When the concentration of salt in the blood becomes high, water goes into the blood vessels from the cells around to make the concentration thinner. That makes the amount of blood increase, pressing the wall of the blood vessel. This is the condition of high blood pressure.
High blood pressure causes arteriosclerosis that the blood vessel becomes hard and narrow. It can lead to serious diseases such as stroke and heart attack.
So it is important to reduce salt to improve high blood pressure. But it is difficult to continue reducing salt in daily life. Even if low salt is kept, sometimes high blood pressure is not improved as expected.
A whale gave us the secret of how to solve this unconquerable problem?
A whale is the biggest mammal on the earth. The characteristic is that they live very long. Some of them live for more than 200 years.
So a researcher thought that whales must have maintained healthy blood vessels because they lived long. What is the difference between whales and human beings which are the same mammals? Is the difference related to dive under sea water? Based on such unique hypothesis, the researcher studied about blood vessels of the people who dived a lot into the sea. The people who the researcher paid attention to were Japanese female pearl divers who dived into the sea daily. When the researcher checked the condition of their blood vessel, surprising results were found out.
115 of Japanese female pearl divers whose average age was 65 years old were checked about their age of blood vessels (vascular age). The average of their vascular ages were 11 years younger than their actual ages. This proved that they could be controlling their blood pressure.
Why are their vascular ages young?
That their vascular ages are young is related to a hormone called ANP (Atrial Natriuretic Peptide) which is secreted by water pressure at the time of their diving. When we dive into water, the veins in our arms and legs are especially compressed because they are soft. That increases the amount of blood returning to the heart, making a part of the heart larger. At that time, the hormone called ANP is secreted by the muscles of the heart and is sent to all over the body. Especially the kidney is influenced by ANP and is promoted to excrete urine and excessive salt is discharged with the urine. As a result of that, blood pressure goes down and blood vessels are kept young.
Actually ANP is used as medication for heart failure because it lowers blood pressure and reduces a burden on the heart.
ANP of three Japanese female pearl divers was checked and the amount of ANP drastically increased right after diving. Also their blood pressures are within the normal range and their vascular ages were less than their actual ages.
Age: 69 / 72 / 72
Before diving: 28.8 / 21 / 30
Right after diving: 44.5 / 73.1 / 129.6
Blood pressure: 134 / 126 / 123 (mmHg)
Vascular age: early 50’s / early 50’s / late 60’s
Divers dive to a depth of more than 5 meters (16.4 feet), but we can’t do that. So how deep do we need to dive or soak in the water to increase ANP?
According to an experiment, it is possible to increase ANP if you soak into the pool above the pit of the stomach.
52 years old male whose blood pressure was about 140 mmHg tried to spend all day in a pool with his wife and daughters (9 and 11 years old). As a result, his ANP increased and blood pressure lowered after playing in the pool with his family as follows.
ANP: Before 12.6 / After 31.6
Blood pressure: Before 143 mmHg / After 132 mmHg
ANP and Cancer
Cancer occurs everywhere in the body except the heart. One of the reasons that the heart doesn’t have cancer is ANP which is secreted from the heart. When ANP is administered to patients with cancer, the metastasis and recurrence are suppressed.
How to increase ANP other than playing in the pool
ANP is secreted by raising heart rate so it is effective to exercise as hard as breathing becomes a little heavy.