Health Reference Ranges
Standard guideline ranges for blood pressure, heart rate, BMI, sleep, A1C, glucose and cholesterol, gathered in one place with their sources noted.
⚠ Educational reference only — these are standard adult guideline ranges, not a diagnosis. Labs set their own reference intervals; talk to a clinician about your numbers.
The two max-heart-rate formulas agree at exactly one age
The panel above shows both, which needs explaining. 220 − age is the version everybody knows. The formula most often quoted against it is Tanaka's, 208 − 0.7 × age, published in 2001 from a review of the underlying studies. They do not agree, and the tool prints a range rather than picking a winner because the reason to prefer one over the other is weaker than it looks.
| Age | 220 − age | Tanaka | Difference |
|---|---|---|---|
| 20 | 200 | 194 | +6 |
| 30 | 190 | 187 | +3 |
| 40 | 180 | 180 | identical |
| 50 | 170 | 173 | -3 |
| 60 | 160 | 166 | -6 |
| 70 | 150 | 159 | -9 |
| 80 | 140 | 152 | -12 |
Setting them equal gives 220 − a = 208 − 0.7a, so 12 = 0.3a and a = 40 exactly. Sweeping every whole age from 1 to 100 finds that one agreement and no other. The sign of the disagreement flips there: 220 − age runs high for the young and low for the old. The gap widens by 0.3 beats for every year away from forty, in either direction, because the two lines differ only in slope — 6 high at twenty and 12 low at eighty. (A small aside for anyone who checks: computing that crossing in floating point gives 39.99999999999999, because 1 − 0.7 is not exactly 0.3. The answer is forty by algebra, not by arithmetic.)
And the zones inherit every bit of that
The exercise zones above are percentages of the estimated maximum, so any error in the maximum passes straight through, scaled by the percentage. The floor of the vigorous zone, by formula:
| Age | From 220 − age | From Tanaka | Difference |
|---|---|---|---|
| 20 | 140 bpm | 136 bpm | +4 |
| 30 | 133 bpm | 131 bpm | +2 |
| 40 | 126 bpm | 126 bpm | identical |
| 50 | 119 bpm | 121 bpm | -2 |
| 60 | 112 bpm | 116 bpm | -4 |
| 70 | 105 bpm | 111 bpm | -6 |
| 80 | 98 bpm | 106 bpm | -8 |
At seventy the threshold comes out 6 beats apart depending on which formula produced the maximum, which is why the zones above are printed spanning both rather than as one line. At forty they agree exactly, as the maximums do.
Neither formula is precise about an individual in any case. The published spread around 220 − age is roughly ±11 beats, so two people of forty could have true maximums of 169 and 191 and both be entirely ordinary — a 22-beat range, wider than the gap between the two formulas at every age up to a hundred. Which formula to prefer is a smaller question than it looks. That does not make the estimate useless; it makes it a starting point rather than a measurement, and the zones derived from it carry the same uncertainty.
How to use
- Find the measure you are looking for.
- Read the guideline range and what the categories mean.
- Note which body publishes the guideline.
- Take any result outside the range to a clinician.
Frequently asked questions
What is a normal blood pressure?
Under 120 over 80 is normal by current American guidance, with 120 to 129 over under 80 classed as elevated and 130 over 80 as stage 1 hypertension. European and UK thresholds differ somewhat, which is why the same reading can be labelled differently depending on the guideline used.
Why do guideline ranges differ between countries?
Because expert bodies weigh the same evidence differently, particularly on where the benefit of treatment starts to outweigh its cost and risk. The 2017 American reclassification of hypertension moved millions into a diagnostic category overnight without any change in their health — a good illustration of how much these thresholds are decisions rather than facts.
What does a result just outside the range mean?
Usually very little on its own. Reference ranges are typically set to include the middle 95 per cent of a healthy population, which means one healthy person in twenty falls outside a given range by definition. Trends over time and the full clinical picture matter far more than a single borderline value.
What is A1C?
A measure of average blood glucose over roughly the previous three months, expressed as the percentage of haemoglobin that has become glycated. It is more informative than a single glucose reading because it is not affected by what you ate that morning.
Does age affect these ranges?
For several of them, considerably. Resting heart rate, blood pressure targets and cholesterol interpretation all shift with age, and some ranges differ by sex as well. A single set of numbers for all adults is a simplification that most guidelines qualify heavily.
Can I use this to interpret my results?
For context, yes; for a conclusion, no. Interpreting a result requires knowing your history, medications, symptoms and what else was measured alongside it. This page is a reference, not a diagnosis, and nothing here is medical advice.
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