A blood pressure of 118/66 mmHg is a good reading. Both numbers fall within the normal range defined by the American Heart Association, where normal means a systolic (top number) below 120 and a diastolic (bottom number) below 80. In fact, the latest 2024 European Society of Cardiology guidelines would classify this as “non-elevated” blood pressure, their best category.
Where 118/66 Falls on the Scale
The National Heart, Lung, and Blood Institute breaks blood pressure into five categories:
- Normal: below 120 systolic and below 80 diastolic
- Elevated: 120 to 129 systolic with diastolic still below 80
- High blood pressure, Stage 1: 130 to 139 systolic or 80 to 89 diastolic
- High blood pressure, Stage 2: 140+ systolic or 90+ diastolic
- Hypertensive crisis: above 180 systolic or above 120 diastolic
At 118/66, you’re just under the line for normal on systolic and well within it on diastolic. If your systolic crept up just two points to 120, you’d shift into the “elevated” category. So this reading puts you in a favorable spot, but it’s worth keeping an eye on over time.
Why a Systolic Below 120 Matters
A landmark trial called SPRINT, which followed over 9,300 adults aged 50 and older, found that keeping systolic pressure below 120 mmHg reduced heart attacks, heart failure, and strokes by 25% compared to a target of 140. It also lowered the overall risk of death by 27%. Those benefits held across age groups, sexes, and races. There was even a 20% reduction in mild cognitive impairment among participants who maintained the lower target.
The 2024 ESC guidelines reinforce this thinking. They note that cardiovascular risk from blood pressure isn’t a simple on/off switch at a certain number. Risk rises on a continuous scale, which is why they now avoid using the term “normal” altogether and instead distinguish between “non-elevated” (below 120/70) and “elevated” (120 to 139 systolic or 70 to 89 diastolic). Your reading of 118/66 falls into their most favorable zone.
Is 66 Too Low for Diastolic?
A diastolic of 66 is healthy and not a cause for concern on its own. Low blood pressure generally isn’t diagnosed until readings drop below 90/60 mmHg. At 66 diastolic, you’re comfortably above that threshold.
The only time a lower diastolic number becomes worrisome is if you’re experiencing symptoms like dizziness, lightheadedness, blurred vision, fatigue, or fainting. Even a 20 mmHg sudden drop in systolic pressure (say, from standing up too fast) can trigger those symptoms temporarily. But a steady diastolic of 66 without symptoms is simply a sign that your heart and blood vessels are in good shape.
What Your Pulse Pressure Tells You
Pulse pressure is the gap between your top and bottom numbers. For a reading of 118/66, that’s 52 mmHg. A pulse pressure of around 40 is considered ideal, and readings above 60 become a risk factor for heart disease, particularly in older adults. A wider gap can signal stiffer arteries.
At 52, your pulse pressure is slightly above the textbook ideal of 40 but well below the 60 threshold that raises red flags. This is a normal finding and not something most people need to act on. Pulse pressure tends to widen naturally with age as blood vessels lose some flexibility.
One Reading Isn’t the Full Picture
Blood pressure fluctuates throughout the day. It’s typically lowest during sleep, rises in the morning, peaks around midday, and drops again in the late afternoon and evening. A single reading of 118/66 is encouraging, but patterns over time matter more than any one measurement.
If you’re monitoring at home, consistency in how you take the reading makes a big difference. Sit quietly for five minutes beforehand with your back supported and feet flat on the floor, legs uncrossed. Rest your arm on a surface at heart level, and use the same arm each time. Taking readings at roughly the same time of day helps you spot real trends rather than normal daily swings.
Two or three readings taken a minute apart, averaged together, give a more reliable number than a single check. If your readings consistently land below 120/80, you’re in a strong position. If they start creeping above 120 systolic, that’s an early signal to look at lifestyle factors like sodium intake, physical activity, and stress before the numbers climb further.