An integrated exercise response and muscle fatigue model for performance decrement estimates of workloads in oxygen-limiting environments

Abstract

The performance dynamic physiology model (DPM-PE) integrates a modified muscle fatigue model with an exercise physiology model that calculates the transport and delivery of oxygen to working muscles during exposures of oxygen-limiting environments. This mathematical model implements a number of physiologic processes (respiration, circulation, tissue metabolism, diffusion-limited gas transfer at the blood/gas lung interface, and ventilatory control with afferent feedback, central command and humoral chemoreceptor feedback) to replicate the three phases of ventilatory response to a variety of exertion patterns, predict the delivery and transport of oxygen and carbon dioxide from the lungs to tissues, and calculate the amount of aerobic and anaerobic work performed. The ventilatory patterns from passive leg movement, unloaded work, and stepped and ramping loaded work compare well against data. The model also compares well against steady-state ventilation, cardiac output, blood oxygen levels, oxygen consumption, and carbon dioxide generation against a range of exertion levels at sea level and at altitude, thus demonstrating the range of applicability of the exercise model. With the ability to understand and predict gas transport and delivery of oxygen to working muscle tissue for different workloads and environments, the correlation between blood oxygen measures and the recovery factor of the muscle fatigue model was explored. Endurance data sets in normoxia and hypoxia were best replicated using arterial oxygen saturation as the correlate with the recovery factor. This model provides a physiologically based method for predicting physical performance decrement due to oxygen-limiting environments.

Finite Element Modeling of Blast Lung Injury in Sheep

“…A dynamic physiology model (DPM) that incorporates blunt and blast trauma injury and chemical damage to the lungs has been developed [24,25]. Damage in the DPM has been correlated with fluid infiltration, which can be quantified during necropsy by measurements of lung weight.…”

An integrated physiology model to study regional lung damage effects and the physiologic response

“…The alveolar diffusing capacities for oxygen (40 ml/mmHg-min) and carbon dioxide (800 ml/mmHg-min) were based on the data of Hill [37], The alveolar oxygen diffusing capacity was assumed to be a function of oxygen partial pressure and workload as described by Graeser [38] (Equation 15), where $P_{\mathrm{italicAlv},O_2}$ is alveolar oxygen (mmHg) and Work is the exercise load in Watts. All DPM parameters outside of the pulmonary system are modeled as previously described [20,21]. The airway volumes measured by Horsfield represent an average human.…”

“…To maintain similar structure, surface areas were scaled by body mass to the 2/3 power. Scaling in the non-airway compartments of the DPM has been previously described [20,21]. …”

“…Our group has previously developed a dynamic physiology model (DPM) which predicts the ventilatory responses to oxygen-limiting environments, toxic gas inhalation and exercise [20,21]. The DPM ties together several independent modules into a single compartmentalized model with the ability to predict the physiological impact (e.g.…”

Changes in Aerobic Productivity due to the Influence of Non-training Facilities on Representatives of Racetrack Exercises

“…Враховуючи тісний зв'язок між аеробною про-дуктивністю та продуктивністю м'язової роботи [17], можна припустити, що одним з можливих механізмів такого зростання є саме покращання процесів енергозабезпечення скорочувальної діяльності скелетних м'язів під дією АТФ-лонг. Таким чином, отримані дані вказують на наявність позитивного впливу пливу метаболічного препара-ту на процес аеробного енергозабезпечення у бігунів на середні дистанції, одним з можливих механізмів якого є стимулююча дія АТФ-лонг на функціональні можливості серцево-судинної систе-ми та скелетних м'язів.…”