Joyner, Michael J.

Abstract BACKGROUND Studies demonstrate an association between aortic hemodynamics and cognitive function. The impact of pregnancy history on this association is unknown. METHODS Postmenopausal women (age 59 ± 5 years; years since last pregnancy 35 ± 3) with either a history of preeclampsia (PE; n = 34) or a history of a normotensive pregnancy (NP; n = 30) underwent cognitive testing: Letter-Number Sequencing, Digit Span, Trail Making Test, and letter and category fluency. Applanation tonometry was used to derive aortic systolic and diastolic blood pressure and augmentation index. RESULTS Distribution of cognitive scores and aortic hemodynamic measures was similar between the PE and NP groups. Principal component (PC) analysis was used to reduce the 3 aortic hemodynamic measures and the 5 cognitive variables to single summary indices, each representing a weighted average of their respective constituent variables. Using a multivariable linear model based on these PCs that adjusted for pregnancy history and body mass index, the composite index of aortic hemodynamics was associated with the summary cognitive index, whether taking into account a potential interaction with pregnancy history (P = 0.035) or not (P = 0.026) (interaction P = 0.178). Multivariable modeling of individual cognitive tests revealed a differential association for letter fluency by pregnancy history (test for interaction P = 0.023); this score correlated with the aortic hemodynamic index in the PE (partial R2 = 0.20), but not the NP (partial R2 = 0.00) group. CONCLUSIONS Elevated aortic hemodynamics may negatively impact cognitive function in postmenopausal women with specific executive functions, such as letter fluency, being impacted more by a pregnancy history of PE.

AbstractBackgroundRapid gastric emptying, increased food intake, and alterations in gastrointestinal hormones are associated with obesity. The effect of regular physical activity (PA) on food intake, gastric emptying (GE), gastric accommodation, and gastrointestinal (GI) hormones in adults with obesity remains unclear. Our aim was to compare, at time of presentation, weight trends, eating behavior, GE, and GI hormone levels among individuals with obesity who engage in regular PA compared to those who do not.MethodsIn 270 participants with obesity, we performed validated measurements of GI phenotypes: GE of solids and liquids, gastric volume (GV) during fasting and after consumption of 200 mL Ensure®, satiety by kcal intake (T‐kcal) during a buffet meal, satiation (volume to fullness [VTF] and maximal tolerated volume [MTV]) of a liquid nutrient, and plasma levels of fasting and postprandial GLP‐1, PYY, CCK, and ghrelin. Physical Activity Stages of Change Questionnaire was used to assess whether participants were regularly PA or not.Key resultsPA was associated with lower BMI (Δ 2.01 kg/m2, P = .001) and body weight (Δ 4.42 kg, P = .0278). GE of solids (T‐50% Δ 7.54 min, P = .021) and liquids (T‐50% Δ 2.99 min, P = .029%) was significantly more rapid in physically active participants. PA was also associated with relatively higher postprandial ghrelin AUC (Δ 10.4 pg/mL, P = .015). There was no significant difference in postprandial satiation, satiety, GV, or other GI hormones (CCK, PYY, or GLP‐1) between groups.Conclusions & InferencesPhysical activity is associated with lower BMI, but faster GE and higher postprandial ghrelin levels, two factors that are also associated with obesity.

Aging increases autonomic support of blood pressure; however, the impact of aerobic fitness on autonomic support of blood pressure has not been addressed in women. As such, we hypothesized that aerobic fitness would be related to the change in blood pressure during ganglionic blockade such that women with greater aerobic fitness would have a blunted fall in blood pressure during ganglionic blockade due to increased vagal tone. Thirteen young premenopausal and 13 older postmenopausal women completed a screening visit where aerobic fitness (maximal oxygen consumption, VO 2max ) was measured. On a separate study day, participants were instrumented for assessment of muscle sympathetic nerve activity, heart rate (electrocardiography), and beat by beat blood pressure (arterial catheter and pressure transducer) and underwent pharmacological blockade of the autonomic ganglia using trimethaphan camyslate. Heart rate, blood pressure, and muscle sympathetic nerve activity were analyzed before and during ganglionic blockade. In young women, there was a significant relationship between aerobic fitness and the change in blood pressure during ganglionic blockade ( r =0.761, P =0.003). In older women, there was no relationship between aerobic fitness and the change in blood pressure during ganglionic blockade ( r =−0.106, P =0.73). Measures of heart rate variability were related to fitness in young women, but not older women (root mean square of successive differences between normal heartbeats, r =0.713, P =0.006 versus r =−0.172, P =0.575). Our data suggest that in young women, autonomic support of blood pressure is attenuated in those that are highly fit; however, this relationship is not significant in older women.

In humans, a novel allosteric hemoglobin-oxygen affinity modulator was administered to comprehensively examine the cardiopulmonary consequences of stabilizing a portion of the available hemoglobin in a high-oxygen affinity state during submaximal exercise in normoxia and hypoxia. Oral administration of voxelotor enhanced arterial oxygen saturation during submaximal exercise without altering oxygen consumption and central hemodynamics; however, the partial pressure of arterial carbon dioxide was reduced and the partial pressure of arterial oxygen was increased implying that hyperventilation also contributed to the increase in oxygen saturation. The preservation of arterial oxygen saturation and content was particularly evident during hypoxic submaximal exercise, when arterial desaturation typically occurs, but this did not influence arterial-venous oxygen difference.

ABSTRACT Although over 100 studies and reviews have examined the ergogenic effects of dietary nitrate (NO 3 − ) supplementation in young, healthy men and women, it is unclear if participant and environmental factors modulate the well-described ergogenic effects—particularly relevant factors include biological sex, aerobic fitness, and fraction of inspired oxygen (F i O 2 ) during exercise. To address this limitation, the literature was systematically reviewed for randomized, crossover, placebo-controlled studies reporting exercise performance outcome metrics with NO 3 − supplementation in young, healthy adults. Of the 2033 articles identified, 80 were eligible for inclusion in the meta-analysis. Random-effects meta-analysis demonstrated that exercise performance improved with NO 3 − supplementation compared with placebo ( d = 0.174; 95% confidence interval (CI), 0.120–0.229; P < 0.001). Subgroup analyses conducted on biological sex, aerobic fitness, and F i O 2 demonstrated that the ergogenic effect of NO 3 − supplementation was as follows: 1) not observed in studies with only women ( n = 6; d = 0.116; 95% CI, −0.126 to 0.358; P = 0.347), 2) not observed in well-trained endurance athletes (≥65 mL·kg −1 ·min −1 ; n = 26; d = 0.021; 95% CI, −0.103 to 0.144; P = 0.745), and 3) not modulated by F i O 2 (hypoxia vs normoxia). Together, the meta-analyses demonstrated a clear ergogenic effect of NO 3 − supplementation in recreationally active, young, healthy men across different exercise paradigms and NO 3 − supplementation parameters; however, the effect size of NO 3 − supplementation was objectively small ( d = 0.174). NO 3 − supplementation has more limited utility as an ergogenic aid in participants with excellent aerobic fitness that have optimized other training parameters. Mechanistic research and studies incorporating a wide variety of subjects (e.g., women) are needed to advance the study of NO 3 − supplementation; however, additional descriptive studies of young, healthy men may have limited utility.