.png)
Strength as a Vital Sign — How We Measure It in Clinic and at Home
- Dr Edward Leatham
- May 9
- 8 min read
Updated: May 12
For busy people, or to tune in when on the move, Google Notebook AI audio podcast and an explainer slide show are available for this story beneath.
Strength as a Vital Sign — How We Measure It in Clinic and at Home
By Dr Edward Leatham, Consultant Cardiologist, Surrey Cardiovascular Clinic
Most patients arriving for a cardiometabolic assessment expect to have their blood pressure, weight and waist measured. Fewer expect us to ask them to squeeze a small device in their hand, or to count how many times they can stand up from a chair in 30 seconds. Yet these two simple measurements tell us more about the resilience of your metabolic system than almost anything else we can do in the clinic — and crucially, they are tests you can also do at home.
This article explains why we measure strength alongside the more familiar cardiovascular numbers, how the two tests are performed, and how you can repeat them at home to track your progress.
Figure 1 — The two-test battery: grip strength for the upper body, 30-second sit-to-stand for the lower body.
Why we measure strength at all
When most people think about ageing, they think about losing muscle mass. The clinical reality is more specific: what really determines how well someone ages is muscle function — the force their muscles can actually generate. The medical terms for this are sarcopenia (loss of muscle mass) and dynapenia (loss of muscle strength). Of the two, dynapenia is the better predictor of poor outcomes.
This matters for cardiovascular and metabolic health for two related reasons. First, large skeletal muscle is the single biggest disposal site for circulating glucose; when it shrinks or weakens, glucose handling deteriorates. Second, strong muscles are the chief opponents of visceral fat (VAT) — the metabolically active fat that drives the cluster of problems we associate with mid-life weight gain: high blood pressure, raised triglycerides, fatty liver and type 2 diabetes. Loss of muscle strength and accumulation of visceral fat are not separate problems. They are two ends of the same lever.
Body composition scales — including the ones at the gym, and even DEXA scans — measure muscle size, not muscle strength. They can also be misleading during weight loss: reductions in muscle bulk during a successful programme often reflect loss of intramuscular fat and stored glycogen (the so-called muscle “marbling”), not loss of functional capacity. This is why directly testing what your muscles can do is far more informative than imaging how big they are.
The two tests we use
Strength assessment in clinic needs to be quick, reproducible and meaningful. We use one test for the upper body and one for the lower body. Together they take about three minutes.
Test 1 — Grip strength (upper body)
Grip strength is measured with a small device called a hand dynamometer. You squeeze it as hard as you can, and a digital display reads off the force you generated, in kilograms. It looks deceptively simple, but it is one of the most powerful single measurements in cardiometabolic medicine: in large international studies, reduced grip strength has been shown to predict cardiovascular events and overall mortality more reliably than blood pressure or BMI.
Grip is a useful surrogate for the strength of the whole upper-body chain — the forearm, the upper arm and the shoulder girdle. We test the dominant hand by default. If there is a recent injury, arthritis or pain in that hand, we test the other side. If both hands are affected, the test is not considered valid and we rely on the lower-body test alone.
In clinic we demonstrate the device, then ask you to squeeze it as firmly as you can for about three seconds. We take the best of three attempts. If both hands are healthy, we test both and record the higher value.
Test 2 — 30-second sit-to-stand (lower body)
Grip strength tells us about the upper body, but the largest muscle groups in the body — the thighs, glutes, hips and core — are below the waist. These are the muscles that keep you mobile, stable and metabolically healthy, and they are the first to decline with sedentary middle age. Grip strength does not assess them, so we use a second test.
The 30-second sit-to-stand test is exactly what it sounds like. Sitting on a standard chair without arms, you cross your arms over your chest and stand up fully, then sit back down — and repeat as many times as you can in 30 seconds. Like grip strength, it has been validated against long-term outcomes in large population studies: people who manage fewer repetitions tend to have worse cardiovascular and metabolic prognosis. Unlike grip strength, it requires no equipment at all.
There is a useful side-effect to this test: the test is itself a training exercise. Repeating it once or twice a week, or doing two or three sets at home, will measurably improve your score over a few months. Few clinical measurements double up so neatly as therapy.
Reading your numbers
We compare new patients’ results against population-based reference charts derived from large studies. These tell us whether someone is broadly within the expected range for their age and sex, and they help us flag clearly low values that warrant further attention. As a rough orientation only:
Test | Typically low for age 50–70 | What we like to see |
Grip strength (men) | Below 30 kg | 35 kg or higher |
Grip strength (women) | Below 18 kg | 22 kg or higher |
Sit-to-stand in 30 sec (50–60 yrs) | Fewer than 11–12 reps | 14 or more |
Sit-to-stand in 30 sec (60–70 yrs) | Fewer than 10–11 reps | 13 or more |
These figures are illustrative bands derived from published norms; they are not personalised targets. Your clinician will interpret your number against more detailed nomograms specific to your age and sex or why not use our free calculator app at the top of this article- where your results are calculated and compared against population normal values.
However, the most important comparison is not against the population — it is against yourself. There is a wide spread of “normal” at any given age, and a single reading taken in isolation can be misleading. What matters is the trajectory: are your numbers stable, climbing, or sliding downwards over the months?
You are your own benchmark: 12 months of monthly tracking can show whether your strength is being lost or gained.
A modest decline of one or two kilograms on the dynamometer between adjacent months is not concerning — biological measurements always have some scatter. A sustained downward trend over three or four readings is. The earlier such a trend is identified, the easier it is to reverse.
Why we ask patients to track at home
There are two situations where home tracking really earns its keep.
The second is during weight loss, particularly weight loss assisted by GLP-1 medications such as tirzepatide or semaglutide. These drugs are powerful, and they work — but they suppress appetite indiscriminately, which means that without active effort, both fat and muscle can be lost. Our policy at SCVC is that nobody should be losing weight without simultaneously protecting their strength. A baseline grip and sit-to-stand at the start of the programme, repeated monthly, is the simplest possible safeguard. If strength holds steady or improves while weight falls, the programme is doing its job. If strength is sliding, we intervene — typically by increasing dietary protein, adding resistance training, or reviewing the rate of weight loss.
Next steps
If you would like to have your strength formally assessed alongside the rest of your cardiometabolic profile, our cardiometabolic clinic includes both grip and sit-to-stand testing as part of the standard work-up. If you are already a patient and would like a dynamometer recommendation for home use, please ask the team — we can point you to the model we use in clinic.
Download and print
© Medicalspace Ltd · scvc.co.uk
This article is intended for educational purposes and does not constitute individual medical advice. Please consult a qualified clinician regarding your personal cardiovascular health.
REFERENCES (Vancouver)
1. Alcazar J, Losa-Reyna J, Rodriguez-Lopez C, Alfaro-Acha A, Rodriguez-Mañas L, Ara I, García-García FJ, Alegre LM. The sit-to-stand muscle power test: An easy, inexpensive and portable procedure to assess muscle power in older people. Exp Gerontol. 2018;112:38-43. doi: https://doi.org/10.1016/j.exger.2018.08.006
2. Alcazar J, Kamper RS, Aagaard P, Haddock B, Prescott E, Ara I, Suetta C. Relation between leg extension power and 30-s sit-to-stand muscle power in older adults: validation and translation to functional performance. Sci Rep. 2020;10(1):16337. doi: https://doi.org/10.1038/s41598-020-73395-4
3. Alcazar J, Alegre LM, Van Roie E, Magalhães JP, Nielsen BR, González-Gross M, Júdice PB, Casajús JA, Delecluse C, Sardinha LB, Suetta C, Ara I. Relative sit-to-stand power: aging trajectories, functionally relevant cut-off points, and normative data in a large European cohort. J Cachexia Sarcopenia Muscle. 2021;12(4):921-932. doi: https://doi.org/10.1002/jcsm.12737
4. Alcazar J, Aagaard P, Haddock B, Kamper RS, Hansen SK, Prescott E, Ara I, Alegre LM, Frandsen U, Suetta C. Assessment of functional sit-to-stand muscle power: Cross-sectional trajectories across the lifespan. Exp Gerontol. 2021;152:111448. doi: https://doi.org/10.1016/j.exger.2021.111448
5. Gill S, Hely R, Page RS, Hely A, Harrison B, Landers S. Thirty second chair stand test: Test-retest reliability, agreement and minimum detectable change in people with early-stage knee osteoarthritis. Physiother Res Int. 2022;27(3):e1957. doi: https://doi.org/10.1002/pri.1957
6. Kuo YL. The influence of chair seat height on the performance of community-dwelling older adults' 30-second chair stand test. Aging Clin Exp Res. 2013;25(3):305-9. doi: https://doi.org/10.1007/s40520-013-0041-x
7. Sawada S, Ozaki H, Natsume T, Deng P, Yoshihara T, Nakagata T, Osawa T, Ishihara Y, Kitada T, Kimura K, Sato N, Machida S, Naito H. The 30-s chair stand test can be a useful tool for screening sarcopenia in elderly Japanese participants. BMC Musculoskelet Disord. 2021;22(1):639. doi: https://doi.org/10.1186/s12891-021-04524-x
8. Wright AA, Cook CE, Baxter GD, Dockerty JD, Abbott JH. A comparison of 3 methodological approaches to defining major clinically important improvement of 4 performance measures in patients with hip osteoarthritis. J Orthop Sports Phys Ther. 2011;41(5):319-27. doi: https://doi.org/10.2519/jospt.2011.3515
9. Campitelli A, Paulson S, Vincenzo J, Glenn JM, Gills JL, Jones MD, Powers M, Gray M. Sit-to-Stand Power Across the Lifespan: A Cross-Sectional Analysis. J Aging Phys Act. 2021;30(4):678-688. doi: https://doi.org/10.1123/japa.2021-0066
10. Tolk JJ, Janssen RPA, Prinsen CAC, Latijnhouwers DAJM, van der Steen MC, Bierma-Zeinstra SMA, Reijman M. The OARSI core set of performance-based measures for knee osteoarthritis is reliable but not valid and responsive. Knee Surg Sports Traumatol Arthrosc. 2019;27(9):2898-2909. doi: https://doi.org/10.1007/s00167-017-4789-y
11. Leong DP, Teo KK, Rangarajan S, Lopez-Jaramillo P, Avezum A Jr, Orlandini A, Seron P, Ahmed SH, Rosengren A, Kelishadi R, Rahman O, Swaminathan S, Iqbal R, Gupta R, Lear SA, Oguz A, Yusoff K, Zatonska K, Chifamba J, Igumbor E, Mohan V, Anjana RM, Gu H, Li W, Yusuf S. Handgrip strength and its association with prevalent and incident cardiovascular disease: a pooled analysis of international studies. Lancet. 2015;386(9996):266-73. doi: https://doi.org/10.1016/S0140-6736(14)62000-6
12. García-Hermoso A, Cavero-Redondo I, Ramírez-Vélez R, Ruiz JR, Ortega FB, Lee DC, Martínez-Vizcaíno V. Muscular strength as a predictor of all-cause mortality in an apparently healthy population: a systematic review and meta-analysis of data from approximately 2 million men and women. Arch Phys Med Rehabil. 2018;99(10):2100-2113.e5. doi: https://doi.org/10.1016/j.apmr.2018.01.008
13. Celis-Morales CA, Welsh P, Lyall DM, Steell L, Petermann F, Anderson J, Iliodromiti S, Sillars A, Graham N, Mackay DF, Pell JP, Gill JMR, Sattar N, Gray SR. Associations of grip strength with cardiovascular, respiratory, and cancer outcomes and all cause mortality: prospective cohort study of half a million UK Biobank participants. BMJ. 2018;361:k1651. doi: https://doi.org/10.1136/bmj.k1651
14. DeFronzo RA, Tripathy D. Skeletal muscle insulin resistance is the primary defect in type 2 diabetes. Diabetes Care. 2009;32 Suppl 2:S157-63. doi: https://doi.org/10.2337/dc09-S302
15. Cruz-Jentoft AJ, Bahat G, Bauer J, Boirie Y, Bruyère O, Cederholm T, Cooper C, Landi F, Rolland Y, Sayer AA, Schneider SM, Sieber CC, Topinkova E, Vandewoude M, Visser M, Zamboni M. Sarcopenia: revised European consensus on definition and diagnosis. Age Ageing. 2019;48(1):16-31. doi: https://doi.org/10.1093/ageing/afy169
============================================================
RELATED READING
1. 30s Chair Stand Test
