Changes in memory performance, heart rate, and blood oxygen saturation due to 30% oxygen administration

The effect of acute normobaric hyperoxia on cognition: a systematic review, meta-analysis and meta-regression

This systematic review, meta-analysis and meta-regression examined the effect of acute normobaric hyperoxia breathing on cognition in healthy humans. 23 studies were included providing 76 effect estimates (EE). Hyperoxic breathing improved memory accuracy (22 EEs; g = 0.34) and speed (9 EEs; g = 0.59), attention accuracy (7 EEs; g = 0.59) and speed (7 EEs; g = 0.51), reaction speed (8 EEs; g = 0.82), crystallised intelligence (7 EEs; g = 0.73), executive function (6 EEs; g = 0.88) and information processing (10 EEs; g = 0.62). However, the overall quality of evidence was low (average Rosendal score of 47%) and there was a large range of study heterogeneity, with prediction intervals often crossing 0; therefore, reducing the reliability of the magnitude of these favourable effects. Oxygen percentage, 100% compared with 22-99% oxygen, temporal position of administration to task performance, and study quality did not influence the overall weighted mean effects for most cognitive domains. Altogether, despite beneficial results, further high quality research is required prior to recommending hyperoxic breathing to enhance cognition.

Effects of Cardiorespiratory Exercise on Cognition in Older Women Exposed to Air Pollution

The aim was to analyze the effects of cardiorespiratory exercise and air pollution on cognition and cardiovascular markers in four groups of older women: the active/clean air group (AC), the active/polluted air group (AP), the sedentary/clean air group (SC), and the sedentary/polluted air group (SP). Active groups performed a training task based on progressive walking. Prior to and after the experiment, the following parameters were assessed: cognition, by Mini Mental State Examination (MMSE); maximum oxygen uptake (VO_2max), estimated by the Six-Minute Walk Test (6mWT); heart rate (HR); and oxygen saturation (SpO₂). There were significant differences (p < 0.05) between the AC and the SP in all the MMSE dimensions except “Registration”, and in all the physiological variables (VO_2max, SpO₂, HR). Aerobic exercise may be a protective factor against the effects that pollution have on cognition and on the mechanisms of oxygen transport.

Cerebral Hypoxia can lead to Personality Changes: A Review

The term ‘Cerebral hypoxia’ refers to reduced supply of oxygen to the brain tissues. If a brain cell becomes completely deprived of oxygen, the condition is referred to as cerebral anoxia. Since brain needs constant supply of oxygen for its vital functioning, cerebral hypoxia can have major impact of cerebral hemispheres, leading to cognitive, behavioural as well as personality changes including anxiety, depression and memory loss.

Effects of 92% oxygen administration on cognitive performance and physiological changes of intellectually and developmentally disabled people

Background

The present study addressed how 92% oxygen administration affects cognitive performance, blood oxygen saturation (SpO₂), and heart rate (HR) of intellectually and developmentally disabled people.

Methods

Seven males (28.9 ± 1.8 years) and seven females (34.4 ± 8.3 years) with intellectual and developmental disabilities (disabled level 2.1 ± 0.5) completed an experiment consisting a 0-back task with normal air (21% oxygen) administered in one run and hyperoxic air (92% oxygen) administered in the other run. The experimental sequence in each run consisted of a 1-min adaptation phase, 2-min control phase, and 2-min 0-back task phase, where SpO₂ and HR were gauged for each phase.

Results

The administration of 92% oxygen increased 0-back task performance of intellectually and developmentally disabled people, in association with increased SpO₂ and decreased HR. Our results demonstrate that sufficient oxygen supply subserving cognitive functions, even as a short-term effect, could increase cognitive ability for the intellectually and developmentally disabled people.

Conclusions

It is concluded that enriched oxygen can positively affect, at least in the short-term, the working memory of those with intellectual and developmental disability.

Effects of oxygen concentration and flow rate on cognitive ability and physiological responses in the elderly

The supply of highly concentrated oxygen positively affects cognitive processing in normal young adults. However, there have been few reports on changes in cognitive ability in elderly subjects following highly concentrated oxygen administration. This study investigated changes in cognitive ability, blood oxygen saturation (%), and heart rate (beats/min) in normal elderly subjects at three different levels of oxygen [21% (1 L/min), 93% (1 L/min), and 93% (5 L/min)] administered during a 1-back task. Eight elderly male (75.3 ± 4.3 years old) and 10 female (71.1 ± 3.9 years old) subjects, who were normal in cognitive ability as shown by a score of more than 24 points in the Mini-Mental State Examination-Korea, participated in the experiment. The experiment consisted of an adaptation phase after the start of oxygen administration (3 minutes), a control phase to obtain stable baseline measurements of heart rate and blood oxygen saturation before the task (2 minutes), and a task phase during which the 1-back task was performed (2 minutes). Three levels of oxygen were administered throughout the three phases (7 minutes). Blood oxygen saturation and heart rate were measured during each phase. Our results show that blood oxygen saturation increased, heart rate decreased, and response time in the 1-back task decreased as the concentration and amount of administered oxygen increased. This shows that administration of sufficient oxygen for optimal cognitive functioning increases blood oxygen saturation and decreases heart rate.

Correlation between cognitive ability measured by response time of 1-back task and changes of SpO2 by supplying three different levels of oxygen in the elderly

AIM

This study investigated the correlation between response time of the 1-back task and changes of blood oxygen saturation (SpO2 ) by supplying three different levels of oxygen (21%, 1 L/min; 93%, 1 L/min; 93%, 5 L/min) in the elderly.

METHODS

A total of 17 older adults (mean age 72.9 ± 4.7 years) participated in the experiment. A 1-back task was used as a cognitive task. The experiment consisted of three phases, which included the adaptation phase (3 min) after oxygen administration, the control phase (2 min) that maintained a stable condition before the task, and the task phase (2 min) where the 1-back task was carried out. SpO2 was measured during each phase.

RESULTS

As concentration level and supply of oxygen increased, SpO2 increased and response time of the 1-back task decreased.

CONCLUSION

Highly concentrated oxygen administration can increase SpO2 in the elderly and an increase in cognitive performance, such as a decrease in response time, can be observed.

Changes of 2-back task performance and physiological signals in ADHD children due to transient increase in oxygen level

This study investigated the effect of 92% oxygen administration on 2-back task performance, blood oxygen saturation (SpO(2) [%]), and heart rate (HR [bpm]) of Attention Deficit Hyperactivity Disorder (ADHD) children. Subjects were thirteen boys (mean 12.9±1.3 years) who were diagnosed as ADHD and are under treatment, having no disease or abnormality in a respiratory system or a periphery vascular flow system. The experiment consisted of two runs: one was a 2-back task under normal air (21% oxygen) condition and the other under hyperoxic air (92% oxygen) condition. The experiment sequence in each run consisted of three phases, which included the Adaptation phase (1 min) after oxygen administration, the Control phase (2 min) that maintained a stable condition before the task, and the Task phase (2 min) that performed 2-back task. SpO(2) and HR were measured during each phase. The analysis of cognitive performance with 92% oxygen administration when compared to 21% oxygen revealed that the response time decreased. When 92% oxygen in the air was supplied, the blood oxygen saturation increased while the heart rate decreased compared to those under the 21% oxygen condition. The response time also decreased for the subjects with a high SpO(2) during the Task phase. This showed that due to sufficient oxygen supply necessary for cognitive processing, SpO(2) increased and heart rate decreased. Therefore, an increase in cognitive ability such as a decrease in response time was observed in a transient period for ADHD children.

Activation of the limbic system under 30% oxygen during a visuospatial task: an fMRI study

The purpose of this study was to observe activation of the limbic system during the performance of visuospatial tasks under 21% O(2) or 30% O(2). Eight right-handed male college students were selected as subjects for this study. A visuospatial task was presented while brain images were scanned by a 3T fMRI system. The experiment consisted of the following two runs: a visuospatial task under normal air (21% O(2)) and a visuospatial task under hyperoxia (30% O(2)). The accuracy rate on the visuospatial task was enhanced during 30% O(2) compared to 21% O(2). The neural activation areas of the limbic system were similar in the cingulate gyrus, thalamus, limbic lobe and parahippocampal gyrus. Increased neural activation was observed in the cingulate gyrus and thalamus under 30% O(2) compared to 21% O(2). Under 30% O(2), the improvement in visuospatial task performance was related to an increase in neural activation of subcortical structures, such as the thalamus and cingulate gyrus, as well as the cerebral cortex.

Heart rate recovery predicts memory performance in older adults

The current study examined cardiovascular reactivity and recovery during memory testing in a sample of 28 younger and 28 older adults. Heart rate (HR) levels were measured before, during, and after a memory test (word list recall). Contrary to prediction, older adults did not have a blunted cardiovascular response to memory tasks compared to younger adults. Word list recall performance was predicted by both Age and an Age x HR recovery interaction. As expected, younger adults performed better on the word list task than older adults. In addition, older adults with better posttest HR recovery performed significantly better than older adults with poor posttest HR recovery, whereas HR recovery differences in younger adults were inconsequential. These relationships were not affected by subjective appraisals of anxiety and task difficulty. Overall, cardiac dysregulation, seen here as low HR recovery, represents an important, potentially modifiable, factor in memory performance in older adults. In addition to being beneficial to overall health, interventions designed to help older adults regulate their HR responses may help offset certain memory declines.