The Missing Metric: Why I’m Rethinking My Approach to Longevity and Switching from WHOOP to Hilo

There is something deeply seductive about being able to quantify the human body.

A number for the quality of your sleep. A score for your recovery. A percentage representing how prepared you are to train. A measurement of your cardiovascular fitness. An algorithm that takes the events of the previous 24 hours and turns them into an apparently objective assessment of how well you are looking after yourself.

For those of us fascinated by longevity, this is both the promise and the problem of modern health technology.

We have become accustomed to measuring almost everything. We can wake up, open an application and immediately begin interrogating our physiology. How did I sleep? Did my heart rate variability improve? Have I accumulated too much strain? Is my body ready for another session in the gym, a long run or a competitive match?

I have been part of this movement for some time. WHOOP has become a familiar part of my relationship with training, sleep and recovery, providing a framework through which I can observe the consequences of my habits. As someone who enjoys experimenting with technology that promises to improve health and performance, I find that ability genuinely compelling.

But the longer I have been interested in longevity, the more I have questioned whether we are paying sufficient attention to the measurements that matter most.

We talk endlessly about recovery scores, cold exposure, supplements, sleep optimisation and the latest developments in wearable technology. We discuss the merits of a particular training protocol or the potential of a new intervention to improve biological ageing. Yet one of the most consequential indicators of cardiovascular health is comparatively unglamorous.

Blood pressure.

It does not have the marketing appeal of a new fitness algorithm. It cannot be improved simply by collecting more data. It is not a measure of how many kilometres I have run or how quickly I can recover after a demanding padel match.

But it is a fundamental physiological measurement, closely connected to the health of the cardiovascular system and the long-term risk of serious disease.

That realisation has prompted me to broaden my approach to health monitoring and spend a month incorporating Hilo, formerly Aktiia, into my routine.

This is not a story about abandoning WHOOP or declaring one wearable the definitive winner. It is about recognising that the pursuit of longevity requires a broader set of questions than the pursuit of athletic performance alone.

I want to know how well I am training. I also want to understand the cardiovascular health that allows me to keep doing it.

And increasingly, I believe those are two different conversations.

01.

The problem with optimising everything except the fundamentals

The longevity industry has an extraordinary ability to turn almost any aspect of human biology into a project for improvement.

There are protocols for sleep, breathing, strength, aerobic capacity, nutrition, glucose regulation, stress management and cognitive performance. There are wearables, smart scales, rings, watches and devices that promise to reveal increasingly detailed aspects of our physiology.

Some of these developments are genuinely valuable. Others are still being evaluated. Many are useful only when interpreted within the context of an individual's health, habits and objectives.

The difficulty is knowing which measurements deserve our attention first.

For me, longevity has never been simply about trying to live to an arbitrary age. It is about maintaining the physical and cognitive freedom to enjoy life for as long as possible.

I want to keep playing tennis and padel competitively. I want to develop my running, complete the London Marathon and explore cycling further. I want to remain strong, mobile and aerobically capable as I get older.

These are not abstract ambitions. They are the activities through which I experience the benefits of being healthy.

The question, therefore, is not merely how I can improve my performance over the next three months. It is how I can build the foundations that make sustained performance possible over the next three decades.

That requires looking beyond the metrics most closely associated with exercise.

Consider blood pressure. It is possible to feel fit, exercise regularly and have no obvious symptoms while still having elevated blood pressure. Hypertension can develop silently, which is one reason routine measurement is so important.

The World Health Organization estimated that 1.4 billion adults aged 30–79 had hypertension in 2024, equivalent to approximately one in three people in that age group worldwide. Around 600 million were unaware that they had the condition.

Those figures are a reminder that cardiovascular risk does not always announce itself.

We cannot infer blood pressure from appearance, athletic ability or how energetic we feel when we wake up. Nor can a favourable recovery score establish that our cardiovascular health is optimal.

This is where I think the modern wellness conversation sometimes becomes distorted. We have become remarkably sophisticated at optimising the things we can see on a dashboard, but the presence of a dashboard does not guarantee that we are measuring the most important things.

My interest in Hilo began with a relatively simple proposition: if blood pressure is so consequential to long-term health, why should measuring it remain something I do only occasionally?

02.

Why blood pressure deserves a place in the longevity conversation

To understand why I have become more interested in blood-pressure monitoring, it helps to understand what the measurement actually represents.

Blood pressure is expressed as two numbers, measured in millimetres of mercury, or mmHg.

The first is systolic blood pressure: the pressure in the arteries when the heart contracts and pumps blood around the body.

The second is diastolic blood pressure: the pressure in the arteries when the heart relaxes between beats.

A reading of 120/80 mmHg, for example, represents a systolic pressure of 120 and a diastolic pressure of 80.

The numbers are simple. The physiology behind them is not.

Blood pressure reflects the interaction between cardiac output, the resistance offered by the blood vessels, circulating blood volume and the mechanisms through which the body regulates its circulation. The nervous system, kidneys, hormones and the properties of the blood vessels all contribute to that regulation.

The body is constantly adjusting this system to maintain the delivery of oxygen and nutrients to its tissues.

When we stand up, exercise, experience stress or move from one environment to another, our cardiovascular system responds. Blood pressure is therefore not a fixed characteristic, but a dynamic variable that changes in response to both internal and external demands.

That variation is normal. The important question is whether blood pressure is persistently elevated, whether it behaves as expected in different circumstances and whether a pattern warrants further investigation.

Arteries are designed to accommodate the pulsatile flow of blood, but persistent hypertension increases the workload imposed on the cardiovascular system.

Over time, elevated pressure is associated with structural and functional changes in the blood vessels and heart. It can contribute to damage affecting the brain, kidneys and other organs.

The relationship between blood pressure and cardiovascular risk is particularly important because it is modifiable. Lifestyle changes and, when indicated, medication can reduce blood pressure and help lower the risk of complications.

The WHO identifies physical inactivity, excess body weight, high-salt diets, tobacco use, alcohol consumption, genetics and age among the factors relevant to hypertension risk. The relative importance of each varies between individuals.

This is why I see blood pressure as a foundational longevity metric rather than simply another performance variable.

It is not the only metric that matters. Cholesterol, glucose regulation, cardiorespiratory fitness, body composition, sleep, diet and family history all contribute to a more complete assessment of health.

But blood pressure has a particularly compelling combination of characteristics: it is clinically important, it can be measured relatively easily, and sustained elevation is something that can often be addressed.

The opportunity is not to obsess over every fluctuation. It is to understand the broader pattern and recognise when action is appropriate.

Why a single reading can be misleading

Imagine taking your blood pressure immediately after climbing several flights of stairs, during a stressful meeting or following an intense training session. The result would not necessarily reflect your usual resting blood pressure.

The reverse is also true. A reassuring reading on one occasion does not establish that your blood pressure is consistently healthy.

Clinical practice therefore relies on appropriate measurement methods and, when necessary, repeated readings taken under standardised conditions. Home monitoring and ambulatory blood-pressure monitoring can help clinicians understand patterns that a single clinic measurement may miss.

This is the conceptual appeal of more frequent monitoring: the possibility of understanding a dynamic physiological process through repeated observations rather than isolated snapshots.

However, frequency alone does not guarantee accuracy or clinical usefulness. The quality of the measurements, the conditions under which they are obtained and the way the data are interpreted remain essential.

That distinction becomes particularly important when we move from conventional blood-pressure cuffs to wearable technology.

03.

WHOOP taught me to look at recovery. Hilo is changing the question.

WHOOP has played an important role in how I think about my training.

Its approach encourages me to consider the relationship between physical strain, sleep and recovery rather than treating every workout as an isolated event. It provides a framework for identifying patterns and reflecting on whether my habits are consistent with my goals.

For someone training across several sports, that can be valuable.

Running places repetitive mechanical demands on the body. Tennis and padel involve acceleration, deceleration, rotation and repeated bursts of high-intensity effort. Cycling introduces prolonged aerobic work, with its own relationship between duration, intensity and recovery.

The challenge is balancing those demands without accumulating fatigue faster than the body can adapt.

WHOOP helps me ask questions about that process. Hilo has encouraged me to consider another set of questions, centred on blood pressure and cardiovascular health.

The distinction is subtle but important.

WHOOP is fundamentally designed around understanding the body's response to daily life, particularly through its sleep, strain and recovery framework. Hilo places greater emphasis on repeated blood-pressure monitoring through a wrist-worn device.

I am interested in the latter because I want to make blood pressure a more visible part of my everyday health routine.

It would be inaccurate, however, to suggest that WHOOP cannot provide blood-pressure insights. WHOOP now offers a Blood Pressure Insights feature on its WHOOP Life membership, using overnight physiological data to estimate systolic and diastolic blood-pressure ranges. The company describes this as a wellness feature, not a diagnostic tool.

The distinction is therefore not simply that one device measures blood pressure and the other does not.

It is a question of emphasis, measurement approach, data availability and how I want to organise my personal monitoring routine.

I want to understand blood pressure as a repeated measurement throughout ordinary life, rather than focusing exclusively on a nightly estimate. HIlo's approach is particularly interesting to me because it is designed around repeated optical measurements during the day and night.

That does not make Hilo universally superior. It makes it a better fit for the particular question I want to explore.

I also do not see a need to turn the decision into a competition between brands. If a device helps me understand one aspect of my health, and another helps me understand something different, there is value in recognising their complementary roles.

The objective is not to become loyal to a wearable. It is to become more informed about my body.

04.

Hilo explained: what is happening beneath the surface?

The first thing that makes Hilo interesting is its approach to blood-pressure measurement.

Traditional automated blood-pressure monitors generally use an inflatable cuff around the upper arm. The cuff temporarily restricts blood flow and then measures pressure as it deflates, allowing the device to estimate systolic and diastolic blood pressure.

It is a familiar process, supported by decades of clinical use and established validation standards.

The disadvantage is practical rather than scientific: taking a measurement requires the user to stop, position the cuff correctly and complete the measurement procedure. Many people do this infrequently, even when more regular monitoring would be useful.

Hilo attempts to reduce that friction.

Hilo uses optical blood-pressure monitoring technology. Its sensors collect photoplethysmography, commonly abbreviated to PPG, signals from the wrist.

PPG is a technique that uses light to detect changes associated with blood volume in the microvascular tissue beneath the skin. It is widely used in consumer wearables to support measurements such as heart rate and blood-oxygen saturation, although the specific implementation and accuracy requirements vary by application.

For blood-pressure estimation, the waveform contains information about the way blood volume changes with each heartbeat. Hilo's algorithms process the optical signal to estimate systolic and diastolic pressure and resting heart rate.

The important word is estimate.

An optical sensor does not directly measure arterial pressure in the way a conventional cuff measures it. The relationship between the optical signal and blood pressure is indirect and depends on the device's underlying model, validation and ability to account for sources of variation.

That makes the engineering problem more complicated than simply adding a light sensor to a wristband.

The device must distinguish useful physiological information from noise, identify when conditions are unsuitable for a reliable reading and process the signal through an algorithm that has been developed and tested for its intended use.

Hilo states that its technology has undergone clinical validation and that its bracelet received CE marking as a Class IIa medical device in December 2020 under the applicable European regulatory framework.

That regulatory context matters, but it is equally important to understand what it does and does not establish. The classification and evidence apply to the specific device and intended purpose, not automatically to every cuffless blood-pressure wearable on the market.

Why repeated measurements matter

The promise of a wearable like Hilo is that it can make measurement less disruptive.

Rather than relying solely on occasional readings taken with a cuff, the device is designed to collect measurements repeatedly across the day and night when conditions permit.

That can offer a richer picture of the user's blood-pressure profile.

For example, it may be possible to observe differences between measurements collected during ordinary daily activity and those obtained during quieter periods. Repeated observations may also help identify patterns that deserve closer examination using conventional monitoring.

However, repeated readings should not be confused with uninterrupted, beat-by-beat measurement. Hilo's system obtains individual measurements when its technology determines that conditions are suitable; it does not provide a direct invasive measurement of arterial pressure continuously.

This is an important technical distinction, and one that is often lost in consumer health marketing.

The value is not necessarily in capturing every second. It is in making useful measurements easier to collect over time.

The limitations of cuffless technology

Cuffless blood-pressure monitoring is a rapidly developing field, but it remains an area where enthusiasm must be balanced with scrutiny.

In December 2025, the American Heart Association published a scientific statement examining the potential and limitations of cuffless blood-pressure technologies. It highlighted concerns around real-world accuracy, calibration, movement, posture and the need for stronger evidence linking the large volumes of data these devices generate to meaningful clinical outcomes.

This is particularly relevant for anyone interested in sports.

A device that performs well under suitable measurement conditions should not automatically be assumed to produce equally reliable blood-pressure readings during a tennis rally, a fast padel exchange or a hard cycling interval.

Movement, wrist position and other factors can affect optical measurements. Devices may reject readings when the signal quality is insufficient, which is preferable to presenting an unreliable number as though it were precise.

The wider lesson is that the quality of health technology is not determined by how much data it produces. It is determined by the validity of the measurements and whether those measurements can be interpreted responsibly.

That is the standard I want to apply to Hilo and every other health technology I choose to use.

05.

One month with HIlo: what changes when blood pressure becomes part of your routine?

There is a difference between understanding the importance of a health metric intellectually and making it part of your daily life.

Before using a wearable, blood pressure can feel like something that belongs in a GP's consulting room. You might measure it during an annual health check, after a clinician recommends monitoring, or because a particular reading has prompted you to pay closer attention.

It is easy to understand why. Blood pressure measurement has traditionally required a deliberate action: finding a monitor, sitting down, positioning the cuff and taking a reading.

Hilo changes the proposition by making repeated monitoring less cumbersome.

Instead of having to remember to take every measurement manually, the device is designed to collect readings as part of everyday life. That convenience is central to its appeal.

During the first week, the most important adjustment is conceptual.

I am accustomed to looking at wearable data through the lens of performance. A recovery score is easy to contextualise against a demanding training session or a poor night's sleep. Blood pressure requires a different kind of attention.

The objective is not to chase a perfect number every morning. It is to understand what my measurements generally look like and to recognise that individual readings are influenced by circumstances.

I find this distinction important because health tracking can easily become another form of performance anxiety. Once a number is available, there is a temptation to treat every deviation as a problem that needs solving.

Blood pressure does not work that way.

A measurement is a piece of information, not a verdict on my health. Its significance depends on the value, the circumstances, the broader pattern and, where appropriate, clinical assessment.

The most useful early habit is therefore consistency: wearing the device as intended, following its instructions and allowing enough time to establish a meaningful record.

The second week: learning to think in patterns

The next step is moving away from isolated readings.

Blood pressure naturally varies. A person may have different measurements at different times of day, and physical activity, stress, posture and other physiological factors can contribute to those differences.

The temptation is to explain every fluctuation. A poor night's sleep might appear to coincide with a higher reading. A quieter day might appear to coincide with a lower one.

But correlation is not causation.

Without a controlled approach, it is difficult to establish whether a particular behaviour caused a change, whether the difference reflects ordinary variation, or whether another factor was responsible.

This is where I think health technology should encourage curiosity rather than certainty.

I want to ask better questions about my habits, not manufacture answers from incomplete information.

The third week: connecting the data to behaviour

By the third week, the value of any monitoring routine should be judged by whether it helps inform sensible behaviour.

Blood pressure is influenced by a combination of factors, including genetics, age, body composition, physical activity, diet, sleep, stress and certain medications. Some are modifiable; others are not.

If repeated monitoring reveals a pattern that deserves attention, the appropriate response might be to review measurement quality, take conventional readings, speak to a clinician or investigate relevant lifestyle factors.

If the measurements are reassuring, that is useful context too, although it does not eliminate the need for appropriate health checks.

The important point is that monitoring creates an opportunity to act. It does not guarantee that action will be necessary, nor does it automatically improve the underlying physiology.

The fourth week: assessing the technology, not just the numbers

After a month, I would judge Hilo against four practical criteria.

Usability: Does the device fit comfortably into everyday life, and is wearing it consistently realistic?

Data quality: Does it obtain readings regularly enough to be useful, and do the results make sense when compared with properly taken conventional measurements?

Interpretability: Does the app make it possible to understand longer-term patterns without encouraging me to overreact to individual fluctuations?

Actionability: Does the information help me identify questions worth investigating or support a more informed conversation with a healthcare professional?

These are the questions that determine whether a health wearable becomes a useful part of my routine or simply another device that competes for my attention.

I would not claim that a month of monitoring has independently improved my blood pressure, reduced my cardiovascular risk or made me a better athlete. Those outcomes would require evidence that I have not established simply by wearing the device.

What I can say is that blood pressure deserves more attention than it traditionally receives in consumer fitness culture, and a device that makes monitoring more accessible offers an interesting way to explore that principle.

The next step is not to collect more numbers indefinitely. It is to understand which measurements are trustworthy, which patterns are meaningful and what, if anything, should change as a result.

06.

Four sports, one cardiovascular system

My interest in Hilo is not separate from my sporting ambitions. It is closely connected to them.

I am training across tennis, padel, running and cycling, and each sport presents a different combination of cardiovascular, muscular, mechanical and psychological demands.

It would be convenient if one wearable could tell me everything I needed to know about all four. In reality, each requires a different approach to training and monitoring.

Blood pressure adds another layer to the picture, but it needs to be used for the right purpose.

Tennis: preserving the capacity to compete

Returning to tennis after a long absence is an interesting exercise in rediscovery.

The game requires more than aerobic fitness. There are repeated accelerations, rapid changes of direction, rotational movements, overhead strokes and periods of intense concentration. A competitive match can produce considerable physiological stress, particularly when long rallies and demanding conditions accumulate.

I want to improve my movement, endurance and ability to sustain quality throughout a match. I also want to build those capabilities in a way that allows me to continue playing for years.

Blood-pressure monitoring cannot tell me whether my footwork is improving or whether my shoulder is tolerating the demands of serving. Those questions require different forms of assessment.

What it can contribute is a broader focus on cardiovascular health. Tennis is one part of an active lifestyle; it is not, by itself, proof that every aspect of my cardiovascular health is optimal.

Padel: the importance of intermittent intensity

Padel presents a different challenge, despite sharing some of tennis's physical demands.

Rallies can be explosive, with short bursts of acceleration and repeated changes in direction interspersed with recovery periods. The social and competitive nature of the sport also makes it easy to play longer or harder than originally intended.

For someone who enjoys competing, that is part of the attraction.

But it reinforces the importance of distinguishing training intensity from long-term health monitoring.

Heart rate and perceived exertion can help me understand how hard I am working during a match. Hilo's measurements may provide additional information during suitable periods outside the most intense activity, but I should not assume that a wrist-based optical device will provide reliable blood-pressure readings during every rally.

The aim is not to turn padel into a medical experiment. It is to enjoy the sport while remaining attentive to the broader health of the system that makes it possible.

Running: building endurance without losing perspective

Running brings longevity and performance into particularly sharp focus.

My preparation for the London Marathon is an exercise in progressive adaptation. I need to build aerobic capacity, increase training volume appropriately, strengthen the tissues involved in running and allow sufficient recovery between sessions.

For a returning runner, consistency matters far more than trying to accelerate every aspect of performance simultaneously.

Blood pressure is relevant, but it answers a different question from running pace or VO₂ max.

VO₂ max describes the body's capacity to take up and use oxygen during intense exercise. Blood pressure describes the force exerted by circulating blood against arterial walls. Both are relevant to cardiovascular health, but they are not interchangeable.

A person can improve aerobic fitness without every blood-pressure measurement changing in parallel. Equally, a healthy blood-pressure reading does not establish that aerobic fitness is high.

That is precisely why I want a broader set of measurements.

I can use running metrics to assess my training and blood-pressure monitoring to learn more about cardiovascular health, while recognising that neither provides a complete picture on its own.

Cycling: developing the aerobic engine

Cycling complements running by allowing me to accumulate aerobic work with a different mechanical loading profile.

It can be useful for developing endurance while managing the impact associated with running. It also provides opportunities to work at different intensities and durations.

However, the same principles apply. A longer ride does not necessarily mean better health, and a single physiological measurement cannot establish whether my training is well balanced.

The goal is to build fitness sustainably.

For me, that means considering the totality of my training, including how different sessions interact, how much recovery I need and whether I am maintaining the physical capabilities that support my wider sporting ambitions.

Hilo contributes a different perspective on cardiovascular health. It does not replace the metrics that guide my training, and I would not use an isolated blood-pressure reading to determine whether I am ready for a demanding ride.

The most important connection between these sports is not a particular training zone or a target number.

It is the desire to remain capable.

I want to improve, but I also want to protect the health that makes improvement possible. That requires an approach in which training data, cardiovascular monitoring, sensible lifestyle habits and appropriate medical care complement one another.

The most useful wearable is therefore not necessarily the one that produces the largest quantity of information. It is the one that provides trustworthy information relevant to the decision I am trying to make.

07.

The relationship between exercise and blood pressure

One reason blood pressure deserves a place in my training philosophy is that regular physical activity can contribute to better blood-pressure control.

Exercise influences the cardiovascular system in several ways. Over time, appropriate aerobic training can improve vascular function, support the regulation of the cardiovascular system and contribute to reductions in resting blood pressure in people with elevated levels.

Resistance training can also contribute to cardiovascular health, alongside its benefits for strength, muscle mass and physical function.

However, the relationship is not as simple as exercising more and expecting every reading to improve.

Blood pressure normally responds to exercise. During dynamic aerobic activity, systolic pressure generally rises as the body increases blood flow to working muscles. Diastolic pressure often changes less, although the response varies with the type and intensity of exercise.

Heavy resistance exercise can produce substantial temporary increases in blood pressure, particularly when lifting near maximal loads or holding the breath during exertion.

These short-term responses are not equivalent to chronically elevated resting blood pressure.

This distinction matters because I want to interpret my data intelligently. A reading obtained immediately after a demanding session should not be treated as directly comparable with one obtained under standard resting conditions.

For routine home blood-pressure assessment, the conventional approach remains important: rest quietly before measuring, use a validated upper-arm cuff of the correct size, sit with the back supported and feet flat on the floor, and support the arm at heart level. Avoid exercise, caffeine and smoking for at least 30 minutes beforehand, and follow the monitor's instructions.

The point is not to eliminate every source of variation from daily life. It is to use the appropriate measurement method for the question being asked.

A wearable may be useful for observing patterns under everyday conditions. A properly performed cuff measurement is the more appropriate reference when establishing resting blood pressure for clinical purposes.

08.

Can monitoring itself improve blood pressure?

This is one of the most interesting questions raised by Hilo.

It is tempting to assume that if a person measures a health variable more frequently, the variable will improve. But the relationship between measurement and outcome is more complicated.

Monitoring can make a problem more visible. It can encourage a person to take their health seriously, help establish a baseline and support a conversation with a clinician. It may also help identify patterns that would otherwise remain unnoticed.

Yet collecting information does not automatically change physiology.

A wearable does not lower blood pressure simply by measuring it. The potential benefit comes from what happens next: appropriate interpretation, changes to modifiable risk factors and medical intervention where needed.

HIlo reports that users with high or very high blood pressure were able to reduce systolic readings by up to 7 mmHg after six months of monitoring in a study cited on its clinical information page. The company also notes that the results come from its own research and user data.

That finding is interesting, but it needs to be interpreted carefully. A result reported by a manufacturer is not the same as independent proof that monitoring alone caused the reduction. The study design, population, comparison group and other interventions all matter when determining what produced the change.

It would be premature to conclude that wearing Hilo for a month will reduce my blood pressure by a particular amount.

I am more interested in the broader principle: can making blood pressure more visible help people recognise patterns, engage with their health and take appropriate action?

That is a question worth investigating, provided the technology is sufficiently accurate for its intended use and the resulting data are interpreted responsibly.

09.

The uncomfortable truth about wearable accuracy

There is a temptation to regard consumer health technology as increasingly sophisticated simply because the underlying hardware and software are becoming more advanced.

But sophistication does not automatically equal accuracy.

In December 2025, the American Heart Association published a scientific statement specifically examining cuffless blood-pressure devices. It concluded that significant questions remain about their precision, reliability in real-world conditions and suitability for clinical decisions. The 2025 American College of Cardiology/American Heart Association hypertension guideline likewise advises against relying on cuffless devices for diagnosing or managing high blood pressure until they demonstrate greater reliability.

This is not an argument against innovation. It is an argument for understanding what a particular device has demonstrated.

Hilo's technology has its own clinical-validation history, and that evidence should be considered on its own merits. But its results should not be generalised automatically to other wearables, nor should regulatory status be treated as proof that every reading is interchangeable with a conventional cuff.

WHOOP's blood-pressure estimates deserve the same scrutiny. The company publishes its own validation information and explicitly states that its Blood Pressure Insights feature is intended for wellness tracking rather than diagnosis or treatment.

For me, this is one of the most important lessons in the entire category.

A wearable can be genuinely useful without being a replacement for clinical measurement. Its limitations do not necessarily eliminate its value, but they determine how that value should be understood.

The appropriate question is not, 'Which device produces the most impressive graph?'

It is, 'What has this device actually been shown to measure reliably, under which conditions, and what decisions can reasonably be based on that information?'

That is a more demanding question, but it is the one health technology deserves.

10.

The practical protocol: how I would use Hilo alongside conventional monitoring

My ideal approach to blood-pressure monitoring is not to treat Hilo as a standalone authority. It is to use the device as one part of a broader system.

First, I would follow the manufacturer's instructions for wearing and maintaining the device. Consistent use matters if the aim is to understand patterns over time.

Second, I would establish a conventional resting blood-pressure baseline using a validated upper-arm monitor. For a more reliable picture, I would follow a standard home-monitoring protocol, taking repeated measurements at consistent times and recording the results as recommended by a healthcare professional.

Third, I would compare the broader picture with the information provided by Hilo. I would not expect every individual measurement to match perfectly, particularly when the devices are measuring under different conditions. Persistent discrepancies, however, would be a reason to check technique and seek professional advice rather than simply choosing the more reassuring result.

Fourth, I would avoid making medical decisions from isolated wearable readings. If a concerning pattern emerged, I would confirm it using appropriate conventional measurements and discuss it with a clinician.

Finally, I would focus on the behaviours that have a credible relationship with cardiovascular health: regular physical activity, a balanced diet, appropriate weight management, adequate sleep, avoiding tobacco, moderating sodium intake and managing stress. Medication may be necessary for some people, and wearable data should never be used as a reason to stop or alter prescribed treatment.

This is not an elaborate biohacking protocol. That is precisely the point.

The most valuable health routines are often the ones that are straightforward enough to sustain and grounded enough to trust.

11.

What longevity really means to me

There is a philosophical question underneath all of this.

Why do we want to live longer?

For me, the answer has very little to do with an arbitrary target age. It has far more to do with the quality of the years in between.

I want to remain physically capable. I want to keep learning, competing, travelling and exploring. I want to maintain the strength to do the things I enjoy and the cardiovascular capacity to support them.

That is why I find the distinction between lifespan and healthspan so compelling.

Lifespan refers to how long we live. Healthspan is concerned with the period during which we remain healthy and functionally capable. The two are related, but they are not identical.

A longevity strategy should therefore be concerned with more than adding years. It should seek to preserve the capabilities that make those years meaningful.

Regular exercise, strength training, cardiovascular fitness, nutrition, sleep and preventive healthcare all have roles to play. So does identifying and managing risk factors that may not produce obvious symptoms.

Blood pressure fits into that picture because it offers a measurable indicator of cardiovascular health and an opportunity to address elevated risk when it is identified.

Hilo appeals to me because it makes that measurement more accessible. It gives me a practical way to bring blood pressure into a routine that has previously focused more heavily on exercise, sleep and recovery.

But I am not interested in wearing technology for its own sake. I am interested in using it to ask better questions, make better decisions and become more informed about the relationship between my habits and my health.

The objective is not to eliminate uncertainty from biology. It is to make better decisions despite it.

12.

My verdict: an evolution in how I think about health technology

After a month with Hilo, the most important question is not whether it has replaced WHOOP. It is whether it has helped me pay more attention to a dimension of health that deserves a more prominent place in my routine.

That is the distinction I want readers to take away.

WHOOP has helped me organise my thinking around sleep, recovery and training. HIlo is giving me a different perspective by making repeated blood-pressure monitoring part of my everyday health technology experience.

I would not claim that the month has improved my cardiovascular health without verified before-and-after measurements. I would not claim that it has made me faster on the tennis court, more resilient on the padel court or better prepared for the London Marathon. Those outcomes require evidence, not enthusiasm.

But I do believe the experience has reinforced an important principle: performance and longevity overlap, yet they are not the same objective.

A person can train hard without paying sufficient attention to their cardiovascular risk factors. Equally, a person can monitor dozens of health metrics without making the lifestyle changes that actually matter.

The value of a wearable lies in its ability to support a better relationship with health, rather than creating another set of numbers to pursue.

For me, HIlo is an interesting addition because it shifts some of my attention towards blood pressure, a metric that can be clinically consequential even when I feel perfectly well.

The next stage is to evaluate the measurements carefully, compare them appropriately and understand whether the information changes any decisions I make.

That is what I want from the next generation of health technology: not bigger dashboards, more notifications or an endless stream of optimisation targets, but trustworthy information that helps me understand my body more intelligently.

Longevity is not achieved by wearing a device. It is supported by the cumulative decisions we make about how we live, train, eat, sleep and manage our health.

Technology can help us make those decisions better, but it cannot make them for us.

And that is why I am expanding my approach to monitoring.

I do not want to spend my life chasing a better score. I want to preserve the health, strength and freedom that make the score worth having in the first place.