Blood Pressure Throughout the Day

Once high, then lower, then the value rises again, and so on; those who check their blood pressure several times a day soon realize that it is not a static value that is always the same.

Blood pressure is subject to natural fluctuations throughout the day. To prepare the body for getting up in the morning, blood pressure rises even before waking. The first real blood pressure peak is recorded between 8 and 9 a.m. At this time, the highest values of the day are often measured. Around noon, the blood pressure curve usually drops again, only to rise to a second peak in the late afternoon between 4:00 and 6:00 p.m. The lowest values are typically measured at night. This is known as nocturnal dipping. In cases of secondary hypertension, this nocturnal dipping is often absent, which can indicate a cause of high blood pressure. These fluctuations are referred to as the circadian rhythm. This rhythm affects blood pressure in people with normal blood pressure values as well as in most hypertensives. This rhythm is controlled by our autonomic nervous system - the part of the nervous system that is hardly under our voluntary control.

Further normal blood pressure fluctuations throughout the day can be more or less voluntarily controlled. For example, blood pressure rises in stressful situations and during physical exertion. This is a completely normal reaction. In healthy individuals, the values quickly return to a normal level afterward. After physical activity, they often even drop slightly below the values before exercise. Therefore, exercise is an important means of lowering blood pressure.

So far, the fluctuations in blood pressure throughout the day are normal. But what happens in the case of high blood pressure?

In the case of high blood pressure, the normal fluctuations occur at a higher level. This means that starting from a higher baseline blood pressure, the fluctuations also happen in a higher range, which can lead to critically elevated values.

Sometimes, as already mentioned, the circadian rhythm is disturbed in cases of high blood pressure. The values do not drop at night or hardly drop, or they even rise during the night hours. This can be determined through a 24-hour blood pressure measurement.

Particularly significant is an excessive rise in blood pressure in the morning hours - the so-called morning hypertension. There is a correlation with the increased incidence of strokes, heart attacks, and cases of sudden cardiac death during this time.

Our graphics show in the first image (blue) the blood pressure course in normal blood pressure. The values are within the normal range. They rise during exertion but also fall again and show a nice drop at night to the lowest level throughout the day.

Blood Pressure Throughout the Day in a Healthy Person

The second representation (red) shows an example of a course in high blood pressure. The higher baseline level and the absence of nocturnal dipping are clearly visible. The blood pressure peak in the morning hours is significantly too high. Additionally, the high difference between the upper and lower blood pressure values indicates increased pulse pressure.

Blood Pressure Throughout the Day in a Hypertensive Patient

The drop in blood pressure at night is referred to as "dipping." If blood pressure drops to a normal extent, i.e., by about 10 - 20% of the daily average, overnight, this is called "normal dipping." If this drop is less than 10%, it is referred to as "non-dipping." "Reverse dipping" occurs when blood pressure rises above the daily averages at night. However, a drop in blood pressure of more than 20% of the daily average at night can also occur, especially in older individuals, which is referred to as "extreme dipping."

Any absence of, or excessive nocturnal dipping poses an increased risk and must be taken into account in diagnosis and medication.

Sources:

By Sabine Croci. This article is medically reviewed. Last updated (10/2024).
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Blood Pressure Throughout the Day

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