Как физ нагрузки влияют на состояние крови - разжижают или сгущают кровь?

The narrator tested her blood after cycling 5 km and 10 km at different speeds, finding it thicker each time with red blood cells clumping together. She did not drink water during the exercise to keep the experiment clean, and observed that the blood did not improve after workouts. She explains that thick blood increases the heart’s workload, especially during exercise when dehydration occurs, and recommends drinking water during training to prevent this.