The impact of prolonged exercise in a cold environment upon cardiac function

Area of Science:

• Exercise Physiology
• Cardiovascular Research
• Environmental Medicine

Background:

• Understanding the physiological responses to extreme exercise conditions is crucial for athlete health and performance.
• Investigating the impact of cold exposure on cardiac function during prolonged exertion is an area of growing interest.

Purpose of the Study:

• To assess the effects of cold (0°C) versus temperate (19°C) ambient temperatures on left ventricular (LV) function post-exercise.
• To evaluate markers of myocardial damage following prolonged cycling in different thermal conditions.

Main Methods:

• Eight elite male cyclists completed two 100-mile cycling trials at 0°C and 19°C.
• Echocardiography and blood samples (CK-MBmass, cTnT) were collected pre-, immediately post-, and 24-h post-exercise.
• Analysis included LV systolic and diastolic parameters, with statistical comparison using two-way repeated-measures ANOVA.

Main Results:

• No significant changes in systolic function were found between trials or over time.
• A significant difference in the early (E) to late (A) diastolic filling ratio (E:A) was observed immediately post-exercise between the 19°C and 0°C trials (P < 0.05).
• Creatine kinase isoenzyme MB (CK-MBmass) levels increased significantly post-exercise in both trials, and cardiac troponin T (cTnT) was elevated in two subjects after the 19°C trial.

Conclusions:

• Prolonged cycling at 19°C, unlike at 0°C, acutely affects diastolic filling parameters.
• Minimal cardiac damage markers were observed in some athletes, appearing independent of the observed diastolic filling changes.