Temperature Control of Hypertensive Rats during Moderate Exercise in Warm Environment

Area of Science:

• Physiology
• Exercise Science
• Thermoregulation

Background:

• Physical exercise in warm environments is increasingly relevant due to rising global temperatures.
• Understanding thermoregulation in hypertensive models is crucial for public health.
• This study is the first to examine body temperature control in Spontaneously Hypertensive Rats (SHR) during exercise in a warm environment.

Purpose of the Study:

• To investigate the body temperature control mechanisms of SHR during moderate exercise in temperate and warm conditions.
• To compare the physiological responses of SHR and Wistar rats to exercise-induced heat stress.
• To determine the relationship between mechanical efficiency and hyperthermia in SHR during exercise.

Main Methods:

• Male SHR and Wistar rats underwent moderate exercise in 25°C and 32°C environments.
• Body and tail skin temperatures, oxygen consumption, exercise duration, and workload were monitored.
• Mechanical efficiency and heat storage were calculated to assess thermoregulatory responses.

Main Results:

• SHR demonstrated significantly higher heat production, body temperature, and heat storage compared to Wistar rats (p < 0.05).
• SHR exhibited a more rapid and intense rise in body temperature during exercise in the warm environment (p < 0.05).
• Reduced mechanical efficiency in SHR was strongly correlated with elevated body temperature at fatigue in warm conditions (p < 0.05).

Conclusions:

• SHR display distinct thermoregulatory differences during exercise in warm environments, characterized by increased heat production and storage.
• These physiological alterations in SHR lead to exacerbated hyperthermia and diminished exercise capacity.
• The findings highlight impaired thermoregulation in hypertensive rats, impacting their ability to exercise safely in heat.