AimTo investigate the effects of the coronavirus disease 2019 (COVID-19) lockdown on sleep habits... more AimTo investigate the effects of the coronavirus disease 2019 (COVID-19) lockdown on sleep habits in the Croatian general population.MethodsIn this cross-sectional study, 1173 respondents from the general population (809 women) completed a self-report online questionnaire that gathered demographic data and data on sleep habits and mood changes before and during the COVID-19 lockdown.ResultsDuring the lockdown, bedtime (from 23:11 ± 1:07 to 23:49 ± 1:32 h, P < 0.001) and waketime were delayed (from 6:51 ± 1:09 to 7:49 ± 1:40 h, P < 0.001). Sleep latency increased from 10 (5-20) to 15 (10-30) minutes (P < 0.001). Bedtime and waketime delays were more pronounced in women and respondents younger than 30. Compared with other age groups, respondents younger than 30 more frequently reported insomnia for the first time during the lockdown and had less frequent night-time awakenings (P < 0.001), less common problems falling asleep (P < 0.001), less frequently felt calm (P < 0.001) and rested (P < 0.001), but more frequently felt sadness (P < 0.001) and fear (P = 0.028).ConclusionThe effect of the lockdown on sleep needs to be better understood. Sleep hygiene education could serve a first-line lifestyle intervention for people in lockdown experiencing sleep disruption.
Activation of the sympathetic nervous system plays an important role in the pathophysiology of sl... more Activation of the sympathetic nervous system plays an important role in the pathophysiology of sleep-related breathing disorders. The aim of the present study was to examine the effects of different levels of hypercapnia in the presence of various background oxygen levels on the magnitude of sympathoexcitation, measured by the renal sympathetic nerve activity (RSNA) in the acute intermittent hypercapnia (AIHc) rat model. The study was conducted on 56 urethane-anesthetized, vagotomized and mechanically ventilated Sprague-Dawley rats (n = 7/group). Each experimental group was subjected to a distinct AIHc protocol that varied in the applied levels of hypercapnia and background oxygen. Mean arterial pressure and RSNA were analyzed in 7 experimental time points: baseline, five hypercapnic episodes (each lasting 3 min) and 15 minutes following the last hypercapnic episode. Exposure to severe hypercapnia (FiCO2 = 0.15) evoked an increase in RSNA, which was preserved throughout the protocol, whereas in moderate hypercapnia (FiCO2 = 0.05) groups there was a trend of progressive diminution of RSNA magnitude following the first hypercapnic episode. Exposure to severe hypercapnia elicited significantly greater RSNA response during first hypercapnic episode and it was enhanced during subsequent episodes compared to exposure to moderate hypercapnia. Additionally, hyperoxic2 background (50% O2) blunted the RSNA response to AIHc compared to room air background, both in severe and moderate hypercapnia groups. Mean arterial blood pressure was preserved throughout the experimental protocol in all studied groups. These findings indicate that acute intermittent hypercapnia evokes increased renal sympathetic nerve activity that is dependent on the severity of hypercapnic exposures and the background oxygen level.
AimTo construct a single-format questionnaire on sleep habits and mood before and during the COVI... more AimTo construct a single-format questionnaire on sleep habits and mood before and during the COVID-19 pandemic in the general population.MethodsWe constructed the Split Sleep Questionnaire (SSQ) after a literature search of sleep, mood, and lifestyle questionnaires, and after a group of sleep medicine experts proposed and assessed questionnaire items as relevant/irrelevant. The study was performed during 2021 in 326 respondents distributed equally in all age categories. Respondents filled out the SSQ, the Pittsburgh Sleep Quality Index (PSQI), and State Trait Anxiety Inventory (STAI), and kept a seven-day sleep diary.ResultsWorkday and work-free day bedtime during the COVID-19 pandemic assessed with SSQ were comparable to the sleep diary assessment (P = 0.632 and P = 0.203, respectively), as was the workday waketime (P = 0.139). Work-free day waketime was significantly later than assessed in sleep diary (8:19 ± 1:52 vs 7:45 ± 1:20; P < 0.001). No difference in sleep latency was found between the SSQ and PSQI (P = 0.066). Cronbach alpha for Sleep Habits section was 0.819, and 0.89 for Mood section. Test-retest reliability ranged from 0.45 (P = 0.036) for work-free day bedtime during the pandemic to 0.779 (P < 0.001) for sleep latency before the pandemic.ConclusionThe SSQ provides a valid, reliable, and efficient screening tool for the assessment of sleep habits and associated factors in the general population during the COVID-19 pandemic.
The bones of divers are subjected to stress from water pressure, from the forces generated when t... more The bones of divers are subjected to stress from water pressure, from the forces generated when their muscles resist water pressure, and from weightlessness. Several previously published studies have shown conflicting results. The aim of this study was to determine bone mineral density (BMD) and biochemical markers of bone turnover in experienced SCUBA divers. In this study we included 10 experienced SCUBA divers with a mean age of 47±2.4 years (mean±SEM). The average number of diving years was 26.1 with 381 diving hours per year. The control group included 10 healthy man who were matched by age, weight, and height. The BMD of lumbar spine and hip regions was assessed by dual energy x‐ray absorptiometry and biochemical markers of bone turnover were measured. The BMD value for total lumbar spine in divers was 1.252±0.031 vs. 1.136±0.041 g/cm2 in control group and for total hip was 1.172±0.047 vs. 1.102±0.041 g/cm2 in control group. T scores were 1.54±0.28 vs. 0.42±0.37 and 1.05±0.27 ...
AimTo investigate the effects of the coronavirus disease 2019 (COVID-19) lockdown on sleep habits... more AimTo investigate the effects of the coronavirus disease 2019 (COVID-19) lockdown on sleep habits in the Croatian general population.MethodsIn this cross-sectional study, 1173 respondents from the general population (809 women) completed a self-report online questionnaire that gathered demographic data and data on sleep habits and mood changes before and during the COVID-19 lockdown.ResultsDuring the lockdown, bedtime (from 23:11 ± 1:07 to 23:49 ± 1:32 h, P < 0.001) and waketime were delayed (from 6:51 ± 1:09 to 7:49 ± 1:40 h, P < 0.001). Sleep latency increased from 10 (5-20) to 15 (10-30) minutes (P < 0.001). Bedtime and waketime delays were more pronounced in women and respondents younger than 30. Compared with other age groups, respondents younger than 30 more frequently reported insomnia for the first time during the lockdown and had less frequent night-time awakenings (P < 0.001), less common problems falling asleep (P < 0.001), less frequently felt calm (P < 0.001) and rested (P < 0.001), but more frequently felt sadness (P < 0.001) and fear (P = 0.028).ConclusionThe effect of the lockdown on sleep needs to be better understood. Sleep hygiene education could serve a first-line lifestyle intervention for people in lockdown experiencing sleep disruption.
Activation of the sympathetic nervous system plays an important role in the pathophysiology of sl... more Activation of the sympathetic nervous system plays an important role in the pathophysiology of sleep-related breathing disorders. The aim of the present study was to examine the effects of different levels of hypercapnia in the presence of various background oxygen levels on the magnitude of sympathoexcitation, measured by the renal sympathetic nerve activity (RSNA) in the acute intermittent hypercapnia (AIHc) rat model. The study was conducted on 56 urethane-anesthetized, vagotomized and mechanically ventilated Sprague-Dawley rats (n = 7/group). Each experimental group was subjected to a distinct AIHc protocol that varied in the applied levels of hypercapnia and background oxygen. Mean arterial pressure and RSNA were analyzed in 7 experimental time points: baseline, five hypercapnic episodes (each lasting 3 min) and 15 minutes following the last hypercapnic episode. Exposure to severe hypercapnia (FiCO2 = 0.15) evoked an increase in RSNA, which was preserved throughout the protocol, whereas in moderate hypercapnia (FiCO2 = 0.05) groups there was a trend of progressive diminution of RSNA magnitude following the first hypercapnic episode. Exposure to severe hypercapnia elicited significantly greater RSNA response during first hypercapnic episode and it was enhanced during subsequent episodes compared to exposure to moderate hypercapnia. Additionally, hyperoxic2 background (50% O2) blunted the RSNA response to AIHc compared to room air background, both in severe and moderate hypercapnia groups. Mean arterial blood pressure was preserved throughout the experimental protocol in all studied groups. These findings indicate that acute intermittent hypercapnia evokes increased renal sympathetic nerve activity that is dependent on the severity of hypercapnic exposures and the background oxygen level.
AimTo construct a single-format questionnaire on sleep habits and mood before and during the COVI... more AimTo construct a single-format questionnaire on sleep habits and mood before and during the COVID-19 pandemic in the general population.MethodsWe constructed the Split Sleep Questionnaire (SSQ) after a literature search of sleep, mood, and lifestyle questionnaires, and after a group of sleep medicine experts proposed and assessed questionnaire items as relevant/irrelevant. The study was performed during 2021 in 326 respondents distributed equally in all age categories. Respondents filled out the SSQ, the Pittsburgh Sleep Quality Index (PSQI), and State Trait Anxiety Inventory (STAI), and kept a seven-day sleep diary.ResultsWorkday and work-free day bedtime during the COVID-19 pandemic assessed with SSQ were comparable to the sleep diary assessment (P = 0.632 and P = 0.203, respectively), as was the workday waketime (P = 0.139). Work-free day waketime was significantly later than assessed in sleep diary (8:19 ± 1:52 vs 7:45 ± 1:20; P < 0.001). No difference in sleep latency was found between the SSQ and PSQI (P = 0.066). Cronbach alpha for Sleep Habits section was 0.819, and 0.89 for Mood section. Test-retest reliability ranged from 0.45 (P = 0.036) for work-free day bedtime during the pandemic to 0.779 (P < 0.001) for sleep latency before the pandemic.ConclusionThe SSQ provides a valid, reliable, and efficient screening tool for the assessment of sleep habits and associated factors in the general population during the COVID-19 pandemic.
The bones of divers are subjected to stress from water pressure, from the forces generated when t... more The bones of divers are subjected to stress from water pressure, from the forces generated when their muscles resist water pressure, and from weightlessness. Several previously published studies have shown conflicting results. The aim of this study was to determine bone mineral density (BMD) and biochemical markers of bone turnover in experienced SCUBA divers. In this study we included 10 experienced SCUBA divers with a mean age of 47±2.4 years (mean±SEM). The average number of diving years was 26.1 with 381 diving hours per year. The control group included 10 healthy man who were matched by age, weight, and height. The BMD of lumbar spine and hip regions was assessed by dual energy x‐ray absorptiometry and biochemical markers of bone turnover were measured. The BMD value for total lumbar spine in divers was 1.252±0.031 vs. 1.136±0.041 g/cm2 in control group and for total hip was 1.172±0.047 vs. 1.102±0.041 g/cm2 in control group. T scores were 1.54±0.28 vs. 0.42±0.37 and 1.05±0.27 ...
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