Biomedical subjects

M B Maron

Publications and source records attributed to M B Maron.

61 records · Page 4Linked to original sources

PubMed1979

Visual evoked potentials and signal detection following a marathon race.

Five marathon runners participated in a visual sustained attention experiment 1 week prior to a competitive martathon race and from 1.5 to 8.5 h following the race. The task was designed to help assess changes in central nervous system function by examinining both behavioral deficits and electroencephalogram (EEG) visual evoked potentials as a function of the race. A significant increase in heart rate was observed during the behavioral task. No changes in any of the wave forms of the EEG visual evoked response were observed during the vigilance task as a function of the race. Sustained visual attention responses were unchanged for correct detections, but post-marathon performance gave significantly fewer false positive responses. The results provided evidence that central nervous system dysfunction was not observed following the completion of a competitive marathon race.

Adult↗

PubMed1979

Alterations in pulmonary function consequent to competitive marathon running.

This study was designed to investigate the mechanisms underlying the significant reductions in vital capacity after marathon racing originally reported over 50 years ago. Spirometric, maximum expiratory flow-volume (MEFV), DLCO and residual volume (RV) measurements were made on 13 runners (11 males and 2 females) 1--2 weeks prior to the marathon, immediately after finishing the race, and again the next day. An average 0.48 L (8.6%) reduction in post-race forced vital capacity (FVC) was accompanied by an equivalent increase in RV. Thus, total lung capacity did not change, and the reduction in FVC was a result of an expiratory rather than an inspiratory limitation. Post-race FEV1 and FEF200-1200 remained unchanged while FEV1-2, FEF1 and FEF2 were reduced 19.7, 26.7 and 23.3%, respectively. Mean DLCO was unchanged. Pulmonary function on the following day was similar to that observed on the control day. These data indicated that after the race, expiratory flow was unaffected at high lung volumes, but was decreased at low lung volumes (within the effort-independent portion of the MEFV curve). The results are compatible with small airway closure occurring at an increased lung volume, which would result in a decreased FVC and an increased RV.

Adult↗

PubMed1978

The marathon: a history and review of the literature.

An evaluation of the physiological, biochemical and psychological results obtained by various investigators on participants in competitive marathons is provided. The historical background of the studies on marathon runners suggests that much of the early information has been forgotten and has resulted in repetitive studies providing no additional insight into the physiological problems of these runners. However, the basic information obtained since the first scientific studies of participants in the 1899 marathon race has provided interesting and valuable information. The value of this older basic information to present and future investigators is emphasized. Suggestions for additional research based on results from both the earliest and the latest studies of marathon runners are made. Increasing participation in marathon races by individuals of both sexes, by individuals with various kinds of pathology as well as individuals of varying levels of physical competence suggests the value and need for research on these individuals before, during and after their involvement in such a strenuous and physiologically demanding physical task.

Blood Chemical Analysis↗

PubMed1977

Blood biochemical alterations during recovery from competitive marathon running.

The occurrence of possible prolonged alterations in plasma levels of cortisol, epinephrine, norepinephrine, selected energy metabolites, and water and electrolyte balance was assessed in six highly trained male marathon runners by measuring blood biochemical constituents on the 10th day before and for the three days following the running of a marathon. Post-race changes in hemoglobin, hematocrit, and protein levels indicated that a hemodilution had occurred, possibly as a result of elevated sodium levels. Epinephrine remained elevated until the second day. Cortisol was depressed on the first and third post-race days while variable levels were observed on the second day. No prolonged alterations were noted in norepinephrine, FFA, glycerol, triglycerides, glucose, lactate, and pyruvate.

Blood Glucose↗

PubMed1977

Thermoregulatory responses during competitive marathon running.

To assess thermoregulatory responses occuring under actual marathon racing conditions, rectal (Tre) and five skin temperatures were measured in two runners approximately every 9 min of a competitive marathon run under cool conditions. Race times and total water losses were: runner 1 = 162.7 min, 3.02 kg; runner 2 = 164.6 min, 2.43 kg. Mean skin temperature was similar throughout the race in the two runners, although they exhibited a marked disparity in temperature at individual skin sites. Tre plateaued after 35--45 min (runner 1 = 40.0--40.1, runner 2 = 38.9--39.2 degrees C). While runner 2 maintained a relatively constant level for the remainder of the race, runner 1 exhibited a secondary increase in Tre. Between 113 and 119 min there was a precipitous rise in Tre from 40.9 to 41.9 degrees C. Partitional calorimetric calculations suggested that a decrease in sweating was responsible for this increment. However, runner 1's ability to maintain his high Tre and running pace for the remaining 44 min of the race and exhibit no signs of heat illness indicated thermoregulation was intact.

Adult↗

PubMed1976

Oxygen uptake measurements during competitive marathon running.

Oxygen uptakes and running speeds of two marathon runners as well as average slopes of the running terrain were measured approximately every 3 miles of a competitive marathon. The runners had energy expenditures requiring from 68 to 100% of their Vo2 max, confirming previous estimates. As the race progressed, both runners exhibited decreases in V92 while running at similar rates and slopes. At 23.4 miles, one runner was found to be utilizing 4.54 l/min, a value equivalent to his Vo2 max.

Humans↗

PubMed1975

Acute blood biochemical alterations in response to marathon running.

Adrenal-sympathico function, blood carbohydrates and lipids, and water and electrolyte balance were studied in six highly trained male marathon runners prior to and after running a marathon (26.2 miles; 42.2 km) and on control days corresponding to the above times. Fluid intake was not sufficient to maintain body weight, the runners losing approximately 2.8 kg. Estimated plasma volume losses (161 ml, 4.4%) indicated that most of the fluid loss was extravascular. Tre rose an average 2.4 degrees C and a significant negative correlation between running time and rise in Tre was observed. Glucose, fatty acids, glycerol, hemoglobin, and plasma proteins were significantly elevated after the race. Small but statistically significant increments in lactate and pyruvate were also observed. Alterations in adrenal-sympathico function were indicated by increased levels of cortisol, epinephrine, and norepinephrine.

Adrenal Medulla↗