Objectively Measured Sitting and Standing in Workers: Cross-Sectional Relationship with Autonomic Cardiac Modulation

Joint association of sedentary time and physical activity with abnormal heart rate recovery in young and middle-aged adults

BACKGROUND

Abnormal heart rate recovery (HRR), representing cardiac autonomic dysfunction, is an important predictor of cardiovascular disease. Prolonged sedentary time (ST) is associated with a slower HRR. However, it is not clear how much moderate-to-vigorous physical activity (MVPA) is required to mitigate the adverse effects of sedentary behavior on HRR in young and middle-aged adults. This study aimed to examine the joint association of ST and MVPA with abnormal HRR in this population.

METHODS

A cross-sectional analysis was conducted on 1253 participants (aged 20-50 years, 67.8% male) from an observational study assessing cardiopulmonary fitness in Fujian Province, China. HRR measured via cardiopulmonary exercise tests on a treadmill was calculated as the difference between heart rate at peak exercise and 2 min after exercise. When the HRR was ≤ 42 beats·minute-1 within this time, it was considered abnormal. ST and MVPA were assessed by the IPAQ-LF. Individuals were classified as having a low sedentary time (LST [< 6 h·day-1]) or high sedentary time (HST [≥ 6 h·day-1]) and according to their MVPA level (low MVPA [0-149 min·week-1], medium MVPA [150-299 min·week-1], high MVPA [≥ 300 min·week-1]). Finally, six ST-MVPA groups were derived. Associations between ST-MVPA groups with abnormal HRR incidence were examined using logistic regression models.

RESULTS

53.1% of the young and middle-aged adults had less than 300 min of MVPA per week. In model 2, adjusted for possible confounders (e.g. age, sex, current smoking status, current alcohol consumption, sleep status, body mass index), HST was associated with higher odds of an abnormal HRR compared to LST (odds ratio (OR) = 1.473, 95% confidence interval (CI) = 1.172-1.852). Compared with the reference group (HST and low MVPA), the HST and high MVPA groups have a lower chance of abnormal HRR (OR, 95% CI = 0.553, 0.385-0.795). Compared with individuals with HST and low MVPA, regardless of whether MVPA is low, medium, or high, the odds of abnormal HRR in individuals with LST is significantly reduced (OR, 95% CI = 0.515, 0.308-0.857 for LST and low MVPA; OR, 95% CI = 0.558, 0.345-0.902 for LST and medium MVPA; OR, 95% CI = 0.476, 0.326-0.668 for LST and high MVPA).

CONCLUSION

Higher amounts of MVPA appears to mitigate the increased odds of an abnormal HRR associated with HST for healthy young and middle-aged adults.

Acute Effects of Fatigue on Cardiac Autonomic Nervous Activity

The onset of fatigue disrupts the functioning of the autonomic nervous system (ANS), potentially elevating the risk of life-threatening incidents and impairing daily performance. Previous studies mainly focused on physical fatigue (PF) and mental fatigue (MF) effects on the ANS, with limited knowledge concerning the influence of physical-mental fatigue (PMF) on ANS functionality. This study aimed to assess the immediate impact of PMF on ANS function and to compare its effects with those of PF and MF on ANS function. Thirty-six physically active college students (17 females) without burnout performed 60-min cycling exercises, AX-Continuous Performance Task (AX-CPT), and cycling combined with AX-CPT to induce PF, MF, and PMF respectively. Subjective fatigue levels were measured using the Rating of Perceived Exertion scale and the Visual Analog Scale-Fatigue. Heart rate variability was measured before and after each protocol to assess cardiac autonomic function. The proposed tasks successfully induced PF, MF, and PMF, demonstrated by significant changes in subjective fatigue levels. Compared with baseline, PMF decreased the root mean square of successive differences (RMSSD) between normal heartbeats (P < 0.001, d = 0.50), the standard deviation of normal-to-normal RR intervals (SDNN) (P < 0.01, d = 0.33), and the normalized high-frequency (nHF) power (P < 0.001, d = 0.32) while increased the normalized low-frequency (nLF) power (P < 0.001, d = 0.35) and the nLF/nHF ratio (P < 0.001, d = 0.40). Compared with MF, PMF significantly decreased RMSSD (P < 0.001, η2 = 0.431), SDNN (P < 0.001, η2 = 0.327), nLF (P < 0.01, η2 = 0.201), and nHF (P < 0.001, η2 = 0.377) but not the nLF/nHF ratio. There were no significant differences in ΔHRV (i.e., ΔRMSSD, ΔSDNN, ΔnLF/nHF, ΔnLF, and ΔnHF), heart rate, and training impulse between PF- and PMF-inducing protocols. Cognitive performance (i.e., accuracy) in AX-CPT during the PMF-inducing protocol was significantly lower than that during the MF-inducing protocol (P < 0.001, η2 = 0.101). PF and PMF increased sympathetic activity and decreased parasympathetic activity, while MF enhanced parasympathetic activity.

Patterns of sedentary behavior in adults: A cross-sectional study

Introduction

Sedentary behavior (SB) has been associated with adverse health outcomes, however, it is not completely clear whether total time in SB during the day or prolonged uninterrupted SB are interrelated. The aim of the current study was to describe the different patterns of SB of adults, their relationships, and associated factors.

Methods

The sample included 184 adults aged ranging from 18 to 59 years old. SB was objectively measured by an accelerometer and the following SB pattern parameters were obtained: total time in sedentary bouts, mean time of sedentary bouts, and total time in sedentary breaks. Demographic data (age and sex), anthropometry [weight, height, body mass index (BMI)], blood pressure (BP), medical history (self-reported comorbid conditions), and cardiac autonomic modulation, were assessed to identify factors associated with SB. Multiple linear regressions were used to analyze the relationship between SB parameters and the associated factors.

Results

The parameters of SB indicated 2.4 (0.9) h/day for total time in sedentary bouts, 36.4 (7.9) min for the mean time of sedentary bouts, and 9.1 (1.9) h/day for the total time in sedentary breaks. Multiple adjusted regression indicated that age was the only factor associated with SB patterns (p &lt; 0.05) after adjustment for confounding variables (sex, age, BMI, dyslipidemia, systolic and diastolic BP). Young adults (18–39 years old) spent more time in sedentary bouts and less time in uninterrupted sedentary bouts compared to middle-aged adults (40–59 years old) (2.58 (0.88) h/day vs. 2.13 (0.90) h/day, respectively; p = 0.001 and 34.5 (5.8) min 18–39 years old vs. 38.8 (9.6) min 40–59 years old; p  ≤ 0.001; respectively). The total time in sedentary breaks was similar between age groups (p = 0.465). The total time in sedentary bouts was significantly correlated with the mean time of sedentary bouts (r = −0.58; p ≤ 0.001), and with the total time in sedentary breaks (r = −0.20; p = 0.006). The mean time of sedentary bouts was significantly related to the total time in sedentary breaks (r -= 0.19; p = 0.007).

Discussion and Conclusion

In conclusion, age seems to be a relevant factor associated with sedentary behavior with young adults spending more time in SB and accumulating this behavior in a higher amount of sedentary bouts compared to middle-aged adults.

Factors affecting resting heart rate in free-living healthy humans

Resting heart rate (RHR) is a potential cardiac disease prevention target because it is strongly associated with cardiac morbidity and mortality, yet community-based monitoring of RHR remains in its infancy. Recently, smartwatches have become available enabling measurement with non-intrusive devices of relationships between RHR and other factors outside the laboratory. We carried out cross-sectional observational retrospective analysis of anonymised smartwatch data obtained by participants in their everyday lives between 2016 and 2021 in a single centre community-based study, using convenience sampling. Between participants, overall RHR means strongly or moderately inversely correlated with means of stand hour (SH), calculated VO₂ max, walking and running distance (WRD), steps and flights climbed (FC). Within participants, in quarterly averages, RHR inversely correlated moderately with frequency of standing (stand hours, SH). RHR also inversely correlated moderately with heart rate variability (HRV), consistent with the known impact of increasing parasympathetic dominance on RHR. These within participant correlations suggest that RHR might be modifiable by changes in SH and HRV within individuals. Indeed, analysing paired daily data, relationships between these three categories were dose dependent. 15 SH versus 5 SH associated with a reduction of 10 beats per minute in mean RHR and increase in mean HRV of 14 ms, respectively. We conclude that within individuals, RHR inversely correlates with frequency of standing and HRV, with paired daily measurements indicating effects are mediated that day. RHR also inversely correlates with fitness and activity measures between participants. Our findings provide initial community-based observational evidence supporting further prospective interventional investigation of frequency of standing or HRV modifiers, alongside more familiar interventions, for cardiac disease prevention.

Association of Physical Activity and Sedentary Time with Cardio-Autonomic Regulation in Women

Background: Low moderate-to-vigorous-intensity physical activity (MVPA) and high sedentary time (ST) may contribute to cardiovascular disease (CVD) risk in women, perhaps via cardiac autonomic dysregulation. We examined associations of total, leisure, and occupational MVPA and ST with cardiac autonomic regulation in women. Methods: Data were from 522 women (age = 37.7 ± 5.7 years; 59%white) who participated in the follow-up study of the Pregnancy Outcomes and Community Health Study (between 2011 and 2014). MVPA and ST (hours/day) were self-reported using the Modifiable Activity Questionnaire. Cardiac autonomic regulation was assessed by calculating heart rate variability (HRV) indices (resting heart rate, natural logarithm standard deviation of normal R-R intervals; lnSDNN [total variability], natural logarithm root mean square of the successive differences; lnRMSSD [cardiac parasympathetic activity]) with Kubios software from a 5-minute, seated electrocardiogram. Progressive generalized linear models evaluated associations of total, leisure, and occupational MVPA and ST with HRV indices while adjusting for confounders (demographics, health-related factors), and then potential mediators (clinical variables). A final model evaluated the relationship between ST and HRV stratified by MVPA level. Results: Adjusting for confounders, total and leisure MVPA were associated with favorable lnSDNN (B = 0.027 [p = 0.014] and B = 0.074 [p = 0.009], respectively) and lnRMSSD (B = 0.036 [p = 0.015] and B = 0.075 [p = 0.043], respectively). Adjustment for mediators tended to strengthen the observed significant associations. No associations were found between occupational MVPA or any ST measure with HRV indices (p > 0.05). Neither MVPA nor ST were associated with heart rate. When stratified by MVPA level, leisure ST was associated with unfavorable lnRMSSD (B = -0.041, [p = 0.042]) only among women who did not meet leisure MVPA recommendations. Conclusion: Cardiac autonomic dysregulation may be a mechanism through which low leisure MVPA and, among low-active women, high leisure ST contribute to CVD risk among women.

Psychophysiological Reactivity, Postures and Movements among Academic Staff: A Comparison between Teleworking Days and Office Days

The aim of this study was to determine if psychophysiological activity, postures and movements differ during telework (i.e., work performed at home) and work performed at the conventional office. We performed twenty-four-hour pulse recordings and accelerometry measurements on 23 academic teaching and research staff during five consecutive workdays, with at least one day of telework. Additionally, we conducted salivary sampling during one day of telework, and one day of office work. Heart rate and heart rate variability indices, postural exposure and cortisol concentration were analyzed using repeated measures analysis of variance with Workplace and Time (i.e., before, during and after workhours) as within-subject effects. We found a significant interaction effect of Workplace and Time in heart rate variability indices and in the number of transitions between seated and standing postures. This shows more parasympathetic activity among academic teleworkers during telework than office work, which may indicate more relaxation during telework. They had an overall sedentary behavior at both workplaces but switched between sitting and standing more often during telework, which may be beneficial for their health.

Associations of Sedentary Time with Heart Rate and Heart Rate Variability in Adults: A Systematic Review and Meta-Analysis of Observational Studies

PURPOSE

To evaluate if sedentary time (ST) is associated with heart rate (HR) and variability (HRV) in adults.

METHODS

We systematically searched PubMed and Google Scholar through June 2020. Inclusion criteria were observational design, humans, adults, English language, ST as the exposure, resting HR/HRV as the outcome, and (meta-analysis only) availability of the quantitative association with variability. After qualitative synthesis, meta-analysis used inverse variance heterogeneity models to estimate pooled associations.

RESULTS

Thirteen and eight articles met the criteria for the systematic review and meta-analysis, respectively. All studies were cross-sectional and few used gold standard ST or HRV assessment methodology. The qualitative synthesis suggested no associations between ST and HR/HRV. The meta-analysis found a significant association between ST and HR (β = 0.24 bpm per hour ST; CI: 0.10, 0.37) that was stronger in males (β = 0.36 bpm per hour ST; CI: 0.19, 0.53). Pooled associations between ST and HRV indices were non-significant (p > 0.05). Substantial heterogeneity was detected.

CONCLUSIONS

The limited available evidence suggests an unfavorable but not clinically meaningful association between ST and HR, but no association with HRV. Future longitudinal studies assessing ST with thigh-based monitoring and HRV with electrocardiogram are needed.

Acute effects of breaking up sitting time with isometric exercise on cardiovascular health: Randomized crossover trial

The objective of this study was to analyze the acute effects of breaking up prolonged sitting with isometric exercise on the cardiovascular health of sedentary adults. This is a three-condition randomized crossover trial. The sample was comprised of 17 subjects (11 women; 29 ± 10 years old; 25,1 ± 5,1 kg/m² ). The participants completed, in randomized order, three experimental conditions (control, breaks with isometric leg extension exercise, and breaks with walking), with the order of the conditions determined through simple automatic randomization. All the conditions had in common a sitting period of 3 h. During the conditions with isometric exercise and walking breaks the participants performed breaks with isometric leg extension exercise and with walking every 30 min, while in the control condition they remained seated with no breaks. Before and after this period, vascular function (primary outcome), blood pressure, and cardiac autonomic modulation (secondary outcomes) were measured. Generalized estimated equations were used to analyze the data. The results did not indicate significant interaction effects for vascular function among experimental conditions (p > 0,05 for all). We also did not find significant interaction effects for systolic or diastolic blood pressure among the conditions (p > 0,05 for all). The heart rate variability parameters did not present significant interaction effects among conditions (p > 0,05 for all). In conclusion, breaking up sitting with isometric exercise does not seem to lead to significant effects on the cardiovascular health of sedentary adults.

Decreased continuous sitting time increases heart rate variability in patients with cardiovascular risk factors

Aim

The purpose of the present study was to elucidate the relationship between high-frequency heart rate variability (HF HRV) and continuous daytime sitting time in patients with cardiovascular risk factors such as mild hypertension and/or stable angina pectoris.

Background

Decreased HF HRV precedes the progression and worsening of cardiovascular diseases. Continuous sitting behavior is a major risk factor for developing metabolic syndrome and is associated with cardiovascular disease, diabetes mellitus, renal failure, sarcopenia and osteoporosis. Risk factors for cardiovascular disease can be affected by continuous daytime sitting behaviors.

Design

The present study design was a post-hoc comparison.

Methods

Patients treated at two different primary care clinics from 2014 to 2018 were enrolled in this study (n = 53). We assessed HF HRV and continuous sitting time using 24-hour Holter electrocardiography and an activity meter at baseline and 6 months. HF HRV was calculated during sleep.

Results

Sitting time had decreased in 22 patients (decreased group) and increased in 31 patients (increased group) after 6 months. The mean patient ages were 73.1 and 72.0 years in the decreased and increased sitting time groups, respectively (p = 0.503). HF HRV during sleep had increased after 6 months in the decreased sitting time group. Compared with the increased group, the decreased group showed significantly higher HF HRV during sleep after 6 months by two-way repeated-measures ANOVA after adjustment for age, sex and change in activity (p = 0.045).

Conclusion

These results suggest that a decrease in sitting time might induce parasympathetic activity during sleep. Therefore, reducing continuous sitting time during the day might contribute, in part, to improving the prognosis of patients with cardiovascular risk factors not only by avoiding muscle loss but also by providing positive influences on parasympathetic tone during sleep.

Resting Heart Rate Measurement in Elite Athletes during COVID-19 Lockdown: The Impact of Decreased Physical Activity

The purpose was to observe the effects of a four-week lockdown on the resting heart rate (RHR) and well-being perception of elite swimmers. Twenty elite swimmers performed RHR measurements upon waking in supine and standing positions. Baseline values and those measured after four weeks of lockdown were compared. Swimmers completed a questionnaire on their training volume and state of well-being. During the lockdown, swimmers reported a weekly mean physical activity of 10.4 ± 3.6 h (an estimated reduction of 254% compared to their usual training volume). After four weeks of lockdown, RHR in the supine position increased by more than two beats per minute (58.8 ± 8.2 vs. 56.5 ± 7.4 bpm, p < 0.05). In the standing position, RHR increased by almost 15 beats per minute (103.3 ± 13.2 vs. 88.4 ± 9.4 bpm, p < 0.0001). Fifty percent of these athletes expressed a decrease in well-being. These results underline that the lockdown circumstances induced a large reduction in parasympathetic activity in elite athletes, which was associated with a decrease in training volume. This increase in RHR may reflect that a highatly strenuous environment and maintaining a high level of physical activity in this population could be favorable to preserve physical and psychological health.

Thigh-worn accelerometry for measuring movement and posture across the 24-hour cycle: a scoping review and expert statement

Introduction

The Prospective Physical Activity Sitting and Sleep consortium (ProPASS) is an international collaboration platform committed to harmonise thigh-worn accelerometry data. The aim of this paper is to (1) outline observational thigh-worn accelerometry studies and (2) summarise key strategic directions arising from the inaugural ProPASS meeting.

Methods

(1) We performed a systematic scoping review for observational studies of thigh-worn triaxial accelerometers in free-living adults (n≥100, 24 hours monitoring protocols). (2)Attendees of the inaugural ProPASS meeting were sent a survey focused on areas related to developing ProPASS: important terminology (Q1); accelerometry constructs (Q2); advantages and distinct contribution of the consortium (Q3); data pooling and harmonisation (Q4); data access and sharing (Q5 and Q6).

Results

(1) Eighty eligible articles were identified (22 primary studies; n~17 685). The accelerometers used most often were the ActivPAL3 and ActiGraph GT3X. The most commonly collected health outcomes were cardiometabolic and musculoskeletal. (2) None of the survey questions elicited the predefined 60% agreement. Survey responses recommended that ProPASS: use the term physical behaviour or movement behaviour rather than 'physical activity' for the data we are collecting (Q1); make only minor changes to ProPASS's accelerometry construct (Q2); prioritise developing standardised protocols/tools (Q4); facilitate flexible methods of data sharing and access (Q5 and Q6).

Conclusions

Thigh-worn accelerometry is an emerging method of capturing movement and posture across the 24 hours cycle. In 2020, the literature is limited to 22 primary studies from high-income western countries. This work identified ProPASS's strategic directions-indicating areas where ProPASS can most benefit the field of research: use of clear terminology, refinement of the measured construct, standardised protocols/tools and flexible data sharing.

The Relation between Domain-Specific Physical Behaviour and Cardiorespiratory Fitness: A Cross-Sectional Compositional Data Analysis on the Physical Activity Health Paradox Using Accelerometer-Assessed Data

In contrast to leisure time physical activity (LTPA), occupational physical activity (OPA) does not have similar beneficial health effects. These differential health effects might be explained by dissimilar effects of LTPA and OPA on cardiorespiratory fitness (CRF). This study investigated cross-sectional associations between different physical behaviours during both work and leisure time and CRF by using a Compositional Data Analysis approach. Physical behaviours were assessed by two accelerometers among 309 workers with various manual jobs. During work time, more sedentary behaviour (SB) was associated with higher CRF when compared relatively to time spent on other work behaviours, while more SB during leisure time was associated with lower CRF when compared to other leisure time behaviours. Reallocating more time to moderate-to-vigorous physical activity (MVPA) from the other behaviours within leisure time was positively associated with CRF, which was not the case for MVPA during work. The results of our study are in line with the physical activity health paradox and we call for further study on the interaction between LTPA and OPA by implementing device-worn measures in a longitudinal design. Our results highlight the need for recommendations to take into account the different effects of OPA and LTPA on CRF.

[Efficiency of heart rate and heart rate difference at different time points during head-up tilt test in the diagnosis of postural tachycardia syndrome in children and adolescents]

OBJECTIVE

To study the efficiency of heart rate (HR) and heart rate difference (HRD) at different time points during head-up tilt test (HUTT) in the diagnosis of postural tachycardia syndrome (POTS) in children and adolescents.

METHODS

A total of 217 children and adolescents, aged 6-16 years, who were diagnosed with POTS were enrolled as the POTS group, and 73 healthy children and adolescents, matched for sex and age, were enrolled as the control group. The POTS group was further divided into ≤12 years old group with 127 children/adolescents and >12 years old group with 90 children/adolescents. The two groups were compared in terms of HR at baseline and at 5 and 10 minutes of HUTT (HR0, HR5, and HR10 respectively), difference between HR5/HR10 and HR0 (HRD5 and HRD10 respectively). The efficiency of HR5, HR10, HRD5 and HRD10 in the diagnosis of POTS was assessed.

RESULTS

Compared with the control group, the POTS group had significant increases in HR5, HR10, HRD5, and HRD10 (P<0.05). The coincidence rate of HR or HRD for the diagnosis of POTS in males was higher than that in females at 5 minutes of HUTT (P<0.05), while the coincidence rate of HR or HRD for the diagnosis of POTS in males was lower than that in females at 10 minutes of HUTT (P<0.05). The coincidence rate of HR for the diagnosis of POTS was higher in the >12 years old subgroup (P<0.05), while the coincidence rate of HRD for the diagnosis of POTS was higher in the ≤12 years old subgroup (P<0.05). The combination of HR5, HR10, HRD5, and HRD10 for the diagnosis of POTS had a greater area under the curve (0.974; 95%CI: 0.949-0.989) than HR5, HR10, HRD5, or HRD10 alone, with a sensitivity of 87.80% and a specificity of 95.83%. The diagnostic efficacy of HRD for POTS was higher than that of HR (P<0.05).

CONCLUSIONS

HR and HRD at different time points during HUTT have a good value in the diagnosis of POTS in children and adolescents, and the accuracy of diagnosis varies with age and gender.

[Efficiency of heart rate and heart rate difference at different time points during head-up tilt test in the diagnosis of postural tachycardia syndrome in children and adolescents]

OBJECTIVE

To study the efficiency of heart rate (HR) and heart rate difference (HRD) at different time points during head-up tilt test (HUTT) in the diagnosis of postural tachycardia syndrome (POTS) in children and adolescents.

METHODS

A total of 217 children and adolescents, aged 6-16 years, who were diagnosed with POTS were enrolled as the POTS group, and 73 healthy children and adolescents, matched for sex and age, were enrolled as the control group. The POTS group was further divided into ≤12 years old group with 127 children/adolescents and >12 years old group with 90 children/adolescents. The two groups were compared in terms of HR at baseline and at 5 and 10 minutes of HUTT (HR0, HR5, and HR10 respectively), difference between HR5/HR10 and HR0 (HRD5 and HRD10 respectively). The efficiency of HR5, HR10, HRD5 and HRD10 in the diagnosis of POTS was assessed.

RESULTS

Compared with the control group, the POTS group had significant increases in HR5, HR10, HRD5, and HRD10 (P<0.05). The coincidence rate of HR or HRD for the diagnosis of POTS in males was higher than that in females at 5 minutes of HUTT (P<0.05), while the coincidence rate of HR or HRD for the diagnosis of POTS in males was lower than that in females at 10 minutes of HUTT (P<0.05). The coincidence rate of HR for the diagnosis of POTS was higher in the >12 years old subgroup (P<0.05), while the coincidence rate of HRD for the diagnosis of POTS was higher in the ≤12 years old subgroup (P<0.05). The combination of HR5, HR10, HRD5, and HRD10 for the diagnosis of POTS had a greater area under the curve (0.974; 95%CI: 0.949-0.989) than HR5, HR10, HRD5, or HRD10 alone, with a sensitivity of 87.80% and a specificity of 95.83%. The diagnostic efficacy of HRD for POTS was higher than that of HR (P<0.05).

CONCLUSIONS

HR and HRD at different time points during HUTT have a good value in the diagnosis of POTS in children and adolescents, and the accuracy of diagnosis varies with age and gender.

Occupational, Transport, Leisure-Time, and Overall Sedentary Behaviors and Their Associations with the Risk of Cardiovascular Disease among High-Tech Company Employees

This study examined the associations of overall and domain-specific (i.e., occupational, transport, and leisure-time) sedentary behaviors with cardiovascular disease (CVD) risk factors among high-tech company employees in Taiwan. A total of 363 participants employed at high-tech companies (mean age ± standard deviation: 37.4 ± 7.2 years) completed a questionnaire administered by email regarding their overall, occupational, transport, and leisure-time sedentary behaviors. Self-reported data of height and weight, blood pressure, blood sugar, and total cholesterol levels were also collected in 2018. An adjusted binary logistic regression model was employed in the analysis. After adjusting for sociodemographic variables, high-tech company employees who used a computer (or Internet) for more than 2 h per day during their leisure time were more likely to have CVD risk factors (odds ratio: 1.80; 95% confidence interval: 1.08-3.00). No significant associations with CVD risk factors were detected for total sedentary time, occupational sitting, television viewing time, and transport-related sitting. Despite the nature of cross-sectional design in this study, our findings may have considerable implications for intervention designers and policymakers of Taiwan. Developing effective strategies for limiting leisure-time computer use should be considered for the prevention of CVD among high-tech company employees.