If you plan to donate blood, it is important to familiarize yourself with the donation process and what to expect before and after your appointment. Following the basic blood donation guidelines can make the experience smoother and more relaxing. If you exercise, the staff at your donation site will most likely recommend limiting your physical activity for the remainder of the day. Whether you should exercise before your donation appointment may depend on a few factors.
Blood Donation
When you donate blood, you are actually giving up both red blood cells and other formed elements of your blood, as well as blood plasma, the fluid portion of your blood. About 8 to 10 percent of your blood volume and red blood cells are donated in one unit, or 500 ml. Your blood plasma is made up mostly of water and you can return to your normal volume in about a day or two. For the red blood cells to build up again to pre-donation levels, it can take up to six weeks.
Strenuous Exercise
During vigorous intensity or long duration exercise, your blood plasma volume and electrolyte levels can actually decrease, especially with high sweat rates or if you are dehydrated. If you perform a strenuous workout the same day that you plan to donate blood, your body may have a lower than normal plasma level before the donation. Reducing your plasma levels more through donation can impair your body's regular functions by increasing the viscosity of the blood, altering the electrolyte balances and creating a dehydrated state. Therefore, it is typically recommended that you avoid strenuous exercise before donating.
Light to Moderate Exercise
Typically with a light to moderate exercise session, plasma volumes are not significantly effected as long as you stay hydrated before, during and after your exercise session. Therefore, light exercise before donation probably will not pose a concern for most individuals. If you have any concerns, err on the side of caution and consider your blood donation day a rest day in your weekly exercise schedule.
Other Preparation Considerations
If the weather is warmer or more humid than usual on your donation day, take extra caution with your decision to exercise before donation. If you choose to exercise, reduce your intensity and duration to avoid effecting your plasma levels. Whether you exercise or not, be sure that you are well hydrated before your donation appointment and begin drinking extra fluids the day before. If you do exercise prior to your appointment, increase the amount of extra fluids you consume to compensate for any fluids or electrolytes that may be lost in that session.
References
- American Red Cross at Yale University: General Guidelines
- "Physiology of Sport and Exercise: Fourth Edition"; Jack Wilmore, David Costill and W. Kenney; 2008
- "Transfusion": Predonation Hydration and Applied Muscle Tension Combine to Reduce Presyncopal Reactions to Blood Donation; C.R. France et al.; June 2010
