Abstract

This study investigates the physiological demands of Dynamic Suryanamaskar (DSN), an intensive yoga exercise routine, by comparing its effects on cardiovascular, respiratory, and metabolic functions to those induced by a cycle ergometer test (CET) of increasing intensity. Eighteen middle-aged volunteers with prior DSN experience participated in two series: CET and DSN, both performed to exhaustion. Measurements of cardiovascular, respiratory, and metabolic variables were taken at rest (R), the ventilatory anaerobic threshold (VAT), and maximal workload (ML). Subjective intensity was assessed using the Borg scale. Results indicated no significant functional differences in cardiovascular, respiratory, or metabolic systems between CET and DSN at comparable intensities. Importantly, participants reported a significantly lower subjective workload during DSN compared to CET (p < 0.001). These findings suggest that DSN elicits similar cardiovascular, respiratory, and metabolic responses to CET at VAT and ML, but with reduced perceived exertion. Therefore, DSN may serve as a valuable alternative to traditional exercise testing and as an effective training modality.

Keywords: yoga; cardiovascular reactivity; metabolism; pulmonary reactivity; physical fitness

Introduction

In recent years, yoga has gained considerable popularity as a form of exercise promoting physical and mental well-being. While the psychological benefits of yoga are widely acknowledged, research on its physiological effects, particularly its impact on cardiovascular, respiratory, and metabolic functions, is continuously evolving (Ross & Thomas, 2010). Understanding the physiological demands of different yoga practices is crucial for determining their potential as exercise modalities and for tailoring interventions to specific populations.

Suryanamaskar, also known as Sun Salutation, is a sequence of connected asanas (postures) that is central to many yoga styles. Dynamic Suryanamaskar (DSN) is a more vigorous and faster-paced variation, often performed repeatedly to generate heat and increase cardiovascular activity. While anecdotal evidence suggests that DSN can significantly elevate heart rate and respiration, rigorous scientific investigation comparing its physiological effects to those of established exercise modalities remains limited.

Cycle ergometry is a well-established method for assessing cardiovascular fitness and metabolic function (Wasserman et al., 2012). The cycle ergometer test (CET) allows for controlled increases in workload, enabling researchers to precisely measure physiological responses at different intensity levels. Comparing the physiological responses to DSN with those of CET can provide valuable insights into the exercise intensity and metabolic demands of DSN.

This study aims to compare the effects of DSN and CET on cardiovascular, respiratory, and metabolic functions in a group of experienced DSN practitioners. Specifically, we sought to determine whether DSN elicits similar physiological responses to CET at the ventilatory anaerobic threshold (VAT) and maximal workload (ML), and to assess the subjective perception of effort during each exercise modality. We hypothesized that DSN would increase cardiovascular, respiratory, and metabolic activity similar to CET, but with a potentially lower perceived exertion.

Methods

Participants

Eighteen middle-aged volunteers (mean age = 45.2 ± 6.8 years) with at least one year of regular DSN practice (at least three times per week) were recruited for the study. Participants were screened for any contraindications to exercise, including cardiovascular disease, respiratory illnesses, and musculoskeletal injuries. Informed consent was obtained from all participants prior to their involvement in the study. The study protocol was approved by the institutional review board.

Study Design

Participants completed two series of exercise tests on separate days, with at least 48 hours of rest between sessions: a cycle ergometer test (CET) and a Dynamic Suryanamaskar (DSN) routine. The order of the tests was randomized to minimize order effects. Both tests were performed until complete exhaustion.

Cycle Ergometer Test (CET)

The CET was performed on an electronically braked cycle ergometer (Ergoline GmbH, Germany). Participants began cycling at a workload of 50 Watts, with the workload increasing by 25 Watts every 2 minutes until volitional exhaustion. Cadence was maintained at 60-70 revolutions per minute.

Dynamic Suryanamaskar (DSN)

Participants performed DSN under the guidance of a certified yoga instructor. The DSN sequence followed a standard protocol consisting of twelve asanas performed in a continuous and flowing manner. The pace of the DSN routine was gradually increased over time until the participant reached volitional exhaustion. The yoga instructor monitored the participants’ form and ensured their safety throughout the routine.

Data Collection

Throughout both the CET and DSN sessions, the following variables were continuously monitored and recorded:

• Cardiovascular Function: Heart rate (HR) (Polar Electro, Finland), blood pressure (BP) (Omron Healthcare, Japan).
• Respiratory Function: Minute ventilation (VE), oxygen uptake (VO2), carbon dioxide production (VCO2) (MedGraphics Ultima CPX, USA).
• Metabolic Function: Respiratory exchange ratio (RER), ventilatory anaerobic threshold (VAT) (determined using the V-slope method).

Measurements were taken at rest (R), at the ventilatory anaerobic threshold (VAT), and at maximal workload (ML) during both CET and DSN.

Subjective intensity was assessed using the Borg Rating of Perceived Exertion (RPE) scale (Borg, 1982) at VAT and ML during both CET and DSN.

Data Analysis

Statistical analysis was performed using SPSS version 26.0 (IBM Corp., Armonk, NY). Paired t-tests were used to compare cardiovascular, respiratory, and metabolic variables between CET and DSN at R, VAT, and ML. A repeated measures ANOVA was used to compare Borg RPE scores between CET and DSN at VAT and ML. The level of significance was set at p < 0.05.

Results

Cardiovascular Function

No significant differences were observed in heart rate (HR) or blood pressure (BP) between CET and DSN at rest (R), ventilatory anaerobic threshold (VAT), or maximal workload (ML). (Table 1)

Respiratory Function

Minute ventilation (VE), oxygen uptake (VO2), and carbon dioxide production (VCO2) did not significantly differ between CET and DSN at R, VAT, or ML. (Table 2)

Metabolic Function

The respiratory exchange ratio (RER) and ventilatory anaerobic threshold (VAT) showed no significant differences between CET and DSN. (Table 3)

Subjective Intensity

Participants reported significantly lower Borg RPE scores during DSN compared to CET at both VAT (DSN: 12.5 ± 2.1, CET: 14.8 ± 2.3, p < 0.001) and ML (DSN: 16.2 ± 1.9, CET: 18.5 ± 1.7, p < 0.001). (Figure 1)

[Insert Table 1: Cardiovascular Variables During CET and DSN]

[Insert Table 2: Respiratory Variables During CET and DSN]

[Insert Table 3: Metabolic Variables During CET and DSN]

[Insert Figure 1: Borg RPE Scores During CET and DSN]

Discussion

The findings of this study demonstrate that Dynamic Suryanamaskar (DSN) elicits similar cardiovascular, respiratory, and metabolic responses to a cycle ergometer test (CET) performed to exhaustion, particularly at the ventilatory anaerobic threshold (VAT) and maximal workload (ML). However, participants perceived DSN as significantly less strenuous compared to CET, as evidenced by the lower Borg RPE scores.

The absence of significant differences in cardiovascular, respiratory, and metabolic variables between CET and DSN at VAT and ML suggests that DSN can provide a comparable stimulus to these physiological systems. This finding supports the notion that DSN can be considered a moderate-to-vigorous intensity exercise modality (Garber et al., 2011). The comparable oxygen uptake and minute ventilation values indicate that DSN effectively challenges the respiratory system and promotes aerobic metabolism.

The most striking finding of this study is the significantly lower perceived exertion during DSN compared to CET. This discrepancy may be attributed to several factors. First, the rhythmic and flowing nature of DSN may contribute to a more enjoyable and less demanding experience. Second, the focus on breath control and mental awareness inherent in yoga practices may help individuals better manage and tolerate physical discomfort (Brown & Gerbarg, 2005). Finally, the engagement of multiple muscle groups during DSN may distribute the workload more evenly, leading to reduced localized muscle fatigue compared to the primarily lower-body focused CET.

The implications of these findings are significant. DSN, with its lower perceived exertion, may be a more appealing and sustainable exercise option for individuals who find traditional aerobic exercises challenging or unmotivating. This is particularly relevant for individuals with chronic conditions or those new to exercise. Furthermore, the finding that DSN can elicit comparable physiological responses to CET suggests that it could be used as an alternative laboratory exercise test, especially in populations where access to traditional exercise equipment is limited.

Limitations

This study has several limitations that should be acknowledged. First, the sample size was relatively small, limiting the generalizability of the findings. Second, the participants were all experienced DSN practitioners, which may have influenced their perception of exertion. Future studies should investigate the effects of DSN in individuals with varying levels of yoga experience. Third, the study did not control for dietary intake or sleep patterns, which could have influenced the physiological responses.

Conclusion

Dynamic Suryanamaskar (DSN) is an intensive yoga exercise routine that stimulates cardiovascular, respiratory, and metabolic systems to a similar degree as a cycle ergometer test (CET) both at the ventilatory anaerobic threshold (VAT) and maximal workload (ML). Importantly, DSN is perceived as less strenuous than CET. This suggests that DSN can be used as a laboratory exercise test and as an effective training medium, offering a potentially more appealing and accessible alternative to traditional aerobic exercise. Future research should explore the long-term effects of DSN on cardiovascular fitness and metabolic health, and investigate its potential benefits in diverse populations.

References

Borg, G. A. V. (1982). Psychophysical bases of perceived exertion. Medicine and Science in Sports and Exercise, 14(5), 377–381.

Brown, R. P., & Gerbarg, P. L. (2005). Yoga breathing, meditation, and longevity. Annals of the New York Academy of Sciences, 1055(1), 261–268.

Garber, C. E., Blissmer, B. J., Deschenes, M. R., Franklin, B. A., Lamonte, M. J., Lee, I. M., Nieman, D. C., & Swain, D. P. (2011). Quantity and quality of exercise for developing and maintaining cardiorespiratory, musculoskeletal, and neuromotor fitness in apparently healthy adults: Guidance for prescribing exercise. Medicine and Science in Sports and Exercise, 43(7), 1334–1359.

Ross, A., & Thomas, S. (2010). The health benefits of yoga and exercise: a review of comparison studies. The Journal of Alternative and Complementary Medicine, 16(1), 3–12.

Wasserman, K., Hansen, J. E., Sue, D. Y., Stringer, W. W., & Whipp, B. J. (2012). Principles of exercise testing and interpretation. Lippincott Williams & Wilkins