Role of respiration in the cardiovascular response to orthostatic and mental stress.
Am J Physiol Regul Integr Comp Physiol
; 314(6): R761-R769, 2018 06 01.
Article
in En
| MEDLINE
| ID: mdl-29443551
ABSTRACT
The objective of this study was to determine the response of heart rate and blood pressure variability (respiratory sinus arrhythmia, baroreflex sensitivity) to orthostatic and mental stress, focusing on causality and the mediating effect of respiration. Seventy-seven healthy young volunteers (46 women, 31 men) aged 18.4 ± 2.7 yr underwent an experimental protocol comprising supine rest, 45° head-up tilt, recovery, and a mental arithmetic task. Heart rate variability and blood pressure variability were analyzed in the time and frequency domain and modeled as a multivariate autoregressive process where the respiratory volume signal acted as an external driver. During head-up tilt, tidal volume increased while respiratory rate decreased. During mental stress, breathing rate increased and tidal volume was elevated slightly. Respiratory sinus arrhythmia decreased during both interventions. Baroreflex function was preserved during orthostasis but was decreased during mental stress. While sex differences were not observed during baseline conditions, cardiovascular response to orthostatic stress and respiratory response to mental stress was more prominent in men compared with women. The respiratory response to the mental arithmetic tasks was more prominent in men despite a significantly higher subjectively perceived stress level in women. In conclusion, respiration shows a distinct response to orthostatic versus mental stress, mediating cardiovascular variability; it needs to be considered for correct interpretation of heart rate and blood pressure phenomena.
Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Respiration
/
Stress, Physiological
/
Stress, Psychological
/
Cardiovascular Physiological Phenomena
Type of study:
Prognostic_studies
Limits:
Adolescent
/
Adult
/
Female
/
Humans
/
Male
Language:
En
Journal:
Am J Physiol Regul Integr Comp Physiol
Journal subject:
FISIOLOGIA
Year:
2018
Type:
Article
Affiliation country:
Slovakia