Research reveals that exercise is beneficial not just for the body, but also for the mind. According to the Alzheimer’s Association, exercising for 30 minutes five times a week can lower one’s risk of developing dementia. But it turns out that not all exercise is created equal — different types of exercise might have a bigger impact on your risk, and the type could even vary from person to person. So how do you know what exercise best fits you?

Imagine if doctors could give you a prescription for exercise — a personalized workout that helps minimize the risks of dementia…

OK, let’s be honest: a doctor can’t compute a fully optimized exercise regime of exactly 15 minutes of jogging, 20 crunches, 35 squats, and 10 minutes of weightlifting, perfectly tailored to you and your health — at least, not yet.

Jonathan Stamler, M.D., a physician-scientist at the Harrington Discovery Institute, and his colleagues are currently developing an exercise wearable to help personalize exercise, funded in part through an award from the American Heart Association-Allen Initiative in Brain Health and Cognitive Impairment. It can be difficult to know what exercise improves your cognitive health, so the team is designing the device to provide real-time feedback and identify what’s most beneficial for you.

“As a nation, we’re exercising blindly,” Stamler said. “We personalize many other aspects of our drug development today, and I would suggest we should be personalizing and understanding how we exercise to optimize health.”

Most of the fitness wearables currently on the market, including the Apple Watch, measure heart rate and blood levels of oxygen, but those are not entirely accurate measurements of fitness. Instead, Stamler’s device uses biosensors to measure the levels of nitric oxide in the blood.

You might remember from a high school biology class that you breathe in oxygen to oxygenate your tissues and breathe out carbon dioxide to expel waste from the body. But this two-gas system is outdated. Stamler discovered that there is a third gas involved called nitric oxide.

There are many forms of nitric oxide in the body, but Stamler focuses on a particular type found in the microvasculature — the small blood vessels responsible for supplying oxygen to our organs, including the brain. Red blood cells release this nitric oxide to dilate the microvasculature, which increases blood flow and allows more oxygen to be delivered to organs. This process is so important for respiration that without nitric oxide, oxygen can’t be delivered effectively. Stamler and his team found that mice with a normal oxygen supply but deficient in releasing nitric oxide still experienced hypoxia — their organs were deprived of oxygen.

“It’s not about how much oxygen you carry in your blood; it’s about how much oxygen is actually delivered,” Stamler said.

Because nitric oxide facilitates blood flow and oxygen delivery to organs like the brain, there is a growing school of thought that impairments in blood flow may contribute to, or even cause, age-related dementia. According to Stamler, people living with Alzheimer’s disease have low levels of nitric oxide, meaning that their organs, including the brain, are not receiving enough oxygen.

However, there are currently no drugs to improve oxygenation to tissues and scientists still do not understand why nitric oxide is low in people at risk of or living with dementia. But in better news, levels of nitric oxide are not static; you can increase these levels through exercise.

According to Stamler’s colleague and integrative physiologist Evan Peikon, exercise causes nitric oxide to be released into the bloodstream, increasing blood flow to the brain. Therefore, consistent and routine exercise can improve nitric oxide levels over time. But the type of exercise that best increases those levels can vary from person to person, Peikon said, adding that the optimal duration and intensity of that exercise can also differ. As such, the new wearable will capture in real-time how nitric oxide levels improve per exercise session, providing a quantitative measure that can inform your exercise regime.

“Everyone knows that we need to exercise more but it’s such an ambiguous term. It’s like saying, ‘We need to eat healthily,’ but that doesn’t really give us anything practical to go off of,” Peikon said. “We’re hoping to create an objective measurement of health, fitness and performance that you can track.”

By knowing what works best for ourselves, we can make sense of exercise. And perhaps doctors might start prescribing exercise in the future, specifying the type, duration, and intensity that increase nitric oxide levels, Peikon said. Overall, we can more easily design our own workouts and waste less time on what doesn’t work for us in terms of reducing dementia risk.

“Especially in this day and age, so many of us are busy. We have so many different things that we need to be doing on a day-to-day basis. And even if we do make time to exercise 30 minutes or an hour a day, wouldn’t we like to know that all of that time is spent well?” Peikon said.

According to Peikon, this will be the first device to measure nitric oxide in tissues noninvasively. Traditional measurements require a blood sample and cannot predict oxygen delivery; such limitations are why there are no exercise science trials in current literature that measure nitric oxide, Peikon said. The exercise wearable, which is currently in development, utilizes biosensors and AI-powered analytics. The scientists hope to use it to further investigate the importance of nitric oxide in delivering oxygen to the brain.

However, Alzheimer’s disease is incredibly complicated and exercise is likely only one of a multitude of factors that contribute to a person’s individual risk of disease. But scientists are now starting to appreciate the role vascular health has on cognitive health — and healthy aging. For many in the Alzheimer’s field, the goal may not be to prevent Alzheimer’s entirely, but to stave it off for long enough to allow people to live more years dementia-free. – By Leila Okahata / Allen Institute

“If we can do this right, my hope is that everyone over 60 years old and at risk for dementia will be designing their exercise to promote a longer, healthier and better life,” Stamler said.

The American Heart Association-Allen Initiative in Brain Health and Cognitive Impairment is funded by the American Heart Association and the Paul G. Allen Family Foundation. The Paul G. Allen Frontiers Group, a division of the Allen Institute, recommends funding and supports the administration of the initiative.