Related Experiment Videos
Compensatory tracking in humans with elevated carboxyhemoglobin
V A Benignus1, K E Muller, M V Smith
1United States Environmental Protection Agency, Human Studies Division, Research Triangle Park, NC 27711.
Insights
This study found that while higher carboxyhemoglobin (COHb) levels slightly increased tracking errors in men, the effects were not statistically significant. Even rapid carbon monoxide (CO) exposure did not notably worsen performance compared to slow exposure.
Area of Science:
- Environmental Health
- Human Physiology
- Occupational Safety
Background:
- Carbon monoxide (CO) exposure can lead to carboxyhemoglobin (COHb) formation in the blood.
- Elevated COHb levels may potentially impair cognitive and motor functions, including performance on tracking tasks.
Purpose of the Study:
- To investigate the impact of varying carboxyhemoglobin (COHb) levels on compensatory tracking task performance in adult males.
- To compare the effects of rapid versus slow COHb formation on performance.
Main Methods:
- Seventy-four men were divided into five groups, exposed to CO to achieve mean COHb levels ranging from 0.9% to 16.6%.
- Participants performed a 4-hour compensatory tracking task.
- COHb levels were maintained for the duration of the experiment, with one group experiencing slow COHb formation as a control.
Main Results:
- Tracking error scores showed a near-monotone increase with rising COHb levels.
- Despite the trend, these increases in tracking errors were not statistically significant.
- The magnitude of tracking error increase was small, even at the highest COHb levels.
- Rapid COHb formation resulted in similar performance decrements as slow COHb formation.
Conclusions:
- Moderate levels of carboxyhemoglobin (up to 16.6%) did not produce statistically significant impairments in compensatory tracking performance in this study.
- The rate of COHb formation (rapid vs. slow) did not substantially alter the observed performance effects.
- Further research may be needed to explore potential subtle effects or impacts on different tasks.
Abstract:
A total of seventy-four men divided into five groups performed a compensatory tracking task for 4 hr with group mean carboxyhemoglobin (COHb) levels of 0.9, 5.6, 6.1, 11.4 or 16.6%. In all but one group, COHb was formed in approximately 5 min by having the subject breathe a high concentration of carbon monoxide (CO) from a Douglas bag. An appropriate low level of CO in the exposure/test chamber maintained the elevated COHb for the 4-hr duration of the experiment. A slow COHb formation group, not exposed to CO during bag breathing, which was only exposed to low-level CO in the exposure/testing chamber, served as a positive control. Even though mean tracking error scores increased in a nearly monotone manner as a function of COHb, the effects were not statistically significant. Even at the highest dose, the increase in tracking error was small. The increased mean error score due to rapid formation was virtually the same as that due to slow formation.