Scientists have discovered a surprising connection between the muscles in the abdomen and blood flow in the brain. The finding could change how researchers understand the way blood moves through the brain during movement, breathing, and sleep.
When we think about blood flow to the brain, we usually think about the heart and the arteries that carry oxygen-rich blood to brain cells. But new research suggests that another part of the body may also play an important role: the belly. Researchers studying mice found that contractions of the abdominal muscles can quickly affect large veins around the brain. Within a fraction of a second after the belly muscles tightened, some of the brain’s largest veins became narrower, and blood flow through brain tissue briefly increased.
The Brain’s Blood Flow Is More Complicated Than We Thought
The brain needs a constant supply of blood because its cells require oxygen and nutrients to work properly. For many years, scientists have focused mainly on arteries when studying how the brain controls its blood supply. When an area of the brain becomes active, its blood vessels can widen, allowing more blood to reach the working tissue.
Veins, on the other hand, have often been viewed mainly as channels that carry blood away from the brain. The new research suggests that this view may be incomplete. Researchers Qingguang Zhang and Patrick Drew found evidence that large veins are not simply passive tubes. Their shape can change in response to pressure produced elsewhere in the body.
What Happens When the Belly Muscles Tighten?
The researchers watched mice as they walked. They found that the animals’ abdominal muscles became active before their legs actually began moving.
Soon after the abdominal muscles contracted, large veins draining blood from the brain became narrower. This happened very quickly—within roughly one-tenth of a second. The researchers believe that pressure is the important link between the abdomen and the brain. When the abdominal muscles tighten, pressure inside the body increases. Because some veins provide a continuous pathway between the abdomen, spine, and head, that pressure can travel upward and influence blood vessels around the brain.
In another experiment, the scientists used a controlled device to gently squeeze the abdomen of anesthetized mice. The large brain veins narrowed, while blood flow through the brain increased by about 3%. This helped the researchers show that the effect was not simply caused by the animals walking.
Breathing May Also Affect the Brain
The connection does not appear to happen only during exercise. The researchers also observed changes linked to breathing. As the mice breathed in and out, the large veins around the brain changed slightly in size. The changes caused by normal breathing were much smaller than those seen during walking, but they happened continuously.
This suggests that breathing may create small mechanical changes inside the body that are connected to the brain’s blood circulation. The researchers say that movement and breathing both affect pressure inside the abdomen, which can influence the mechanical environment around the brain and its blood vessels.
What About Sleep?
The study also revealed an interesting difference between being awake and asleep. When the mice were sleeping, their muscle activity and blood pressure decreased. During this period, the large veins around the brain became wider. When the animals woke up, abdominal muscle activity increased and the veins became narrower again. This adds another piece to the puzzle of how the brain’s circulation changes with different states of activity.
Could This Explain Some Headaches?
The researchers are also interested in whether these changes could help explain why some headaches become more intense during movement. Large blood vessels in the brain are surrounded by sensory nerves. The scientists suggest that changes in the blood vessels could potentially stimulate these nerves.
However, this idea still needs to be tested. It is important to remember that the current research was conducted in mice, not humans. Although humans and mice have similar vascular structures, scientists still need direct evidence showing that the same mechanism occurs in people.
A New Way to Think About the Brain
The discovery highlights just how connected different parts of the body can be. The brain does not operate in isolation. Every breath, movement, and muscle contraction can create physical changes throughout the body—and some of those changes may reach the brain.
The researchers believe that understanding this connection could eventually provide new ways to study pressure and blood flow inside the brain without directly measuring them. For now, the main message is simple: the muscles in your belly may be doing more than helping you move. They could also be playing a small but important role in how blood moves through your brain.
Read the Original: Your belly could be controlling blood flow in your brain
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