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Use of Minimally Invasive Methods to Assess Fuel Utilization and Circadian Rhythms in Older Adults

Aging is associated with multiple physiological changes that contribute synergistically and independently to physical disability and the risk of chronic ...

University of Florida

A growing body of evidence indicates that time restricted feeding (TRF), a popular form of intermittent fasting, can activate similar biological pathways as caloric restriction, the only intervention consistently found to extend healthy lifespan in a variety of species. Thus, TRF may have the potential to also improve function in older adults. Given the challenges many individuals have in following calorie restriction regimens over long-time periods, evaluation of alternative approaches that may produce weight loss and improve function in overweight, older adults is important. Ten overweight, sedentary older adults (≥65 years) at risk for, or with mobility impairments, defined by slow gait speed (<1.0 m/s) participated in this trial. All participants received the intervention and were instructed to fast for approximately 16 h per day over the entire four-week intervention. Outcomes included changes in body weight, waist circumference, cognitive and physical function, health-related quality of life, and adverse events. Adherence levels were high (mean = 84%) based on days goal was met, and mean weight loss was 2.6 kg ( < 0.01). Since body composition was not measured in this study, it is unclear if the observed weight loss was due to loss of fat mass, muscle mass, or the combination of fat and muscle mass. There were no significant changes in other outcomes; however, there were clinically meaningful changes in walking speed and improvements in quality of life, with few reported adverse events. The findings of this pilot study suggest that time restricted feeding is an acceptable and feasible eating pattern for overweight, sedentary older adults to follow.

The Effects of Time Restricted Feeding on Overweight, Older Adults: A Pilot Study.

Time-restricted feeding (TRF) is a type of intermittent fasting in which no calories are commonly consumed for approximately 12-18 hours on a daily basis. The health benefits of this eating pattern have been shown in overweight adults, with improvements in cardiometabolic risk factors as well as the preservation of lean mass during weight loss. Although TRF has been well studied in younger and middle-aged adults, few studies have evaluated the effects of TRF in older adults. Thus, the goal of this study was to evaluate older-adult perspectives regarding the real-world advantages, disadvantages, and challenges to adopting a TRF eating pattern among participants aged 65 and over. A four-week single-arm pre- and post-test design was used for this clinical pilot trial TRF intervention study. Participants were instructed to fast for approximately 16 h per day with the daily target range between 14 and 18 h. Participants were provided with the TRF protocol at a baseline visit, along with a pictorial guide that depicted food items and beverages that were allowed and not allowed during fasting windows to reinforce that calorie-containing items were to be avoided. The trial interventionist called each participant weekly to promote adherence, review the protocol, monitor for adverse events, and provide support and guidance for any challenges faced during the intervention. Participants were instructed to complete daily eating time logs by recording the times at which they first consumed calories and when they stopped consuming calories. At the end of the intervention, participants completed an exit interview and a study-specific Diet Satisfaction Survey (Table 1) to assess their satisfaction, feasibility, and overall experience with the study intervention. Of the 10 participants who commenced the study (mean age = 77.1 y; 6 women, 4 men), nine completed the entire protocol. Seven of the ten participants reported easy adjustment to a 16-hour fast and rated the difference from normal eating patterns as minimal. Eight participants reported no decrease in energy during fasting periods, with greater self-reported activity levels in yardwork and light exercise. Adverse events were rare, and included transient headaches, which dissipated with increased water intake, and dizziness in one participant, which subsided with a small snack. The findings of the current trial suggest that TRF is an eating approach that is well tolerated by most older adults. Six participants, however, did not fully understand the requirements of the fasting regimen, despite being provided with specific instructions and a pictorial guide at a baseline visit. This suggests that more instruction and/or participant contact is needed in the early stages of a TRF intervention to promote adherence.

Determinants of Adherence in Time-Restricted Feeding in Older Adults: Lessons from a Pilot Study.

Aging is the primary risk factor for functional decline; thus, understanding and preventing disability among older adults has emerged as an important public health challenge of the 21st century. The science of gerontology - or geroscience - has the practical purpose of "adding life to the years." The overall goal of geroscience is to increase healthspan, which refers to extending the portion of the lifespan in which the individual experiences enjoyment, satisfaction, and wellness. An important facet of this goal is preserving mobility, defined as the ability to move independently. Despite this clear purpose, this has proven to be a challenging endeavor as mobility and function in later life are influenced by a complex interaction of factors across multiple domains. Moreover, findings over the past decade have highlighted the complexity of walking and how targeting multiple systems, including the brain and sensory organs, as well as the environment in which a person lives, can have a dramatic effect on an older person's mobility and function. For these reasons, behavioral interventions that incorporate complex walking tasks and other activities of daily living appear to be especially helpful for improving mobility function. Other pharmaceutical interventions, such as oxytocin, and complementary and alternative interventions, such as massage therapy, may enhance physical function both through direct effects on biological mechanisms related to mobility, as well as indirectly through modulation of cognitive and socioemotional processes. Thus, the purpose of the present review is to describe evolving interventional approaches to enhance mobility and maintain healthspan in the growing population of older adults in the United States and countries throughout the world. Such interventions are likely to be greatly assisted by technological advances and the widespread adoption of virtual communications during and after the COVID-19 era.

Innovations in Geroscience to enhance mobility in older adults.

Despite the utility of social cognitive theory for facilitating individual behavior changes needed for initial weight loss, this model has been less effective in facilitating adherence to recommended lifestyle changes required for sustainable weight-loss maintenance. One potential reason for the limited long-term effectiveness of lifestyle interventions guided by this model is that the model does not consider the important influence that biology can have on weight-relevant behaviors, during both weight loss and weight-loss maintenance, via sensations of hunger and satiety and changes in energy metabolism (expenditure and fat oxidation). We describe here a proposed revision to social cognitive theory that allows for biological factors to exist in reciprocal determinism with behavioral, environmental, and personal factors, with the goal of creating a theoretical basis for lifestyle interventions with greater personalization in order to facilitate better long-term adherence and improve weight-loss maintenance.

Application of social cognitive theory in weight management: Time for a biological component?

Aging is associated with a host of biological changes that contribute to a progressive decline in cognitive and physical function, ultimately leading to a loss of independence and an increased risk of mortality. The unprecedented growth of the aging population has thus created an urgent need for interventions that can preserve older adults' capacity to live independently and to function well. To date, there is no conclusive evidence supporting the efficacy of an intervention to prevent or reverse physical disability in older persons at risk of functional decline. A growing body of evidence indicates that prolonged fasting periods and different types of intermittent fasting regimens can have positive effects on anthropometric and metabolic health parameters in middle-aged adults similar to that of calorie restriction. For this reason, there is increasing scientific interest in further exploring the biological and metabolic effects of intermittent fasting approaches, as well as the feasibility and safety of popular types of intermittent fasting regimens in older adults. Thus, the purpose of the present review is to describe the state of evidence of different types of intermittent fasting regimes, specifically time-restricted eating and 5:2 intermittent fasting, in the growing population of middle-aged and older adults. A small, but growing body of evidence indicates both time restricted eating (TRE) and 5:2 intermittent fasting approaches can produce modest weight loss; however, only the 5:2 approach produced clinically meaningful weight losses. Reductions in blood pressure were observed for both TRE and 5:2 fasting approaches, but the effects were not consistent across studies. The majority of studies to date, in middle-age and older adults, however, have been of short duration in small study samples. Future clinical trials with larger populations and longer intervention durations are required to better understand the risks versus benefits of different types of intermittent fasting regimens in middle-age and older individuals.

The effects of intermittent fasting regimens in middle-age and older adults: Current state of evidence.

Muscle contraction type in resistance exercise training may confer benefits besides strength in individuals with osteoarthritis and cardiovascular disease (CVD) risks. The purpose of the study was to explore whether Eccentric-resistance training (RT) improved hemodynamic responses to acute walking exercise stress compared to Concentric-RT among individuals with knee OA over four months.

Christian McLaren

Department of Physiology and Aging,
Department of Clinical and Health Psychology,
College of Public Health and Health Professions,
Department of Clinical and Health Psychology, College of Public Health and Health Professions

University of Florida

Use of Minimally Invasive Methods to Assess Fuel Utilization and Circadian Rhythms in Older Adults