Blood pressure 160/80: why the gap matters

At first glance, 160/80 seems contradictory: the upper value is well above the threshold, the lower one is perfect. Many people conclude that it is “only half as bad”. The opposite is true – this very combination is medically significant, and it has its own name.

The classification

An upper value of 140 mmHg or more with a lower value below 90 mmHg is called isolated systolic hypertension. At 160 systolic, you are in the range of hypertension grade 2.

The less favourable of the two values always applies. The fact that the lower value is normal does not cancel out the classification – the complete system is set out in Blood pressure chart: what your numbers mean.

Why the lower value stays low

This is the really interesting part. A young, elastic aorta works like a buffer reservoir (the so-called Windkessel effect): it stretches with each heartbeat, absorbs part of the pressure peak and releases it again in the pause between two beats. This caps the upper value and keeps the lower one up.

As the large blood vessels become stiffer over the years, this buffer disappears. The pressure peak comes through in full – the upper value rises. And because the recoil force that maintained the pressure between beats is missing, the lower value stays the same or even falls.

That is why many older people see 160/80 on the display and not 160/105. Here, the low lower value is not a sign that all is well, but part of the finding.

The fact that such readings become more common with age does not make them the norm: the threshold of 140/90 applies regardless of year of birth. What counts instead in later life is explained in Blood pressure chart by age: what really applies.

The gap as a measure in its own right

160 minus 80 gives a pulse pressure of 80 mmHg. About 40 to 50 is typical. In large observational studies, a value that is persistently above 60 – especially over the age of 60 – is regarded as an indication of stiffened large blood vessels and is statistically associated with a higher cardiovascular risk.

This explains why 160/80 and 160/110 are not the same, even though both land in the same row of the chart. More on this in Pulse pressure: what the gap between your blood pressure readings reveals.

Why it is treated

For a long time, isolated systolic hypertension was regarded as a harmless sign of ageing. That view is outdated. Especially in later life, the upper value is the more meaningful of the two for the risk of stroke and heart failure.

Treatment is more demanding than for classic high blood pressure: the aim is to lower the upper value without pulling the already low lower value down too far. That is why treatment here is often adjusted more cautiously and in smaller steps – a medical judgement that takes individual factors into account.

What you can do before your appointment

A single reading of 160/80 is not yet a diagnosis. It becomes meaningful like this:

1. Measure for seven days, twice each morning and evening, after five minutes of rest.
2. Write down all readings, together with the pulse each time.
3. Leave out the first day and calculate the average from the rest.
4. Compare with the home measurement threshold: at home, hypertension already applies from 135/85.
5. Take the sheet with you to the surgery.

With these readings, pay particular attention to cuff size – a cuff that is too small pushes the upper value up in particular and can turn 150 into 160. The other sources of error are covered in Measuring blood pressure correctly, the question of which device in Which blood pressure monitor is the most accurate?

When you shouldn’t wait

• If your weekly average stays at these readings – make an appointment soon
• With repeated readings above 180/110 mmHg, even without symptoms
• If you have headaches, visual disturbances, shortness of breath, dizziness or a racing heart
• If you have swollen ankles or reduced exercise tolerance

In the event of a sudden severe headache, chest pain, speech or vision problems, or one-sided paralysis: call the emergency services immediately on 112 (the European emergency number). Do not change existing medication on your own.