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Biomedical subjects

P M Mihevic

Publications and source records attributed to P M Mihevic.

6 recordsLinked to original sources
PubMed1984

Submaximal exercise quantified as percent of normoxic and hyperoxic maximum oxygen uptakes.

Maximum oxygen uptake (VO2max) was measured in six college-aged males under normoxic (NVO2max) and hyperoxic (HVO2max; 70% oxygen) conditions. Subjects then randomly performed the following three 20-min submaximal exercise bouts: 75% normoxic VO2max under normoxia (NVO2N), 75% normoxic VO2max under hyperoxia (NVO2H), and 75% hyperoxic VO2max under hyperoxia (HVO2H). Metabolic parameters were obtained at 5-min intervals. Hyperoxia resulted in a 13% increase (P less than 0.01) in VO2max (NVO2max = 3.54 l X min-1 vs HVO2max = 4.00 l X min-1). Significant (P less than 0.05) decreases were observed in VE (ventilation) (13%), epinephrine (37%), norepinephrine (26%), and blood lactate (28%), with no change in oxygen uptake (VO2), carbon dioxide production (VCO2), or respiratory exchange ratio (R) during hyperoxia at the same absolute power output (NVO2N vs NVO2H). However, at the same relative power outputs (NVO2N vs HVO2H) no significant changes in VE, epinephrine, norepinephrine, or blood lactate were observed when hyperoxia and normoxia were compared.

Epinephrine↗
PubMed1983

Carbon monoxide exposure and information processing during perceptual-motor performance.

This study examined the influence of exposure to ambient carbon monoxide resulting in final carboxyhemoglobin (COHb) levels of approximately 5.0% on the ability to process information during motor performance. Subjects (n = 16) performed a primary reciprocal tapping task and a secondary digit manipulation task singly and/or concurrently during 2.5 h exposure to room air (0 ppm CO) or 100 ppm CO. Five levels of tapping difficulty and two levels of digit manipulation were employed. Tapping performance was unaffected when COHb levels were as high as 5%. However, at this level of COHb it was noted that CO exposure interacted with task difficulty of both tasks to influence reaction time on the digit manipulation task. It was concluded that motor performance was not influenced by exposure to CO leading to COHb concentrations of 5%. Task difficulty was a significant factor mediating behavioral effects of CO exposure.

Adult↗
PubMed1983

Carbon monoxide and human performance in a single and dual task methodology.

Does carbon monoxide (CO) exposure limit man's ability to time share two concurrent tasks? In our study 15 subjects underwent two different 2.5-h exposures to either filtered air or to 100 ppm CO. They performed two tasks singly and in combination. The central task was a compensatory tracking task with three levels of difficulty, whereas the peripheral task was a signal detection task with three probabilities of signal occurrence. When HbCO levels reached 5% (during the last half hour of the exposure) performance on the peripheral signal detection task was altered. This was demonstrated by a 6% decline in signals detected correctly (p less than 0.05). This decline in signals detected was found when the signal detection task was performed alone. These results suggested that exposure to CO decreased arousal and interacted with fatigue to produce decreases in performance.

Adult↗
PubMed1981

Sensory cues for perceived exertion: a review.

A variety of physiological responses, classified as local or central factors, have been suggested as providing the primary input for perception of effort during exercise. The potency of these responses as perceptual cues, however, has seldom been addressed in terms of relevant modifying variables such as exercise intensity, exercise duration, exercise modality, and steady-state vs progressive exercise. This paper provides a critical review of the most relevant perceived exertion literature in terms of these considerations. It has been proposed that the impact of physiological responses as perceptual cues is dependent on their availability to conscious monitoring during exercise. The viability of this suggestion as a criterion for determining the importance of local and central cues for perceived exertion is also examined.

Body Temperature↗
PubMedDate not supplied

Spectral analysis of electroencephalogram during perceptual-motor learning.

Spectral analysis of the electroencephalogram was utilized to determine attention demands during learning of a perceptual motor task. Fifteen subjects participated in the task which consisted of 15 trials of the mirror star learning task. EEG was monitored bilaterally from the occipital and parietal lobes during each trial and analyzed for intensity and mean frequency components within five different bandwidths. All subjects rapidly improved performance in terms of both time and error reduction although the former measure appeared to be a better fit of the supradiagonal form of matrix typically found for this type of learning. Mean alpha frequency increased slightly during the task while delta frequency decreased.

Adolescent↗