Cardiac autonomic activity during daytime nap in young adults

AbstractIn healthy, young individuals, a reduction in cardiovascular output and a shift from sympathetic to parasympathetic (vagal) dominance is observed from wake into stages of nocturnal and daytime sleep. This cardiac autonomic profile, measured by heart rate variability (HRV), has been associated with significant benefits for cardiovascular health. Aging is associated with decreased nighttime sleep quality and lower parasympathetic activity during both sleep and resting. However, it is not known whether age-related dampening of HRV extends to daytime sleep, diminishing the cardiovascular benefits of naps in the elderly. Here, we investigated this question by comparing the autonomic activity profile between young and older healthy adults during a daytime nap and a similar period of wakefulness (quiet wake; QW). For each condition, from the electrocardiogram (ECG), we obtained beat-to-beat HRV intervals (RR), root mean square of successive differences between adjacent heart-beat-intervals (RMSSD), high frequency (HF), low frequency (LF) power and total power (TP), HF normalized units (HFnu), and the LF/HF ratio. As previously reported, young subjects showed a parasympathetic dominance during NREM, compared with REM, pre-nap rest, and WASO. On the other hand, older, compared to younger, adults showed significantly lower vagally-mediated HRV (measured by RMSSD, HF, HFnu) during NREM. Interestingly, however, no age-related differences were detected during pre-nap rest or QW. Altogether, our findings suggest a sleep-specific reduction in parasympathetic modulation that is unique to NREM sleep in older adults.Impact StatementSleep is naturally modulated by the autonomic nervous system (ANS), with greater dominance of parasympathetic over sympathetic activity during non-rapid-eye-movement (NREM) sleep. As such, sleep has been termed a “cardiovascular holiday” and has been associated with positive health outcomes. Aging, however, is linked to decreases in cardiac autonomic activity and sympathovagal imbalance. While the impact of aging on ANS activity during nocturnal sleep has received some attention, the cardiac profiles during a daytime nap, to our knowledge, have not yet been studied under the context of aging. Herein, young adults demonstrated increased parasympathetic activity during deep sleep. Older adults, however, showed less parasympathetic modulation during NREM sleep, suggesting loss of the cardiovascular holiday. Importantly, no age-related declines in parasympathetic activity were detected during wake, suggesting a sleep-specific reduction in parasympathetic modulation that is unique to NREM sleep in older adults.

Download Full-text

Autonomic Activity during a Daytime Nap Facilitates Working Memory Improvement

Journal of Cognitive Neuroscience ◽

10.1162/jocn_a_01588 ◽

2020 ◽

Vol 32 (10) ◽

pp. 1963-1974 ◽

Cited By ~ 2

Author(s):

Pin-Chun Chen ◽

Lauren N. Whitehurst ◽

Mohsen Naji ◽

Sara C. Mednick

Keyword(s):

Working Memory ◽

Young Adults ◽

Cognitive Aging ◽

Parasympathetic Activity ◽

Autonomic Activity ◽

Autonomic Nervous ◽

Operation Span ◽

Cardiac Parasympathetic Activity ◽

Daytime Nap

Recent investigations have implicated the parasympathetic branch of the autonomic nervous system in higher-order executive functions. These actions are purported to occur through autonomic nervous system's modulation of the pFC, with parasympathetic activity during wake associated with working memory (WM) ability. Compared with wake, sleep is a period with substantially greater parasympathetic tone. Recent work has reported that sleep may also contribute to improvement in WM. Here, we examined the role of cardiac parasympathetic activity during sleep on WM improvement in healthy young adults. Participants were tested in an operation span task in the morning and evening, and during the intertest period, participants experienced either a nap or wake. We measured high-frequency heart rate variability as an index of cardiac, parasympathetic activity during both wake and sleep. Participants showed the expected boost in parasympathetic activity during nap, compared with wake. Furthermore, parasympathetic activity during sleep, but not wake, was significantly correlated with WM improvement. Together, these results indicate that the natural boost in parasympathetic activity during sleep may benefit gains in prefrontal executive function in young adults. We present a conceptual model illustrating the interaction between sleep, autonomic activity, and prefrontal brain function and highlight open research questions that will facilitate understanding of the factors that contribute to executive abilities in young adults as well as in cognitive aging.

Download Full-text

The Health Effects of Mercury on the Cardiac Autonomic Activity According to the Heart Rate Variability

Korean Journal of Occupational and Environmental Medicine ◽

10.35371/kjoem.2008.20.4.302 ◽

2008 ◽

Vol 20 (4) ◽

pp. 302 ◽

Cited By ~ 1

Author(s):

Sinye Lim ◽

Min Cheol Choi ◽

Kee Ock Joh ◽

Domyung Paek

Keyword(s):

Heart Rate ◽

Heart Rate Variability ◽

Health Effects ◽

Autonomic Activity ◽

Cardiac Autonomic Activity

Download Full-text

Sleep Indices and Cardiac Autonomic Activity Responses during an International Tournament in a Youth National Soccer Team

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph18042076 ◽

2021 ◽

Vol 18 (4) ◽

pp. 2076

Author(s):

Pedro Figueiredo ◽

Júlio Costa ◽

Michele Lastella ◽

João Morais ◽

João Brito

Keyword(s):

Heart Rate ◽

Frequency Domain ◽

Sleep Duration ◽

Time Domain ◽

Soccer Players ◽

Autonomic Activity ◽

Male Youth ◽

Youth Soccer ◽

Wrist Actigraphy ◽

Cardiac Autonomic Activity

This study aimed to describe habitual sleep and nocturnal cardiac autonomic activity (CAA), and their relationship with training/match load in male youth soccer players during an international tournament. Eighteen elite male youth soccer players (aged 14.8 ± 0.3 years; mean ± SD) participated in the study. Sleep indices were measured using wrist actigraphy, and heart rate (HR) monitors were used to measure CAA during night-sleep throughout 5 consecutive days. Training and match loads were characterized using the session-rating of perceived exertion (s-RPE). During the five nights 8 to 17 players slept less than <8 h and only one to two players had a sleep efficiency <75%. Players’ sleep duration coefficient of variation (CV) ranged between 4 and 17%. Nocturnal heart rate variability (HRV) indices for the time-domain analyses ranged from 3.8 (95% confidence interval, 3.6; 4.0) to 4.1 ln[ms] (3.9; 4.3) and for the frequency-domain analyses ranged from 5.9 (5.6; 6.5) to 6.6 (6.3; 7.4). Time-domain HRV CV ranged from 3 to 10% and frequency-domain HRV ranged from 2 to 12%. A moderate within-subjects correlation was found between s-RPE and sleep duration [r = −0.41 (−0.62; −0.14); p = 0.003]. The present findings suggest that youth soccer players slept less than the recommended during the international tournament, and sleep duration was negatively associated with training/match load.

Download Full-text