Blood pressure and longevity: the number that quietly decides your odds

If you could only track one number for the rest of your life and use it to estimate your odds of dying early, blood pressure would be a genuinely defensible choice. It’s not the most fashionable longevity metric — there’s no app gamifying it, no influencer doing breathwork to flex their diastolic — but according to the Global Burden of Disease project, high systolic blood pressure is the single leading modifiable risk factor for death on the planet. Above smoking. Above blood sugar. Above basically everything.

And almost nobody under 50 knows their number off the top of their head. I certainly didn’t, until I bought a cuff out of mild research curiosity and then spent a slightly unhinged week measuring everyone who came round for dinner.

What blood pressure actually measures

Blood pressure is exactly what it sounds like — the force your blood exerts against the walls of your arteries as it moves around. It’s reported as two numbers, and the order matters.

• Systolic (the top number) is the pressure when your heart contracts and pushes blood out.
• Diastolic (the bottom number) is the pressure between beats, while the heart relaxes and refills.

So 118/76 means 118 mmHg at the peak of each beat, 76 between them. The unit, mmHg, is millimetres of mercury — a holdover from the original mercury-column gauges, which is delightfully Victorian for a measurement this important.

Underneath the number, blood pressure reflects two things at once: how hard your heart is pumping, and how much resistance your arteries put up. Stiff, narrowed, or constricted arteries push the number up. Stress hormones constrict vessels and raise it. A heart working against a high-salt, high-volume load raises it. Over years, chronically high pressure damages the delicate inner lining of arteries, accelerates atherosclerosis, strains the heart muscle, and quietly stresses the kidneys, eyes and brain. It’s a whole-body tax, collected slowly.

The cruel bit is that it does all of this silently. The phrase “silent killer” is a cliché, but it earned the title — most people with high blood pressure feel completely fine, which is precisely why it goes untreated for years.

What the research actually says

This is where blood pressure stops being a boring number on a chart and starts being one of the most thoroughly evidenced relationships in all of medicine.

The landmark dataset is the Prospective Studies Collaboration, published in The Lancet in 2002 (Lewington and colleagues). It pooled 61 prospective studies — around one million adults with no prior vascular disease — and the finding was startlingly clean. Across the entire range from 115/75 upward, each 20 mmHg rise in systolic pressure (or 10 mmHg in diastolic) was associated with roughly a doubling of the risk of death from stroke and heart disease. And crucially, the relationship was continuous all the way down to 115/75 — there was no threshold below which lower stopped being better. That reframes the whole question. It’s not “do I have high blood pressure or not,” it’s “where do I sit on a continuous risk curve.”

Then there’s SPRINT — the Systolic Blood Pressure Intervention Trial, published in the New England Journal of Medicine in 2015. This one actually tested causation. Over 9,000 high-risk adults were randomised to a systolic target of either under 140 (standard care at the time) or under 120 (intensive). The intensive group had 25% fewer major cardiovascular events and — the headline that stopped the trial early — a 27% lower rate of death from any cause. They stopped it early because it would have been unethical to keep the standard-care group where they were. That’s about as strong as cardiovascular evidence gets.

A 2019 follow-up analysis, SPRINT MIND (JAMA), added that the intensive group also had a significantly lower rate of mild cognitive impairment. Blood pressure isn’t just about the heart — the brain runs on the same plumbing, and protecting one tends to protect the other.

Worth a caveat: SPRINT used a slightly unusual automated, unattended measurement method that tends to read a few mmHg lower than a typical clinic reading, so the “under 120” target doesn’t map perfectly onto the number you’d get at the GP. But the direction of the finding — that pushing pressure lower, within reason, saves lives in high-risk adults — has held up.

The 2017 ACC/AHA guidelines (Whelton and colleagues) responded to this accumulating evidence by lowering the definition of hypertension itself, from 140/90 to 130/80. Overnight, that reclassified millions of people. It was controversial, and reasonable people argued about over-medicalisation — but the underlying point stands: the old thresholds were set higher than the risk data actually justified.

So what’s a “good” blood pressure?

Here’s a rough map, drawn from the 2017 ACC/AHA framework:

• Below 120 systolic and below 80 diastolic — Normal. The mortality curves keep gently improving as you move down through this range, so this is the territory to live in.
• 120-129 systolic and below 80 diastolic — “Elevated.” Not yet hypertension, but a nudge to pay attention to the lifestyle levers below.
• 130-139 systolic or 80-89 diastolic — Stage 1 hypertension. Often very responsive to lifestyle change, especially if caught early.
• 140 systolic or higher, or 90 diastolic or higher — Stage 2 hypertension. Usually warrants medication alongside lifestyle change, and a conversation with a doctor.
• Above 180 systolic and/or above 120 diastolic — Hypertensive crisis. Not a “watch the trend” situation — that’s a same-day medical concern.

The usual caveat applies, and applies hard here: a single reading means very little. Blood pressure swings throughout the day, jumps with stress, and famously spikes in clinical settings — “white-coat hypertension” is real and common. Your best data comes from multiple readings, taken calmly, at home, averaged over time. Which, conveniently, is exactly the logic behind tracking biomarkers as trends rather than snapshots.

How it connects to the other heart numbers

Blood pressure doesn’t sit on its own. It’s part of a small family of cardiovascular metrics that, read together, tell you far more than any one does alone.

Resting heart rate tells you how efficiently your heart pumps at rest; blood pressure tells you the load it’s pumping against. A fit cardiovascular system tends to show a low resting heart rate and a healthy blood pressure — the same underlying conditioning improves both. Heart rate variability adds a third angle: how flexibly your autonomic nervous system shifts between states, which is closely tied to the same sympathetic stress signals that drive pressure up.

None of these is “the” longevity number. The reason Sarvita builds a biological age from several signals at once is precisely that each one captures a different facet of the same cardiovascular reality. Blood pressure happens to be the facet with the largest body of hard outcome data behind it.

What actually moves your blood pressure

The genuinely encouraging news: blood pressure is one of the most modifiable risk factors there is. You’re not stuck with your number. Here are the levers that actually have evidence behind them, roughly in order of impact.

Aerobic exercise

Regular aerobic training is one of the most reliable non-drug interventions. Meta-analyses of exercise trials consistently find that consistent endurance work lowers resting systolic pressure by around 5-8 mmHg in people with elevated readings — an effect size comparable to a single blood pressure medication. The mechanism is partly improved arterial flexibility and partly reduced sympathetic tone. Zone 2 cardio — the comfortable, conversational-pace stuff — is ideal, because it’s sustainable enough to actually do several times a week, and it’s the volume over months that drives the adaptation.

Interestingly, isometric exercise (think wall-sits and static holds) has shown surprisingly strong blood-pressure-lowering effects in recent meta-analyses — a 2023 review in the British Journal of Sports Medicine by Edwards and colleagues found isometric training produced some of the largest reductions of any single modality. Not a reason to abandon cardio, but a nice bonus for anyone already doing strength work.

Sodium and the DASH diet

The DASH diet (Dietary Approaches to Stop Hypertension) is one of the few eating patterns tested in proper randomised trials for blood pressure specifically. The original DASH-Sodium trial showed that combining a diet rich in vegetables, fruit, whole grains and low-fat dairy with reduced sodium lowered systolic pressure by over 11 mmHg in people with hypertension — again, drug-comparable. Most of us eat far more sodium than we need, largely from processed food rather than the salt shaker, so the lever is more about packaged food than about being precious at the dinner table.

Body weight and alcohol

Excess body weight raises blood pressure, and losing even 5-10% of body weight produces measurable reductions. Alcohol is the other big, unglamorous one: it raises blood pressure both acutely and chronically, in a dose-dependent way. Cutting back is one of the faster-acting levers — many people see a few mmHg drop within weeks of reducing intake. I mention this with the weary solidarity of someone who enjoys wine.

Stress, sleep and breathing

Chronic stress keeps the sympathetic nervous system switched on, which keeps vessels constricted and pressure elevated. Poor sleep — particularly untreated sleep apnoea — is a major and frequently missed driver of stubborn hypertension. And slow breathing, at around six breaths per minute, has reproducible short-term blood-pressure-lowering effects in controlled studies. None of these replace the heavy hitters above, but they stack on top, and they’re free.

How to measure it properly

This is where most people go wrong, so it’s worth being a bit pedantic.

The reference standard is still a validated upper-arm cuff, not a wrist device and not (yet) a smartwatch. Optical and wrist-based blood pressure estimates are improving and can be genuinely useful for spotting trends, but they drift and need regular calibration against a proper cuff. For any number you’d actually make a decision on, use the arm.

The technique matters more than people realise:

• Sit quietly for five minutes first, back supported, feet flat, arm resting at heart height.
• No caffeine, exercise or smoking in the 30 minutes before.
• Take two or three readings a minute apart and average them — the first is often the highest.
• Measure at roughly the same times on different days. Morning and evening readings differ.

A single elevated reading at the GP, taken after you’ve rushed in and sat down flustered, is close to meaningless. A two-week log of calm morning-and-evening home readings is genuinely diagnostic — so much so that home and ambulatory monitoring are now recommended to confirm a hypertension diagnosis before anyone starts medication.

The bit about trajectories

The thing I keep coming back to is the same theme that runs through every one of these biomarker posts: the trend matters more than the snapshot.

Systolic pressure tends to drift upward with age as arteries stiffen, and it’s so common that it gets quietly accepted as just part of getting older. But studies of physically active, low-sodium populations show dramatically flatter age-related rises — which strongly suggests a big chunk of the “normal” increase is accumulated lifestyle load, not an immutable law of biology. The trajectory is more in your hands than the population averages make it look.

So if you’re 35 with a blood pressure of 124/78, the interesting question isn’t “is that bad?” (it isn’t — it’s elevated but fine). It’s where is it heading over the next decade? If consistent exercise, less processed sodium, moderate drinking and decent sleep keep it parked around there, brilliant. If it drifts to 138/88 over five years while you’re not looking, that’s a signal worth catching early — when it’s still cheap to fix with lifestyle rather than later, when it isn’t.

The practical takeaway

Blood pressure is, by the cold numbers, the most important modifiable longevity metric most people are ignoring. It’s the leading global risk factor for early death, it’s backed by some of the strongest causal evidence in medicine, and it responds reliably to exactly the boring, sustainable habits that drive cardiovascular health generally — aerobic fitness, sensible eating, moderation on alcohol, decent sleep, managing stress.

You don’t need to obsess over it. You do want to actually know your number, measure it properly a few times a year (more often if it’s drifting), and treat the trend as the signal. A validated arm cuff costs about as much as a few takeaways and tells you more about your odds than almost anything else you could measure at home.

It’s the least glamorous number in longevity. It’s also, quietly, one of the most important. Worth knowing yours.

Anyway. Link’s there if you’re curious. No pressure — which, for once, is exactly the point.