Although sleep disturbance is commonly reported in pregnancy, there have been few studies on sleep characteristics in pregnancy. In this study, all women attending the antenatal clinic at Sapporo Medical College Hospital for 1 month during autumn and 3 months during winter were surveyed with a questionnaire and sleep log. Of the 192 patients, 169 (88.0%) stated that sleep was altered from their usual experience. A principal components analysis identified three sleep factors from the ten items in the measure of sleep used (Sleep Log). The three factors were: Sleep Duration and Quality, Insomnia and Daytime Alertness. Although no significant differences across trimesters were found on the three sleep factors, Sleep Duration and Quality, and Insomnia were worst during the first trimester. Sleep normalized in the second trimester, but the third trimester was characterized by increased Insomnia and decreased Daytime Alertness. The most frequent reasons cited by women for sleep alterations were urinary frequency, backache or ache in the hips and fetal movement. Contingency X2 analyses were used to investigate a relationship between the frequency of reporting the reasons and the trimester of pregnancy. Significant increases were found in reporting as the reasons for sleep difficulties, fetal movement in the third trimester, and heartburn, nausea and vomiting in the first trimester. The description of sleep patterns during pregnancy has clinical relevance as sleep alterations in pregnancy are common.
The purposes of this study were to demonstrate the transition of heart rate variability (HRV) during trials in the field and to examine the relationship between peak frequency of high-frequency band (HF) and stride frequency. Ten healthy long-distance college female runners (age 19-21 years) performed a 3000 m realistic time trial. The time-series power spectrum analysis by maximum entropy method was used to evaluate cardiac autonomic nervous activity during the race. Cross-correlation coefficients were calculated to estimate the degree of linear co-ordination between the central peak frequency of HF and stride frequency. Just after starting, the decrease in HF (0.15-1.00 Hz) and a transient increase of low-frequency band (LF)/HF were found. After that, the HF remained at a low level and LF/HF decreased sharply. These findings suggested that the parasympathetic activity was suppressed and sympathetic activity increased just after starting, and the sympathetic activity reached the saturated level according to continuation of high-intensity exercise. In spite of the significant decrease of HRV during trials, peak frequency of HF could be differentiated clearly. The cross-correlation coefficient of peak frequency of HF and stride frequency was from 0.703 to 0.868. This finding indicated that exercise rhythm reflected HRV during high-intensity running in the field.
Although sleep disturbance is commonly reported in pregnancy, there have been surprisingly few studies on the etiology of this condition. Since most hormones show circadian rhythmicity and maintain specific phase relationships with that of the sleep-wake cycle, it was of interest to establish whether sleep disturbances covaried with endocrine changes. This overnight study of pregnant women compared melatonin, cortisol, and prolactin secretion rhythms in six good sleepers and six poor sleepers. The groups were compared by ratios of the areas under the various hormonal curves. Significant differences in the cortisol/melatonin ratio were found between the poor sleeper group (lower values) and the good sleeper group (higher values). Nonsignificant trends, which might be expected to become significant with larger sample sizes, were found for decreased amplitude in the cortisol rhythm and increased amplitude in the melatonin rhythm in poor sleepers. The decreased amplitude of the cortisol rhythm in poor sleepers appeared to be due to a suppression of the early morning (0500-0800) rise. Prolactin levels were high and showed no rhythmicity in both groups. These differences may reflect changes in the circadian pacemaker system of poor sleepers, with increases in melatonin release being a response to counteract poor sleep.
The purpose of this study was to examine the timing of recovery of the high-frequency (HF) component of heart rate variability (HRV) after exercise in female distance runners using frequency analysis of HRV. Twenty-two female young (nϭ11; YG) and middle-aged (nϭ11; MG) distance runners participated in this study. The two groups performed incremental cycle exercise with progressive intensity until exhaustion. The R-R intervals were processed by the maximum entropy method for determination of HF power on successive 7-second segments of 70 seconds of the recovery period. In the YG, the HF power of the second 7-sec segment showed significantly higher values than the 7 sec before cessation of exercise (pϽ0.005), whereas the MG exhibited significantly higher values in the third segment (pϽ0.005). The YG indicated significantly higher HF power than the MG in the fifth segment (pϽ0.0045). These findings suggested the occurrence of parasympathetic reactivation at an earlier period compared to the previous findings. Multiple influences of various factors including the subjects' characteristics to HF recovery were suggested. However, the detection of the timing of HF recovery despite the duration of sharp change in HR indicated that HRV was an effective evaluation technique for determination of autonomic control immediately after exercise.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.