PROJECTS
Physical Activity
What does your daily physical activity pattern say about your physical and cognitive health? We currently have two NIA-funded awards to better understand the links among physical activity , physical function, and cognitive health in older adults. Through collaborations with NIA investigators, we are seeking to understand how quantities and patterns of movement are associated with brain pathology in the Baltimore Longitudinal Study of Aging.
Energy Expenditure
Energy expenditure is about more than just fitness! Energy is utilized at various levels of intensity - from resting to maximal exertion - throughout the day, and the way we utilize energy changes dramatically with aging. We are currently investigating the intersection of energy expenditure and fatigability with aging and its effects on physical and cognitive functioning with aging.
Accelerometry
We oversee the data collection, processing, and analysis of accelerometry data in multiple studies, including: ACHIEVE, ARIC, BLSA, MACS, NHATS, PASOS/SOL, SPRING, and STURDY.
Published research on physical activity patterns
"Assessing the Physical Cliff"
One of our first papers detailing age related differences in physical activity quantities and patterns
Fragmented physical activity linked with mortality
We demonstrated that fragmented physical activity patterns in older adults are more predictive of mortality than total volume of daily activity
Fragmented physical activity linked with low physical functioning
We demonstrated that a simple fragmentation index was strongly linked with physical performance in older adults, suggesting it is a signal of physiological decline
Older cancer survivors demonstrated reduced and more fragmented daily physical activity
Older cancer survivors demonstrated lower and more fragmented levels of physical activity throughout the day compared to those with no history of cancer
Defining activity intensity thresholds for older adults
Relative exertion of physical activity varies widely among older adults. We demonstrated that "one size does not fit all" for defining physical activity intensity by examining minute-level heart rate response to daily activities
High fatigability alters physical activity patterns
We showed that high fatigability contributes to reduced daily physical activity and altered diurnal patterns in older adults
Published research on Energy Expenditure & Fatigability
The Energetic Pathway to Mobility Loss
Our first energetics paper, which provided a conceptual framework of how energy expenditure affects mobility with aging
Higher fatigability linked with body composition
Our analysis examined the underlying contribution of body composition to fatigability in older adults across multiple measures. Greater body fatness, especially visceral fat was linked with higher fatigability in older adults.
"Inflammaging" linked with fatigability
We demonstrated that elevated IL-6, a hallmark of "inflammaging," is a biomarker of physiological dysregulation associated with greater fatigability
Fatigability & Endurance Peformance Among Cancer Survivors
Our research found that a history of cancer was associated with greater fatigability and poor endurance performance in older adults, even among long-term survivors
Rising Energy Costs Linked with Gait Speed Decline
We demonstrated a direct link between energetic efficiency and physical functioning by linking a higher energetic cost of usual-paced walking with gait speed decline in late life
Lower Resting Metabolic Rate Linked with Healthier Aging
Older well functioning adults who were free of major medical conditions had lower RMR than those with disease and functional impairments, suggesting a direct link between efficiency of energy utilization and health status.
published research on accelerometry methods
Monitors, Measures & Methods
This review article discusses the use of wearable accelerometers in older adults, and highlights methodological considerations in their application to older populations
Age related bias in step measurement
This letter to the editors of JAMA Internal Medicine highlights how slower speed of movement and altered biomechanics may lead to an age-related bias in the measurement of daily step counts
"ADEPT," a method to detect walking from accelerometry data
This work introduces the concept of "ADEPT" a pattern recognition method to detect walking from accelerometry data. Application of this methodology will allow future studies to compare in-lab measure of gait with free-living measures of ambulation.
Using raw accelerometry data for research
In this paper, we discuss problems related to the collection and analysis of raw accelerometry data and refer to published solutions. In particular, we describe the size and complexity of the data, the within- and between-subject variability, and the effects of sensor location on the body. We also discuss challenges related to sampling frequency, device calibration, data labeling and multiple PA monitors synchronization.
Accelerating accelerometry research in older adults
This invited commentary discusses opportunities and challenges for future accelerometry research in older populations
Understanding gait characteristic from raw accelerometry data
This research highlights differences between walking measured "in-the-lab" and using accelerometers. Features of accelerometry-derived walking were associated with measures of physical function, mobility, fatigability, and fitness.