Effect of prolonged running on physiological responses to subsequent exercise

Area of Science:

• Exercise Physiology
• Sports Science
• Human Performance

Background:

• Understanding the physiological impact of prolonged high-intensity exercise is crucial for training and recovery protocols.
• Previous research has explored acute fatigue but the specific effects of extensive high-intensity running on subsequent maximal and submaximal exercise responses require further investigation.

Purpose of the Study:

• To compare metabolic and cardiopulmonary responses during submaximal and maximal exercise before and after a high-intensity running bout.
• To identify physiological changes indicative of fatigue following 21 miles of high-intensity (70% VO2 max) treadmill running.

Main Methods:

• Seven aerobically trained subjects completed pre-test and post-test exercise sessions.
• Metabolic and cardiopulmonary variables (oxygen uptake, heart rate, blood lactate, etc.) were measured during graded exercise tests.
• The post-test occurred 45 minutes after completing 21 miles of high-intensity treadmill running.

Main Results:

• Submaximal exercise showed no significant differences in oxygen uptake, oxygen pulse, pulmonary ventilation, or ventilatory equivalent for oxygen.
• Submaximal heart rate was higher and respiratory exchange ratio was lower in the post-test.
• Maximal exercise capacity was reduced post-running, with significant decreases in maximal work time (12%), maximal oxygen uptake (6%), and maximal blood lactate concentration (47%).

Conclusions:

• A single bout of 21 miles of high-intensity running impairs subsequent maximal exercise performance.
• Mechanisms such as thermal stress and glycogen depletion may contribute to the observed performance decrements.
• While submaximal responses were largely preserved, maximal capacity was notably compromised, indicating significant acute fatigue.