• Participant ratings of negative (vasovagal) reactions [ Time Frame: Measured within 30 minutes of donating ] [ Designated as safety issue: No ]
  
• Phlebotomist ratings of donor reactions [ Time Frame: Measured immediately following donation ] [ Designated as safety issue: Yes ]
  
• Number of repeat donations [ Time Frame: Measured 2 years post-donation ] [ Designated as safety issue: No ]
  

• Subjective ratings of muscle soreness and fatigue [ Time Frame: Measured 24 hours post-donation ] [ Designated as safety issue: No ]
  
• Negative (vasovagal) reactions [ Time Frame: Measured 24 hours post-donation ] [ Designated as safety issue: No ]
  

Severe and potentially dangerous shortages in the blood supply are increasingly common in the United States. As the population ages and as more stringent donor eligibility restrictions are enforced, blood shortages are expected to worsen. One way to meet the increasing demand for blood is to recruit new blood donors. Ideally, these individuals would become lifelong donors, and contribute up to six times per year and up to hundreds of units of blood within a lifetime. Unfortunately, less than half of all new donors provide a second donation. Many individuals who donate blood experience dizziness, weakness, lightheadedness, or in severe cases, fainting. As a result of these negative reactions, many individuals never donate blood again. Preventing these reactions may be an effective way to encourage subsequent blood donations. The purpose of this study is to evaluate the effectiveness of consuming water prior to donation and performing a muscle tensing exercise during donation as ways to reduce negative reactions in new blood donors. The study's long-term goal is to provide blood collection agencies with simple and inexpensive strategies to prevent negative reactions and enhance donor retention.

This study will enroll American Red Cross blood donors who have donated blood no more than twice previously. Participants will be randomly assigned to one of the following four groups: 1) pre-donation water consumption and muscle tensing exercise during donation; 2) pre-donation water consumption; 3) pre-donation muscle tensing exercise; or 4) no treatment. Participant reactions will be assessed at the time of donation by self-report and phlebotomist ratings, as well as by self-report 24 hours following the donation. Participants' subsequent donation history will be tracked for two years by reviewing the American Red Cross national donor database.