Doctoral defence: Triin Kaldur "Effect of acute heat exposure and heat acclimation on arterial stiffness, oxidative stress and inflammation in healthy young men"

On 13th of September 2024 Triin Kaldur will defend her thesis "Effect of acute heat exposure and heat acclimation on arterial stiffness, oxidative stress and inflammation in healthy young men".

Supervisors: 
Associate professor Eve Unt, University of Tartu
Professor Jaak Kals, University of Tartu

Opponent: 
Associate professor Renata Žumbakytė-Šermukšnienė, Lithuanian University of Health Sciences (Lithuania)

Summary
High ambient temperature is an important factor that increases the risk of cardiovascular disease and mortality. Heavy physical exertion in a high-temperature environment puts a strain on a person’s physiological systems, reduces endurance working capacity and increases the risk of heat stroke. During acclimation in a hot environment, several physiological adaptation processes are triggered in the body, as a result of which the tolerance to heat stress improves, the level of health risk decreases and endurance working capacity increases. Therefore, acclimation plays an important role both in sports and in the military sphere.
Increased arterial stiffness is considered one of the earliest sign of the adverse functional changes of the cardiovascular system. The stiffness of the arteries characterizes the ability of the arteries to expand in response to blood pressure, which reflects the condition of the cardiovascular system, as well as its adaptation to various environmental factors. Heavy physical exertion in a high-temperature environment can increase aretrial stiffness due to inflammatory response and increased oxidative stress level. So far, there are very few studies that address the effects of acute heat stress and acclimation in hot environments on arterial stiffness and markers of oxidative stress and inflammation.
Present doctoral thesis shows that acute passive heat stress increases arterial stiffness and raises the level of the inflammation marker IL-6, but does not affect markers of oxidative stress in young men. In contrast, 10-day acclimation in a high-temperature environment has a reducing effect on the stiffness of the arteries. There are no significant associations between the extent of the change in arterial stiffness, the level of training and the improvement in endurance performance. The 10-day heat acclimation induces beneficial adaptive responses of oxidative stress and inflammation markers to the exhausting endurance exercise in the heat in young men.
The results of this doctoral thesis will help to understand the importance of acclimation in reducing cardiovascular risk during heavy physical work in a high-temperature environment.