Biomedical subjects

M W Busse

Publications and source records attributed to M W Busse.

23 records · Page 2Linked to original sources

PubMed1989

The relationship between lactic acid and work load: a measure for endurance capacity or an indicator of carbohydrate deficiency?

The influence of low and high carbohydrate diets on the relationship between blood lactate concentration ([Lac]) and work load (WL) in incremental exercise tests (cycle ergometer) and endurance tests was evaluated in trained subjects. The relationship between relative work load (WLrel) and [Lac] in arterialized blood was compared in untrained subjects (UT) and trained male athletes (TR) after 2 days without training while consuming a high carbohydrate diet (HCD). In both groups [Lac] of 2 mmol.l-1 was reached at about 60% [(mean +/- SD) UT 57.7% +/- 6%, TR 62.7% +/- 3.8%] and 4 mmol.l-1 at about 75% (UT 75.2% +/- 3.6%, TR 77.8 +/- 2.2) of the maximal work load (WLmax). In eight cyclists the relationship between [Lac] and WL was not influenced by a 13-day training camp; however, heart rate was lower after the training camp. During their normal training programme, trained subjects had high relative work loads at their [Lac] thresholds, but after an HCD combined with an interruption of the training of 3 days, the relationship between [Lac] and WLrel was the same as in UT. In six TR a low carbohydrate diet (LCD) combined with training led to high absolute (WLabs) and WLrel at [Lac] at 2 and 4 mmol.l-1; an HCD combined with 3 days without training led to low WLabs and WLrel at the same [Lac] and to higher WLmax. In spite of the apparently lower endurance capacities TR were able to work significantly longer after HCD than after LCD (23 +/- 10.5 min and 49 +/- 16.2 min, respectively) at 65% of their WLmax. The variability of the relationship between [Lac] and WL following the dietary regimes leads to the conclusion that the "typical" [Lac] versus WL curve of endurance TR may result from a permanent glycogen deficiency.

Adult↗

PubMed1989

Interrelationship between pH, plasma potassium concentration and ventilation during intense continuous exercise in man.

During resting conditions plasma hydrogen ion concentration ([H+]P) is known to influence ventilation (VE), whereas the control of plasma potassium concentration ([K+]P) at rest and of both [K+]P and VE during exercise are controversial issues. To obtain more information about these variables during muscular work, eight trained men performed two successive intense continuous cycle-ergometer tests, the first (test I) during metabolic acidosis, the second (test II) with an alkalotic pH. No correlation was found between [H+]P and [K+]P or VE in the direction of change of these variables in test I. Furthermore, no correlation between [H+]P and [K+]P in test I and II was seen. Instead [K+]P and VE changed in relation to the exercise intensity. We suggest that the results confirm [K+]P as an indicator of muscular stress. In addition, the similar behaviour of relative values of [K+]P and VE changes in test I (r = 0.9, m = 1.0, where m is the slope of the regression curve) supports the hypothesis that extracellular potassium controls VE and thereby [H+]P also.

Adult↗

PubMed1989

The calculation of the osmotic volumes of distribution of hypertonic sodium bicarbonate and other hypertonic solutions: a theoretical approach.

Correction of a base deficit with hypertonic sodium bicarbonate (NaHCO3) according to the formula 0.3 x body weight (kg) x BE may overestimate the real demands, especially during shock and cardiopulmonary resuscitation (CPR). Life threatening alkalosis and osmolal poisoning may be the consequence. As an explanation, the possibly impaired functional distribution space related to low cardiac output and volume centralization during CPR is proposed. By application of our own and outside literature, data equations are specified for an approximate precalculation of osmolality and pH changes due to infusion of hypertonic NaHCO3. Calculation of the osmotic volumes of distribution of NaHCO3 during cardiopulmonary resuscitation (CPR) from emergency literature data demonstrates a possible reduction of the functional distribution spaces of about 70 to 80% compared with normal values. This is in good agreement with the reported reduction of cardiac output to about 25% of normal during CPR. The calculated amount of sodium bicarbonate to be recommended during CPR, thus, should not exceed 50 mmol given in time intervals of at least 10 min, severe acidosis and sufficient ventilation presumed.

Acid-Base Imbalance↗

PubMed1989

Effect of consecutive exercise bouts on plasma potassium concentration during exercise and recovery.

During and after two similar incremental treadmill tests, one with increasing, the other with initially decreasing blood acidosis, plasma potassium was measured in 11 volunteers. Independent of increasing or decreasing hydrogen ion, lactate, or bicarbonate concentrations, plasma potassium rose in relation to muscular stress with nearly equal concentrations for comparable exercise intensities in both tests. During the first 3 min of recovery, plasma potassium fell rapidly in spite of nearly unchanged blood acidosis and significantly decreasing bicarbonate concentration. After the 5th min of recovery, plasma potassium concentration was even slightly below pre-exercise values despite severe metabolic acidosis. It was concluded that there was little or no effect of plasma hydrogen ion, lactate, or bicarbonate on plasma potassium concentration during and after exercise. We propose that plasma potassium is primarily regulated by intracellular effects of inorganic phosphate, pH, and temperature on (Na+-K+)-ATPase. We suggest that these results reflect a model of grand mal seizure-induced lactic acidosis. The noted low blood potassium concentrations despite the presence of severe metabolic acidosis secondary to epileptic seizure is thus suggested to reflect the "normal" post-exercise state of potassium concentration.

Acidosis, Lactic↗

PubMedDate not supplied

[Rope pulley isokinetic system in shoulder rehabilitation--initial results].

AIM: Of this study was to evaluate the results of a shoulder rehabilitation program of different shoulder diseases, based on an isokinetie pulley system ("Moflex", Recotec/Bernina, Swiss). METHOD: In this prospective study 70 patients participated in a standardized rehabilitation program (instability: n = 19; rotator cuff disorders: n = 23; impingement syndrome without lesion: n = 16; others: n = 12; operative therapy: n = 47). The major aspect of the program was an isokinetic pulley system. RESULTS: Isokinetic training with the used device affords strict monitor-feedback to avoid critical torque values. Strength which was attained without relevant pain was almost linearly increased by a mean of 31% until the 20th day of rehabilitation, workload by 79%. At the end of the rehabilitation program the strength of the affected (mostly dominant) shoulder was 15% higher than in the unaffected shoulder; the respective workload values were almost equal. CONCLUSION: These first results demonstrate the value of the isokinetic pulley system in the rehabilitation of the investigated shoulder diseases. The equipment may be used already in an early postoperative state. First results of strength increases using an isokinetic pulley system in shoulder rehabilitation are presented.

Adult↗