Grip Strength, Fitness, and Mortality Risk in MASLD

A weaker handgrip may flag a higher long-term risk of death in people with metabolic dysfunction-associated steatotic liver disease (MASLD). It does not prove that weak muscles cause death. It does suggest that a simple measure of physical reserve captures information that diagnoses and lab values may miss.

That distinction matters. A grip dynamometer cannot diagnose liver fibrosis, predict an individual lifespan, or substitute for medical care. But in a large UK Biobank analysis, lower grip strength tracked with higher all-cause, cardiovascular, cancer, liver-related, and diabetes-related mortality over more than a decade. Exercise testing tells a related, more complicated story: cardiorespiratory fitness matters, but so does how blood pressure and heart rate respond under load.

Functional reserve is a prognostic readout: it identifies higher-risk people. The available evidence does not show that increasing a test score, by itself, reduces mortality.

A handgrip test predicted mortality risk in MASLD

In a 2026 UK Biobank cohort study of grip strength in MASLD, Li et al. followed 92,263 participants for a median of 13.3 years. During follow-up, 9,923 participants died. Researchers grouped men and women into sex-specific grip-strength tertiles and adjusted their analyses for potential confounders.

Compared with the highest-strength tertile, the lowest-strength tertile had a 36% higher relative risk of all-cause mortality (hazard ratio [HR] 1.36, 95% confidence interval [CI] 1.28-1.43). The associations also appeared for cardiovascular mortality (HR 1.54, 95% CI 1.28-1.87), extrahepatic cancer mortality (HR 1.25, 95% CI 1.14-1.38), liver-related mortality (HR 1.76, 95% CI 1.08-2.87), and diabetes-related mortality (HR 2.40, 95% CI 1.36-4.23).

The spline analyses showed a linear inverse relationship rather than a clean biological cliff where one grip score suddenly becomes dangerous. Lower strength tracked with higher risk across the range. That makes grip strength more useful as a graded signal than as a pass-fail biohacking badge.

The all-cause estimate is the most precise result. Liver-related and diabetes-related mortality had wider confidence intervals, consistent with less precise estimates for those less common outcomes. Age also changed the cardiovascular interpretation: among participants aged 60 or older, higher grip strength was associated with lower cardiovascular mortality (HR 0.86, 95% CI 0.82-0.91); in those younger than 60, the estimate was weaker and crossed the null (HR 0.96, 95% CI 0.88-1.04).

Strength is static; exercise testing shows reserve under stress

Grip strength is quick, cheap, and largely static. Cardiorespiratory fitness (CRF) measures the body's ability to deliver and use oxygen during exertion. It also has a substantial mortality literature. A 2025 systematic review and meta-analysis combined 42 studies from 35 cohorts, representing 3.8 million observations. Both objectively measured and estimated CRF predicted all-cause and cardiovascular mortality across heterogeneous adult populations.

Individual cohorts point in the same general direction. In the CARDIA study of 4,808 adults, each additional minute of baseline CRF was associated with lower all-cause mortality in women (HR 0.73, 95% CI 0.64-0.82) and men (HR 0.87, 95% CI 0.80-0.96), as well as fewer fatal or nonfatal cardiovascular events overall (HR 0.89, 95% CI 0.82-0.96).

Other large cohorts found that estimated CRF also carries prognostic information. A midlife cohort study linked lower estimated CRF with later cardiometabolic outcomes and mortality, while the NIH-AARP study linked non-exercise estimated CRF with all-cause, cardiovascular, and cancer mortality. These estimates can scale assessment when treadmill testing is impractical, though an estimate assembled from age, body size, activity, smoking, and resting heart rate is not the same measurement as directly measured oxygen uptake.

Fitness did not predict outcomes only in healthy populations. In a 2026 study of 1,306 stroke survivors, higher estimated CRF was associated with lower long-term mortality risk. The study followed participants for a median of 78 months, during which 566 participants died, including 225 cardiovascular deaths.

Fitness does not erase an abnormal exercise blood-pressure response

Dynamic exercise testing adds another layer. It records performance capacity, but it can also reveal how the cardiovascular system responds to stress. In a prospective Finnish cohort of 1,481 men with 231 cardiovascular deaths, Jae et al. found independent associations of exercise systolic blood pressure and CRF with cardiovascular mortality. An exercise systolic blood pressure of at least 210 mm Hg was associated with higher cardiovascular mortality risk (HR 1.43), while the highest CRF tertile was associated with lower risk (HR 0.64).

The joint analysis prevents a comforting but inaccurate conclusion: high fitness did not cancel the risk associated with elevated exercise blood pressure. Participants who were fit but had elevated exercise systolic blood pressure still had higher cardiovascular mortality than the normal-blood-pressure, fit reference group (HR 1.95, 95% CI 1.20-3.18).

A related Finnish study of 1,634 men aged 42 to 61 used cardiopulmonary exercise testing to calculate a hemodynamic gain index from resting and peak heart rate and systolic blood pressure. Over a median 28.7 years, 439 cardiovascular deaths occurred. In the hemodynamic gain index study, each one-unit higher index was associated with lower cardiovascular mortality (HR 0.80, 95% CI 0.71-0.89). This does not make the index a magic number; it shows that circulatory adaptation during exercise may add prognostic information beyond a single measure of fitness.

Why the evidence does not prove a treatment effect

These are observational studies. Lower grip strength or lower CRF may partly reflect frailty, insulin resistance, inflammation, undiagnosed disease, existing cardiovascular damage, or illness severity that already raises mortality risk. The associations remained after statistical adjustment in several studies, but adjustment cannot remove every source of bias or reverse causation.

Clinical transportability also has limits. UK Biobank participants tend to be healthier and less diverse than the population at large. Several exercise-hemodynamic analyses came from Finnish cohorts of men, which limits confidence about identical effects in women and more diverse populations. The MASLD study abstract also does not report the exact grip-tertile cut points, full covariate list, MASLD definition, or formal measures of improvement beyond established risk models.

Even the long-term CRF literature contains restraint. In CARDIA, retaining CRF through year 20 had a borderline association with fatal or nonfatal cardiovascular disease (HR 0.89, 95% CI 0.78-1.00), and researchers found no race or sex interaction. A lower score can identify risk without producing the same predictive strength in every age group, demographic group, or endpoint.

Exercise remains valuable for many established health reasons, but it would overreach to say that raising grip strength or CRF necessarily lowers mortality in MASLD. A 2026 Cochrane review of high-intensity interval training in healthy sedentary adults addressed cardiometabolic risk factors, not whether changing these markers in people with MASLD changes survival.

What to do with a functional-reserve signal

For people with MASLD or cardiometabolic risk, low grip strength deserves attention as a low-cost marker of vulnerability. It can prompt a fuller look at physical activity, nutrition, muscle loss, frailty, metabolic health, liver disease severity, cardiovascular risk, and symptoms that merit clinical evaluation. A supervised exercise test can provide a richer picture when it is clinically appropriate, especially because fitness and exercise blood-pressure response can point in different directions.

The evidence supports a narrow conclusion: lower strength and poorer exercise reserve consistently identify groups with higher mortality or cardiovascular risk. That makes functional capacity worth measuring. It does not turn a handgrip score, VO₂max estimate, or exercise blood-pressure reading into a diagnosis-or a guarantee of what comes next.