Systolic vs Diastolic Blood Pressure: What Each Number Means — and What It Means for Athletes
Table of Contents
Key Takeaways: Systolic vs Diastolic Blood Pressure
- Systolic vs diastolic blood pressure describes two different parts of the cardiac cycle. Systolic pressure is the peak pressure during contraction, while diastolic pressure is the lowest pressure during relaxation.
- Both numbers matter. In a cohort of 1.3 million adults, both systolic and diastolic hypertension independently predicted cardiovascular events, although the hazard ratio was larger for systolic pressure [3].
- Blood pressure categories differ between guidelines. The 2025 AHA/ACC guideline labels systolic 130–139 or diastolic 80–89 mmHg as stage 1 hypertension, while the 2024 ESC guideline and Finnish Käypä hoito use 140/90 mmHg as the main office threshold for hypertension or elevated blood pressure [1][2][16].
- One office reading is not enough. Repeated and out-of-office measurements can give a better picture of usual blood pressure, particularly when white-coat effects or measurement conditions may influence the result [2][16].
- Exercise changes systolic vs diastolic pressure differently. During dynamic exercise, systolic pressure rises with intensity while diastolic pressure remains relatively stable; heavy resistance exercise can temporarily raise both to very high levels [7][8].
- Exercise training can lower resting blood pressure, but athletes do not necessarily have lower blood pressure than controls. Randomised exercise trials show reductions in resting blood pressure, while observational athlete data found no significant overall difference between athletes and controls [11][13].
- Athletic fitness does not rule out hypertension. For most clinical decisions, resting and repeated blood pressure measurements are more informative than a single exercise or office value.
Introduction: Systolic vs Diastolic Blood Pressure
Blood pressure is one of the most basic measurements in clinical medicine, but it can tell us a surprising amount. I measure it frequently in my own practice, whether as part of a routine health assessment or early in the evaluation when a patient has symptoms or a condition that may involve haemodynamic changes. Sometimes an elevated reading is discovered unexpectedly in someone who was not aware of having high blood pressure. At the other end of the spectrum, a low reading can become clinically relevant in situations such as dizziness, infection, or an acute cardiopulmonary illness.
Every blood pressure reading contains two numbers: the upper value is systolic pressure and the lower value is diastolic pressure, and each carries information of its own. The distinction is more than terminology. Systolic and diastolic pressure reflect different phases of the cardiac cycle, change differently with age, behave differently during exercise, and each provides prognostic information. In an analysis of 1.3 million adults followed for 8 years, the burden of systolic hypertension and the burden of diastolic hypertension each independently predicted a composite of myocardial infarction, ischaemic stroke, and haemorrhagic stroke [3].
For athletes, the interpretation can become more nuanced. Is a high systolic reading in a fit 22-year-old simply part of athletic physiology? Why can blood pressure rise so dramatically during a heavy squat? And if a well-trained cyclist reaches 230 mmHg during an exercise test, is that necessarily abnormal? These are the kinds of questions where the two numbers need to be interpreted in context rather than in isolation.
In this article, I look at what systolic and diastolic pressure actually measure, how current guidelines classify them, which number carries more prognostic weight, and what these readings may mean specifically in athletes.
Systolic vs Diastolic Blood Pressure: What Each Number Actually Measures
Blood pressure is the pressure that circulating blood exerts against the artery walls. It is recorded in millimetres of mercury (mmHg) and written as systolic over diastolic.
- Systolic pressure (the upper number) is the highest arterial pressure during a heartbeat, reached when the left ventricle contracts and ejects blood into the aorta.
- Diastolic pressure (the lower number) is the lowest arterial pressure during a heartbeat, reached while the heart muscle relaxes and the ventricles refill.
Two derived values are useful when comparing systolic vs diastolic pressure:
- Pulse pressure is simply systolic minus diastolic. A reading of 140/70 mmHg has a pulse pressure of 70 mmHg.
- Mean arterial pressure is the average pressure across the whole cardiac cycle. Because, at normal resting heart rates, the heart spends more time in the relaxation phase than in the ejection phase, it sits closer to the diastolic value than to the midpoint between the two numbers.
The two numbers are shaped by partly different mechanisms. In young adults studied in the ENIGMA cohort, isolated systolic hypertension appeared to result from a larger stroke volume and/or a stiffer aorta, whereas the main haemodynamic abnormality in essential hypertension was increased peripheral vascular resistance [5]. Later in life, the pattern changes: in the Framingham Heart Study, the late decline in diastolic pressure combined with a continuing rise in systolic pressure was consistent with increased large-artery stiffness [4].
This distinction explains much of what follows — why the two numbers drift apart with age, why they react differently to exercise, and why a young athlete can present with a high systolic value alongside a completely normal diastolic value.
In practice, however, the physiology is only part of the interpretation. The circumstances of the measurement matter. I see patients who are visibly tense during the consultation, others who have hurried or even run to the appointment, and some who are still talking while the cuff is inflating or have not had enough time to settle beforehand. In these situations, I am cautious about drawing conclusions from a single office value.
When an office reading is elevated, I often find home measurements more informative than repeatedly focusing on one isolated number from the consultation. Depending on the situation, I may ask the patient to record a series of readings at home over the following couple of weeks so that we can get a better picture of their usual blood pressure outside the clinic. If the first office measurement has been taken before the patient has properly settled, I also tend to repeat it and place more weight on the subsequent readings rather than treating the initial value as definitive. This is particularly useful when white-coat hypertension is a possibility.
Blood Pressure Categories: How Systolic and Diastolic Values Are Classified
There is no single global classification for blood pressure. The same reading can receive a different label depending on whether you are using American, European, or Finnish guidance.
This matters particularly in the mildly elevated range. The American AHA/ACC classification labels blood pressure as hypertension at a lower threshold than either the European ESC guideline or the Finnish Käypä hoito guideline [1][2][16].
| Category | 2025 AHA/ACC (United States) [1] | 2024 ESC (Europe) [2] | 2026 Finnish Käypä hoito [16] |
|---|---|---|---|
| Lowest category | Normal: systolic <120 and diastolic <80 mmHg | Non-elevated: systolic <120 and diastolic <70 mmHg | Optimal: systolic <120 and diastolic <80 mmHg |
| Mildly higher values | Elevated: systolic 120–129 and diastolic <80 mmHg | Elevated: systolic 120–139 or diastolic 70–89 mmHg | Normal: systolic 120–129 and/or diastolic 80–84 mmHg |
| Higher but below the Finnish/European hypertension threshold | Stage 1 hypertension: systolic 130–139 or diastolic 80–89 mmHg | Elevated: systolic 120–139 or diastolic 70–89 mmHg | High-normal: systolic 130–139 and/or diastolic 85–89 mmHg |
| Hypertension / elevated blood pressure | Stage 2 hypertension: systolic ≥140 or diastolic ≥90 mmHg | Hypertension: systolic ≥140 or diastolic ≥90 mmHg | Elevated blood pressure: systolic ≥140 and/or diastolic ≥90 mmHg |
The Finnish system is therefore somewhat less aggressive than the American classification when it comes to labelling mildly elevated readings. For example, a blood pressure of 135/85 mmHg is stage 1 hypertension under the AHA/ACC classification, but it remains within the high-normal range in the Finnish Käypä hoito classification. The Finnish threshold for elevated office blood pressure is ≥140 systolic and/or ≥90 diastolic mmHg [16].
From a clinical perspective, I think this difference is useful to keep in mind when patients read American health information online. A number that is described as “stage 1 hypertension” on an American website may not receive the same diagnostic label in Finland. That does not mean the reading is irrelevant; it means that the terminology and thresholds are different.
There are four practical points worth remembering.
First, either the systolic or the diastolic value can determine the category. In the American classification, a reading of 126/84 mmHg is stage 1 hypertension because the diastolic value is in the 80–89 mmHg range, even though the systolic value is only in the “elevated” range [1]. Under the 2024 ESC classification, the same reading is classified as elevated blood pressure [2]. In Finland, 126/84 mmHg falls within the normal category because the Finnish normal range includes systolic values of 120–129 mmHg and/or diastolic values of 80–84 mmHg [16].
Second, a single office reading is not enough to define a person’s usual blood pressure. The 2024 ESC guideline recommends out-of-office blood pressure measurement to confirm the diagnosis and to assess for masked hypertension [2]. The Finnish Käypä hoito guideline takes a similar practical approach: if blood pressure is elevated during office measurements, the diagnosis should primarily be confirmed with measurements outside the clinic [16].
This is also close to how I approach elevated readings in practice. If a patient’s blood pressure is unexpectedly high during an appointment, I usually want to know what it looks like outside that setting before drawing conclusions. The Finnish guideline considers an office pressure of 140/90 mmHg approximately equivalent to a home blood pressure of 135/85 mmHg [16].
When I ask patients to monitor their blood pressure at home, I often explain that the average home readings are generally expected to remain below 135/85 mmHg. In practice, patients usually keep a written or electronic record of their measurements, and over a monitoring period of roughly a couple of weeks we can look at the average values rather than focusing on any single reading. I find this much more useful clinically than reacting to one isolated high number, especially when the office measurement may have been affected by stress or the circumstances of the visit.
Third, the Finnish and European thresholds for hypertension are much closer to each other than either is to the American threshold. Both the 2024 ESC guideline and the Finnish Käypä hoito guideline use an office threshold of systolic ≥140 mmHg and/or diastolic ≥90 mmHg for hypertension or elevated blood pressure [2][16]. The terminology below that threshold differs, but the main diagnostic boundary is similar.
Finally, sports cardiology uses the same 140/90 mmHg office threshold. The 2020 ESC sports cardiology guideline considers a person hypertensive when systolic pressure is persistently ≥140 mmHg and/or diastolic pressure is persistently ≥90 mmHg [14]. For an athlete reading both American and European sources, this difference in classification is worth recognizing before interpreting a single number as either normal or abnormal.
Systolic vs Diastolic: Which Number Matters More?
The relationship between outpatient systolic and diastolic pressure and cardiovascular outcomes has been considered unclear, particularly since guidelines began using two different treatment thresholds [3]. A large analysis that addressed the systolic vs diastolic question directly used outpatient readings from 1.3 million adults and followed them for 8 years [3]. Its main findings were:
- The continuous burden of systolic hypertension (≥140 mmHg) and of diastolic hypertension (≥90 mmHg) each independently predicted the composite of heart attack and stroke, with hazard ratios per unit increase in z score of 1.18 and 1.06, respectively [3].
- The results were similar when the lower 130/80 mmHg threshold was used, and when blood pressure was analysed as a continuous variable without any threshold [3].
- The hazard ratio was larger for systolic than for diastolic hypertension, but diastolic hypertension still influenced risk independently [3].
- Diastolic pressure showed a J-shaped relationship with outcomes — meaning the lowest values were also associated with more events — but this was at least partly explained by age, other covariates, and a stronger effect of systolic hypertension among people in the lowest quartile of diastolic pressure [3].
Age changes how the two numbers behave. In up to 30 years of Framingham data from 2036 participants, systolic pressure rose linearly from age 30 through 84. Diastolic pressure rose alongside it until about 50 to 60 years of age, after which it declined while pulse pressure increased steeply [4].
Clinical synthesis: The practical answer to “which number matters more?” is both, read together. In that large cohort, systolic hypertension had the larger hazard ratio. However, a normal or even low diastolic value does not cancel out a high systolic value — particularly in older adults, including athletes, in whom a falling diastolic pressure combined with a rising systolic pressure may be consistent with increasing arterial stiffness rather than simply reflecting good cardiovascular fitness. An elevated diastolic pressure should not automatically be dismissed simply because the systolic value is acceptable.
In my experience, many patients instinctively associate high blood pressure mainly with the upper number. An elevated systolic reading is often the value that catches their attention and brings them to the clinic, while the diastolic value may receive less notice unless they already understand what it represents.
From a clinical perspective, that is an important distinction. A normal-looking systolic pressure does not automatically make an elevated diastolic pressure irrelevant, and I try to assess both numbers rather than focusing only on the one that appears more obviously abnormal. For patients, simply understanding that either value can matter often changes how they interpret their own blood pressure readings.
Blood Pressure During Exercise: What Happens When Athletes Train
Exercise is where the systolic vs diastolic difference becomes most visible.
Endurance and dynamic exercise
During dynamic exercise, systolic pressure typically rises in a linear fashion as intensity increases, reflecting greater cardiac output and sympathetic activation. Diastolic pressure, by contrast, remains relatively stable and may even fall slightly, mainly because the blood vessels in the working muscles dilate [7].
Fitness itself shifts the systolic response. Higher fitness levels are often associated with larger systolic increases during graded exercise testing, and testing on a cycle ergometer tends to produce higher systolic readings than treadmill testing [7].
Heavy resistance exercise
Strength training produces a very different pattern. In a classic study that measured blood pressure directly through a catheter in the brachial artery of five experienced bodybuilders, double-leg presses performed to failure produced a mean peak pressure of 320/250 mmHg, and one participant exceeded 480/350 mmHg [8]. Even single-arm curls continued to failure produced a mean peak of 255/190 mmHg [8]. The authors attributed part of this rise to the Valsalva manoeuvre — straining against a closed airway — combined with mechanical compression of blood vessels and a strong pressor response [8].
These are peak values recorded during lifting, not resting values, but they explain why breathing technique matters. The ESC sports cardiology guideline notes that holding the breath during muscular contraction is associated with greater rises in both systolic and diastolic pressure, and that correctly executed heavy dynamic resistance training (up to 80% of 1RM with fewer than 10 repetitions) does not raise blood pressure more than light, high-repetition training (<50% of 1RM, ≥20 repetitions) [14].
When is an exercise reading “too high”?
There is no universally agreed cut-off. A 2023 review summarised that the American Heart Association considers a peak systolic value of 210 mmHg in men and 190 mmHg in women potentially concerning during exercise, while noting that athletes may exceed such thresholds because of training adaptations [7]. The ESC sports cardiology guideline states that among young Olympic athletes, a peak systolic pressure above 220 mmHg in men and above 200 mmHg in women during cycle ergometry lies beyond the 95th percentile [14]. The same guideline states that clinical evaluation — including ECG and echocardiography — should be considered if systolic pressure exceeds 200 mmHg at a workload of 100 W, even when the athlete is normotensive at rest [14].
Does an exaggerated exercise response matter? The evidence points in two directions:
- In people undergoing exercise stress testing, a meta-analysis found that a hypertensive response at moderate exercise intensity carried a 36% greater rate of cardiovascular events and mortality, after adjustment for age, office blood pressure, and cardiovascular risk factors. Each 10 mmHg increase in systolic pressure during moderate-intensity exercise was associated with a 4% increase in events; systolic pressure at maximal workload, by contrast, was not significantly associated with the outcome [9].
- In highly trained athletes, 141 normotensive athletes with a high blood pressure response were compared with 141 matched athletes with a normal response and followed for 6.5 ± 2.8 years. No cardiac events occurred, but 24 athletes (8.5%) developed essential hypertension, and both resting blood pressure and a high exercise response at baseline were the strongest predictors of incident hypertension [10].
- On the other hand, a review focused on endurance-trained athletes concluded that there is no consensus on what constitutes a normal systolic response in highly fit individuals, that applying general-population exercise thresholds to endurance athletes appears unsupported, and that a high peak systolic value in this group may more likely reflect training adaptation than disease [15].
Clinical synthesis: These findings are not contradictory once the outcome is separated. A high peak systolic value alone does not establish cardiac pathology in a well-trained endurance athlete, and its prognostic significance in this population remains uncertain. But in highly trained, normotensive athletes, it was associated with a higher risk of developing resting hypertension over the following years — which is a reason for periodic follow-up of resting blood pressure, not for alarm.
From a practical clinical perspective, however, athlete status alone is not usually a reason for me to monitor blood pressure differently from everyone else. Blood pressure is a basic cardiovascular measurement that matters across the population, whether someone is sedentary, recreationally active, or highly trained.
I also find that the exact blood pressure reached during exercise is often less clinically actionable than the patient’s resting and out-of-office blood pressure. Exercise values can be physiologically interesting, particularly when an exaggerated response is seen during formal testing, but they do not automatically lead to a specific intervention on their own. In most situations, what matters more to me is whether blood pressure is persistently elevated at rest and whether repeated measurements outside the clinic show the same pattern.
This is why I tend to interpret exercise blood pressure as one piece of context rather than as a diagnosis in itself. An unusual exercise response may justify closer follow-up in selected cases, but the measurements most likely to influence longer-term clinical decisions are usually the patient’s resting values and the average pattern seen across repeated measurements.
Do Athletes Have Lower Blood Pressure? What the Evidence Shows
It is easy to assume that athletes are protected from high blood pressure. A large systematic review does not support that assumption.
A systematic review of 51 studies including 138,390 athletes, mostly aged 18 to 40 years, found [11]:
- No significant difference in blood pressure between athletes and controls overall.
- Strength-trained athletes had higher blood pressure than endurance-trained athletes (131.3/77.3 vs 118.6/71.8 mmHg).
- A trend towards higher blood pressure in athletes training ≥10 hours per week compared with those training less (p = 0.058).
- Reported hypertension prevalence ranging from 0% to 83%, with the highest figure in professional male Chinese strength athletes — predominantly weightlifters in the unlimited weight class.
- Among the 34 studies that reported blood pressure values, two-thirds reported mean values in what was then classified as the prehypertensive range.
The same review found that blood pressure measurement in athlete studies was poorly standardised. Only eight studies reported whether an appropriately sized cuff had been used, and studies that relied on a single reading reported significantly higher systolic values than studies that used two readings (127 vs 118 mmHg) [11]. The authors also suggested that cuffs may have been too small for athletes’ muscular upper arms, which would make readings falsely high [11].
How large can the cuff error be? A randomised crossover trial in 195 community-dwelling adults (not athletes) found that using a regular cuff on people who required a large cuff raised the systolic reading by 4.8 mmHg on average, and on people who required an extra-large cuff by 19.5 mmHg [12]. In principle, an error of this size could move a systolic reading of roughly 121–129 mmHg up to ≥140 mmHg, which is stage 2 under the AHA/ACC classification; note that this estimate comes from community-dwelling adults, not athletes.
Finally, some causes of high blood pressure in athletes are external. Berge and colleagues note that some athletes may use blood pressure–raising drugs, which is why medication use should be recorded during pre-participation screening [11]. The ESC sports cardiology guideline adds that non-selective non-steroidal anti-inflammatory drugs (NSAIDs) used for musculoskeletal pain may contribute to raised blood pressure [14].
How Training Changes Resting Blood Pressure
At first glance, the athlete data above may seem to conflict with exercise-intervention studies, but they answer different questions. In the systematic review of athletes, resting blood pressure was not significantly different between athletes and controls overall [11]. That does not mean exercise has no blood-pressure-lowering effect.
Randomised trials ask a different question: what happens to blood pressure when exercise training is introduced as an intervention? In a network meta-analysis of 270 randomised controlled trials involving 15,827 participants, all major exercise modes reduced resting systolic and diastolic blood pressure compared with control conditions [13]:
| Training mode | Systolic reduction | Diastolic reduction |
|---|---|---|
| Aerobic exercise | −4.49 mmHg | −2.53 mmHg |
| Dynamic resistance training | −4.55 mmHg | −3.04 mmHg |
| Combined aerobic + resistance | −6.04 mmHg | −2.54 mmHg |
| High-intensity interval training | −4.08 mmHg | −2.50 mmHg |
| Isometric exercise training | −8.24 mmHg | −4.00 mmHg |
Isometric training ranked as the most effective mode overall. In secondary analyses, the isometric wall squat was the most effective individual exercise for lowering systolic pressure, while running was the most effective for lowering diastolic pressure [13]. For more on the mechanisms and practical protocols, see isometric exercise for pain.
One nuance is especially relevant for athletes: all exercise modes produced substantially larger systolic reductions in people with hypertension than in those with normal baseline blood pressure [13]. In other words, the expected additional effect in an already highly trained, normotensive athlete is less certain — and, as the athlete data above show, high training volume does not guarantee low blood pressure.
Conclusion: Systolic vs Diastolic Blood Pressure
The systolic vs diastolic question has a simple answer: both numbers matter. Systolic pressure carries more prognostic weight, but diastolic pressure also independently predicts cardiovascular risk [3].
In practice, I pay less attention to a single reading than to the overall pattern. Office values can be affected by stress, recent activity, cuff size, and measurement technique, so repeated and out-of-office measurements are often more informative. In Finland, an office pressure of 140/90 mmHg corresponds roughly to a home average of 135/85 mmHg [16].
For athletes, exercise can produce large temporary increases in blood pressure, but the values that usually matter most clinically are resting and repeated measurements. Exercise training can lower resting blood pressure [13], yet athletes as a group do not necessarily have lower blood pressure than controls [11].
Ultimately, athletic fitness does not rule out hypertension, and one high reading does not establish it. The most useful approach is to interpret systolic and diastolic pressure together, measure them correctly, and look at the pattern over time.
References
[1] https://doi.org/10.1161/HYP.0000000000000249
[2] https://doi.org/10.1093/eurheartj/ehae178
[3] https://doi.org/10.1056/NEJMoa1803180
[4] https://doi.org/10.1161/01.cir.96.1.308
[5] https://pubmed.ncbi.nlm.nih.gov/15867140/
[7] https://doi.org/10.3390/jcdd10120480
[8] https://doi.org/10.1152/jappl.1985.58.3.785
[9] https://doi.org/10.1093/ajh/hps053
[10] https://pubmed.ncbi.nlm.nih.gov/30590485/
[11] https://doi.org/10.1136/bjsports-2014-093976
[12] https://doi.org/10.1001/jamainternmed.2023.3264
[13] https://doi.org/10.1136/bjsports-2022-106503
[14] https://doi.org/10.1093/eurheartj/ehaa605
[15] https://doi.org/10.1111/sms.13914
[16] https://www.kaypahoito.fi/hoi04010
