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.
You can also try to slow your heart rate via breathing and relaxation techniques, by practicing other mind/body therapies such as biofeedback, or by taking supplemental calcium and magnesium. For women, start with 100 mg of magnesium (citrate, glycinate, or chelate) and increase the dose up to 350 mg daily.