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Biomedical subjects

N L Coplan

Publications and source records attributed to N L Coplan.

At least 19 recordsLinked to original sources
PubMed1995

Effects of blood donation on exercise performance in competitive cyclists.

This study evaluated 10 male cyclists before and after phlebotomy to determine the effect of donation of 1 U of blood on exercise performance. Each subject underwent maximal exercise testing with oxygen consumption measurement at baseline, 2 hours after phlebotomy, 2 days after phlebotomy, and 7 days after phlebotomy. Maximal performance was decreased for at least 1 week. Submaximal performance was unaffected by blood donation.

Bicycling↗
PubMed1994

Effect of athletic training on heart rate variability.

The time and frequency domain components of heart rate variability have been used to assess prognosis in patients with different types of heart disease. However, the effect of habitual exercise, which influences baseline parasympathetic tone, on heart rate variability has not been fully evaluated. To determine the effect of chronic exercise on heart rate variability, we studied 12 athletes and 18 control subjects. Time domain and frequency domain analysis was performed on 15-minute resting heart rate acquisitions. Athletes had evidence of increased vagal activity in the time domain compared with control subjects (eg, increased standard deviation of R-R intervals) but showed evidence of decreased power in variables reflecting vagal activity in the frequency domain (eg, total power and high-frequency power). Of note, there was good correlation between time and frequency domain variables, which reflected parasympathetic tone in the control group that was not seen in athletes. These data suggest that frequency domain analysis of heart rate variability may not be an accurate indicator of cardiac vagal tone in chronically trained endurance athletes and activity level may have to be considered when using heart rate variability to carry out prognostic stratification in patients with heart disease.

Adult↗
PubMed1992

Predictive accuracy of criteria used to assess maximal oxygen consumption.

To evaluate criteria frequently used to designate an exercise test as maximal, 33 men and 18 women completed progressive incremental cycle ergometry to exhaustion with direct measurement of oxygen consumption (VO2). On a separate day, subjects exercised at 115% of the maximal work rate attained in the first test following a 5-minute warm-up. If VO2 exceeded that of the progressive test by greater than or equal to 150 ml/min, subjects returned on a third day and pedalled at 125% of the first day's work ratepeak. This procedure was repeated until VO2 increased less than 150 ml/min, and defined whether the progressive test was a maximal or nonmaximal test. There were 45 tests that met the criterion for maximum during the progressive test and six nonmaximal tests. Respiratory exchange ratio and 85% age-predicted maximal heart rate were sensitive criteria for a maximal test but were not specific. Attainment of age-predicted maximal heart rate and peak lactate greater than 8 mmol/L were highly specific but insensitive measures of a maximal test. In the absence of a VO2 plateau, age-predicted maximal heart rate and lactate greater than 8 mmol/L can be used as indicators of maximal tests with a high degree of confidence. When age-predicted maximal heart rate or lactate greater than 8 mmol/L are not attained, the test may still be maximal because negative predictive value is low.

Aging↗
PubMed1991

Gender differences in the systolic blood pressure response to exercise.

Previous work has shown a gender difference in the normal cardiac response to exercise. Men had significantly higher absolute systolic blood pressure responses at 50%, 75%, and 100% peak heart rate on all modalities (p less than 0.05). This difference is absent when systolic blood pressure is adjusted for body surface area, is reduced when adjusted for body weights, and is reversed when systolic blood pressure is adjusted for lean body mass. The influence of gender on the systolic blood pressure response to dynamic exercise was independent of exercise modality. Men had a higher systolic blood pressure in spite of the fact that they had similar sympathetic nervous system response as indicated by urinary norepinephrine excretion. Gender differences in systolic blood pressure responses were altered when adjusted for body weight, body surface area, and lean body mass.

Blood Pressure↗