The effect of a standard whole blood donation on oxygen uptake and exercise capacity: a systematic review and meta-analysis.

BACKGROUND: Blood is a life-saving product for many people worldwide. Voluntary blood donation serves the demand for blood but there are concerns among potential donors about the impact of blood loss on exercise performance. This systematic review aimed to collect the best available evidence of the effect of a standard whole blood donation on aerobic exercise performance.

STUDY DESIGN AND METHODS: Studies from six databases dealing with a standard whole blood donation (400-500 mL) followed by (sub)maximal exercise were retained. The outcomes included exercise-related blood variables (hemoglobin [Hb] concentration, hematocrit, and red blood cell count) and endurance exercise variables ((sub)maximal oxygen uptake, peak work rate, and time to exhaustion). Overall effects at different time points postdonation were investigated by performing meta-analyses and calculating mean differences (and 95% confidence intervals). The GRADE methodology (Grades of Recommendation, Assessment, Development, and Evaluation) was used to assess the quality of evidence.

RESULTS: We identified 6237 references and finally included 18 before-after studies of low quality. Twenty-four to 48 hours after a blood donation, 1) Hb concentration was reduced (7% decrease) until 14 days after the blood donation (4% decrease), 2) maximal oxygen uptake (VO2max ) was lower (7% decrease), and 3) a reduction in maximal exercise capacity (10% decrease) was present.

CONCLUSION: The best available evidence indicates that a standard whole blood donation (400-500 mL) leads to small but potentially physiologically important reductions in Hb levels, VO2max , and maximal exercise capacity in the first 2 days after the blood donation.