Determining menstrual cycle phase: An empirical examination of methodologies and recommendations for improvement in behavioral and brain sciences

Daily energy expenditure and water turnover in female netball players from the Netball Super League: A doubly labeled water observation study

To establish the criterion-assessed energy and fluid requirements of female netball players, 13 adult players from a senior Netball Super League squad were assessed over 14 days in a cross-sectional design, representing a two- and one-match microcycle, respectively. Total energy expenditure (TEE) and water turnover (WT) were measured by doubly labeled water. Resting and activity energy expenditure were measured by indirect calorimetry and Actiheart, respectively. Mean 14-day TEE was 13.46 ± 1.20 MJ day-1 (95% CI, 12.63-14.39 MJ day-1). Resting energy expenditure was 6.53 ± 0.60 MJ day-1 (95% CI, 6.17-6.89 MJ day-1). Physical activity level was 2.07 ± 0.19 arbitrary units (AU) (95% CI, 1.95-2.18 AU). Mean WT was 4.1 ± 0.9 L day-1 (95% CI, 3.6-4.7 L day-1). Match days led to significantly greater TEE than training (+2.85 ± 0.70 MJ day-1; 95% CI, +1.00- +4.70 MJ day-1; p = 0.002) and rest (+4.85 ± 0.70 MJ day-1; 95% CI, +3.13-+6.56 MJ day-1; p < 0.001) days. Matches led to significantly greater energy expenditure (+1.85 ± 1.27 MJ; 95% CI, +0.95-+2.76 MJ day-1; p = 0.001) than court-based training sessions. There was no significant difference in TEE (+0.03 ± 0.35 MJ day-1; 95% CI, -0.74-+0.80 MJ day-1; p = 0.936) across weeks. Calibrated Actiheart 5 monitors underestimated TEE (-1.92 ± 1.21 MJ day-1). Energy and fluid turnover were greatest on match days, followed by training and rest days, with no difference across weeks. This study provides criterion-assessed energy and fluid requirements to inform dietary guidance for female netball players.

Hormonal contraceptives and behavior: Updating the potent state of the nascent science

Hundreds of millions of people worldwide use hormonal contraceptives (HCs), which have been an essential part of women's reproductive health care for decades. Throughout that time, however, research on the neural and behavioral consequences of HCs was minimal and plagued by poor methodology. HC effects - and users - were assumed to be homogenous. Fortunately, there has been a recent upswell in the number and quality of investigations, affording tentative conclusions about the roles of HCs in spatial cognition and mental health, particularly depression. Thus, this paper leverages findings from the past few years to highlight the heterogeneous aspects of use that seem to matter for behavior - ranging from variation in hormonal contraceptive formulations and routes of administration to individual differences among users linked to age and reproductive health history. This paper closes with five tips for future research that will help capture and clarify heterogeneity in potential relations between HCs and behavior, namely data collection, regional access, lifespan factors, gender, and collaboration. HCs are sociopolitically provocative and research on their potential behavioral neuroendocrine impacts is becoming increasingly popular. It is, therefore, imperative for scientists to conduct replicable and robust empirical investigations, and to communicate findings with the nuance that the heterogeneity among users and effects requires.

The link between daily affective complexity and anxiety is altered by oral contraceptive use

Affective complexity - the unique ways in which individuals' emotions covary and differentiate - is an important aspect of internalizing problems. For instance, daily affective complexity has been linked to anxiety increases in women and to decreases in men. The mechanisms underlying this gender difference have not been widely investigated, but a role for ovarian hormones is likely. Research on oral contraceptives (OCs) provides promising insights into such mechanisms, as OCs suppress endogenous ovarian hormone production and vary in exogenous hormone formulations. Thus, the goal of this study was to examine links between daily affective complexity and internalizing problems in OC users (n = 84), focusing on dimensionally-assessed anxiety, and to investigate whether the links varied by pill formulation. Affective complexity was operationalized as number of factors for each person, as estimated by p-technique (i.e., person-specific factor analysis) of 75-day intensive longitudinal data. There was not a relation between affective complexity and anxiety in OC users, and this did not depend on OC pill formulation (i.e., estrogenic, progestational, or androgenic activities). Thus, OC use may blunt the relation between affective complexity and anxiety, as OC users had a relation in between the established positive relation for naturally cycling women and the inverse for men (despite a similar range of factors). Findings are consistent with a growing literature showing that OC use modulates stress and anxiety-linked processes, and suggest that gendered mechanisms underlying the relation between affective complexity and anxiety may be suppressed along with ovarian hormones in OC users.