Blood pressure creeping up at 40? What should I change?

If your blood pressure has started to creep up around 40, first have the reading checked again and read by a doctor, because a single reading does not tell the whole story. Then look at the everyday habits that matter for blood pressure: salt, alcohol, movement, smoking and weight. You are not alone in this: in Thailand's national health survey of 2019–2020, 25.6% of adults aged 40 to 59 had readings of 140/90 mmHg or more or were taking medicine for blood pressure, against 7.7% of adults aged 20 to 39. And Thai adults take in about 3,600 mg of sodium a day, while the Thai Reference Daily Intake (Thai RDI) is 2,000 mg.

What do the two numbers on a reading mean?

Systolic and diastolic

England's NHS explains that a reading is given as 2 numbers, for example 130/80:

The levels doctors look at

The NHS says blood pressure is usually considered high if it is 140/90 or more when checked by a health professional, or 135/85 or more when checked at home. A reading below those levels but higher than your previous ones is still worth noting, because the trend matters.

How common is it for blood pressure to rise in your 40s?

What Thailand's national survey found

Thailand's National Health Examination Survey measures the blood pressure of adults about every 5 years, between about 19,000 and 38,000 people in each round (19,062 in 2019–2020). Aekplakorn and colleagues reported the share of adults whose measured blood pressure was 140/90 mmHg or more, or who were taking medicine for blood pressure:

In 2019–2020, about 1 in 4 adults aged 40 to 59 were in this group, compared with fewer than 1 in 10 adults aged 20 to 39. Among all adults in the group, only 51.5% knew about it. In other words, about half of them did not know.

A screening campaign with similar findings

In the May Measurement Month campaign in Thailand in 2022, 10,562 adults with an average age of 50.4 were measured at hospitals and co-working spaces in all regions. Of these, 44.2% had readings of 140/90 mmHg or more or were taking medicine for blood pressure. People were not chosen at random, so the figure is not a national rate, but it shows how often raised readings turn up when people in midlife are simply measured.

How the survey measured

Trained staff measured each person 3 times, 1 minute apart, after 5 minutes of seated rest, and used the average of the 2nd and 3rd readings. That is one visit for each person, so it is not the same as a diagnosis, which a doctor makes from repeated readings.

Other figures from the same survey

In the table describing the participants, the share of adults with low physical activity rose from 22.1% in 2004 to 30.5% in 2019–2020, the share with a BMI of 25 to under 30 rose from 23.2% to 30.2%, and the share with a BMI of 30 or more from 7.3% to 13.7%. These figures are not adjusted for age, and the age mix differed between rounds: adults aged 20 to 39 made up 50% in 2004 and 32.5% in 2019–2020.

Should I recheck before changing anything?

One reading is not the whole story

Readings can differ from one time to the next, so if one reading is high, measure again first; there is no need to worry yet. Ask the doctor whether to recheck at the clinic, at home or both, and how often.

Measuring at home

Measure at home if your doctor or nurse asks you to. The NHS describes taking a reading, noting the numbers, waiting 1 minute and taking another, usually twice a day, once in the morning and once in the evening. Write the numbers down with the date and time and take the record to your appointment.

Why 40 is a good age to start checking

The NHS lists being aged 40 or over as one reason to have your blood pressure checked, along with eating too much salt, drinking too much alcohol or caffeine, smoking and family history. The NHS Health Check in England, offered to people aged 40 to 74 every 5 years, includes a blood pressure test.

How much salt do Thai adults eat?

Almost twice the recommended level

A nationwide Thai study measured sodium in 24-hour urine samples from 1,599 adults. The average was 3,636 mg of sodium a day: highest in the South, at about 4,108 mg, and lowest in the Northeast, at about 3,316 mg. Younger adults were more likely to eat 2,000 mg or more. The researchers describe Thai intake as nearly twice the recommended level.

Instant foods carry a lot

A study by Chailek and colleagues pooled data on instant food products sold in the Bangkok area in 2018, 2019 and 2021, 788 products in all. In 2021, the median sodium content was 1,750 mg per 100 g, 11.6% lower than in 2018. Among 57 products sold in both years, 33.3% had less sodium, 19.3% had more and 47.4% were unchanged, and their median sodium did not change significantly overall. Products carrying the Healthier Choice logo rose from 4.5% to 21.1%. The study covered packaged foods in shops around Bangkok, not cooked dishes.

The NHS also notes that about three quarters of the salt people eat is already in packaged and everyday foods. For practical ways to cut back on fish sauce, dips and broth, see Love salty food and can't cut back? What can you do?

Which everyday habits are worth changing at 40?

Salt, step by step

Taste before adding fish sauce or seasoning sauce, keep dipping sauces on the side, leave some of the broth, use half the seasoning sachet in instant noodles, and check the sodium per serving on labels. Ramathibodi Hospital explains that our sense of taste adapts: a cut of about 10% in saltiness is hard for the tongue to notice, so cut back gradually.

Alcohol

The NHS advises no more than 14 units a week (1 unit is 8 g of pure alcohol), spread over 3 or more days if you regularly drink that much, and to have several drink-free days each week if you want to cut down. Work dinners and weekend drinking add up quickly in your 40s.

Moving more and sitting less

WHO's 2020 guidelines advise adults to do 150 to 300 minutes of moderate activity a week, such as brisk walking, or 75 to 150 minutes of vigorous activity, plus muscle-strengthening on 2 or more days, and to limit time spent sitting. For where to start, see I sit at work all day and barely exercise. Where do I start?

Smoking, weight and waist

Smoking is one of the reasons the NHS gives for having blood pressure checked; if you smoke, ask a doctor or pharmacist about help to stop. Weight and waist are also part of the picture; see Weight went up and my check-up got worse. Where to start?

When should I see a doctor, and what should I bring?

Book an appointment if

• your readings at home are often 135/85 or more, or a clinic reading is 140/90 or more
• your readings keep going up from one check to the next
• close family members have had blood pressure or heart problems

What to bring

• your home readings with dates and times, and earlier health check results
• a list of every medicine you take, including vitamins and herbal products
• how much salt, alcohol, smoking and activity is typical in your week

Whether you need medicine is a decision to make with your doctor. If you already take regular medicines, keep taking them as prescribed and do not change them on your own. Sudden severe symptoms such as chest pain, severe breathlessness or sudden weakness on one side of the body need emergency help: call 1669 in Thailand. For warning signs in older family members, see How can we care for older parents' heart and blood vessels?