Comparative effects of pre-donation hydration and applied muscle tension on vasovagal reactions in blood donors: Original article

Vasovagal reactions (VVRs), including dizziness and fainting, are common adverse events during blood donation and may affect donor safety and experience. This study evaluates the effectiveness of pre-donation hydration and applied muscle tension (AMT) as practical strategies to reduce VVRs in a tertiary care setting.

To determine the incidence, severity, and risk factors of VVRs among blood donors and to compare the effectiveness of pre-donation hydration and AMT in reducing these reactions.

A prospective, non-randomized, observational comparative study was conducted from June 2022 to June 2025. A total of 70,860 healthy donors aged 18-65 years were included. Donors were grouped based on routine practice: Group A (non-hydration, n=40,419), Group B (hydration with 250mL water 15-20minutes before donation, n=28,581), and Group C (AMT, n=1,860). VVR severity was classified according to DGHS guidelines.

The overall VVR incidence was 2.1% (1,494/70,860). The hydration group showed the lowest incidence (1.1%), followed by AMT (1.6%) and non-hydration (2.8%) (P<0.001). Younger age and lower body weight were significantly associated with increased VVR risk. Preventive interventions were also associated with reduced severity of reactions.

Pre-donation hydration and AMT were associated with reduced incidence and severity of VVRs. These simple, low-cost interventions may enhance donor safety and immediate donation experience.