Some people may have been told that they have high blood pressure during a health checkup and are worried that their numbers aren't going down even though they're cutting down on salt and alcohol
The cause of high blood pressure may not only be excessive salt intake, but also a decrease in muscle mass. Muscles are important organs that not only move the body but also play a major role in regulating blood pressure
In this article, we explain the medical mechanism behind why muscle loss due to aging leads to high blood pressure
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The fear of sarcopenia (muscle loss) starting in your 40s
Medically, the loss of muscle mass that occurs with aging is called sarcopenia. Even if you feel like you're still young, a 2010 study of Japanese people reported that men's muscle mass increases slightly until around age 40, after which it starts to decrease (while women's muscle mass remains flat until around age 50). In other words, you could say that your 40s are a turning point for muscle development
So why does blood pressure rise when muscle mass decreases? One factor is a change in the body's thermoregulation function. Muscles generate a lot of heat even when at rest, but when muscle mass decreases, basal metabolism slows and body temperature is more likely to drop. The body then tries to maintain the temperature of vital organs such as the brain and heart by constricting peripheral blood vessels on the surface of the skin and other areas to prevent heat from escaping. When blood vessels constrict, the blood passage becomes narrower, resulting in increased blood pressure and increased strain on the blood vessel walls
One thing to be particularly careful of is "sarcopenic obesity," a condition in which muscle mass decreases and fat increases while weight remains constant. Even if you don't look fat, there are many cases where strain on blood vessels is silently progressing inside the body, so after the age of 40, it is important not to be reassured by just the number on the scale
reference:Japan Society for Sarcopenia and Frailty | Sarcopenia Clinical Practice Guidelines 2017
reference:J-stage | Characteristics of muscle mass with aging in Japanese people
reference:J-stage | Sarcopenic Obesity
Muscles are the "second heart": the mechanism of pumping and vasodilation
When talking about the relationship between muscles and blood pressure, two terms are essential: "pump function" and "vascular resistance." Muscles are not only a physical pump, but also function as chemical factories in the body that produce drug-like substances that dilate blood vessels
Why muscles are called the "second heart"
The heart is a powerful pump that sends blood throughout the body, but it has almost no power to collect the blood it has sent out. In particular, blood that reaches the toes must return to the heart against gravity. At this time, the muscles in the legs act as a pump. By repeatedly contracting and relaxing muscles such as the calf, they compress blood vessels and push blood upward (milking action). This pumping function is why muscles are called the "second heart."
However, if you continue to sit for long periods of time, such as when doing desk work, this pumping function does not work. This causes blood to pool in the lower limbs, which not only increases the risk of swelling and blood clots, but also reduces the amount of blood returning to the heart, placing excessive strain on the entire circulatory system
reference:Chiba Medical Association | Take care of your feet, your “second heart”!
Why muscle disuse increases peripheral vascular resistance
Another important mechanism is the "stiffness" and "resistance" of blood vessels. When you exercise your muscles and blood flow increases, a substance called nitric oxide (NO) is secreted from the inner walls of your blood vessels (endothelial cells). This NO has the effect of softening and widening your blood vessels. In other words, exercise itself acts like an antihypertensive drug
Conversely, lack of exercise due to aging or a decrease in muscle mass reduces the amount of NO secreted. When NO is insufficient, blood vessels tend to remain constricted and harden, making it difficult for blood to flow (high vascular resistance). As blood tries to force its way through narrow, hardened blood vessels, blood pressure inevitably rises
In other words, reduced muscle stimulation is the same as accelerating the aging of blood vessels. In order to reduce the risk of arteriosclerosis, which causes blood vessels to harden and become brittle, it is necessary to keep the muscles, which are the original blood pressure lowering system, in operation at all times
reference:The role of nitric oxide (NO) in motor function
The relationship between muscles and blood vessels has been gaining attention in recent years
Research has been published that supports the theory that "people with more muscle mass are less likely to develop high blood pressure." A large-scale cohort study (a research method in which a person is followed over a certain period of time) of 872 middle-aged and elderly people in Europe reported in 2025 showed that skeletal muscle mass (total mass, mass relative to body weight, etc.) is inversely correlated with the onset of high blood pressure. In other words, the more muscle mass there is, the lower the risk of hypertension, and the less muscle there is, the higher the risk. This trend was particularly pronounced in women in this study, but it suggests that muscle is an important factor in protecting cardiovascular health regardless of gender
Until now, health management has tended to focus solely on reducing fat, but the latest findings show that maintaining muscle mass is also important in blood pressure management
summary
Protecting muscles leads to protecting blood vessels. Dietary therapy, such as restricting salt intake, is important, but unless you supplement the muscles that weaken with age, it will not be fundamental to managing blood vessels. Start by correctly understanding your own muscle mass and the condition of your blood vessels. Our clinic also proposes approaches to maintaining health and addressing muscle weakness at the cellular level based on knowledge of regenerative medicine. Take measures now to ensure your future health
Rather than simply treating symptoms by lowering the numbers with medication, a new health strategy for the era of 100-year lifespans is to keep blood vessels and muscles youthful by increasing the repair ability of one's own cells
Supervised by: Dr. Yuzo Terakawa (neurosurgery specialist)