Research into longevity and extending the human lifespan seems to be all the rage these days. Scientific articles about this topic abound, and more than one book intended for laypeople has been released recently as well. But with obesity rates among adults in the US projected to approach 50 percent by 2030, and a whopping 14 million people projected to be living with Alzheimer’s disease by 2050, perhaps we should be more concerned with healthspan than with lifespan. Extending a human lifespan to ages never dreamed of before may not be quite so desirable if one’s last several years are spent weak, frail, and incapacitated mentally or physically. Recommendations for healthy aging aren’t much different—if at all—from those aimed at younger people. Aside from the obvious—not smoking, drinking alcohol only in moderation, and following a healthy diet—exercising and staying physically active in general are key foundational pieces for healthy aging.
Any physical movement is better than none, but activities specifically geared toward building and maintaining muscle mass may be the most beneficial. Weightlifting and other forms of resistance training have even been called “the fountain of youth.” Considering the Alzheimer’s projection cited above, aging individuals may be as concerned with their cognitive health as they are with their physical mobility and independence—maybe more. With this in mind, the importance of exercise for brain function can’t be overstated.
Observational and epidemiological evidence suggests that greater physical activity is associated with better cognitive function in older people. A 2019 systematic review and meta-analysis determined that for adults with cognitive impairments, the best results were seen with exercise sessions of short duration but high frequency and recommended that exercise be structurally embedded into daily life. Among its recommendations for cognitive health for older individuals, the National Institute on Aging (NIA) lists being physically active, such as through dedicated exercise, but also via other activities such as household chores. (Anyone who’s ever vacuumed a large house, mowed a lawn, or scrubbed a bathroom can confirm housework can be a workout!)
Yoga is popular among some seniors, but NIA notes, “Aerobic exercise, such as brisk walking, is thought to be more beneficial to cognitive health than non-aerobic stretching and toning exercise.” In particular, activities that improve insulin sensitivity and glucose tolerance may be especially helpful for preserving cognitive function during aging. Alzheimer’s disease is considered a form of brain insulin resistance, and researchers have even coined the term “metabolic-cognitive syndrome” to underscore the strong associations between metabolic syndrome and cognitive decline.
According to a leading researcher in brain fuel metabolism and Alzheimer’s disease, “Skeletal muscle is the main site of insulin-mediated glucose utilization in the body and so declining muscle mass (sarcopenia) in the elderly may be a factor contributing to the increased risk of insulin resistance associated with aging.” It stands to reason then, that maintaining muscle mass and strength may help promote healthy cognition in one’s older years. It’s difficult to build muscle mass without adequate protein, and evidence indicates that many older individuals habitually under-consume protein, so making a point to increase protein intake may be another important part of a healthy aging strategy—one that goes hand-in-hand with maintaining an active lifestyle.
It’s worth noting that for people already afflicted with dementia, exercise alone may not have a significant impact. In these cases, it may be necessary to make multiple lifestyle changes beyond increased activity. Dietary intervention can have a substantial effect and may be especially powerful when combined with exercise. Intriguing case reports assessing the effects of very-low-carbohydrate ketogenic diets together with high-intensity interval training have shown dramatic improvements in cognitive function in subjects with mild cognitive impairment and mild Alzheimer’s disease, including in a subject heterozygous for the ApoE4 gene (the strongest known genetic risk factor for Alzheimer’s).
If metabolic syndrome, insulin resistance, and type 2 diabetes are risk factors for Alzheimer’s disease, then interventions that address these issues earlier in life may have a potential role in reducing risk for cognitive decline as the years pass. A study published not long ago showed that a low-carb Paleo-style diet, by itself, improved various measurements of cognition (including increased brain-derived neurotrophic factor [BDNF]), but even greater improvements were seen when the diet was combined with high-intensity exercise. (A previous article covered this study in detail.)
What about people claiming they don’t have time to exercise, or that they can’t afford a membership to a fancy health club? Frequently cited obstacles to getting regular exercise fall by the wayside when they’re scrutinized more closely. Those who feel they don’t have enough time to incorporate activity into their daily routine might be surprised to learn that they can make dramatic improvements in their cardiometabolic health with mere minutes of exercise just a few days a week—minutes! We can also get rid of the excuse that gym memberships are too expensive, or that’s too much of a hassle to drive to and from the gym, change clothes, and get wrapped up in the other off-putting logistics involved in going to a specific place to exercise. Workouts done at home have been shown to improve insulin sensitivity, endothelial function, and VO2 max, so people don’t even need to leave their homes to get at least some of the benefits of exercise. It might be a good idea to do some physical activity outdoors, though, and preferably in a green space. Research supports a beneficial role for spending time in nature for improving physical and mental health. Green spaces may be so therapeutic that they’ve actually been referred to as “vitamin G.”
Old or young, trying to maintain health or get back to better health, make exercise part of the plan for 2020.