Caffeine is a compound found in the leaves, seeds and fruits of plants such as coffee and guarana. The aim of the systematic review was to determine the effect of caffeine on cardiorespiratory functions and physical performance. The method was to collect relevant literature in the period of 2011-2022 and analyze them. The results clearly show the benefit and the positive effect of caffeine in both the investigated areas. The recommended intake of caffeine should be more than 75 mg to expect positive changes and effects. Also, due to side effects, especially for the heart, doses above 600 mg should not be exceeded. To ensure complete absorption, caffeine should be consumed at least 45 minutes before planned activity. Caffeine is a very powerful supplement. You just need to pay attention to the method and dosage. Also, in this article, we will find out about the effect of caffeine on the cardiovascular system, which evidence shows that if it is consumed in the right dose, it is even useful for heart diseases such as cardiac arrhythmia, and also We read the effect of caffeine on the performance of different sports, which has a positive effect on explosive and fast sports than on delicate sports that require more precision and attention, and it also has a greater effect on the upper limbs than the lower limbs. In addition to the physical and physiological effect, caffeine also has a psychological effect, and because of this, most non-athletes and even athletes use different doses of caffeine to wake up late and feel refreshed. In general, if this substance is consumed in appropriate doses, it is harmful. does not deliver