However, they are absorbed, usually as methyl mercury, by algae at the start of the food chain. This algae is then eaten by fish and other organisms higher in the food chain. Fish efficiently absorb methyl mercury, but excrete it very slowly. Methyl mercury is not soluble and therefore not excreted.
For example, a 10- to 15-minute brisk walk typically elevates the heart rate to 110 to 120 beats per minute. Also, the sinus node increases the heart rate when the body is stressed because of illness. In all of these circumstances, the heart rate increase is a normal response. Likewise, the sinus node signals the heart to slow down during rest or relaxation.
Hence, the heart beats faster, which actually helps to increase the rate of heat loss from the body. Also, the dilation of blood vessels lowers the blood pressure. Hence, in order to restore normal blood pressure, the heart beats faster and pushes more blood through the blood vessels.here are several factors that affect the heart rate, the most common being exercise and noise. However, a little unknown factor that has shown to influence heart rate is temperature. A rise in body temperature, be it from environmental factors or a medical condition, causes an increase in the heart rate.