Shawn D Youngstedt

• University of South Carolina

Introduction Chronic overlapping pain conditions (COPCs), such as chronic low back pain (cLBP) and fibromyalgia, frequently cooccur and incur substantial healthcare costs. However, to date, much focus has been placed on individual anatomically based chronic pain conditions, whereas little is known about the mechanisms underlying progression to mult...

Purpose Several studies have shown that aerobic exercise training improves obstructive sleep apnea (OSA) severity. However, a dose-response relationship has never been shown. This study aimed to quantify any dose-response relationships between time spent per week in aerobic exercise and key sleep apnea outcomes. Methods Randomized controlled trial...

Study Objectives The postpartum period is a unique time when sleep deficiency often occurs. Black and White adults are reported to have differences in sleep characteristics, but little is known if these differences exist in the postpartum period. Therefore, the purpose of this study was to examine sleep characteristics in a cohort of Black and Whit...

Objectives To determine the feasibility for middle-aged and older adults to extend their time in bed by 2 h per night for 3 consecutive weeks. Other aims were to examine the effects of sleep extension on mood, cognitive performance, and cardiovascular health. Methods Ten healthy middle-aged to older adults (9 women; M = 65.20 ± 4.78 years) who repo...

Introduction Sleeping pills are assumed to be the most efficacious means of treating acute insomnia, but their use has associated risks. Exercise could provide a healthy alternative treatment for insomnia, particularly if it could be shown to have comparable efficacy to sleeping pills. Objective The purpose of this study was to compare the effects...

Introduction Jet lag is associated with transmeridian travel across at least two time zones, associated with sleep disturbance as well as daytime dysfunction. The presence of jet lag has been hypothesized to be associated with adverse cardiovascular outcomes; however, objective data are not available. Jet lag can have many negative effects on physi...

Introduction Jet lag is a circadian rhythm disorder whose effects on QTc and QT variability are unknown. QTc and QT variability are markers of ventricular repolarization associated with ventricular arrhythmias including torsade de pointes and overall mortality. The objective of this study is to understand the impact of simulated jet lag on QTc and...

Chronobiology investigations have revealed much about cellular and physiological clockworks but we are far from having a complete mechanistic understanding of the physiological and ecological implications. Here we present some unresolved questions in circadian biology research as posed by the editorial staff and guest contributors to the Journal of...

Circadian Biology intersects with diverse scientific domains, intricately woven into the fabric of organismal physiology and behavior. The rhythmic orchestration of life by the circadian clock serves as a focal point for researchers across disciplines. This retrospective examination delves into several of the scientific milestones that have fundame...

Two-a-day training is common for endurance athletes with training sessions typically beginning at 6 a.m. and 3 p.m. or 4 p.m. However, the early morning workouts could contribute to significant sleep loss, especially for night owls. Chronic sleep loss over a season could result in impaired performance, as well as an increased risk of physical and m...

Objective: The aim of this study was to investigate the effects of exercise and exercise plus acupuncture on chronic insomnia. Material and Methods: suggest replacing with “effects of” no feasibility things are reported chronic insomnia were randomized to a 12-week treatment with exercise or exercise plus acupuncture. Exercise treatment included 50...

Introduction Long sleep duration is associated with many health risks, particularly in older adults, but little is known about other characteristics associated with long sleep duration. Methods Across 5 sites, adults aged 60-80 years who reported sleeping 8-9 h (“long sleepers”, n = 95) or 6-7.25 h (“average sleepers”, n = 103) were assessed for tw...

Studies have identified insomnia as having significant influence on chronic pain. A rising body of research has also underscored the association between eveningness and chronic pain. However, co-assessment of insomnia and eveningness in the context of chronic pain adjustment has been limited. The present study sought to investigate the effects of i...

Introduction In the postpartum period, decreased sleep time is associated with increased postpartum weight retention. Increasing sleep time in the postpartum period may be beneficial; however, increasing total sleep time will reduce the time available for light physical activity (LPA), moderate to vigorous activity (MVPA), or sedentary behavior (SE...

Studies suggest associations between cortisol and sleep, and cortisol shows a profound diurnal rhythm. The evidence about the relationship between chronic insomnia and cortisol is mixed. Chronic insomnia is associated with the risk of mental health disorders. The aim of this study was to evaluate the association of insomnia severity and objective s...

The question that guided this review is whether exercise can add to the improvements in insomnia in patients treated with cognitive behavioral therapy for insomnia (CBT-I). CBT-I has long been recommended as the first-line treatment of chronic insomnia. However, CBT-I is not effective for as many as 30% to 40% of patients with insomnia. There is ac...

Introduction: Patients with obstructive sleep apnea (OSA) are at risk for QTc prolongation, a known risk factor for increased mortality. The pro-QTc score can help identify individuals at increased risk for mortality associated with increased QTc however, it has not been evaluated in patients with OSA. The goal of this study was to evaluate the pr...

Misalignment between the environment and one’s circadian system is a common phenomenon (e.g., jet lag) which can have myriad negative effects on physical and mental health, mental and physiological performance, and sleep. Absent any intervention, the circadian system adjusts only 0.5-1.0 h per day to a shifted light-dark and sleep-wake schedule. Br...

Exercise is a cornerstone of preventive medicine and a promising strategy to intervene on the biology of aging. Variation in the response to exercise is a widely accepted concept that dates back to the 1980s with classic genetic studies identifying sequence variations as modifiers of the VO2max response to training. Since that time, the literature...

Purpose of Review The goal is to examine the link between circadian rhythms and pain, which may shed further light on improving pain management strategies and preventing the development and/or worsening of chronic pain. Recent Findings In part I, we provide evidence that the rhythmicity of pain may be regulated by the central circadian clock. We a...

Introduction In the postpartum period, many women experience sleep deficiency due to caring for their infant. Racial disparities exist in sleep characteristics in the adult population, with Black adults having shorter total sleep time (TST) and worse sleep efficiency (SE) than White adults. However, few studies have investigated sleep changes in po...

Introduction Positive airway pressure (PAP) therapy is the mainstay treatment for obstructive sleep apnea (OSA). Continuous PAP (CPAP) therapy has been shown to decrease QTc length in electrocardiograms in patients with OSA in small studies. The impact of higher pressures of CPAP and Bilevel PAP (BPAP) on ventricular repolarization—QTc length and Q...

Introduction Theoretically, napping could have positive effects on health (e.g., by reducing stress and compensating for short night time sleep) or negative effects (e.g., by disrupting nighttime sleep or impairing circadian synchronization). Epidemiologic studies have produced mixed results regarding associations of napping with health. Causality...

Introduction Evidence suggests that patients with obstructive sleep apnea (OSA) are at risk for QTc prolongation which, is a known risk factor for arrhythmias, sudden cardiac death and all cause mortality. QTc risk scores have been implemented widely to help physicians identify patients at risk for mortality however, these risk scores have not been...

Purpose To examine long-term cognitive effects of chemotherapy and identify predictors among women with breast cancer (WBC). Patients and methods Sixty-nine WBC scheduled to receive chemotherapy, and 64 matched-controls with no cancer, participated. Objective and subjective cognition, total sleep time, nap time, circadian activity rhythms (CAR), s...

The aim of this study was to compare sex differences in energy expenditure and enjoyment in older adults during Active Video Game activities and sedentary behavior (watching television). In a within-subjects design, n = 32 older adults were included (15 men and 17 women). Energy expenditure was measured during each activity using indirect calorimet...

Purpose The goal of this study was to examine whether daily increased morning light exposure would maintain or improve sleep and the circadian pattern of relatively more activity in the day and less during the night in women undergoing chemotherapy for breast cancer. Patients and Methods Participants were 39 women with newly diagnosed breast cance...

ROIG, M., J. CRISTINI, Z. PARWANTA, B. AYOTTE, L. RODRIGUES, B. DE LAS HERAS, J-F. NEPVEU, R. HUBER, J. CARRIER, S. STEIB, S.D. YOUNGSTEDT, and D.L. WRIGHT. Exercising the sleepy-ing brain: exercise, sleep, and sleep loss on memory. Exerc. Sport Sci. Rev., Vol. 50, No. 1, pp. 38–48, 2022. We examine the novel hypothesis that physical exercise and s...

PurposeExperts have recommended exercise for improved sleep, but often with the caveat that one should avoid nighttime exercise. The aim of this study was to challenge this recommendation in a sample who might be most prone to sleep impairment after nighttime exercise. The secondary aims were to assess whether or not post-treatment sleep was correl...

The aim of this study was to examine the effects of an Xbox Kinect exercise program on sleep quality, anxiety and functional capacity in older adults. Twenty-nine older adults were randomized into two treatment groups: XBOX (n = 15) or CONTROL (n = 14). The XBOX group performed exercise with an Xbox Kinect for 60 min, three times per week for 6 wee...

We examine the novel hypothesis that physical exercise and sleep have synergistic effects on memory. Exercise can trigger mechanisms that can create an optimal brain state during sleep to facilitate memory processing. The possibility that exercise could counteract the deleterious effects of sleep deprivation on memory by protecting neuroplasticity...

Objectives We contrasted the relative risks (RR) of short [<7 h] and long [>8 h] sleep experienced by middle-aged (45–64 years) and older (≥65 years) adults, compared with young adults (20–44 years). Methods We utilized NHANES data (2005–2016), capturing sociodemographic, socioeconomic, and health-related data among US adults. Results The Relativ...

Per principles outlined in the Belmont Report, research involving human subjects should minimize risks to participants and maximize benefits to participants and society. Recruitment of participants should be equitable. Once enrolled, participants have the right to withdraw at any point. Researchers must balance these principles with pressures to me...

Objectives: To describe changes in sleep patterns during the coronavirus disease 2019 (COVID-19) pandemic, develop profiles according to these patterns, and assess sociodemographic, economic, COVID-19 related, and sleep and mental health factors associated with these profiles. Design, setting, and participants: A 25-minute online survey was dist...

Aim: Insomnia is associated with cardiovascular disease (CVD), particularly the phenotype with objective short sleep duration and associated physiological arousal. However, what objective sleep and arousal characteristics among patients with insomnia are related to markers of cardiovascular structure and function remains unknown. The present study...

Introduction Evening chronotype (i.e., night owl preference) is associated with worse insomnia and depressive symptoms, and poorer health behaviors. The aim of this study was to examine the association between chronotype and these symptoms and health behaviors during COVID-19 pandemic quarantine. Methods An online survey, distributed international...

Introduction The coronavirus disease 2019 (COVID-19) pandemic may have negatively impacted children's weight status owing to the closure of schools, increased food insecurity and reliance on ultra-processed foods, and reduced opportunities for outdoor activity. Methods In this interrupted time series study, height and weight were collected from ch...

Background Structure may mitigate children's accelerated summer BMI gain and cardiorespiratory‐fitness (CRF) loss. Objectives Examine BMI and CRF change during school and summer for year‐round and traditional calendar school children. Methods Three schools (N = 2279, 1 year‐round) participated in this natural experiment. Children's BMI z‐score (z...

Introduction Post-traumatic stress disorder (PTSD) is a prevalent consequence of combat with significant associated morbidity. Available treatments for PTSD have had limitations, suggesting a need to explore alternative or adjuvant treatments. Numerous rationales for bright light treatment of PTSD include its benefits for common PTSD comorbidities...

Study Objectives This study examined how glucose, glucose regulatory hormones, insulin sensitivity, and lipoprotein subclass particle concentrations and sizes change with sleep restriction during weight loss elicited by calorie restriction. Methods Overweight or obese adults were randomized into an 8-week calorie restriction intervention alone (CR...

Background Children’s BMI gain accelerates during summer. The Structured Days Hypothesis posits that the lack of the school day during summer vacation negatively impacts children’s obesogenic behaviors (i.e., physical activity, screen time, diet, sleep). This natural experiment examined the impact of summer vacation on children’s obesogenic behavio...

Study objectives: Studies examining time-use activity behaviors (sleep, sedentary behavior and physical activity) on school days compared to non-school days have examined these behaviors independently, ignoring their interrelated nature, limiting our ability to optimize the health benefits of these behaviors. This study examines the associations o...

This systematic review provided synthesized evidence regarding the effectiveness of the interventions promoting the human papillomavirus (HPV) vaccination in college-aged population. The HPV infection is the most prevailing sexually transmitted disease. Despite the availability and effectiveness of the 9-Valent HPV vaccine, the vaccine coverage amo...

The aim of this research study was to examine the effects of Assisted Cycling Therapy (ACT) on adaptive/maladaptive behaviors, depression, and self-efficacy in adolescents with Down syndrome (DS). The participants were counterbalanced to either intervention groups of 1) Assisted Cycling Therapy (ACT), in which the participants’ voluntary pedaling r...

Introduction We examined race and sex-dependent effects of metabolic burden across different age-categories on trends in self-reported sleep duration for the U.S. non-institutionalized civilian population. Methods We analyzed data from the National Health Interview Survey (NHIS) adults aged 18-85 from 2004 to 2013 (N=258,158). Metabolic burden was...

Introduction We examined age-categorized trends in self-reported sleep duration using data from the National Health Interview Survey (NHIS) 2004-2013 and explored how these trends may vary based on individuals’ race/ethnicity. Methods Study participants were aged 18-85 (N=258,158). Sleep duration within a 24-hour period on average was categorized...

Introduction Healthy sleep is known to contribute to psychosocial well-being. Pregnancy and postpartum could have profound influences on women’s psychosocial well-being related to physiological changes and interrupted sleep due to caring for the infant. The purpose of this study was to determine the associations between self-reported sleep characte...

Introduction Insomnia is a novel and modifiable risk factor for incident cardiovascular disease (CVD). However, identification of early markers of subclinical CVD in diagnosed insomnia is understudied. Our aim for this ongoing study is to contrast markers of cardiovascular structure and function between people with insomnia and good-sleeping contro...

Introduction In the general population, poor sleep quality and shorter sleep duration is associated with several adverse health outcomes. African American adults are more likely to report poorer sleep quality and shorter total sleep duration compared to White adults. However, there is limited information comparing sleep characteristics in White and...

Aim: Few studies have examined the association between objective sleep metrics and arterial and echocardiographic (left ventricular systolic/diastolic function) markers of sub-clinical cardiovascular disease (CVD). The present study examined the association of wrist actigraphy-assessed sleep metrics with arterial stiffness, endothelial dysfunction,...

Background: Children’s BMI gain accelerates during summer. The Structured Days Hypothesis posits that the lack of the school day during summer vacation negatively impacts children’s obesogenic behaviors (i.e., physical activity, screen time, diet, sleep). This natural experiment examined the impact of summer vacation on children’s obesogenic behavi...

Background: Children’s BMI gain accelerates during summer. The Structured Days Hypothesis posits that the lack of the school day during summer vacation negatively impacts children’s obesogenic behaviors (i.e., physical activity, screen time, diet, sleep). This natural experiment examined the impact of summer vacation on children’s obesogenic behavi...

Background: Children’s BMI gain accelerates during summer. The Structured Days Hypothesis posits that the lack of the school day during summer vacation negatively impacts children’s obesogenic behaviors (i.e., physical activity, screen time, diet, sleep). This natural experiment examined the impact of summer vacation on children’s obesogenic behavi...

Purpose: To evaluate the potential of a year-round school calendar (180-day school year distributed across 12 months) as an intervention compared to a traditional school calendar (180-day school year distributed across 9 months) for mitigating children's weight gain and fitness loss via a natural experiment. Methods: Height, weight, and cardiore...

Introduction: False beliefs about sleep can persist despite contradicting scientific evidence, potentially impairing population health. Identifying commonly held false beliefs lacking an evidence base ("myths") can inform efforts to promote population sleep health. Method: We compiled a list of potential myths using Internet searches of popular...

Key points Exercise elicits circadian phase‐shifting effects, but additional information is needed. The phase–response curve describing the magnitude and direction of circadian rhythm phase shifts, depending on the time of the zeigeber (time cue) stimulus, is the most fundamental chronobiological tool for alleviating circadian misalignment and rela...

Introduction: Insomnia is a prevalent complaint, affecting about 15% of the general population. The most common treatment for chronic insomnia is pharmacotherapy, but non-drug therapies have been increasingly studied, and their clinical use has been encouraged. In the last 10 years, some studies have investigated the effects of exercise on chronic...

Introduction: Sleep debt is a frequent problem around the world. Sleep disturbances has been associated with cardiovascular disease and hypertension. Exercise have been studied as a non-drug alternative to improve sleep, and its positive effects on blood pressure control is well documented. Aims: The aim of this study was to compare self-reported s...

Introduction: Poor sleep quality and negative mood are common among undergraduate students. Anxiety and depression disorders affect women relatively more frequently. Regular exercise has been studied as an adjuvant therapy to improve sleep and positive mood. Aims: The purpose of this study was to evaluate sleep quality and mood in undergraduate stu...

Sleep disturbances, chronotype and social jetlag [SJL] have been associated with increased risks for major chronic diseases that take decades to develop, such as obesity, metabolic syndrome and cardiovascular disease. Potential relationships between poor sleep, chronotype, and social jetlag as they relate to metabolic risk factors for chronic disea...

Purpose: Examine the relationship between pro-inflammatory diet and prostate cancer risk. Methods: Energy-adjusted Dietary Inflammatory Index (E-DII®) scores were computed among 40,161 participants in the California Men's Health Study. Over 9.7±3.8 years of follow-up 2,707 incident prostate cancer cases were diagnosed and categorized as low-, inte...

Study Objectives To examine changes in elementary aged children’s sleep and physical activity during a one-week and a three-week school break. Methods Sleep and physical activity of elementary children (n=154, age=5–9 years, 44.8% female, 65.5% African American) were collected over seven weeks that included a one-week break in two schools and a th...

Objective: The aim of this study was to assess the effects of resistance exercise and stretching on sleep, mood, and quality of life in chronic insomnia patients. Methods: Three 4-month treatments included: resistance exercise (n=10), stretching (n=10), and control (n=8). Sleep was evaluated with polysomnography, actigraphy, and questionnaires....

Introduction Commonly chronic insomnia is treating with sleeping pills, which are associated adverse side effects, tolerance, and mortality. Thus, many nonpharmacological therapies have been studied. Regular exercise and stretching are possible nonpharmacological interventions to improve sleep quality. The propose of this study was to assess the ef...

Introduction Exercise is often recommended as one of the most important sleep hygiene behaviors. In the last 10 years some studies have focused in the effects of exercise on chronic insomnia, as a non-pharmacological treatment with easy access and extensive health benefits. The propose of this study was to assess the effects of resistance exercise...

Cognitive-behavioral therapy for insomnia is superior to sleeping pills for treating insomnia, and its accessibility is rapidly improving. Exercise can also promote sleep in insomnia. A list of recommendations on good sleep practices can be applied prior to consulting with a clinician and can often resolve insomnia symptoms. Summary statement: In...

Study Objectives To examine the effects of moderate sleep restriction on body weight, body composition, and metabolic variables in individuals undergoing caloric restriction. Methods Overweight or obese adults were randomized to an 8-week caloric restriction (CR) regimen alone (n=15) or combined with sleep restriction (CR+SR) (n=21). All participa...

Sleep disruption has been associated with increased risks for several major chronic diseases that develop over decades. Differences in sleep/wake timing between work and free days can result in the development of social jetlag (SJL), a chronic misalignment between a person’s preferred sleep/wake schedule and sleep/wake timing imposed by his/her wor...

BACKGROUND Insufficient sleep has been shown to adversely affect glucose metabolism. Most previous studies have restricted sleep to a very short duration or examined only a few nights of sleep restriction. It is less well known whether moderate sleep restriction over an extended period affects glucose metabolism. This study examined how glucose and...

Dozens of epidemiologic studies spanning over 50 years have established that both short sleep (<6 h of self-reported sleep) and long sleep (≥8 h of self-reported sleep) have been associated with increased mortality and multiple morbidities. Consistently, long sleep has been associated with greater risks than short sleep. Although epidemiologic stud...

Introduction Few studies have compared insomnia prevalence across multiple countries using standardized measures. Further, it is likely that medications/supplements/substances used to treat insomnia varies across countries. Methods An international web-based survey was conducted across 10 countries (United States, France, Japan, China, Brazil, Sou...

Introduction Diabetes is one of the leading causes of health-related morbidity and mortality in the United States. To reduce the burden of diabetes, several behavioral strategies (e.g., healthy diet and increased physical activity) have been implemented. Unfortunately, these strategies have yielded modest improvements, and in some groups (racial/et...

Introduction A central tenant of Cognitive Behavioral Therapy for Insomnia (CBT-I) is that individuals’ thoughts and beliefs about sleep are integral to their sleep quality. Previous research has examined sleep satisfaction in older adults, but little research has focused on how Dysfunctional Beliefs and Attitudes about Sleep (DBAS) may influence s...

PurposeColorectal cancer (CRC) is one of the most common and preventable forms of cancer but remains the second leading cause of cancer-related death. Colorectal adenomas are precursor lesions that develop in 70–90 % of CRC cases. Identification of peripheral biomarkers for adenomas would help to enhance screening efforts. This exploratory study ex...

Study objective To synthesize evidence from available studies on the relative efficacies of continuous positive airway pressure (CPAP), mandibular advancement device (MAD), supervised aerobic exercise training, and dietary weight loss in patients with obstructive sleep apnea (OSA). Design Network meta-analysis of 80 randomized controlled trials (R...

Study objectives: A large proportion of individuals affected by sleep disorders are untreated and susceptible to accidents, injuries, long-term sequelae (e.g., risk of cardiovascular disease, cancer, psychiatric disorders), and increased mortality risk. Few studies have examined the scope and magnitude of sleep disorder diagnoses in the United Sta...

Introduction: Habitual sleep duration is associated with cardiometabolic disease risk and poor mental health. Exercise has been shown to improve cardiometabolic disease risk and mental health. Further, insufficient/excessive sleep is associated with sedentary behavior. It is plausible that benefits of exercise may mitigate some negative effects of...

Limited research has compared the circadian phase-shifting effects of bright light and exercise and additive effects of these stimuli. The aim of this study was to compare the phase-delaying effects of late night bright light, late night exercise, and late evening bright light followed by early morning exercise. In a within-subjects, counterbalance...

Objective: The purpose of this study was to examine the association between self-reported sleep duration and markers of kidney function. Design: A cross-sectional survey from the 2009-2012 National Health and Nutrition Examination Survey. Setting and Participants: The participants were 8690 adults (≥20 years) without a previous sleep disorder diagn...

Context and purpose The literature suggests that severe sleep loss of more than a few hours a night decreases glucose tolerance and insulin sensitivity. The aim of this study was to determine whether moderate sleep restriction had similar effects. Methods Fifteen healthy non-obese (body mass index = 24.5 ± 3.4 kg/m²) young adults (20.6 ± 1.3 years...

Sleep is essential for most health functions, and pharmacological treatments for promoting sleep have limited efficacy. A nonpharmacological treatment such as exercise is appealing given the relative ease with which it can be performed and its concomitant health impact. This chapter reviews the evidence supporting the relationship between exercise...

Background: The National Health Interview Survey (NHIS) was used to ascertain whether increases in inadequate sleep differentially affected black and white Americans. We tested the hypothesis that prevalence estimates of inadequate sleep were consistently greater among blacks, and that temporal changes have affected these two strata differentially...

Background: This study ascertained whether individuals of the black race/ethnicity are unequally burdened by sleep-related overweight/obesity. Methods: Analysis was based on data obtained from Americans (ages, 18-85 years) in the National Health Interview Survey (1977-2009). Sleep duration was coded as either very short sleep (VSS) (≤5 hours), s...

The common assumption that population sleep duration has declined in the past few decades has not been supported by recent reviews, which have been limited to self-reported data. The aim of this review was to assess whether there has been a reduction in objectively recorded sleep duration over the last 50+ years. The literature was searched for stu...

To estimate the effect of pharmacotherapy on PTSD, anxiety, and depression among combat veterans; to determine whether the effects varied according to patient and intervention characteristics; and to examine differential effects of pharmacotherapy on outcomes. Google Scholar, PILOTS, PsycINFO, PubMed, and Web of Science databases were searched thro...