The goal of this study is to explore the impact of two types of yoga-based body stretching (mild and intense) on dynamic changes of Systemic Inflammatory Cytokines (SICs) and Specialized Pro-resolving Mediators (SPMs) in yoga-naïve subjects.

During the last decade, yoga has become increasingly popular in Western cultures. The 2017 NIH report indicated that 14.3% of the adult population practice yoga in the USA. The most common yoga styles tested in randomized clinical trials (RCTs) are Hatha, Iyengar, and Patanjali.

One key physical component of yoga is the stretching that occurs during different postures. Based on animal studies, it is plausible to think that the physical intensity of stretching may affect systemic inflammatory outcomes, i.e. SICs and SPMs. However, human studies have not isolated and quantified the impact of stretching. In consequence, it is not known to what extent the benefits of yoga can be attributed to the physical aspect of stretching. One way to explore the effect of yoga would be to isolate the stretching element and compare two stretching protocols with yoga-based postures on SICs and SPMs.

In previous preclinical studies using an ex-vivo stretching model of mouse connective tissue (AICUC: 04996), the investigators found that fibroblasts are actively involved in the regulation of connective tissue tension, demonstrating that fibroblasts have a more elaborate scheme of responses to mechanical stress than was previously thought.

Later, in the inflammatory active stretch rat model (AICUC 04995), the investigators found that after 10 minutes of an active stretch there was a significant reduction in the inflammatory lesion size area measured with ultrasound and a reduction of infiltrating neutrophils. The SPM Resolvin 1 (RvD1) was also measured and showed a significant difference between the stretch and no stretch group. These promising results encouraged the investigators to keep exploring the fundamental innate mechanism by which the body enhances the healing of an inflammatory process regardless of its etiology; e.g., a mouse breast cancer model with active stretch showed that with four weeks of stretching once a day, tumors were reduced roughly to the half comparing with the no-stretch group and a pig study currently underway is exploring the effects of active stretching on SPMs production and determining changes in Polymorphonuclear Neutrophil (PMN) and macrophages migration toward the inflammatory stimulus.

These pre-clinical results motivated the research group to move forward with a translational pilot study to explore first the feasibility and second, the effect of stretching on the connective tissue and muscles of healthy humans. The investigators presume to find an effect of stretching on a systemic level. Hence, they propose to measure levels of SICs and SPMs, as well as their changes over time after one acute session of yoga-based stretching postures. The investigators plan to collect blood samples at baseline pre-intervention and then at 0 minutes, 30 minutes, 1, 2, and 3, and 24 hours after the intervention. Samples will be analyzed using flow cytometry and ELISA.

Inclusion Criteria:

• Healthy adults
• Age between 40 - 60 years old.
• Non-smoking
• BMI between 19 and 29.

Exclusion Criteria:

• Any history of chronic inflammatory disease or recent acute illness (< 1 month)
• Vaccination within the last 3 months
• Regular medication, or any medication in the preceding week
• Practice of structured higher-intensity exercise at least twice a week for more than 30 minutes
• Pregnancy
• Endocrine disorders (e.g. diabetes)
• Significant soft tissue injury
• Surgical supportive devices (nails, wire, screws, pins, plates) in an area of the body to be stretched (toes, ankles, knees, hips, shoulders, elbows, wrists, fingers and spine)
• Fractures in the past 3 years
• Generalized joint hypermobility or genetic conditions such as Marfan syndrome and Ehlers-Danlos syndrome
• Alcoholism (> 10 drinks per week) and drug abuse.

The results of this study may eventually be published, and information may be exchanged between medical investigators and collaborators, but patient confidentiality will be maintained. Institutional Review Board and regulatory authorities will be granted direct access to original medical and research records for verification of clinical trial procedures and/or data. If the record is used or disseminated for government purposes, it will be done under conditions that will protect the subject's privacy consistent with laws relating to public disclosure of information and the law-enforcement responsibilities of the agency (e.g. NIH and FDA).

Participants and yoga-based stretching instructor are not blinded. Nurses and lab technicians are blinded during blood draws. Laboratory analysts are blinded during sample analyses. Statisticians will be unblinded once all laboratory analyses are completed.