Answer: Normal blood pressure for adults is below 120/80 mm Hg, according to the American Heart Association. The top number, systolic, is the pressure while your heart beats; the bottom number, diastolic, is the pressure while it rests. Readings of 120 to 129 over less than 80 count as elevated, and 130/80 or higher is high blood pressure. One reading is a snapshot, so patterns over days matter most.
- Normal is below 120/80 mm Hg for adults.
- Systolic is the top number; diastolic is the bottom number.
- One high reading is a snapshot; look for a pattern over days.
- Above 180/120 with symptoms means call 911.
The two numbers, explained
A blood pressure reading such as 117/76 mm Hg has two parts. The top number, systolic pressure, is the force of blood against your artery walls while the heart contracts. The bottom number, diastolic pressure, is the force while the heart relaxes and refills between beats. The unit, millimeters of mercury, comes from the old mercury gauges.
Both numbers matter. Systolic pressure tends to rise with age as large arteries stiffen, and after about 50 it is often the stronger signal of risk. Diastolic pressure is commonly the first to rise in younger adults. If either number falls into a higher category, the reading as a whole is classed in that higher category. Our tour of how the heart pumps blood shows where these two pressures come from.
The American Heart Association categories
The American Heart Association groups adult readings into five categories, shown in the table below:
- Normal: below 120 systolic and below 80 diastolic.
- Elevated: 120 to 129 systolic and below 80 diastolic.
- High blood pressure stage 1: 130 to 139 systolic or 80 to 89 diastolic.
- High blood pressure stage 2: 140 or higher systolic or 90 or higher diastolic.
- Hypertensive crisis: above 180 systolic and/or above 120 diastolic.
Note the word "and" in the first two categories and "or" in the stages. A reading of 118/84 is not normal, because the diastolic number alone puts it in stage 1. High blood pressure usually causes no symptoms, which is why the CDC encourages regular checks.
| Category | Systolic (top) | Diastolic (bottom) |
|---|---|---|
| Normal | Below 120 | and below 80 |
| Elevated | 120 to 129 | and below 80 |
| Stage 1 high blood pressure | 130 to 139 | or 80 to 89 |
| Stage 2 high blood pressure | 140 or higher | or 90 or higher |
| Hypertensive crisis | Above 180 | and/or above 120 |
Why one reading is not the whole story
Blood pressure changes minute to minute. It rises with stress, caffeine, a full bladder, talking, cold rooms and recent exercise, and it dips during sleep. Some people read higher in a clinic than at home, a pattern called white coat hypertension; others read normal in the clinic and high at home.
Here is a common scenario. Someone checks their pressure at a pharmacy kiosk after rushing in with a coffee and gets 128/78, which is in the elevated range. Before worrying, we would repeat the measurement properly at home: seated and rested for five minutes, morning and evening, for a week. If the average sits below 120/80, the kiosk reading was likely a moment, not a pattern. If it stays high, that log is exactly what a doctor wants to see. Our home measuring guide shows how.
What about low blood pressure?
There is no single cutoff for low blood pressure. Many healthy, active people run readings around 100/65 and feel perfectly well, and for them a low number is generally fine. Low blood pressure becomes a concern when it causes symptoms: dizziness or lightheadedness, especially when standing up, fainting, blurred vision, nausea or unusual fatigue.
Causes include dehydration, some medicines, heart rhythm problems and other medical conditions. If you have symptoms like these, talk to your doctor. Low blood pressure also matters when choosing supplements. Arginine can add to blood-pressure-lowering effects, so anyone who already runs low, or who takes blood pressure medicine, should ask a doctor before trying an arginine or citrulline product.
Keeping normal numbers normal, and where Melonex fits
The habits with the strongest evidence are well known: eat less sodium, follow a pattern like the DASH plan, stay active, keep a healthy weight, limit alcohol, sleep well and do not smoke. The National Heart, Lung, and Blood Institute lists these as the core of prevention and treatment.
Melonex is positioned to help maintain healthy blood pressure already within the normal range, alongside those habits. Its amino acids are involved in nitric oxide production, explained on our how Melonex works page. It does not treat high blood pressure and does not replace medicine. For the details, see Melonex benefits and Melonex questions and answers. If you are already on blood pressure medicine, read why your doctor comes first.
Limits, and when to call a doctor or 911
Supplement trials of arginine and citrulline on blood pressure are small and mixed. Where reductions appear, they are modest, and they do not show that these amino acids prevent or treat hypertension. A healthy lifestyle and, when needed, prescribed medicine remain the proven tools.
See a doctor if your home average sits at 130/80 or above, or if readings creep upward over months. If a reading is above 180/120, wait five minutes and check again. If it is still that high and you have chest pain, shortness of breath, back pain, numbness, weakness, vision changes or trouble speaking, call 911. Without symptoms, contact your doctor right away.
Keep your normal readings on track
Read how the formula works on the Melonex official website, alongside your doctor's advice.
Get the Melonex DiscountFrequently asked questions
Is 120/80 normal blood pressure?
Strictly, normal is below 120/80. A reading of exactly 120 systolic with a diastolic below 80 falls into the elevated category under American Heart Association guidance.
Which number is more important?
Both matter. Systolic pressure is often the stronger signal of risk after about age 50, but a high diastolic number alone can also place you in a high blood pressure stage.
Can a supplement lower high blood pressure?
No supplement is a treatment for high blood pressure. Melonex is positioned to help maintain healthy blood pressure already in the normal range, alongside diet and activity.