Mitochondrial respiratory chain function and content are preserved in the skeletal muscle of active very old men and women.

"Conflicts of interest The authors have no conflicts of interest to declare."

"Funding This study was funded by a Medical Research Council Confidence in Concept grant to AAS. The research was supported by the NIHR Newcastle Biomedical Research Centre awarded to the Newcastle upon Tyne Hospitals NHS Foundation Trust and Newcastle University, Wellcome Centre for Mitochondrial Research (203105/Z/16/Z), the Medical Research Council (MRC) Centre for Translational Research in Neuromuscular Disease, Newcastle University Centre for Ageing and Vitality (supported by the Biotechnology and Biological Sciences Research Council and MRC) and Mitochondrial Disease Patient Cohort (UK) (G0800674). The views expressed are those of the author(s) and not necessarily those of the NHS, the NIHR or the Department of Health. The following is the supplementary data related to this article.Supplementary Table 1Details of controls.Five younger patients gave written consent for muscle biopsy at the time of orthopaedic surgery.Supplementary Table 1"