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STUDY OBJECTIVE: Identify small molecule biomarkers of insufficient sleep using untargeted plasma metabolomics in humans undergoing experimental insufficient sleep. METHODS: We conducted a crossover laboratory study where 16 normal-weight participants (eight men; age 22 ± 5 years; body mass index < 25 kg/m2) completed three baseline days (9 hours sleep opportunity per night) followed by 5-day insufficient (5 hours sleep opportunity per night) and adequate (9 hours sleep opportunity per night) sleep conditions. Energy balanced diets were provided during baseline, with ad libitum energy intake provided during the insufficient and adequate sleep conditions. Untargeted plasma metabolomics analyses were performed using blood samples collected every 4 hours across the final 24 hours of each condition. Biomarker models were developed using logistic regression and linear support vector machine (SVM) algorithms. RESULTS: The top-performing biomarker model was developed by linear SVM modeling, consisted of 65 compounds, and discriminated insufficient versus adequate sleep with 74% overall accuracy and a Matthew's Correlation Coefficient of 0.39. The compounds in the top-performing biomarker model were associated with ATP Binding Cassette Transporters in Lipid Homeostasis, Phospholipid Metabolic Process, Plasma Lipoprotein Remodeling, and sphingolipid metabolism. CONCLUSION: We identified potential metabolomics-based biomarkers of insufficient sleep in humans. Although our current biomarkers require further development and validation using independent cohorts, they have potential to advance our understanding of the negative consequences of insufficient sleep, improve diagnosis of poor sleep health, and could eventually help identify targets for countermeasures designed to mitigate the negative health consequences of insufficient sleep.
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Metabolômica , Privação do Sono , Adolescente , Adulto , Biomarcadores , Ingestão de Energia , Humanos , Masculino , Sono , Adulto JovemRESUMO
Exercise is accepted as a method to improve weight loss maintenance; however, the mechanisms by which this occurs have yet to be elucidated. In this pilot study, 13 women with obesity underwent a structured weight loss program (goal 8%-10% weight loss) and were then randomized to either a 12-wk diet (n = 7) or an aerobic exercise training (n = 6) intervention aimed at maintaining weight loss. At baseline, post-weight loss, and following the weight loss maintenance interventions, measurements of appetite (hunger and satiety) and appetite-regulating hormones (leptin, ghrelin, peptide tyrosine tyrosine, and glucagon-like peptide 1) were obtained after an overnight fast and for 3 h after a standardized test meal. Ad libitum energy intake was measured at a lunch meal. During the weight loss phase, participants lost 9.1% ± 1.1% of baseline body weight. Participants in both groups maintained weight loss during the 12-wk weight loss maintenance intervention. No differences in fasting leptin (P = 0.68) or in ghrelin (P = 0.30), peptide tyrosine tyrosine (P = 0.93), and glucagon-like peptide 1 (P = 0.98) area under the curve were detected between groups. Similarly, ratings of hunger (P = 0.99) and satiety (P = 0.65) area under the curve after the standardized test meal also did not differ between the groups nor did ad libitum energy intake at lunch. In summary, the 12-wk diet and exercise interventions were equally effective at maintaining weight loss in women, and no differences in measures of appetite regulation and food intake were found.
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INTRODUCTION: Exercise can cause a decrease in serum ionized calcium (iCa) concentration, which stimulates parathyroid hormone (PTH) secretion and activates bone resorption. We postulated that dermal Ca loss during cycling exercise is the major determinant of the serum iCa, PTH, and bone resorption (C-terminal telopeptide of type 1 collagen [CTX]) responses. METHODS: To investigate this, women (n = 13) and men (n = 12) age 18 to 45 yr performed the same exercise bout under cool (18°C) and warm (26°C) conditions. Exercise was 60 min of cycling at ~75% of peak aerobic power. Sweat samples were obtained during exercise using a skin patch method, and blood samples were obtained before and during exercise and during 60 min of recovery. RESULTS: Sweat volume and estimated sweat Ca loss were 50% higher for the warm condition than the cool condition. Despite this, there were no differences between thermal conditions in the changes (mean, 95% confidence interval [95% CI]) in iCa (cool, -0.07 mg·dL; 95% CI, -0.16 to 0.03); warm, -0.07 mg·dL; 95% CI, -0.20 to 0.05), PTH (cool, 34.4 pg·mL; 95% CI, 23.6-45.2; warm: 35.8 pg·mL; 95% CI, 22.4-49.1), or CTX (cool, 0.11 ng·mL; 95% CI, 0.08-0.13; warm, 0.15 ng·mL; 95% CI, 0.11-0.18). Adjusting for exercise-related shifts in plasma volume revealed a marked decline in vascular iCa content in the first 15 min of exercise (cool, -0.85 mg·dL; 95% CI, -1.01 to -0.68; warm, -0.85 mg·dL; 95% CI, -1.05 to -0.66), before substantial sweat Ca loss had occurred. CONCLUSIONS: This indicates that dermal Ca loss was not the primary trigger for the increases in PTH and CTX during exercise. Further research is necessary to understand the causes and consequences of the disruption in Ca homeostasis during exercise and specifically the extravascular shift in iCa.
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Cálcio/metabolismo , Exercício Físico/fisiologia , Hormônio Paratireóideo/sangue , Pele/metabolismo , Sudorese/fisiologia , Acidose/fisiopatologia , Adolescente , Adulto , Reabsorção Óssea/fisiopatologia , Cálcio/sangue , Colágeno Tipo I/sangue , Feminino , Frequência Cardíaca/fisiologia , Homeostase , Humanos , Masculino , Pessoa de Meia-Idade , Peptídeos/sangue , Adulto JovemRESUMO
STUDY OBJECTIVES: To evaluate the associations between sedentary time, total (total-PA), light (light-PA), moderate (MOD-PA), and vigorous (VIG-PA) physical activity with indices of sleep in postmenopausal women. METHODS: Baseline self-reported data from the Women's Health Initiative Observational Study (n = 75 074) were used in this cross-sectional analysis. Total-PA, light-PA, MOD-PA, and VIG-PA were categorized by metabolic equivalents of the activity (MET-hour [hr]/week [wk]) and were estimated using validated questionnaires. Sedentary time was categorized by hr/day and was estimated via questionnaire. Logistic regression was used to examine the associations between these variables and short sleep (≤6 hr/night), long sleep (≥10 hr/night), poor sleep quality, and insomnia symptoms after adjustment for age, race, socioeconomic status, body mass index, health status, depressive symptoms, smoking status, alcohol use, hormone therapy, and comorbidities. RESULTS: Higher sedentary time (>11 hr/day) was associated with higher odds of short sleep (odds ratio [OR] = 1.80, 95% confidence interval [CI]: 1.72-1.88), poor sleep quality (OR = 1.85, 95% CI: 1.74-1.97), and insomnia symptoms (OR = 1.56, 95% CI: 1.49-1.64). Light-PA (>0 MET-hr/wk) was associated with lower odds of short sleep (OR = 0.96, 95% CI: 0.92-1.00), and higher amounts of total-PA (OR = 0.90, 95% CI: 0.84-0.97), light-PA (OR = 0.94, 95% CI: 0.89-1.00), and MOD-PA (OR = 0.91, 95% CI: 0.86-0.97) were associated with lower odds of poor sleep quality. CONCLUSIONS: Our findings suggest that higher levels of light and moderate intensity physical activity are associated with better sleep quality, whereas higher amounts of sedentary time are associated with short sleep and lower quality sleep. Future studies should investigate the directionality of these associations and potential causal pathways.
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Exercício Físico/fisiologia , Comportamento Sedentário , Distúrbios do Início e da Manutenção do Sono/fisiopatologia , Sono/fisiologia , Índice de Massa Corporal , Estudos Transversais , Feminino , Nível de Saúde , Humanos , Masculino , Pessoa de Meia-Idade , Razão de Chances , Pós-Menopausa/fisiologia , Fumar , Inquéritos e Questionários , Fatores de TempoRESUMO
Background: Evidence in humans is equivocal in regards to whether resting energy expenditure (REE) decreases to a greater extent than predicted for the loss of body mass with weight loss, and whether this disproportionate decrease in REE persists with weight-loss maintenance. Objectives: We aimed to1) determine if a lower-than-predicted REE is present in a sample of successful weight-loss maintainers (WLMs) and 2) determine if amount of weight loss or duration of weight-loss maintenance are correlated with a lower-than-predicted REE in WLMs. Design: Participants (18-65 y old) were recruited in 3 groups: WLMs (maintaining ≥13.6 kg weight loss for ≥1 y, n = 34), normal-weight controls [NCs, body mass index (BMI; in kg/m2) similar to current BMI of WLMs, n = 35], and controls with overweight/obesity (OCs, BMI similar to pre-weight-loss maximum BMI of WLMs, n = 33). REE was measured (REEm) with indirect calorimetry. Predicted REE (REEp) was determined via 1) a best-fit linear regression developed with the use of REEm, age, sex, fat-free mass, and fat mass from our control groups and 2) three standard predictive equations. Results: REEm in WLMs was accurately predicted by equations developed from NCs and OCs (±1%) and by 3 standard predictive equations (±3%). In WLMs, individual differences between REEm and REEp ranged from -257 to +163 kcal/d. A lower REEm compared with REEp was correlated with amount of weight lost (r = 0.36, P < 0.05) but was not correlated with duration of weight-loss maintenance (r = 0.04, P = 0.81). Conclusions: We found no consistent evidence of a significantly lower REE than predicted in a sample of long-term WLMs based on predictive equations developed from NCs and OCs as well as 3 standard predictive equations. Results suggest that sustained weight loss may not always result in a substantial, disproportionately low REE. This trial was registered at clinicaltrials.gov as NCT03422380.
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Adaptação Fisiológica , Metabolismo Basal/fisiologia , Manutenção do Peso Corporal/fisiologia , Obesidade/metabolismo , Descanso/fisiologia , Redução de Peso/fisiologia , Adolescente , Adulto , Idoso , Índice de Massa Corporal , Calorimetria Indireta , Estudos de Casos e Controles , Metabolismo Energético , Feminino , Humanos , Modelos Lineares , Masculino , Conceitos Matemáticos , Pessoa de Meia-Idade , Modelos Biológicos , Obesidade/terapia , Sobrepeso , Estudos Prospectivos , Termogênese , Fatores de Tempo , Adulto JovemRESUMO
PURPOSE: This study aimed to determine the effects of 5 months of ovarian hormone suppression in premenopausal women on objectively measured physical activity (PA). METHODS: Participants (age, 35 ± 8 yr; body mass index, 27 ± 6 kg·m) received monthly intramuscular injections of gonadotropin-releasing hormone agonist (GnRHAG) therapy, which suppresses pituitary gonadotropins and results in suppression of ovarian sex hormones. Women were randomized to receive concurrent transdermal E2 (GnRHAG + E2; n = 30) or placebo (GnRHAG + PL, n = 31). PA was assessed for 1 wk before and during each month of the 5-month intervention using a hip-worn accelerometer (Actical, Mini Mitter Co., Inc., Bend, OR). Estimates of time spent in sedentary, light, and moderate-to-vigorous PA (MVPA) were derived using a previously published equation. Subsets of participants in each group were also randomized to a supervised progressive resistance exercise training program. RESULTS: Total MVPA tended toward being higher (P = 0.08) in the GnRHAG + E2 group at month 4. There were no significant effects of intervention or time in sedentary or light PA. In the subset of women who did not participate in structured exercise training for which Actical data were obtained (n = 16 in each group), total MVPA was higher at month 4 (P = 0.01). CONCLUSIONS: PA levels seem to be maintained at a higher level in women undergoing pharmacological suppression of ovarian function with E2 add-back when compared with women treated with placebo. These data provide proof-of-concept data that E2 contributes to the regulation of PA in humans. However, given the exploratory nature of this study, future confirmatory investigations will be necessary.
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Estradiol/fisiologia , Exercício Físico/fisiologia , Ovário/fisiologia , Pré-Menopausa/fisiologia , Adulto , Método Duplo-Cego , Feminino , Hormônio Liberador de Gonadotropina/agonistas , Humanos , Pessoa de Meia-Idade , Ovário/efeitos dos fármacos , Estudo de Prova de Conceito , Treinamento ResistidoRESUMO
UNLABELLED: We have previously shown that motor-driven (passive) stationary cycling elevates energy expenditure (EE). PURPOSE: This study aimed to quantify how acute passive cycling affects glucose and insulin responses to an oral glucose tolerance test (OGTT) and basic cognition compared with sitting and moderate-intensity active cycling. METHODS: Twenty-four physically inactive healthy males completed three trials in randomized order involving 30-min conditions of sitting, passive cycling, and moderate-intensity cycling. During each condition, EE was measured, and participants performed cognitive tests. After each condition, a 2-h OGTT was performed. RESULTS: EE was significantly higher during the cycling conditions compared with sitting (1.36 ± 0.58 and 6.50 ± 1.73 kcal·min greater than sitting for passive and moderate-intensity, respectively). A significant correlation was found between body fat percentage and postsitting OGTT 2-h postplasma glucose (r = 0.30, P < 0.05); thus, participants were divided into lean (n = 11) and nonlean (n = 13) groups. In the nonlean group, compared with sitting, passive cycling lowered 2-h postplasma glucose (7.7 ± 1.3 vs 6.9 ± 1.6 mmol·L, respectively, P < 0.05), and the Matsuda whole-body insulin sensitivity index (WBISI) was higher (2.74 ± 0.86 vs 3.36 ± 1.08, P < 0.05). In addition, passive and moderate-intensity cycling had similar beneficial effects on 2-h postplasma glucose and WBISI. Cognitive performance did not significantly differ between the sitting and passive cycling conditions. CONCLUSIONS: Two-hour postplasma glucose was lower and WBISI after acute passive cycling was higher in nonlean participants. Given that and the increase in EE without changes in cognitive performance, we propose passive cycling as a promising intervention to counteract some of the deleterious effects of prolonged sitting in the workplace.
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Metabolismo Energético/fisiologia , Exercício Físico/fisiologia , Adiposidade , Adulto , Índice de Massa Corporal , Cognição , Estudos Cross-Over , Teste de Esforço , Teste de Tolerância a Glucose , Humanos , Resistência à Insulina , Masculino , Pessoa de Meia-Idade , Postura , Adulto JovemRESUMO
OBJECTIVE: Suppression of ovarian hormones in premenopausal women on gonadotropin-releasing hormone agonist (GnRH(AG)) therapy can cause fat mass (FM) gain and fat-free mass (FFM) loss. Whether this is specifically caused by a decline in serum estradiol (E2) is unknown. This study aims to evaluate the effects of GnRH(AG) with placebo (PL) or E2 add-back therapy on FM, FFM, and bone mineral density (BMD). Our exploratory aim was to evaluate the effects of resistance exercise training on body composition during the drug intervention. METHODS: Seventy healthy premenopausal women underwent 5 months of GnRH(AG) therapy and were randomized to receive transdermal E2 (GnRH(AG) + E2, nâ=â35) or PL (GnRH(AG) + PL, nâ=â35) add-back therapy. As part of our exploratory aim to evaluate whether exercise can minimize the effects of hormone suppression, some women within each drug arm were randomized to undergo a resistance exercise program (GnRH(AG) + E2 + Ex, nâ=â12; GnRH(AG) + PL + Ex, nâ=â12). RESULTS: The groups did not differ in mean (SD) age (36 [8] and 35 [9] y) or mean (SD) body mass index (both 28 [6] kg/m). FFM declined in response to GnRH(AG) + PL (mean, -0.6âkg; 95% CI, -1.0 to -0.3) but not in response to GnRH(AG) + E2 (mean, 0.3âkg; 95% CI, -0.2 to 0.8) or GnRH(AG) + PL + Ex (mean, 0.1âkg; 95% CI, -0.6 to 0.7). Although FM did not change in either group, visceral fat area increased in response to GnRH(AG) + PL but not in response to GnRH(AG) + E2. GnRH(AG) + PL induced a decrease in BMD at the lumbar spine and proximal femur that was prevented by E2. Preliminary data suggest that exercise may have favorable effects on FM, FFM, and hip BMD. CONCLUSIONS: Suppression of ovarian E2 results in loss of bone and FFM and expansion of abdominal adipose depots. Failure of hormone suppression to increase total FM conflicts with previous studies of the effects of GnRH(AG). Further research is necessary to understand the role of estrogen in energy balance regulation and fat distribution.
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Composição Corporal/efeitos dos fármacos , Densidade Óssea/efeitos dos fármacos , Estrogênios Conjugados (USP)/administração & dosagem , Exercício Físico , Hormônio Liberador de Gonadotropina/agonistas , Adulto , Relação Dose-Resposta a Droga , Quimioterapia Combinada , Feminino , Humanos , Ovário/efeitos dos fármacos , Resultado do TratamentoRESUMO
INTRODUCTION: The Personal Calorie Monitor (PCM) is a portable direct calorimeter that estimates energy expenditure (EE) from measured heat flux (i.e., the sum of conductive, convective, radiative, and evaporative heat). PURPOSE: The primary aim of this study was to compare EE estimated from measures of heat flux with those measured using indirect calorimetry in a thermoneutral environment (26°C). A secondary aim was to determine whether exposure to ambient temperature below thermoneutral condition (19°C) influences the accuracy of the PCM. METHODS: Thirty-four adults (mean ± SD: age, 28 ± 5 yr; body mass index, 22.9 ± 2.6 kg · m(-2)) were studied for 5 h in a whole-room indirect calorimeter (IC) in thermoneutral and cool conditions. Participants wore the PCM on their upper arm and completed two 20-min treadmill walking bouts (0% grade, 3 mph). The remaining time was spent sedentary (e.g., watching television, using a computer). RESULTS: In thermoneutral conditions, EE values (mean (95% confidence interval)) measured by IC and PCM were 560.0 (526.5-593.5) and 623.3 (535.5-711.1) kcal, respectively. In cool conditions, EE values measured by IC and PCM were 572.5 (540.9-604.0) and 745.5 (668.1-822.8) kcal, respectively. Under thermoneutral conditions, mean PCM minute-by-minute EE tracked closely with IC, resulting in a small nonsignificant bias (63 kcal (-5.8 to 132.4)). During cool conditions, mean PCM minute-by-minute EE did not track IC, resulting in a large bias (173.0 kcal (93.9-252.1)) (P <; 0.001). CONCLUSIONS: This study demonstrated the validity of using measured heat flux to estimate EE. However, accuracy may be impaired in cool conditions possibly because of excess heat loss from the exposed limbs.
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Calorimetria/instrumentação , Calorimetria/métodos , Metabolismo Energético , Temperatura , Adulto , Calorimetria Indireta/métodos , Temperatura Baixa , Estudos Cross-Over , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Reprodutibilidade dos Testes , Adulto JovemRESUMO
INTRODUCTION: Accurately and precisely estimating free-living energy expenditure (EE) is important for monitoring energy balance and quantifying physical activity. Recently, single and multisensor devices have been developed that can classify physical activities, potentially resulting in improved estimates of EE. PURPOSE: This study aimed to determine the validity of EE estimation of a footwear-based physical activity monitor and to compare this validity against a variety of research and consumer physical activity monitors. METHODS: Nineteen healthy young adults (10 men, 9 women) completed a 4-h stay in a room calorimeter. Participants wore a footwear-based physical activity monitor as well as Actical, ActiGraph, IDEEA, DirectLife, and Fitbit devices. Each individual performed a series of postures/activities. We developed models to estimate EE from the footwear-based device, and we used the manufacturer's software to estimate EE for all other devices. RESULTS: Estimated EE using the shoe-based device was not significantly different than measured EE (mean ± SE; 476 ± 20 vs 478 ± 18 kcal, respectively) and had a root-mean-square error of 29.6 kcal (6.2%). The IDEEA and the DirectLlife estimates of EE were not significantly different than the measured EE, but the ActiGraph and the Fitbit devices significantly underestimated EE. Root-mean-square errors were 93.5 (19%), 62.1 kcal (14%), 88.2 kcal (18%), 136.6 kcal (27%), 130.1 kcal (26%), and 143.2 kcal (28%) for Actical, DirectLife, IDEEA, ActiGraph, and Fitbit, respectively. CONCLUSIONS: The shoe-based physical activity monitor provides a valid estimate of EE, whereas the other physical activity monitors tested have a wide range of validity when estimating EE. Our results also demonstrate that estimating EE based on classification of physical activities can be more accurate and precise than estimating EE based on total physical activity.