From the Guidelines
Hemorrhagic strokes occur frequently in the early morning when patients wake up due to the sudden increase in blood pressure, known as the morning blood pressure surge, which can strain weakened blood vessels, particularly in individuals with untreated hypertension. This phenomenon is supported by recent studies, such as 1, which highlights the importance of blood pressure management in patients with intracerebral and subarachnoid hemorrhage. The study suggests that elevated blood pressure is common in acute stroke, particularly in hemorrhagic forms, and that early blood pressure lowering can help attenuate hematoma growth and improve outcomes.
Some key factors that contribute to the increased risk of hemorrhagic stroke in the early morning include:
- The natural surge in blood pressure that occurs as part of the body's circadian rhythm
- Increased blood clotting activity, higher heart rate, and elevated stress hormone levels upon waking
- Shifts in blood flow and pressure that occur when transitioning from lying down to standing up
- Overnight dehydration, which can make blood more viscous
- Medication timing issues, as the protective effects of blood pressure medications may wear off by early morning if not properly timed
According to 1, the main forms of hemorrhagic stroke, intracerebral hemorrhage (ICH) and aneurysmal subarachnoid hemorrhage (SAH), are often complicated by elevated blood pressure, which increases the likelihood of ongoing and recurrent hemorrhage. The study highlights the importance of initiating blood pressure lowering early after the onset of ICH, and suggests that patients with risk factors for hemorrhagic stroke should consider taking blood pressure medications that provide 24-hour coverage or using split dosing with evening administration to help mitigate this morning risk period. Therefore, it is essential to prioritize blood pressure management in patients with hemorrhagic stroke, particularly in the early morning hours, to reduce the risk of recurrent hemorrhage and improve outcomes.
From the Research
Hemorrhagic Stroke Frequency in Early Morning
- Hemorrhagic stroke occurs frequently in the early morning when the patient wakes up, with the greatest portion of strokes (32.5%) occurring between 03:00 and 06:00 a.m. 2
- Nearly one half of the strokes occur in the very early- to mid-morning hours, with approximately 1 of every 3 strokes (1 of 3 ischemic strokes, 1 of 6 hemorrhagic strokes, and 1 of 8 subarachnoid hemorrhages) attributable to the early morning excess 2
Possible Explanations
- The difference in stroke frequency during early morning hours may be explained by three factors: cold weather, religious factors, and physiological mechanisms 2
- Hypertension is a major risk factor for cardiovascular events, including ischemic stroke and hemorrhagic stroke, and reduction of blood pressure by lifestyle measures and antihypertensive drug therapy reduces stroke in elderly men and women 3
- The use of diuretics, beta blockers, calcium channel blockers, angiotensin-converting enzyme inhibitors, or angiotensin receptor blockers causes a similar reduction in reducing coronary events and stroke for a given reduction in blood pressure 3
Blood Pressure Management
- In the hyperacute phase, a majority of patients shows an elevated blood pressure at the time of presentation because of sympathetic hyperactivity or a physiological response to tissue ischemia 4
- Blood pressure may decrease spontaneously in a few hours and may drop further when complete recanalization is achieved 4
- In stroke guidelines, an elevated BP is usually left untreated up to a systolic BP of 220 mm Hg and a diastolic BP of 120 mm Hg, but in patients in whom administration of recombinant tissue-type plasminogen activator is indicated, BP should be controlled to a level < 185/110 mm Hg before infusion 4