Banca de DEFESA: HELOISA MARTINS FRANCA

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : HELOISA MARTINS FRANCA
DATE: 16/12/2025
TIME: 09:00
LOCAL: Remoto
TITLE:

"INFLUENCE OF DAYTIME NAPS ON CARDIOVASCULAR HEALTH:
AN INTEGRATED APPROACH BETWEEN POLYSOMNOGRAPHY
AND ACTIGRAPHY"


KEY WORDS:

Polysomnography, sleep disorders, actigraphy, heart rate control, 

Psychological Stress

PAGES: 67
BIG AREA: Ciências da Saúde
AREA: Enfermagem
SUMMARY:

This study aimed to investigate the cardiovascular impact during daytime 

naps among students at the Federal University of Rio Grande do Norte 
(UFRN). The data collection instrument consisted of six online 
questionnaires, clinical examinations, actigraphy for at least 5 consecutive 
days, and daytime polysomnography (PSG), where information on the 
cardiovascular autonomic profile was collected in the different wake-sleep 
stages from PSG data. Sleep windows were identified and calculated for 
the N1, N2, N3, and REM sleep stages. Fifteen individuals (7 female and 
8 male) participated in the study, all university students, mostly medical 
(60%, n=9) and biomedical (13.3%, n=2) students, with an average age of 
approximately 23 years (mean 22.6±3.2), predominantly with a Body Mass 
Index (BMI) less than 24 kg/m² (mean 23.7±4.6). As a result, 93.3% (n=14) 
of the volunteers presented poor sleep quality, 33.3% (n=5) presented 
excessive sleepiness, in addition, 86.6% (n=13) presented moderate or 
high stress and approximately 80% (n=12) had some degree of insomnia 
(subthreshold or moderate insomnia). Actigraphic data revealed a typical 
profile of young university students, with relatively short sleep duration 
(mean TTS of 6.5±1 h), moderate sleep efficiency (83.7±9), and highly 
variable sleep onset latencies (4.6±5), demonstrating the frequent sleep 
deprivation in these individuals. Through the assessment of heart rate 
variability (HRV) (frequency and time domains) during wakefulness 
(before the nap), it was possible to identify a positive correlation between 
Social Jet Lag (SJL) and LF (r: 0.54, p-value: 0.034), indicating greater 
sympathetic activation and a state of physiological alertness. Furthermore, 
when comparing HRV during wakefulness and during sleep, it was 
observed that during sleep there was a reduction in SDNN (p-value: 0.00), 
an increase in pNN50 (p-value: 0.02), a significant reduction in LF values 
(p-value: 0.03), and an increase in HF values (p-value: 0.03). Therefore, 
the combination of the three markers (SDNN, pNN50, and LF) presents a 
typical physiological pattern in healthy young adults under laboratory 
conditions: sleep with higher vagal tone, less overall variation, and a 
decrease in slow LF oscillations, while wakefulness maintains greater 
multimodal variability resulting from internal and external stimuli. In 
general, studies show that LF values tend to be higher during wakefulness 
and lower during NREM sleep, due to the more stable vagal predominance 
during sleep. The finding of higher heart rate during sleep reinforces the 
relevance of napping as an autonomic regulation strategy, capable of 
mitigating the effects of stress and promoting sympathovagal balance in 
young populations subjected to intense academic demands. Thus, the 
data indicate that daytime napping may represent a strategy to mitigate 
the negative impacts of psychosocial stress and sleep deprivation in 
young university students.

COMMITTEE MEMBERS:
Presidente - 2888478 - DENISE MORAIS LOPES GALENO
Interno - 2190521 - HINDIAEL AERAF BELCHIOR
Externo à Instituição - MARIO ANDRE LEOCADIO MIGUEL
Notícia cadastrada em: 12/12/2025 13:49
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