The acute effects of whole blood donation on cardiorespiratory and haematological factors in exercise: A systematic review

by Diane Maria Johnson, Justin Roberts, Dan Gordon

This systematic review aimed to collect the relevant historical and current literature to produce an informed analysis of the acute effects on cardiorespiratory and haematological factors following whole blood donation (~ 470 ml) during exercise. Testing the hypothesises that blood donation produces either no changes (Null) or produces significant changes (alternate) in haematology, V.O2, heart rate, exercising power and time.

Four databases of medical and science orientations were searched with terms sensitive to connections regarding exercise, blood donation (400–500 ml)/haematology, V.O2, heart rate, exercising power and time. The study retrieval process utilised the PRISMA approach and selection was via an adapted scoring method according to the Consensus based Standards for the selection of health Measurements Instruments (COSMIN). Systematic review focused on 24–48 hrs post donation. Details of the PRSIMA checklist can be found in the accompanying online document.

Following scrutiny of 48 research papers by two independent assessors 8 experimental studies were included. Four studies showed a mean reduction for difference in V.O2max (- 2.4 ± 1.4 ml∙kg^-1∙min^-1) and a medium effect size (-0.26). No statistical significance was present at the mean meta-analysis level, also the case for heart rate, time to exhaustion and power. A mean reduction was seen in haemoglobin (- 1.05 g^.dL^-1), haematocrit (- 3.71%) and red blood cells (- 0.44 Mio μL^-1), very large effect size was observed (Cohen’s d, -0.75, -1.16 and -4.23 respectively) and statistical significance (95% CI, -2.04, -0.54; -4.59, 2.28 and -4.37, -4.10 respectively).

Although individual studies show that V.O2max Is reduced from blood donation pooled results show that V.O2max is indeed not significantly reduced from blood donation 24–48 hrs post donation. Additionally sub-maximally there isn’t enough data to produce substantial comparatives. Furthermore, this systematic review demonstrates that there are not enough high-quality studies regarding cardiorespiratory outcomes following blood donation.