulthood, which represents critical periods for interventions.

Effectiveness of high intensity interval training combined with resistance training vs. continuous moderate intensity training combined with resistance training in patients with type 2 diabetes - 1 year randomized controlled trial

To evaluate the impact of one‐year high intensity interval training (HIIT) combined with resistance training (RT) vs continuous moderate intensity training (MCT) combined with RT on glycaemic control, body composition and cardiorespiratory fitness (CRF) in patients with type 2 diabetes.