The association between physical activity and risk of mortality is modulated by grip strength and cardiorespiratory fitness: evidence from 498 135 UK-Biobank participants.
It is unclear whether the potential benefits of physical activity differ according to level of cardiorespiratory fitness (CRF) or strength. The aim of this study was to determine whether the association between physical activity and mortality is moderated by CRF and grip strength sufficiently to inform health promotion strategies.



498 135 participants (54.7% women) from the UK Biobank were included (CRF data available in 67 702 participants). Exposure variables were grip strength, CRF, and physical activity. All-cause mortality and cardiovascular disease (CVD) events were the outcomes. 8591 died over median 4.9 years [IQR 4.3–5.5] follow-up. There was a significant interaction between total physical activity and grip strength (P < 0.0001) whereby the higher hazard of mortality associated with lower physical activity was greatest among participants in the lowest tertile for grip strength (hazard ratio, HR:1.11 [95% CI 1.09–1.14]) and lowest among those in the highest grip strength tertile (HR:1.04 [1.01–1.08]). The interaction with CRF did not reach statistical significance but the pattern was similar. The association between physical activity and mortality was larger among those in the lowest tertile of CRF (HR:1.13 [1.02–1.26]) than those in the highest (HR:1.03 [0.91–1.16]). The pattern for CVD events was similar.



These data provide novel evidence that strength, and possibly CRF, moderate the association between physical activity and mortality. The association between physical activity and mortality is strongest in those with the lowest strength (which is easily measured), and the lowest CRF, suggesting that these sub-groups could benefit most from interventions to increase physical activity.
Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow G12 8TA, UK.
Carlos A
CA
Celis-Morales
Institute of Health and Wellbeing, University of Glasgow, Glasgow G12 8RZ, UK.
Donald M
DM
Lyall
Institute of Health and Wellbeing, University of Glasgow, Glasgow G12 8RZ, UK.
Jana
J
Anderson
Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow G12 8TA, UK.|Reproductive and Maternal Medicine, School of Medicine, University of Glasgow, Glasgow G12 8QQ, UK
Stamatina
S
Iliodromiti
Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow G12 8TA, UK.
Yu
Y
Fan
Institute of Health and Wellbeing, University of Glasgow, Glasgow G12 8RZ, UK.
Uduakobong E
UE
Ntuk
Institute of Health and Wellbeing, University of Glasgow, Glasgow G12 8RZ, UK.
Daniel F
DF
Mackay
Institute of Health and Wellbeing, University of Glasgow, Glasgow G12 8RZ, UK.
Jill P
JP
Pell
Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow G12 8TA, UK.
Naveed
N
Sattar
Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow G12 8TA, UK.
Jason M R
JM
Gill
D000328:Adult; D000368:Aged; D018070:Biological Specimen Banks; D000072599:Cardiorespiratory Fitness / Q000502:physiology*; D002318:Cardiovascular Diseases / Q000401:mortality* / Q000503:physiopathology; D015444:Exercise / Q000502:physiology*; D005260:Female; D018737:Hand Strength / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010809:Physical Fitness / Q000502:physiology*; D012307:Risk Factors