Related Experiment Video
Updated: Feb 12, 2026

Randomized, Triple-Blind, and Parallel-Controlled Trial of Transcranial Direct Current Stimulation for Cognitive Rehabilitation after Stroke
Published on: June 6, 2025
Immediate effects of blood donation on physical and cognitive performance-A randomized controlled double-blinded
Håkon S Eliassen1, Tor Hervig, Sebastian Backlund
1From the Faculty of Medicine, University of Bergen, Bergen, Norway (H.S.E., T.H., S.B., A.G., T.A.); Department of Immunology and Transfusion Medicine, Haukeland University Hospital, Bergen, Norway (H.S.E., T.H., J.S., T.F., C.K.B., T.A., G.S.); Norwegian Naval Special Operations Command, Bergen, Norway (H.S.E., T.F., C.K.B.); National Health Service Blood and Transplant, Birmingham, UK (H.D.); Faculty of Education, Arts and Sports, Department of Sport, Food and Natural Sciences, Western Norway University of Applied Sciences, Bergen, Norway (V.V.I., M.K., E.W.); Department of Neurology, Haukeland University Hospital, Bergen, Norway (A.G.); Norwegian Armed Forces Medical Service, Sessvollmoen, Ullensaker, Norway (G.S.); Department of Biological and Medical Psychology, University of Bergen (A.G.), Norway; and Department of Anaesthesia and intensive care, Haukeland University Hospital, Bergen, Norway (T.F., C.K.B.).
Background:
The success of implementing damage control resuscitation principles pre-hospital has been at the expense of several logistic burdens including the requirements for resupply, and the question of donor safety during the development of whole blood programs. Previous studies have reported effects on physical performance after blood donation; however, none have investigated the effects of blood donation on cognitive performance.
Method:
We describe a prospective double-blinded, randomized, controlled study comprised of a battery of tests: three cognitive tests, and VO2max testing on a cycle ergometer. Testing was performed 7 days before blinded donation (baseline day), immediately after donation (Day 0), and 7 days (Day 7) after donation. The inclusion criteria included being active blood donors at the Haukeland University Hospital blood bank, where eligibility requirements were met on the testing days, and providing informed consent. Participants were randomized to either the experimental (n = 26) or control group (n = 31). Control group participants underwent a 'mock donation" in which a phlebotomy needle was placed but blood was not withdrawn.
Results:
In the experimental group, mean ± SEM VO2max declined 6% from 41.35 ± 1.7 mLO2/(min·kg) at baseline to 39.0 ± 1.6 mLO2/(min·kg) on Day 0 and increased to 40.51 ± 1.5 mLO2/(min·kg) on Day 7. Comparable values in the control group were 42.1 ± 1.8 mLO2/(min·kg) at baseline, 41.6 ± 1.8 mLO2/(min·kg)) on Day 1 (1% decline from baseline), and 41.8 ± 1.8 mLO2/(min·kg) on Day 7.Comparing scores of all three cognitive tests on Day 0 and Day 7 showed no significant differences (p > 0.05).
Conclusion:
Our main findings are that executive cognitive and physical performances were well maintained after whole blood donation in healthy blood donors. The findings inform postdonation guidance on when donors may be required to return to duty.
Level Of Evidence:
Randomized, controlled, double-blinded prospective trial study, level 1.
More Related Videos
Related Concept Videos
Blind Procedures
Blinding
Physical Methods for Controlling Microbial Growth: Temperature
Physical Methods for Controlling Microbial Growth: Radiation and Filtration
Cognitive Dissonance
Trial and Error and Algorithm

