The present study investigated the influence of SCUBA dives with compressed air at depths of 10 and 20 m on ECG-derived HRV parameters in apparently healthy individuals. We hypothesized that cardiac ...sympathetic activity (measured by HRV parameters) adapts proportionally to diving depth, and that both time- and frequency-domain parameters are sensitive enough to track changes in cardiac ANS function during diving activities and subsequently during the recovery period. Eleven healthy middle-aged recreational divers (nine men and two women, age 43 ± 8, all nonsmokers) volunteered to participate in the present study. The participants (all open-circuit divers) were equipped with dry suits and ECG Holter devices and were later randomly assigned to dive pairs and depths (10 m vs. 20 m), and each participant served as his or her own control. No interaction effects (diving depth x time epoch) were found for the most commonly used HRV markers. More precisely, in response to two different diving protocols, a significant post hoc effect of time was observed for HR and SDNN, as these parameters transiently decreased during the dives and returned to baseline after ascent (
< 0.001). The ULF, VLF (
< 0.003), TP, and LF parameters decreased significantly during the dives, while HF significantly increased (
< 0.003). SCUBA diving apparently challenges the cardiac ANS, even in healthy individuals. The observed changes reveal possible underwater methods of influencing the parasympathetic activity of the heart depending on the depth of the dive. These results identify autonomic nervous system markers to track the cardiovascular risk related to diving and point to the possibility of tracking cardiovascular system benefits during underwater activities in selected patients.
It has been shown that the measures of social distancing and lockdown might have had negative effects on the physical and mental health of the population. We aim to investigate the sleep and ...lifestyle habits as well as the mood of Croatian medical (MS) and non-medical students (NMS) during the COVID-19 lockdown. The cross-sectional study included 1163 students (21.6% male), whose lifestyle and sleep habits and mood before and during the lockdown were assessed with an online questionnaire. The shift towards later bedtimes was more pronounced among NMS (~65 min) compared to MS (~38 min), while the shift toward later wake-up times was similar in both MS (~111 min) and NMS (~112 min). All students reported more frequent difficulty in falling asleep, night-time awakenings and insomnia (
< 0.001) during lockdown. A higher proportion of MS reported being less tired and less anxious during lockdown compared to pre-lockdown (
< 0.001). Both student groups experienced unpleasant moods and were less content during lockdown compared to the pre-lockdown period (
< 0.001). Our results emphasize the need for the promotion of healthy habits in the youth population. However, the co-appearance of prolonged and delayed sleep times along with decreased tiredness and anxiety among MS during lockdown reveals their significant workload during pre-lockdown and that even subtle changes in their day schedule might contribute to the well-being of MS.
We aimed to investigate the associations between intelligence quotient test scores obtained using the Raven's Advanced Progressive Matrices (APM) and psychomotor testing using the Complex ...Reactionmeter Drenovac (CRD) test battery, while taking into account previous theoretical approaches recognizing intelligent behavior as the cumulative result of a general biological speed factor reflected in the reaction time for perceptual detections and motor decisions. A total of 224 medical students at the University of Split School of Medicine were recruited. Their IQ scores were assessed using Raven's APM, while the computerized tests of CRD-series were used for testing the reaction time of perception to visual stimulus (CRD311), psychomotor limbs coordination task (CRD411), and solving simple arithmetic operations (CRD11). The total test-solving (TTST) and the minimum single-task-solving (MinT) times were analyzed. On the CRD11 test, task-solving times were shorter in students with higher APM scores (r = -0.48 for TTST and r = -0.44 for MinT;
< 0.001 for both). Negative associations between task-solving times and APM scores were reported on CRD311 (r = -0.30 for TTST and r = -0.33 for MinT,
< 0.001 for both). Negative associations between task-solving times in CRD411 and APM scores (r = -0.40 for TTST and r = -0.30 for MinT,
< 0.001 for both) were found. Faster reaction time in psychomotor limbs coordination tasks, the reaction time of perception to visual stimulus, and the reaction time of solving simple arithmetic operations were associated with a higher APM score in medical students, indicating the importance of mental speed in intelligence test performance. However, executive system functions, such as attention, planning, and goal weighting, might also impact cognitive abilities and should be considered in future research.
To investigate the effect of the coronavirus 2019 (COVID-19) lockdown on lifestyle behaviors and mood changes in the Croatian general population.
During ten days of the COVID-19 lockdown in Croatia, ...3027 respondents (70.3% female) from the general population completed an online, self-report questionnaire. Demographic data and data on lifestyle habits and mood changes before and during the COVID-19 lockdown were collected.
A total of 95.64% of respondents reported to follow most or all restrictions, with female sex (P<0.001) and higher education level (P<0.001) being associated with higher restriction compliance. Women smoked an increased number of cigarettes (P<0.001). The proportion of respondents of both sexes who did not drink or drank 7 drinks per week or more increased (P<0.001). Women also reported lower frequency (P=0.001) and duration of physical exercise (P<0.001). In total, 30.7% of respondents gained weight, with female sex (OR, 2.726) and higher BMI (OR, 1.116; both P<0.001) being associated with an increased likelihood of gaining weight. Both men and women felt more frequently afraid (P<0.001), discouraged (P<0.001), and sad (P<0.001).
Public health authorities should promote the adoption of healthy lifestyles in order to reduce long-term negative effects of the lockdown.
Physical and psychosocial stressors in dental schools are associated with adverse health outcome, including low back pain. The aim of this study was to evaluate the physical fitness course included ...in a dental school's curriculum with regard to prevention of low back pain. Ninety first‐year and sixty‐two final‐year dental students completed an anonymous questionnaire on physical fitness habits and low back pain. Fifty voluntarily participated in the Åstrand bicycle ergometer test. The questionnaire revealed that 37 percent of the students have weekly physical exercise only during the physical fitness course included in the curriculum and 62.5 percent of the students reported low back pain. Final‐year dental students had significantly more low back pain than first‐year dental students (r=0.21, χ2=7.91, p=0.005). Female students had significantly more low back pain than male students (r=0.28, χ2=6.61, p=0.0101). The Åstrand test revealed that students who attended the physical fitness course had significantly better physical fitness (p=0.008) than those who did not. Students who exercised more regularly had significantly less low back pain (r =−0.19, χ2=11.89, p<0.01) than those who did not. We conclude that participation in a physical fitness course leads to improved low back health for dental students and may prevent low back pain among final‐year dental students.
An increase in resting motor threshold (RMT), prolonged cortical silent period duration (CSP), and reduced short-latency afferent inhibition (SAI), confirmed with previous transcranial magnetic ...stimulation (TMS), suggest decreased cortical excitability in obstructive sleep apnea syndrome (OSAS). The present study included MRI of OSAS patients for navigated TMS assessment of the RMT, as an index of the threshold for corticospinal activation at rest, and SAI as an index of cholinergic neurotransmission. We hypothesize to confirm findings on SAI and RMT with adding precision in the targeting of motor cortex in OSAS.
After acquiring head MRIs for 17 severe right-handed OSAS and 12 healthy subjects, the motor cortex was mapped with nTMS to assess the RMT and SAI, with motor evoked potentials (MEPs) recorded from the abductor-pollicis brevis (APB) muscle. The 120%RMT intensity was used for the SAI by a paired-pulse paradigm in which the electrical stimulation to the median nerve is followed by magnetic stimulation of the motor cortex at inter-stimulus intervals (ISIs) of 18-28 ms (ISIs
). The SAI control condition included a recording of MEPs without peripheral stimulation. Latency and amplitude of MEP at RMT at 120%RMT for eleven different at ISIs
were analyzed.
The study showed a significantly lower percentage deviation of MEP amplitude at ISIs
from the control condition between OSAS and healthy subjects (U=44.0, p=0.01). The intensity of stimulation at RMT was significantly higher in OSAS subjects (U=55.0, p=0.04*). Correlation analysis showed that BMI significantly negatively correlated (
=-0.47) with MEP amplitude percentage deviation in OSAS patients.
The nTMS study results in increased RMT, and reduced cortical afferent inhibition in OSAS patients for SAI at ISIs
, confirming previous findings of impaired cortical afferent inhibition in OSAS. Future nTMS studies are desirable to elucidate the role of RMT and SAI in diagnostics and treatment of OSAS, and to elucidate the usefulness of nTMS in OSAS research.
Summary
Obstructive sleep apnoea (OSA) is characterized by periods of upper airway collapse accompanied by repeated episodes of hypoxia. In experimental animals repeated bouts of hypoxia may evoke ...sustained augmentation of phrenic nerve activity, known as phrenic long‐term facilitation (pLTF). This form of physiological compensation might contribute to stable breathing, minimizing the occurrence of apnoeas and/or hypopnoeas during sleep in patients with OSA. Serotonin (5‐HT) has been shown to modulate respiratory neuronal activity, possibly via projections originating in the raphe nuclei. Our model focuses on the effects of 5‐HT1A receptors blockade by selective antagonist WAY‐100635 into the caudal raphe region on phrenic long‐term facilitation after exposure to acute intermittent hypoxia (AIH) episodes. Adult, male, urethane‐anaesthetized, vagotomized, paralyzed and mechanically ventilated Sprague–Dawley rats were exposed to AIH protocol. Experimental group received microinjection of WAY‐100635 into the caudal raphe nucleus, whereas the control group received saline into the same site. Peak phrenic nerve activity and respiratory rhythm parameters were analysed during five hypoxic episodes, as well as at 15, 30 and 60 min after the end of hypoxias. In the control group, 1 h post‐hypoxia pLTF was developed. Microinjections of selective 5‐HT1A receptor antagonist WAY‐100635 into the raphe nuclei prior to the AIH protocol prevented induction of pLTF. These results suggest that 5‐HT1A receptor activation at supraspinal level is important for induction of pLTF, which is suggested to be an important respiratory neuroplasticity model in animal studies that possibly correlates with OSA in humans.
The aim of this cross-sectional study was to objectively assess the salivary flow rate and composition and periodontal inflammation in obstructive sleep apnoea (OSA) patients. The subjects, who ...underwent whole-night polysomnography or polygraphy, were referred for saliva sampling and periodontal examination. According to the severity of OSA based on the Apnoea Hypopnea Index (AHI) value, the subjects were classified into groups: no OSA (AHI < 5; N = 17), mild to moderate OSA (AHI 5-29.9; N = 109), and severe OSA (AHI > 30; N = 79). Salivary flow rate, pH, salivary electrolytes, and cortisol were measured from collected saliva samples. Periodontal examination included assessment of the number of teeth, dental plaque, bleeding on probing and periodontal measurements: gingival recession, probing pocket depth, clinical attachment level (CAL) and periodontal inflamed surface area (PISA) score. There were no significant differences in salivary flow rate, salivary pH, salivary electrolyte concentrations or electrolyte ratios among the groups classified according to the severity of OSA. However, subjects without OSA had higher salivary cortisol concentrations than OSA groups (p < 0.001). Increased plaque scores were associated with a higher AHI (r = 0.26; p = 0.003). According to the salivary flow rate, subjects with hyposalivation and reduced salivation had higher concentrations of salivary electrolytes and lower salivary pH than subjects with normal salivation. Subjects with hyposalivation had an increased Mg/PO
ratio (p < 0.001) and a reduced Ca/Mg ratio (p < 0.001). Furthermore, subjects with severe OSA tended to have higher CALs and plaque volumes. In conclusion, under pathological conditions, such as OSA, multiple interactions might impact salivary flow and electrolyte composition. Complex interrelationships might affect the integrity of oral health, especially considering OSA severity, inflammation, concomitant diseases and medications.
Objectives
This cross-sectional study investigated the stages of periodontitis in obstructive sleep apnea (OSA) patients and risk factors associated with periodontitis severity among them.
Materials ...and methods
A total of 194 patients underwent a polysomnography/polygraphy and were referred to periodontal examination. According to apnea–hypopnea index (AHI), patients were classified as mild OSA (AHI < 15) and moderate to severe OSA (AHI ≥ 15), whereas periodontitis severity was determined by the clinical attachment level (CAL) according to the recent Classification of Periodontal Diseases and Conditions. Patients were grouped into two categories: stages 1 and 2, and stages 3 and 4.
Results
Higher AHI values were reported in OSA patients exhibiting periodontitis stages 3 and 4 compared to OSA patients with periodontitis stages 1 and 2 (
p
= 0.043) and the non-periodontitis group (
p
= 0.044). A positive correlation was found between AHI and mean CAL (r = 0.215;
p
= 0.004), and between AHI and plaque scores (r = 0.292;
p
< 0.001). Following a multivariable regression analysis, AHI was a significant predictor of mean CAL (β = 0.169;
p
= 0.031), explaining 16.4% of variability in mean CAL (adjusted R
2
= 0.164;
p
< 0.001). Older patients had higher odds for an increased mean CAL (β = 0.266;
p
= 0.001), as well as patients smoking or formerly smoking (β = 0.305;
p
< 0.001) whereas visiting a dental medicine doctor once a year or more often was associated with a decreased mean CAL (β = − 0.182;
p
= 0.02).
Conclusions
OSA was associated with severe stages of periodontitis along with increased age, smoking, low frequency of dental visits, and poor oral hygiene.
Clinical relevance
Screening for periodontitis is recommended for patients with more severe forms of OSA.
This research was performed to examine the effects of air and oxygen prebreathing on bubble formation, flow-mediated dilatation, and psychomotor performance after scuba dives.
Twelve scuba divers ...performed two dives using a gas mixture of oxygen, nitrogen, and helium (trimix). In a randomized protocol, they breathed air or oxygen 30 min before the trimix dives. Venous bubble formation, flow-mediated dilatation, and psychomotor performance were evaluated. The participants solved three psychomotor tests: determining the position of a light signal, coordination of complex psychomotor activity, and simple arithmetic operations. The total test solving time, minimum single-task solving time, and median solving time were analyzed.
The bubble grade was decreased in the oxygen prebreathing protocol in comparison to the air prebreathing protocol (1.5 vs. 2,
< 0.001). The total test solving times after the dives, in tests of complex psychomotor coordination and simple arithmetic operations, were shorter in the oxygen prebreathing protocol (25 (21-28) vs. 31 (26-35) and 87 (82-108) vs. 106 (90-122) s,
= 0.028).
In the oxygen prebreathing protocol, the bubble grade was significantly reduced with no change in flow-mediated dilatation after the dives, indicating a beneficial role for endothelial function. The post-dive psychomotor speed was faster in the oxygen prebreathing protocol.
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