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Journalism of Courage
Zomato’s Deepinder Goyal (founder & CEO, Eternal), stirred up an online debate when he introduced his research foundation’s findings on longevity. For this he relied on the Gravity Aging Hypothesis, which basically says that gravity ages the brain. The logic is gravity’s lifelong pull on blood circulation in the brain makes it work harder and, therefore, wears it out faster. But Dr Vinit Suri, senior neurologist at Indraprastha Apollo Hospitals, Delhi, insists that brain functioning is far more complex.
“Every now and then, a fresh theory about why humans age captures public attention. One of the latest is the so-called Gravity Aging Hypothesis, which suggests that the constant pull of gravity on blood circulation ages the brain over time. It sounds intuitive. After all, gravity shapes almost everything around us. But as someone who studies how the brain works and what affects it, I can say that this idea oversimplifies a very complex system. Human ageing is influenced by many biological processes, and gravity, by itself, is not the hidden cause of brain ageing,” he says. Besides, he adds, there is no scientific proof that gravity accelerates brain ageing. “There is also no evidence that reducing gravity would slow ageing. What we do know is that healthy ageing depends on how well we care for our bodies and minds.”
Let’s break down the idea and understand what is true, what is exaggerated and what science actually knows today. Excerpts:
What the hypothesis claims
The Gravity Aging Hypothesis argues that because gravity constantly pulls blood downward, the brain has to work harder to maintain healthy circulation. Over many decades, this “effort” is said to contribute to ageing of brain cells, similar to how a machine can wear out with strain. The theory also proposes that humans who stand upright most of their lives face more gravitational pressure compared to animals that walk on all fours, making us more vulnerable to age-related brain changes.
The study talks about Cerebral Blood Flow (CBF), or blood flow to the brain. It says, “When we sit or stand, gravity pulls blood away from the brain, reducing CBF by up to 17% in upright posture. Over decades, this may weaken two key brain regions, the hypothalamus and brain stem, which regulate hormones, metabolism, inflammation and autonomic function.” This simplistic deduction assumes that the brain doesn’t know how to manage blood flow.
How the brain actually manages blood flow
One of the brain’s most remarkable abilities is to regulate its own blood supply. This process, called autoregulation, ensures that the brain gets what it needs even when we change posture, run, bend or sleep. The blood vessels in the brain constantly adjust their width to maintain a steady blood flow. This system is so efficient that standing up, lying down or moving around does not harm the brain.
If gravity were truly a major cause of brain ageing, we would expect people who spend their lives sitting or lying down due to illness to age more slowly. We do not see that happening. Ageing continues because it is driven by cellular changes, genetics and environmental factors, not gravity pulling on blood.
What about astronauts? They do not age backward
If gravity aged the brain, astronauts living in microgravity for months should show slower brain ageing. But space research tells us the opposite. Astronauts often return with brain changes linked to fluid shifts in the skull. These include swelling of the optic nerve, headaches and changes in brain structure. Importantly, these changes reverse once they return to Earth’s gravity.
This tells us two things. First, the brain is extremely adaptable. Second, removing gravity does not protect the brain from ageing. In fact, weightlessness creates its own problems, proving that gravity itself is not harmful.
What really drives brain ageing
Brain ageing is shaped by a mix of biological and lifestyle factors that have been studied for decades. These include inflammation, loss of neuronal connections, oxidative stress, changes in blood vessels and genetic predisposition. Over time, these processes influence memory, thinking and overall brain health.
We also know what slows brain ageing. Regular physical activity improves blood flow and strengthens brain networks. Adequate sleep clears waste from the brain. A balanced diet supports brain cells. Mental engagement builds cognitive reserve. Social interaction protects mood and memory. None of these protective factors involve escaping gravity. Instead, they rely on choices we make and the biology we carry.
A more accurate way to think about it
Rather than blaming gravity, it is more useful to focus on what we can control. Our brain benefits from movement, learning, nutrition and meaningful relationships. These habits strengthen the brain’s resilience, no matter our age. The idea that gravity slowly harms the brain distracts from the real steps that help us stay mentally sharp.
