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Daytime blood pressure elevation after nocturnal hypoxia
Y Arabi1, B J Morgan, B Goodman
1Department of Medicine, University of Wisconsin, Madison 53792, USA.
Journal of Applied Physiology (Bethesda, Md. : 1985)
|August 13, 1999
Summary
Nocturnal hypoxia, or low oxygen at night, can cause a temporary rise in daytime blood pressure (BP). This study found that overnight exposure to simulated high altitude elevated diastolic blood pressure the next morning.
Area of Science:
- Cardiovascular Physiology
- Sleep Medicine
- Altitude Physiology
Background:
- Nocturnal hypoxia is common in conditions like obstructive sleep apnea.
- The impact of acute nocturnal hypoxia on subsequent daytime blood pressure is not fully understood.
Purpose of the Study:
- To investigate if nocturnal hypoxia causes daytime blood pressure elevation.
- To determine if this blood pressure elevation outlasts the hypoxia stimulus.
Main Methods:
- 10 healthy subjects slept in a hypobaric chamber simulating 4,000 m altitude for 8 hours.
- Blood pressure was measured frequently during the day after nocturnal hypoxia and normoxia.
- Principal components analysis evaluated blood pressure response patterns.
Main Results:
- A distinct pattern of elevated diastolic blood pressure (DBP) was observed in 90% of subjects after nocturnal hypoxia.
- This DBP elevation averaged 4 mmHg in the first 60 minutes post-hypoxia.
- Blood pressure returned to baseline within 90 minutes.
Conclusions:
- Nocturnal hypoxia can lead to a transient carryover elevation of daytime diastolic blood pressure.
- This suggests a physiological link between overnight oxygen levels and subsequent cardiovascular regulation.