Associations between physical activity and energy and fatigue depend on sleep quality

ABSTRACT

Objective:

Sleep and physical activity are independent predictors of energy and fatigue, but whether poor sleep quality moderates the association between physical activity and energy and fatigue remains unclear.

Methods:

A sample of 675 young adults (median age 20 years) was recruited from a university town and completed questionnaires regarding sleep quality (Pittsburgh Sleep Quality Index), typical weekly physical activity (moderate and high-intensity), and feelings of mental and physical energy and fatigue. Linear regression analyses were run to evaluate the associations between physical activity and sleep with the energy and fatigue outcomes, adjusting for sex, age, and caffeine. Interaction analyses were run and models were stratified by sleep quality to evaluate effect modification.

Results:

Participants reported a weekly median (Q1, Q3) of 4 h (2,8) of high-intensity physical activity, and 1 h (0,3) of moderate-intensity physical activity, and 50% of the sample had poor sleep quality. Physical activity was positively associated with physical and mental energy, and sleep quality was associated with each of the 4 outcomes. Interaction analyses revealed that high-intensity physical activity was positively related to physical energy only among those with good quality sleep. Further, high-intensity physical activity was more strongly positively associated with physical energy among those with good quality sleep than those with poor quality sleep (β = 0.32 with 95% CI 0.18–0.46 compared to 0.14 with 95% CI −0.01, 0.29).

Conclusion:

Findings suggest that physical activity alone may not be able to overcome the deleterious effects of poor sleep on feelings of mental and physical energy and fatigue.

KEYWORDS:

• Mental energy
• mental fatigue
• physical energy
• physical fatigue
• sleep quality
• exercise

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Notes on contributors

Matthew Miller

Matthew Miller is pursuing his doctrate in physical therapy. His work focuses on optimizing feelings of energy and fatigue.

Jahnée Lee-Chambers

Jahnée Lee-Chambers is pursuing her doctorate in physical therapy at Clarkson University. She is interested in understanding the relationship between sleep, physical activity and moods.

Briana Cooper

Briana Cooper is a doctor of physical therapy candidate at Clarkson University. Her research focuses on the interaction between physical activity, sleep and moods.

Ali Boolani

Ali Boolani is an Associate Professor at Clarkson University in the department of physical therapy who focuses on understanding: 1) psychosocial factors that impact feelings of energy and fatigue in people of color; 2) biological differences in feelings of energy and fatigue; 3) how feelings of energy and fatigue uniquely influence human movement; and 4) developing interventions to increase feelings of energy and decrease feelings of fatigue.

Erica Jansen

Dr. Erica Jansen is a nutritional epidemiologist and research assistant professor at the University of Michigan School of Public Health who focuses on diet and sleep in relation to pediatric health. She has several lines of research, including the examination of: 1) how early nutritional environments affect childhood obesity and timing of puberty; 2) how various aspects of sleep- including duration, timing, and quality- affect development of cardiometabolic risk; 3) the bidirectional associations between sleep and diet; and 4) epigenetic markers or mediators that underlie relationships between sleep and cardiometabolic health.