The Effect of Acute Caffeine Consumption in a Dehydration and Hot and Humid conditions on Aerobic Function, Blood Pressure and Some Factors of the Immune System of Active Men

Background & objectives: Caffeine can affect many physiological functions of the body. The aim of this study was to investigate the response of aerobic function, blood pressure and some immune system factors of trained men to acute caffeine consumption in dehydrated condition and warm and humid environment. Methods: Thirty male athletes with a mean age of 26.6±3.9 years in dehydrated conditions voluntarily participated in this study, which was performed in a double-blind manner. Subjects were divided into three groups: caffeine consumption group (n=10), placebo group (n=10) and control group (n=10). The Caffeine group consumed 6 mg/kg body weight of caffeine. Sixty minutes later, the subjects performed an increasingly exhausting exercise. Blood samples collecting and blood pressure measuring took place before, immediately after and 24 hours after exercise. Analysis of variance with repeated measures (group * time) and one-way analysis of variance were used for statistical calculations. Results: The duration of the exhaustion test in the caffeine consumption group was significantly longer than the control (p≤0.01) and placebo (p≤0.05) groups. In the blood sampling immediately after exercise, the level of leukocytes, neutrophils and lymphocytes in the exercise groups were significantly higher than the control group (p≤0.001). Also, the caffeine group experienced a lower increase in leukocytes and neutrophils compared to the placebo group (p≤0.001). Blood pressure values ​​in the exercise groups were significantly higher than the control group (p≤0.001). Also, the caffeine group experienced a greater increase in systolic blood pressure at baseline and immediately after exercise compared to the placebo group (p≤0.001). Conclusion: In general, exhausting exercise in a warm environment and dehydrated condition increases the number of immune system cells and blood pressure. In addition to improving aerobic function, caffeine seems to prevent further increases in the number of immune system cells, while increasing blood pressure in the normal range in warm and humid environment.