Oxygen Levels and Circadian Rhythms (IMAGE) Cell Press Caption This is an abstract visualization of how variations in oxygen levels can change circadian rhythms through the protein HIF1α. Credit Asher et al./Cell Metabolism 2016 Usage Restrictions Credit Required. License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.