Is high blood pressure at night more dangerous than during the day?
High blood pressure at night is more dangerous than high blood pressure during the day. Have a 24-hour measurement taken if you are uncertain about your night-time values, and discuss with your doctor whether your treatment should be adjusted accordingly.
High blood pressure at night is a stronger predictor of heart disease and premature death than high blood pressure during the day. When researchers included both daytime and night-time values simultaneously in analyses of people with high blood pressure, night-time blood pressure remained a clear risk factor, while daytime blood pressure added nothing extra. That pattern appears robust: it held for men and women, younger and older people, and for people who were already taking blood-pressure-lowering medication.
How large the difference is can be seen clearly in a study of more than 1,300 people. Every one millimetre higher night-time blood pressure was associated with a four per cent greater chance of a serious cardiac event or heart failure. Above a night-time systolic value of 148 mmHg, that risk rose especially quickly. The daytime values in that same group showed no significant association. In people aged 80 and over the effect was even stronger: those with high night-time blood pressure had more than twice the chance of a cardiac event or death, even after adjusting for their daytime values.
In addition to the absolute level of night-time blood pressure, the pattern also plays a role. Normally, blood pressure drops by ten to twenty per cent during the night. People in whom that drop does not occur, or who even show a rise at night, have a clearly higher risk. On the other hand, people in whom blood pressure drops very sharply at night appear to have a lower risk. Which of the two, the absolute night-time pressure or the dipping pattern, is the better measure has not yet been definitively established.
Nocturnal high blood pressure is more common in people with sleep apnoea, kidney disease, diabetes or disorders of the nervous system. In those groups the link with organ damage is most pronounced. Anyone who wants to know what their own night-time blood pressure looks like can have a 24-hour blood pressure measurement taken, which also covers the night-time hours. Home monitors that measure automatically during the night are an alternative. One note of caution: deliberately taking your blood-pressure pill in the evening to lower night-time pressure sounds logical, but several studies have not shown a consistent long-term benefit. Do not adjust this on your own initiative; discuss it with your doctor first.
This answer rests on two large-scale summaries of multiple studies, supplemented by observational studies in specific groups (including people aged 80 and over and matched patient groups). The fact that these are associations rather than proven causal relationships applies to all of these studies: no one was randomly assigned to a "high night-time blood pressure" group. The association itself is, however, consistent and has been found across a variety of patient groups, which makes it fairly reliable. The question of whether chronotherapy (evening intake of medication) prevents cardiac events is weakly supported: the studies contradict one another.
Can sleep deprivation raise your blood pressure?
Yes, sleep deprivation demonstrably raises blood pressure in adults. Seven to eight hours of sleep per night is the most well-supported guideline; if you structurally sleep less than that, it is a reason to have your blood pressure checked.
Does sitting all day increase your risk of heart problems?
Sitting a lot increases your risk of heart failure and heart-related mortality, even if you exercise regularly. Just 30 minutes less sitting per day produces a measurable improvement, so try to break up long periods of sitting regularly.
What does my blood pressure tell me about my long-term health?
Your blood pressure and how much it fluctuates between measurements clearly say something about your risk of heart and vascular disease and dying in the long term. For those who are eligible for treatment, medication is the most evidence-backed step.
Does lowering my blood pressure really reduce my risk?
Lowering blood pressure genuinely works: your risk of stroke and other cardiovascular problems demonstrably decreases. Exercise and dark chocolate also provide a modest additional benefit.
Can high blood pressure in your 40s cause dementia later in life?
High blood pressure in your forties demonstrably increases your risk of dementia later in life, and early treatment appears to reduce that risk. Get your blood pressure checked and discuss with your GP whether treatment is worthwhile.
What is the link between high blood pressure and inflammation?
High blood pressure and inflammation reinforce each other, and higher levels of inflammation signals in the blood mean a measurably greater risk of serious heart and blood vessel disease in people with high blood pressure. Have your blood pressure and CRP checked regularly, especially if you have other risk factors such as diabetes or excess weight.