The 5 Numbers Your Annual Health Screening Misses

Your annual health screening checks you for disease that might already be there. It does not measure how fast you are declining. Five other numbers do, and most Singaporeans have never had any of them tested. Together they predict your next twenty years of healthspan more accurately than your cholesterol panel.

TL;DR

Why your screening misses these numbers

A standard executive medical package in Singapore typically tests fasting blood glucose, a lipid panel, blood pressure, body mass index, a resting electrocardiogram, urinalysis, and on the fuller-tier packages a chest X-ray and a slate of tumour markers. Raffles Medical, Parkway Shenton, Thomson Medical, and SingHealth each run variants of this. The packages are well constructed for what they were designed to do, which is to detect disease that is already present.

They were not designed to predict decline. The distinction matters.

A diagnostic test asks: do you currently have a problem that needs treatment. A predictive test asks: how is your trajectory over the next two decades, and what should you intervene on now to bend it. The five numbers below are predictive instruments. They are not replacements for your screening. They sit on top of it. If your screening tells you whether the floor of your health is holding, these numbers tell you whether the ceiling is rising or falling.

None of them require a referral. None of them are exotic. They are simply not in the package, because the package was scoped for early disease detection at population scale, not individual healthspan optimisation.

Number 1: VO2 max

VO2 max measures the maximum volume of oxygen your body can use per minute, scaled to body weight. It is the gold-standard read of cardiorespiratory fitness, and the cardiology literature has been remarkably consistent about its prognostic weight for forty years. I covered the testing options in Singapore, and why the true treadmill protocol is wrong for the people who most want it, in VO2 max test Singapore: what most clinics get wrong.

In 2018, Mandsager and colleagues at the Cleveland Clinic published the largest cohort study ever conducted on this question, following 122,007 patients who completed a treadmill exercise test over 13 years of follow-up. The relative risk of mortality between elite (top 2.5%) and low (bottom 25%) cardiorespiratory fitness was greater than the combined risk increase from smoking, type 2 diabetes, hypertension, and end-stage renal disease. The authors found no plateau in the dose-response relationship at the upper end. Higher fitness kept being more protective, all the way through.

Read that sentence again. Higher cardiorespiratory fitness was more protective than the combined harm of those four conditions.

Your wearable does not measure VO2 max. It estimates one. Apple Watch, Garmin, and Whoop each infer it from heart-rate response to running pace, and the literature on their accuracy is mixed at best, with errors of plus or minus 10 to 15% common. Acceptable for tracking your own trend over time. Not acceptable as the input to a longevity decision.

The gold-standard read is a graded treadmill test with respiratory gas analysis taken to volitional exhaustion. That test is appropriate for athletes and adults who already train near maximum. For most people it is the wrong test, for two reasons. Running to true failure is not safe without prior conditioning, especially in the 45 to 60 demographic where cardiovascular risk is non-trivial. And people who have never been coached to recognise volitional failure quit early, producing a falsely low reading. Either way the test is wasted. The responsible read for the general population is a validated sub-maximal proxy. Catalyst uses the YMCA 3-minute step test on the 4-Pillar Healthspan Assessment, which estimates cardiorespiratory fitness from recovery heart rate against age- and sex-adjusted norms. The result lands on the Catalyst Healthspan Report as a band, from Excellent to Poor. It is honest information you can act on, with none of the risk of a maximal test attempted by someone who has not been built up for it. The free Healthspan Audit includes a self-report proxy that bands you against your peer group in three minutes before you ever set foot in the studio.

Number 2: Grip strength

Grip strength is a hand-dynamometer reading that takes 90 seconds. It is the most informative 90 seconds of medical data most adults will ever produce.

In the PURE study published in The Lancet in 2015, Leong and colleagues followed 142,861 adults across 17 countries. Each 5 kg reduction in grip strength was associated with a 16% increase in all-cause mortality, a 17% increase in cardiovascular mortality, and a 9% increase in stroke risk, after adjusting for age, sex, BMI, smoking, education, and physical activity level. The relationship held across high-income, middle-income, and low-income countries. It held in adults with and without pre-existing cardiovascular disease. It held when the authors stripped out hand-injury cases.

Why does a handheld test predict so much. The dynamometer reads systemic muscle quality at the periphery, and skeletal muscle is one of the most metabolically integrated organs in the body. Loss of grip is a downstream signal of mitochondrial decline, neuromuscular signal loss, protein-synthesis impairment, and chronic low-grade inflammation. It is a single number that aggregates many systems.

The Asian Working Group for Sarcopenia 2019 consensus update set the diagnostic cutoffs at 28 kg for men and 18 kg for women. These are tighter than the European Working Group cutoffs (27 kg and 16 kg) because Asian body composition differs and the threshold for clinically meaningful weakness sits at a different absolute number. I covered the broader picture in grip strength: the most underrated health metric.

Number 3: Visceral fat and waist-to-height ratio

Body mass index is a height-and-weight ratio. It does not know where the fat sits, and the location matters more than the total.

Visceral fat is the fat that sits inside the abdominal cavity, wrapped around organs. It is metabolically active in a way subcutaneous fat is not, secreting inflammatory cytokines that drive insulin resistance, hypertension, and atherogenic dyslipidaemia. Two adults with identical BMI can carry completely different visceral fat loads, and only one of them is at metabolic risk.

Waist-to-height ratio is a low-tech proxy that catches what BMI misses. Ashwell and colleagues in a 2012 systematic review and meta-analysis pooling 31 cross-sectional studies found WHtR consistently outperformed BMI in identifying cardiometabolic risk in adults of all ethnicities. The simple rule is: keep your waist circumference below half your height. A 175 cm man should be under 87.5 cm at the navel.

For Singaporeans this matters more than it does for Western populations. Asians carry a higher proportion of visceral fat at any given BMI than Caucasians do, which is part of why Singaporean adults can present with metabolic syndrome at BMI levels that would be considered normal in the United States or United Kingdom. The Health Promotion Board adopted lower BMI cutoffs (23.0 for elevated risk, 27.5 for high risk) for exactly this reason.

Catalyst measures WHtR on every assessment and pairs it with InBody segmental analysis to estimate visceral fat directly. I covered the practical relationship between SMI, WHtR, and longevity in body composition: SMI and waist-to-height ratio. For the deeper question of whether to choose InBody or DEXA when you want a precise visceral-fat measurement, the comparison is in DEXA vs InBody Singapore: which body composition test.

Number 4: Heart rate recovery

Heart rate recovery measures how quickly your heart rate drops in the minute after you stop exercising. The drop is driven by the parasympathetic branch of the autonomic nervous system, primarily through the vagus nerve.

In 1999, Cole and colleagues at the Cleveland Clinic published a study in the New England Journal of Medicine following 2,428 adults referred for treadmill testing. Adults whose heart rate dropped by 12 beats per minute or fewer in the first minute after peak exercise had a four-fold higher mortality risk over the next six years, after adjusting for age, sex, medications, cardiac risk factors, and exercise capacity. Jouven and colleagues replicated the finding in 5,713 apparently healthy men in 2005, also in NEJM. The signal is robust across populations and decades.

What HRR captures is autonomic flexibility. A fast drop means your parasympathetic system can take the brakes off the sympathetic response and bring the body back to rest efficiently. A slow drop means that switch is sticky, which is correlated with chronic inflammation, insulin resistance, and elevated cardiovascular risk.

It is also one of the most trainable markers in the longevity panel. Eight to twelve weeks of structured strength training plus Zone 2 cardio produces measurable improvements in most adults. I went deeper on the difference between HRR and what your watch shows in heart rate recovery: what your watch can't measure.

Number 5: Skeletal Muscle Index

Skeletal Muscle Index is appendicular muscle mass divided by height squared, measured by bioimpedance (InBody) or DXA. It is the canonical input to a sarcopenia diagnosis.

The Asian Working Group for Sarcopenia 2019 consensus update set Asian-population thresholds at 7.0 kg/m² for men and 5.7 kg/m² for women on bioimpedance. Below those numbers, with low grip strength or slow gait speed, the formal diagnosis is sarcopenia. Above them, you may still be losing muscle at age-typical rates, just not at the threshold of disease yet. The full diagnostic workflow, including SARC-F, the 6-metre gait speed test, and the three Singapore screening pathways, is in sarcopenia screening Singapore: how to test for muscle loss.

The local data is sobering. Pang and colleagues in the Yishun Study, published in JAMDA in 2021, found that 32% of Singaporeans aged 60 and above met AWGS sarcopenia criteria. The figure rises to 64% by age 80. Most of these adults have never had their muscle mass measured. They learn about sarcopenia after a fall, or a hip fracture, or a hospital admission for something else.

From your 30s, untrained adults lose roughly 1% of muscle mass per year. The trajectory accelerates after 60 if nothing intervenes. Structured strength training stops the loss, and in many cases reverses years of accumulated decline within twelve to sixteen weeks. I covered the Singapore-specific picture in sarcopenia: the muscle-loss problem we are not talking about.

Where this fits in your year

None of this is an argument against your annual checkup. The lipid panel, the fasting glucose, the blood pressure cuff, and the resting ECG are all useful instruments and you should keep doing them. They will tell you if something is wrong now.

They will not tell you if your trajectory is wrong. For that, you need the five numbers above.

My recommendation to most members is straightforward: book the Catalyst Healthspan Assessment in the same week as your annual screening, ideally a day or two before. The data from VO2 max, grip strength, WHtR, HRR, and SMI gives your GP material to work with that the standard screening does not provide. A 50-year-old banking MD with a clean lipid panel but a treadmill VO2 in the 25th percentile and an SMI within a kilogram of the AWGS sarcopenia cutoff is not 'fine'. He is on a slope. The screening cannot see the slope. The five numbers can.

If you want to see where you stand before booking anything, the Healthspan Audit is a free 12-question self-assessment that lands a banded score across all four pillars in your inbox in three minutes. It is the same framework, scaled to a self-report. The in-studio assessment replaces the proxies with real instruments, but the audit is a useful starting point if you want to know what you are walking into.

Frequently asked questions

Q. Where can I get VO2 max measured in Singapore?

A true VO2 max test is a graded treadmill protocol taken to volitional exhaustion with respiratory gas analysis, offered at sports-medicine clinics and a small number of performance labs. For most adults it is the wrong test: running to true failure is not safe without prior conditioning, and people who have not been coached to recognise failure tend to quit early and produce a falsely low reading. Either way the result is unusable. Catalyst uses the YMCA 3-minute step test on the 4-Pillar Healthspan Assessment, a validated sub-maximal protocol that estimates cardiorespiratory fitness from recovery heart rate against age- and sex-adjusted norms. If you are already training near maximum and want a true treadmill-based VO2 max measurement, ask your GP for a referral to a sports-medicine clinic with cardiology backup.

Q. Is grip strength really that informative compared to a full fitness assessment?

As a single number, yes. The PURE study tracked 142,861 adults and found grip strength predicted all-cause mortality after adjusting for every reasonable confounder. It is not a substitute for the other four numbers, but it is the cheapest and fastest one to measure, and the data behind it is among the strongest in modern epidemiology. If you can only have one new number measured this month, this is the one.

Q. Should I replace my annual checkup with a Catalyst assessment?

No. The Catalyst Healthspan Assessment does not test cholesterol, glucose, blood pressure, or resting ECG, and it is not a substitute for medical screening. It is an additional layer of data that sits alongside your screening, focused on the predictive markers the screening does not include. The two are complementary instruments, not competing ones. Keep your GP. Add the assessment.

Citations

Mandsager, K., Harb, S., Cremer, P., Phelan, D., Nissen, S. E., & Jaber, W. (2018). Association of cardiorespiratory fitness with long-term mortality among adults undergoing exercise treadmill testing. JAMA Network Open, 1(6), e183605. jamanetwork.com/journals/jamanetworkopen/fullarticle/2707428

Leong, D. P., Teo, K. K., Rangarajan, S., Lopez-Jaramillo, P., Avezum, A. Jr, Orlandini, A., et al. (2015). Prognostic value of grip strength: findings from the Prospective Urban Rural Epidemiology (PURE) study. The Lancet, 386(9990), 266 to 273. thelancet.com/journals/lancet/article/PIIS0140-6736(14)62000-6/fulltext

Ashwell, M., Gunn, P., & Gibson, S. (2012). Waist-to-height ratio is a better screening tool than waist circumference and BMI for adult cardiometabolic risk factors: systematic review and meta-analysis. Obesity Reviews, 13(3), 275 to 286. onlinelibrary.wiley.com/doi/10.1111/j.1467-789X.2011.00952.x

Cole, C. R., Blackstone, E. H., Pashkow, F. J., Snader, C. E., & Lauer, M. S. (1999). Heart-rate recovery immediately after exercise as a predictor of mortality. New England Journal of Medicine, 341(18), 1351 to 1357. nejm.org/doi/full/10.1056/NEJM199910283411804

Jouven, X., Empana, J. P., Schwartz, P. J., Desnos, M., Courbon, D., & Ducimetiere, P. (2005). Heart-rate profile during exercise as a predictor of sudden death. New England Journal of Medicine, 352(19), 1951 to 1958. nejm.org/doi/full/10.1056/NEJMoa043012

Chen, L. K., Woo, J., Assantachai, P., Auyeung, T. W., Chou, M. Y., Iijima, K., et al. (2020). Asian Working Group for Sarcopenia: 2019 consensus update on sarcopenia diagnosis and treatment. Journal of the American Medical Directors Association, 21(3), 300 to 307.e2. jamda.com/article/S1525-8610(19)30872-2/fulltext

Pang, B. W. J., Wee, S. L., Lau, L. K., Jabbar, K. A., Seah, W. T., Ng, D. H. M., et al. (2021). Prevalence and associated factors of sarcopenia in Singaporean adults: the Yishun Study. Journal of the American Medical Directors Association, 22(4), 885.e1 to 885.e10. jamda.com/article/S1525-8610(20)30836-7/fulltext