Recent Research on Exercise and Aging

There is a mountain of evidence to show that regular exercise and maintaining a state of fitness is good for health and longevity. That mountain continues to grow, new papers arriving on a weekly basis to reinforce these points: don't be sedentary and don't get fat, or you'll pay the price of greater medical expenses over a shorter, less healthy life. A few examples are linked below, spanning a range of topics including associations between fitness and age-related structural damage and decline in the brain, exercise and mortality in middle age, and exercise as a therapeutic option for the elderly.

Regular moderate exercise is among the safest of ways to influence health, and it produces an expected benefit to long-term health that is modest in the grand scheme of things, but for basically healthy individuals still larger than that provided by any other available methodology aside from the practice of calorie restriction. You can't exercise your way to living to 100, a target that less than 1% of the population will reach in the environment of today's medical science, and exercise only modestly improves your 20% odds of making it to 90 in the environment of today's medical science. If exercise required multi-billion-dollar research programs and decades before it could be safely used, then I would be just as dismissive of it as I am of efforts to develop drugs to slightly slow the aging process. But exercise is free, available now, reliable, and backed by an enormous weight of evidence, and that makes all the difference as to whether or not to take advantage.

It is true that the future of practical, low-cost rejuvenation therapies will render academic all questions of whether or not we would gain a year in health here or a year there due to a healthier lifestyle. We'll be gaining decades of healthy life, and losing the marks and damage of age, thanks to therapies that target the causes of degenerative aging and age-related disease. The big question for those of us who stand today at the cusp of age and opportunity, at the whim of small chances that will spiral out to speed or slow the timeline for future medical development, is whether or not we will live long enough to benefit from rejuvenation treatments. That is where the year here and the year there become far more important, especially as the pace of progress in all technologies continues to accelerate.

Cardiorespiratory fitness is associated with white matter integrity in aging

Age-related decline in cerebral macrostructure, such as reductions in gray and white matter volume, is well-documented. More recently, diffusion tensor imaging (DTI) has been used to assess in vivo cerebral white matter microstructure and to evaluate specific white matter fiber bundles that underpin information transmission between gray matter regions. Age-related reductions in white matter microstructure have been reported in healthy older adults (OA), and decreased white matter microstructure in OA has been linked to poorer performance on tasks tapping processing speed, executive functions, and episodic memory.

The pervasive evidence for neural decline in OA has led to substantial interest in individual difference factors that are associated with age-related reductions in cerebral integrity. One such factor is cardiorespiratory fitness (CRF), an indicator of the ability of one's circulatory and respiratory systems to supply oxygen to skeletal muscle during sustained moderate to vigorous physical activity.

Exercise during teen years linked to lowered risk of cancer death later

Women who exercised during their teen years were less likely to die from cancer and all other causes during middle-age and later in life, according to a new study. The investigators used data from the Shanghai Women's Health Study, a large ongoing prospective cohort study of 74,941 Chinese women between the ages of 40 and 70. The women enrolled in the study between 1996 and 2000. Each participant was interviewed at enrollment about exercise during adolescence, including participation in team sports, as well as other adolescent lifestyle factors. They were also asked about exercise during adulthood and other adult lifestyle factors and socioeconomic status, and participants were interviewed again every two to three years. Investigators found that participation in exercise both during adolescence and recently as an adult was significantly associated with a 20 percent reduced risk of death from all causes, 17 percent for cardiovascular disease and 13 percent for cancer.

A Cluster Randomized Controlled Trial of Nonpharmacological Interventions for Old-Old Subjects with a Clinical Dementia Rating of 0.5: The Kurihara Project

The boundary or transitional state between normal aging and dementia, which is defined in various ways such as mild cognitive impairment (MCI) or a Clinical Dementia Rating (CDR) of 0.5, is recognized as a state of being at high risk of dementia. Although it is a serious challenge to control the risk of dementia in these people, pharmacological interventions remain unsuccessful. Meanwhile, recent studies have suggested potential benefits of nonpharmacological interventions. Among a variety of nonpharmacological methodologies, most popular and potentially beneficial interventions to date include cognitive interventions (CI), physical activities (PA) and a group reminiscence approach with reality orientation (GRA).

Previous studies have suggested that exercise may be one of the promising strategies for improving cognitive functions. Resistance as well as aerobic trainings may positively impact cognitive functioning and result in functional plasticity in healthy older adults. Furthermore, exercise training may have cognitive benefits for seniors with MCI, especially improvements in selective attention and conflict resolution, processing speed and verbal fluency in senior women with amnestic MCI. Thus, many previous studies have emphasized the positive impact of PA on the executive functions of subjects in the boundary state between normal aging and dementia. Indeed, our results support these previous findings; however, they also show that the benefit for executive functions may be a nonspecific effect that may occur with CI or the GRA as well. Nevertheless, we cannot exclude the secondary benefit of PA on cognitive functions, because an improvement in physical ability may potentially ameliorate cognition in the course of subsequent daily life.

Physical Activity Is Linked to Greater Moment-To-Moment Variability in Spontaneous Brain Activity in Older Adults

Higher cardiorespiratory fitness (CRF) and physical activity (PA) in old age is associated with greater brain structural and functional integrity, and higher cognitive functioning. In this study we extend our understanding of the different and overlapping roles of CRF and PA in brain resting state function in healthy but low-active older adults. Depending on brain region and task, greater CRF is associated with either increased or decreased change in blood oxygenation level dependent (BOLD) signal, a proxy for neural activity. As a result, it is unclear whether high or low amplitudes of BOLD signal reflect optimal functional brain health. Here we employed a more general measure of neural function: moment-to-moment variability in the BOLD signal during spontaneous brain activity. Moment-to-moment variability in the BOLD signal (SDBOLD) is known to reflect the dynamic range of neural processing, such as the modulation of functional networks and is suggested to be a promising tool in mapping neural correlates of cognitive abilities in aging. Specifically, lower SDBOLD in certain brain regions is associated with older age, slower, and less consistent performance on a perceptual matching task.

In this study, we sought to determine how the level of physical fitness (measured as CRF) and PA (measured via accelerometer) are related to functional brain health measured as SDBOLD. To this end, we collected resting functional magnetic resonance BOLD data from 100 healthy older participants (60-80 years). Given that: 1) advancing age is associated with decreasing SDBOLD; and 2) greater CRF, PA, and lower sedentariness are associated with better cognitive and brain health outcomes in older adults, we predicted that greater SDBOLD in certain regions would reflect greater brain health and therefore positively correlate with CRF and PA, and negatively with sedentariness. We found that older adults who spend more time daily on light PA (LI-PA; housework, gardening, relaxed walking) and moderate-to-vigorous PA (MV-PA, e.g. jogging, walking stairs, biking) had greater SDBOLD in multiple brain regions, and this relationship was positively associated with white matter microstructure.

Comments

One thing I am always a bit troubled by is how "moderate" exercise is defined. From what I've read, some sources define it as a heart rate from 50% to 70% of maximum. However, when I exercise and get my heart rate into that particular zone, it feels very mild like I'm barely getting a workout at all; I don't even have to open my mouth to breathe. On the other hand, doing a gentle jog gets my heart rate in the 70-85% range quite easily which "feels" more like moderate to me.

Anyone know how to be confident you're working out in the optimal "moderate" range?

Posted by: KC at August 6th, 2015 7:08 PM

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