Engaging in increased aerobic activity during middle and later years of life may significantly mitigate the risk of developing dementia, including Alzheimer's disease, as indicated by recent research.

"Our findings highlight the pivotal role that cardiovascular fitness plays in lowering the risk of dementia, even among individuals who are genetically susceptible to Alzheimer's," remarked Weili Xu, a professor at the Aging Research Center of Karolinska Institute in Stockholm. Xu, the lead author of the study, emphasized in a communication, "Promoting gradual enhancements in physical fitness offers a practical and significant approach to bolstering brain health across various demographics."

The research revealed that individuals with superior cardiorespiratory health exhibited enhanced cognitive abilities and a mere 0.6% relative long-term risk of dementia, contrasting with those who were less fit—a difference that postponed the onset of dementia by an average of 1.5 years. Cardiorespiratory endurance, which is cultivated through consistent aerobic training, augments the lungs' and heart's oxygen intake, enabling individuals to maintain vigorous activities over an extended period without fatigue. The study also discovered a more pronounced advantage for individuals predisposed to Alzheimer's genetically—those with the highest levels of cardiorespiratory endurance experienced a 35% reduced relative risk of the disease's development.

"There's a saying that genes are not our fate; we can all make proactive decisions to assist in the struggle against our genetic predispositions. This study fully endorses that notion," stated preventive neurologist Dr. Richard Isaacson, director of research at the Institute for Neurodegenerative Diseases in Florida, who was unaffiliated with the study.

Isaacson, who likens exercise to a miraculous 'medication' with brain-enhancing properties, commented via email, "While in this study, elevated fitness alone postponed the onset of dementia by 1.5 years, we could achieve even better results by also adhering to a healthy diet, managing cholesterol, blood pressure, and blood sugar levels, conducting regular auditory and visual assessments, and prioritizing sleep quality."

Studies have demonstrated that a diminished level of cardiorespiratory fitness is a potent predictor of cardiovascular diseases, such as heart attacks, and premature mortality from a myriad of causes, including cancer. However, without deliberate effort, cardiorespiratory fitness is known to decline with age. According to a scientific statement by the American Heart Association, this decline is at a rate of 3% to 6% during individuals' 20s and 30s, escalating to a rate exceeding 20% per decade in their 70s and beyond.

The recently published study in the British Journal of Sports Medicine analyzed data from over 61,000 dementia-free individuals, aged 39 to 70, who participated in the UK Biobank, a longitudinal study encompassing over half a million UK residents. A baseline assessment of cardiorespiratory fitness was conducted when participants initially enrolled between 2009 and 2010, alongside evaluations of cognitive function and genetic risk factors. After a dozen years, researchers investigated whether there was a correlation between the group's fitness levels from over a decade prior and any current dementia diagnoses.

"The study identified a dose-dependent effect of exercise fitness on several critical cognitive performance types," Isaacson explained. "Across various memory types, such as recalling specific words and numbers or remembering to execute a planned future action, like scheduling an appointment, cardiorespiratory fitness can significantly influence outcomes." Aerobic fitness can also enhance the brain's processing speed, akin to the swiftness with which words and ideas can traverse the brain's neural pathways, he added. "To draw a car analogy, the fitter a person is, the more effectively they can shift to a higher mental gear and the quicker they can progress," Isaacson elaborated.

The study was observational in nature, which means that no direct cause-and-effect relationships can be ascertained, according to cardiologist Dr. Valentin Fuster, president of Mount Sinai Fuster Heart Hospital and chief physician of Mount Sinai Hospital in New York City. Fuster, a former president of the American Heart Association and World Heart Federation, advised caution in interpreting the study's outcomes due to the health concerns associated with individuals who exhibited low cardiorespiratory fitness. "When comparing groups with low cardiovascular respiratory fitness to those with moderate or high fitness, a striking pattern emerges," Fuster noted. "It was the low-fitness group that presented with higher rates of hypertension, diabetes, high cholesterol, and obesity."

All of these health conditions are known to trigger cardiovascular diseases and damage to small blood vessels, including those in the brain, he explained. The study indicated that individuals with high cardiorespiratory fitness were more likely to engage in self-care, thereby safeguarding the heart-brain connection. "This connection is vital for the future," Fuster emphasized. "The same risk factors that impact cardiovascular diseases may also play a role in the development of vascular dementia, and there is some evidence suggesting they may accelerate Alzheimer's disease progression."

What is the most effective method to enhance your cardiorespiratory fitness and protect your heart and brain? Select an aerobic exercise and perform it at an intensity that leaves you breathless and makes conversation difficult, experts recommend. "An aerobic exercise could be cycling with low resistance, walking on a treadmill with low resistance, or walking at a reasonable pace on the street—but ensure to do it for at least thirty minutes, five days a week," Fuster advised. Other options include vigorous dancing, hiking, jogging, running, rowing, stair climbing, or swimming. Team sports such as basketball, soccer, and hockey can also elevate heart rates and increase oxygen flow. High-intensity interval training, which alternates between high-intensity and lower-intensity activities, can improve cardiovascular endurance by up to 79%, according to the Cleveland Clinic. Exercise also offers additional benefits, such as aiding in weight loss, mood regulation, and promoting good sleep. It can even extend one's lifespan.