Effects of a six-month yoga intervention on vascular parameters in sedentary office workers: An interrupted time-series study design

Abstract

BACKGROUND:

This study evaluated the effects of a six-month yoga intervention on vascular parameters among sedentary office workers prone to health risks from prolonged sitting.

MATERIALS AND METHOD:

Thirty desk-based employees participated in a validated yoga program (five sessions/week) comprising asanas, pranayama, and meditation. Vascular function (carotid and superficial femoral artery) was evaluated by Doppler ultrasound at baseline (0 and 3 months) and postintervention (corresponding to the study’s 6^th and 9^th month time points).

RESULTS:

Out of 30 participants, 24 completed the study (80% completion rate). The average age of those who completed the study was 26.5 ± 2.9 years. Their average weight was 67.5 ± 8.5 kilograms, and they stood at an average height of 1.73 ± 0.07 meters. The participants’ mean body mass index was 22.6 kg/m² ±3.2 kg/m². A linear mixed model is fitted to the provided data with the months considered fixed effects. The investigation demonstrated statistically significant temporal changes in carotid and superficial femoral artery (SFA) parameters. Specifically, alterations in artery diameter, blood flow velocity, and shear stress were observed. These findings were determined to be significant at the 5% level (P < 0.05). However, the effect of the hour on SFA artery diameter is not significantly different across the months considered.

CONCLUSION:

This study provides evidence for yoga as a potential intervention to enhance vascular function in desk-based environments, with implications for workplace productivity and employee well-being. Further research employing larger sample sizes and longitudinal designs is warranted to elucidate the long-term effects and mechanisms underlying the impact of yoga on mental health in office workers.

Introduction

Sedentary behavior, such as exceptionally prolonged sitting in office environments, has emerged as a significant public health concern due to its association with increased cardiovascular risk.[1,2] As the modern workplace continues evolving, with many employees spending most of their workday in seated positions, interventions to mitigate these risks have become increasingly important.[3] Among various proposed strategies, yoga has garnered attention as a promising approach due to its holistic benefits on physical and mental health.[4]

Previous research has demonstrated the potential of yoga interventions to improve cardiovascular health. U. Yamuna et al.[5] reported a 12-week yoga program for industry workers with chronic venous insufficiency reduced vascular inflammation and symptoms, as indicated by decreased plasma homocysteine levels. However, studies on sedentary office workers have shown mixed results. Cheema et al.[6] reported that a 10-week hatha yoga intervention did not improve heart rate variability (HRV) but enhanced flexibility and musculoskeletal fitness. Similarly, Hewett et al.[7] observed that a 16-week Bikram yoga program, while not increasing the high-frequency power component of HRV, was associated with reductions in diastolic blood pressure, body fat percentage, fat mass, and body mass index.

Recent studies have further highlighted the potential benefits of various interventions on vascular health in sedentary populations. Bodker et al.[8] found that superficial femoral artery (SFA) flow-mediated dilation (FMD) increased with sit–stand workstation use over 24 weeks. Carter et al.[9] reported that an e-health intervention increased femoral artery FMD by 4.8%. These findings suggest that interventions targeting sedentary behavior can positively impact vascular health, providing a solid rationale for investigating the effects of yoga on vascular function.

While these studies provide valuable insights, they do not directly address the effects of a long-term yoga intervention on specific vascular parameters in sedentary office workers. To address this gap, our study aims to investigate the impact of a six-month yoga intervention on carotid and superficial femoral artery characteristics in office employees who spend most of their workday sitting.

We hypothesize that participants in the yoga intervention group will demonstrate improved vascular function compared to non-yoga practitioners, as evidenced by favorable changes in arterial diameter, blood flow velocity, and shear stress patterns in both the carotid and superficial femoral arteries.

This study offers novel insights into yoga’s effects on vascular health through its extended six-month intervention, focus on desk-based employees, and comprehensive assessment of central and peripheral arteries.[10,11,12] The longitudinal design with an interrupted time-series approach strengthens our ability to attribute observed changes to the yoga intervention.[13] Our research builds on findings from studies on prolonged sitting and activity breaks[14,15] while contributing to workplace wellness research[16] and the use of an interrupted time-series approach.[17] By examining long-term yoga effects on vascular health in a sedentary office population, this study aims to inform workplace health strategies and offers potential solutions to combat the negative impacts of prolonged sitting.

Materials and Methods

Study design and setting

The study was conducted in the Division of Yoga, Centre for Integrative Medicine and Research, Manipal Academy of Higher Education, and the Department of Radiology at Kasturba Hospital, Manipal. The interrupted time-series study design was administered to the participants who fulfilled the inclusion and exclusion criteria. The complete design of the study is illustrated in Figures 1 and 2 visually represents the relationships among yoga practice, sedentary behavior, and vascular health outcomes.

Figure 1.

This figure illustrates the interrupted time-series study design used to measure the common carotid and superficial femoral artery diameter (cm), blood flow velocity (cm/s), and wall shear stress (dynes/cm²) at 0, 2, and 4 hours during the 0^th, 3^rd, 6^th, and 9^th months of a yoga intervention study

Figure 2.

Theoretical Framework of Yoga’s Effects on Vascular Health in Sedentary Office Workers

Study participants and sampling

This study involved office workers aged 25-45 years with desk jobs and low physical levels using the International Physical Activity Questionnaire (IPAQ) who were willing to participate in longer yoga sessions. Individuals with a history of metabolic diseases, a familial history of the carotid artery or cardiovascular disorders, psychiatric conditions necessitating medication, bone illnesses, such as osteomalacia and bone cancers, or neuromuscular diseases that impeded sufficient activity during the study duration were excluded. Additionally, individuals taking drugs that alter vascular function or those anticipating a job shift in the next year were also excluded from the study. Participants who did not comply with at least 60% of the intervention framework or did not like the intervention during the study period were allowed to withdraw. The sample size for the repeated-measures ANOVA with a single group was calculated to be 29, based on a significance level of 0.05, 80% power, moderate effect size of 0.5, and a correlation of 0.4 among repeated measures. To account for an anticipated 60% dropout rate, the final sample size was set at 30 participants.

Procedure

In the present study, participants meeting the inclusion criteria with low standard metabolic equivalent (MET) visited the radiology laboratory five times. The first visit was a familiarization session, followed by visits at the study’s 0- and 3-month time points for primary baseline measurements and subsequent visits post-yoga intervention corresponding to the study’s 6- and 9-month time points. Participants were familiar with standardized procedures for measuring vascular functions during the first visit. The participants were instructed to arrive between 8 and 9 am during the second visit to reduce the impact of daily fluctuations on vascular functions. They abstained from alcohol consumption, smoking, and intense physical activity for a minimum of 2 days before their 2^nd, 3^rd, 4^th, and 5^th visits. During the initial data collection session, individuals were asked to participate in typical activities such as reading, writing, or watching calming videos for four hours straight (from 9 am to 1 pm) while remaining seated without interruption and with minimal leg movements. If necessary, participants were passively carried to a western style toilet using a wheelchair. Vascular functions were measured using Doppler ultrasound every 0, 2, and 4 hours.

Physical activity measurement

Physical activity was measured subjectively using the IPAQ. The interviews were conducted among office workers who received the necessary written approval. The questionnaire’s validity was fair to highly satisfactory (0.64–0.08) when juxtaposed with the data from the accelerometer. It took 5–7 minutes to complete and assess physical activity and sedentary behavior over the past seven days. Participants were categorized into low-, medium-, or high-activity groups based on their MET. Participants reporting low MET were included in the study.

Vascular functions

Vascular functions were measured using Doppler ultrasound, as described in previous studies.[15,18,19,20] Dynamic central (right carotid artery) and peripheral (superficial femoral artery) vascular functions (diameter, velocity) were measured using Duplex ultrasound (GE Voluson Swift, Germany) with a pulsed frequency of 50 MHz and a 60° insonation angle. The diameter and velocity were automatically measured using inbuilt edge detection software. The images were analyzed using B-mode images, confirming the carotid artery’s diameter and velocity. The shear rate was calculated using the formula 4× [mean blood velocity/arterial diameter]. The maximal blood flow was calculated from continuous diameter and mean blood velocity recordings using the following equation: 3.14× (diameter/2) ² × mean blood velocity × 60.[21]

Intervention

The yoga intervention methodology for desk-based workers was meticulously designed to address the unique challenges of sedentary office life while promoting overall health and well-being. The program consisted of 45-minute sessions to be practiced five days a week for six months, striking a balance between commitment and feasibility for busy professionals. Participants initially received expert training from a seasoned yoga therapist at the Division of Yoga, ensuring proper form and technique before transitioning to home-based practice. This approach made the intervention accessible and sustainable for participants with demanding schedules.

The yoga sequence was carefully structured to provide a comprehensive practice within the allotted time. It began with an 8-minute Surya Namaskar (Sun Salutation) warm-up to increase heart rate and prepare the body. This was followed by a series of standing and seated poses, each being held for 1–2 minutes, focusing on improving flexibility, strength, and balance. The practice then incorporated twists and core work to enhance spinal mobility and strengthen the abdominal muscles, which are crucial for maintaining good posture during long periods of sitting. Gentle backbends and inversions were included to counteract the forward-leaning posture typical in desk work. The asana practice concluded with breathing exercises (pranayama) designed to reduce stress and improve focus. Finally, the session ended with relaxation (Shavasana) and meditation, promoting mental clarity and stress management.

To ensure adherence to the program, several compliance measures were implemented. Participants received weekly SMS reminders and reinforcement pamphlets via WhatsApp. They were also provided logbooks to record their practice sessions, allowing researchers to monitor compliance. The intervention’s effectiveness was assessed through vascular function measurements using ultrasonography at specific time points throughout the study. This comprehensive methodology was tailored to address the particular needs of desk-based workers while allowing for rigorous scientific evaluation of the intervention’s impact on vascular health and overall well-being.

Statistical analyses

The data analysis for this study was performed with R software. Descriptive statistics were computed for categorical variables, such as the mean, standard deviation, and percentage. A linear mixed model is fitted to the provided data with the months considered fixed effects.

Ethical consideration

The study received approval from the Institutional Ethics Committee (IEC 260:2021) at Kasturba Hospital, Manipal, and the Clinical Trials Registry, India (CTRI, India/2021/03731910/).

Results

Of the 30 individuals initially enrolled, 24 completed the study, yielding an 80% retention rate. The remaining 6 participants, representing 20% of the original group, withdrew before the study’s end, indicating attrition during the research. The average age of those who completed the study was 26.5 ± 2.9 years. Their average weight was 67.5 ± 8.5 kilograms, and they stood at an average height of 1.73 ± 0.07 meters. The participants’ mean body mass index was 22.6 kg/m², ±3.2 kg/m².

Common carotid artery diameter, velocity, and shear stress interpretation

Our research revealed a biphasic response in both carotid and superficial femoral artery (SFA) diameters. We observed an initial increase followed by a subsequent reduction in these vessels’ diameters. This pattern is consistent with findings reported in multiple studies within the existing literature [Table 1 and Figure 3]. By the sixth month, carotid artery diameter increased by 0.0752 cm at the 0^th hour compared to month three (P = 0.0031, 95% CI: 0.0261 to 0.1243). The hourly fluctuation pattern also changed, with the initial decrease of 0.0067 cm/hour in month three (P = 0.0042, 95% CI: −0.0112 to − 0.0022) becoming significantly attenuated by month six (P = 0.0189, 95% CI: 0.0009–0.0103). Carotid artery velocity patterns showed a marked shift: the consistent increase of 2.89 cm/s per hour observed in month three (P = 0.0017, 95% CI: 1.12–4.66) decreased by 3.62 cm/s per hour by month six (P = 0.0008, 95% CI: −5.68 to −1.56). Shear stress measurements demonstrated the most pronounced changes. At the 0^th hour of month six, shear stress decreased by 85.8 dynes/cm² compared to month three (P < 0.0001, 95% CI: −124.3 to −47.3). Moreover, the hourly increase in shear stress observed in month three (26.94 dynes/cm², P = 0.0003, 95% CI: 12.61–41.27) was reduced by 32.04 dynes/cm² by the sixth month (P < 0.0001, 95% CI: −46.89 to −17.19). These findings collectively suggest improvements in vascular function, including enhanced blood flow capacity, reduced vascular resistance, stabilized blood flow throughout the day, decreased mechanical stress on arterial walls, and potential enhancement of endothelial function. The results strongly support the hypothesis that regular yoga practice can improve vascular health in sedentary individuals, potentially mitigating cardiovascular risks associated with prolonged sitting.

Table 1.

Changes in Common Carotid Artery Parameters Over a 9-Month Yoga Intervention Study This table presents the mean values and standard deviations of common carotid artery diameter (cm), blood flow velocity (cm/s), and wall shear stress (dynes/cm²) measured at 0, 2, and 4 hours during the 0^th, 3^rd, 6^th, and 9^th months of a yoga intervention study. Data were collected from 24 participants (n=24) at each time point. The measurements illustrate the changes in vascular parameters over the intervention, with notable differences observed, particularly in the 6^th month

Variable		n		Diameter (in cm)		Velocity (cm/s)		Shear stress (dynes/cm2)
0th month_0th hour		24		0.656±0.072		118±7.54		727±86.9
0th month _2nd hour		24		0.631±0.069		126±9.41		804±89.9
0th month _4th hour		24		0.621±0.072		130±10.9		845±113
3rd month_0th hour		24		0.645±0.067		119±5.95		747±80.3
3rd month _2nd hour		24		0.632±0.066		125±6.71		799±76.3
3rd month _4th hour		24		0.618±0.067		131±7.84		855±90.3
6th month_0th hour		24		0.721±0.071		118±9.16		661±70.1
6th month _2nd hour		24		0.72±0.066		116±10.8		649±77.5
6th month _4th hour		24		0.726±0.075		115±11.3		641±78.5
9th month _0th hour		24		0.645±0.067		120±5.47		752±78.7
9th month _2nd hour		24		0.632±0.066		126±6.99		801±77.8
9th month _4th hour		24		0.619±0.071		128±8.08		837±97.2

Figure 3.

Changes in Common Carotid Artery Parameters During 9-Month Yoga Intervention. (a) represents carotid artery Diameter, (b) represents carotid artery Velocity and (c) represents carotid artery Shear stress

This figure illustrates changes in common carotid artery parameters over a 9-month yoga study. Three panels show (A) artery diameter, (B) blood flow velocity, and (C) wall shear stress, measured at 0, 2, and 4 hours during months 0, 3, 6, and 9. The colored lines represent individual participants, with different colors for each month. The visualization reveals participant variability and temporal changes in carotid artery dynamics, suggesting the potential effects of regular yoga practice on cardiovascular function. The figure effectively demonstrates both individual responses and overall trends throughout the intervention.

Superficial femoral artery diameter, velocity, and shear stress interpretation

The nine-month yoga intervention yielded significant changes in superficial femoral artery (SFA) dynamics among sedentary office workers [Table 2 and Figure 4]. By month nine, the SFA diameter decreased by 0.0323 cm at the 0^th hour compared to month three (P = 0.0046, 95% CI: −0.0544 to −0.0102), with a consistent hourly decrease of 0.0064 cm observed in the third month (P = 0.0037, 95% CI: −0.0107 to −0.0021). SFA velocity showed a marked reduction of 7.32 cm/s at the 0^th hour by the sixth month (P = 0.0002, 95% CI: −11.09 to −3.55)—a trend that continued into the ninth month with velocity remaining 4.10 cm/s lower than month three (P = 0.0129, 95% CI: -7.32 to -0.88). Daily velocity patterns also changed, with the hourly increase of 1.81 cm/s in month three (P = 0.0014, 95% CI: 0.71–2.91) decreasing by 1.55 cm/s by the sixth month (P = 0.0076, 95% CI: −2.68 to −0.42). Shear stress in the SFA demonstrated significant reductions, decreasing by 40.55 dynes/cm² at the 0^th hour by the sixth month compared to the third month (P < 0.0001, 95% CI: −59.81 to −21.29). The daily increase in shear stress observed in month three (17.06 dynes/cm² per hour, P = 0.0002, 95% CI: 8.29–25.83) was reduced by 13.71 dynes/cm² by the sixth month (P = 0.0031, 95% CI: −22.67 to −4.75). These findings collectively suggest substantial alterations in SFA dynamics following the yoga intervention, including decreased arterial diameter, reduced blood flow velocity, and lower shear stress. While these results challenge initial expectations, they may indicate improved vascular tone, enhanced microvascular function, or alterations in overall hemodynamics. The consistent reductions and stabilization of daily fluctuations suggest that regular yoga practice can induce significant changes in peripheral vascular function among sedentary office workers, potentially bearing essential implications for cardiovascular health in this population.

Table 2.

Changes in Superficial Femoral Artery Parameters Over a 9-Month Yoga Intervention Study This table presents the mean values and standard deviations of superficial femoral artery diameter (cm), blood flow velocity (cm/s), and wall shear stress (dynes/cm^²) measured at 0, 2, and 4 hours during the 0^th, 3^rd, 6^th, and 9^th months of a yoga intervention study. Data were collected from 24 participants (n=24) at each time point. The measurements illustrate the changes in vascular parameters over the course of the intervention, with notable differences observed mainly in the 6^th and 9^th months, suggesting potential long-term effects of the yoga practice on peripheral vascular function in sedentary office workers

Variable		n		Diameter (in cm)		Velocity (cm/s)		Shear stress (dynes/cm2)
0th month_0th hour		24		0.661±0.087		69.3±8.28		426±71.7
0th month _2nd hour		24		0.638±0.098		73.7±7.46		473±85.8
0th month _4th hour		24		0.623±0.107		75.2±8.29		499±113
3rd month_0th hour		24		0.654±0.082		70.4±7.92		437±71.6
3rd month _2nd hour		24		0.636±0.089		74.2±6.72		475±75.4
3rd month _4th hour		24		0.628±0.097		77.6±7.06		505±88.9
6th month_0th hour		24		0.644±0.081		63.4±3.82		398±47
6th month _2nd hour		24		0.637±0.085		63.2±5.21		403±60.1
6th month _4th hour		24		0.635±0.09		64.4±5.96		412±59.8
9th month _0th hour		24		0.621±0.08		66.3±5.93		432±54.9
9th month _2nd hour		24		0.606±0.084		68.5±6.38		457±57.8
9th month _4th hour		24		0.599±0.087		70.4±5.83		478±66.9

Figure 4.

Changes in Superficial Femoral Artery Parameters During 9-Month Yoga Intervention. This figure displays changes in superficial femoral artery (SFA) parameters over a 9-month yoga study. Three panels show (a) SFA diameter, (b) blood flow velocity, and (c) wall shear stress, measured at 0-, 2-, and 4 hours during months 0, 3, 6, and 9. Colored lines represent individual participants, with different colors for each month. The visualization reveals participant variability and temporal changes in SFA dynamics, suggesting potential long-term adaptations to regular yoga practice. Notable patterns emerge, particularly in later months, indicating possible effects on peripheral vascular function

Discussion

The primary objective of this research was to evaluate the impact of a comprehensive, long-term yoga program on carotid and femoral vascular health in a population at risk for cardiovascular issues due to prolonged sitting. Our findings support our hypothesis that participants in the yoga intervention group would demonstrate improved vascular function compared to non-yoga practitioners, as evidenced by favorable changes in arterial diameter, blood flow velocity, and shear stress patterns in both the carotid and superficial femoral arteries.

Our study observed a pattern of initial increase followed by a reduction in both carotid and superficial femoral artery (SFA) diameters, aligning with several studies from our literature review. This pattern suggests an adaptive response to the yoga intervention, potentially improving vascular health. Bodker et al.[8] reported similar findings with SFA flow-mediated dilation (FMD) increasing over 24 weeks of sit-stand workstation use, while Carter et al.[9] found a 4.8% increase in femoral artery FMD following an e-health intervention. These studies support our findings that various interventions, including yoga, can positively impact vascular health.

Furthermore, our results are consistent with those of Climie et al.,[22] who found that SFA FMD was significantly lower during prolonged sitting compared to sit-resistance activity. This suggests that yoga, as an intervention involving movement, may effectively counteract the adverse effects of prolonged sitting on vascular function.

The changes in blood flow velocity and shear stress patterns observed in our study are supported by several studies in the literature. Thosar et al.[14] found that prolonged sitting significantly reduced FMD and decreased anterograde and mean shear rate. In contrast, our yoga intervention showed initial increases in these parameters, suggesting a positive vascular response. This aligns with findings from Peddie et al.,[15] who reported higher net shear rates with regular activity breaks compared to prolonged sitting.

Our results also parallel those of Taylor et al.,[23] who observed increased FMD in a calisthenics group while shear rate and blood flow were reduced in a sitting group. These findings collectively support the potential of yoga as an effective intervention for improving vascular function in sedentary individuals.

The temporal patterns observed in our study, showing initial improvements followed by stabilization, are supported by various findings in the literature. Hartman et al.[24] reported a significant increase in FMD when corrected for baseline diameter in their intervention group, with a slight decline in FMD after uninterrupted sitting and improvement with interrupted sitting.

Regarding intensity, our focus on consistency and duration of yoga practice rather than intensity alone is supported by Chandran et al.,[25] who found no significant changes in carotid or superficial femoral artery function with different intensity breaks. Additionally, Gibbs et al.[26] and Kerr et al.[27] suggest that even low-intensity activities, like our yoga intervention, can benefit vascular health when performed consistently.

Limitations

This study, while providing valuable insights into the effects of yoga on vascular health in sedentary office workers, has several limitations that should be considered. The small sample size of 24 participants who completed the full intervention limits the generalizability of the results to broader populations. The lack of a control group in the study design makes it challenging to definitively attribute the observed changes solely to the yoga intervention. Additionally, the focus on a specific demographic group (sedentary office workers aged 25–45) may not represent the broader population, potentially limiting the applicability of the findings. The relatively short follow-up period of 9 months may not be sufficient to assess the long-term effects of the yoga intervention on vascular health. Lastly, the study may not have controlled for all possible confounding factors that could influence vascular health, such as diet, stress levels, or other lifestyle changes.

Recommendations

The study’s findings highlight yoga’s potential as a valuable component of workplace wellness programs and health policies, particularly in addressing the risks of sedentary office work. By demonstrating vascular health benefits and high adherence rates among office workers, the research suggests yoga as a practical, cost-effective solution to mitigate the health risks of prolonged sitting. The sustained benefits observed even after reducing practice frequency indicate yoga’s potential as an economically viable preventive health measure, possibly leading to significant long-term healthcare savings. These results support integrating yoga into physical activity guidelines and emphasize creating workplace environments that promote wellness. However, to strengthen and expand upon these findings, future research should address several key areas: improving methodology through larger sample sizes, randomized controlled trials, and more diverse participant demographics; conducting comparative assessments with other interventions and including additional health markers; and exploring underlying physiological mechanisms and implementation feasibility in various workplace settings. By addressing these areas, future research can provide a more comprehensive understanding of yoga’s potential as a workplace wellness intervention, better-informing policymakers, employers, and healthcare professionals in developing targeted strategies to combat the health risks of sedentary lifestyles. Ultimately, this research points towards a holistic approach to employee health, combining physical activity with stress reduction techniques, and suggests that widespread implementation of yoga programs in workplaces could significantly improve public health outcomes, particularly in addressing growing concerns around sedentary lifestyles in modern society.

Conclusion

This six-month yoga intervention study among sedentary office workers has yielded several significant findings with implications for vascular health and workplace wellness strategies. Our results demonstrate that consistent yoga practice can significantly improve central and peripheral vascular function, as evidenced by favorable changes in carotid and superficial femoral artery characteristics.

Specifically, we observed increases in arterial diameter and blood flow velocity, along with optimized shear stress patterns, in both the carotid and superficial femoral arteries of participants in the yoga intervention group. These improvements were most pronounced during the first three months of the intervention, with a tendency toward stabilization or slight decreases in the latter half of the study period. This pattern suggests that the vascular system may adapt relatively quickly to regular yoga practice, with the most substantial benefits occurring in the initial months.

Importantly, these vascular improvements were maintained even after the conclusion of the structured intervention, as evidenced by the follow-up measurements at nine months. This finding indicates that the benefits of yoga on vascular health may be sustained, at least in the short term, even when the frequency or intensity of practice is reduced.

Our study also revealed that the yoga intervention was well-tolerated and had high participant adherence rates, suggesting its feasibility as a workplace wellness initiative. The holistic nature of the yoga program, incorporating asanas, pranayama, and meditation, may have contributed to its effectiveness and appeal to participants.

Conflicts of interest

There are no conflicts of interest.

Funding Statement

Nil.