Utility of the actiheart accelerometer for estimating exercise energy expenditure in female adolescent runners.

There is a growing need to accurately assess exercise energy expenditure (EEE) in athletic populations that may be at risk for health disorders because of an imbalance between energy intake and energy expenditure. The Actiheart combines heart rate and uniaxial accelerometry to estimate energy expenditure above rest. The authors' purpose was to determine the utility of the Actiheart for predicting EEE in female adolescent runners (N = 39, age 15.7 ± 1.1 yr). EEE was measured by indirect calorimetry and predicted by the Actiheart during three 8-min stages of treadmill running at individualized velocities corresponding to each runner's training, including recovery, tempo, and 5-km-race pace. Repeated-measures ANOVA with Bonferroni post hoc comparisons across the 3 running stages indicated that the Actiheart was sensitive to changes in intensity (p < .01), but accelerometer output tended to plateau at race pace. Pairwise comparisons of the mean difference between Actiheart- and criterion-measured EEE yielded values of 0.0436, 0.0539, and 0.0753 kcal × kg-1 × min-1 during recovery, tempo, and race pace, respectively (p < .0001). Bland-Altman plots indicated that the Actiheart consistently underestimated EEE except in 1 runner's recovery bout. A linear mixed-model regression analysis with height as a covariate provided an improved EEE prediction model, with the overall standard error of the estimate for the 3 speeds reduced to 0.0101 kcal × kg-1 × min-1. Using the manufacturer's equation that combines heart rate and uniaxial motion, the Actiheart may have limited use in accurately assessing EEE, and therefore energy availability, in young, female competitive runners.

Patterns of objective physical functioning and perception of mood and fatigue in posttreatment breast cancer patients and healthy controls: an ambulatory psychophysiological investigation.

OBJECTIVE: To monitor objective physiological and self-report measures among apparently disease-free breast cancer patients (n = 33) in the first 2 years of posttreatment recovery, using a cross-sectional design, and compare findings with women without histories of cancer or other serious disorders (n =33). Time-since-treatment also served as an independent variable. Few studies have examined adjustment of breast cancer patients after primary treatment or objectively characterized posttreatment, everyday patterns of functioning. METHODS: A 24-hour ambulatory minute-by-minute cardiorespiratory functioning and accelerometry activity were measured during one day, together with multiple repeated assessments of mood and fatigue. Traditional retrospective measures of well-being were also evaluated. Our ambulatory methodology permitted estimation of physiological rhythms of cardiorespiratory and accelerometry activity. RESULTS: Patients reported lower ambulatory levels of energy and poorer mood during the daytime than controls. Time-since-treatment was related directly to both momentary mood and energy as well as to objective measures of activity and respiratory parameters. Retrospective self-reports of impaired mood and symptoms persisted in patients, independently of time-since-treatment and of ambulatory physical or physiological activity. Ambulatory self-report data were associated with concurrent respiratory measures. Chemotherapy-related elevation of heart rate was found but was unrelated to self-report measures. CONCLUSIONS: Impaired sense of well being based on retrospective measures is not associated with pattern of physical or physiological functioning after treatment for breast cancer. However, ambulatory, momentary levels of mood and fatigue seem to be related to concurrent ventilatory activity and time-since-treatment. This is the first investigation that relates ambulatory and retrospective measures of affect and fatigue to concurrent, real-life physical functioning.

Physical activity and restlessness correlate with leptin levels in patients with adolescent anorexia nervosa.

BACKGROUND: In food-restricted rats, leptin suppresses semistarvation-induced hyperactivity (SIH) and decreases exploratory behavior. Leptin ameliorates anxiety-related movement in ob/ob mice. In this study, we assessed the relationship between leptin and qualities of physical activity and restlessness in acute anorexia nervosa (AN). METHODS: Serum leptin, body mass index (BMI), % body fat, and self- and expert-ratings of qualities of physical activity and restlessness were assessed in 26 inpatients with acute AN. Accelerometry was also performed. Regression analyses were used to predict activity and restlessness using BMI, % body fat, and leptin levels as predictor variables. RESULTS: Leptin levels significantly contributed to the prediction of all measures of activity and restlessness. CONCLUSIONS: This is the first study linking hypoleptinemia in AN patients to subjective and objective measures of higher physical activity and motor and inner restlessness. Leptin may directly or indirectly (or both) influence behaviors and cognitions contributing to hyperactivity and motor restlessness.

Repetitividad de los índices de contractilidad apexocardiográficos / Reproducibility of the indices of apex cardiographic contractility

Se valoró la repetividad de la apexocardiografía cuantitativa a través del índice R/dA-dt, y el porcentaje de positividad de la primera derivada del apexocardigrama. Se estudiaron tres pacientes, realizándose les diez trazados a cada uno en días no sucesivos, por dos operadores diferentes. El análisis fue ejecutado por dos intérpretes distintos. Para la variación interdía, se obtuvo el "coeficiente de variación" para cada determinación, y se los comparó con el obtenido por reale y Kolev. Se realizó el análisis de las diferencias, comparando el resultado obtenido por ambos operadores e intérpretes, aplicando el método de la t de Student. Las variaciones del índice R/dA-dt, en el paciente "1", obtenidos por el operador "A", operador "B", intérprete "I", e intérprete "II", fueron: 60,8; 583,; 56,8 y 57,5 msegs. respectivamente (p > 0,5, diferencias n.s.). En el paciente "2" fueron 57,5; 55,3; 56,3 y 53,8 msegs. respectivamente (p > 0,5, diferencias n.s.). En el paciente "3": 46,9; 48,5; 47,2 y 46 msegs. (p > 0,5, diferencias n.s.). Las variaciones del porcentaje de positividad de la primera derivada en el paciente "1" fueron: 51,7; 52,1; 47 y 55% (p > 0,5, diferencias n.s.). En el paciente "2" fueron: 65,6; 62,1; 57 y 59% (p > 0,5, diferencias n.s.).:el el paciente "3": 57,3; 53,1; 55 y 50% (p > diferencias n.s.) El coeficiente de variación para estudiar los cambios interdía del R/dA-dt, osciló entre 0,07 y 0,22; y para el porcentaje de positividad de la primera derivada, entre 0,08 y 0,18. Ambos índices contráctiles mostraron excelente repetividad, valorados en días diferentes, por operadores distintos y, evaluados por intérpretes diferentes (AU)