During this covid-19 pandemic, public health recommendations are to minimise infection spread, with country-specific recommendations. Typically these focus on self isolation, reduced social contact, and scrupulous hand hygiene. Evidence to date indicates that the groups most of risk of serious sequelae of covid-19 have features that cannot be changed, such as advanced age and pre-existing illnesses, the latter typically hypertension, chronic respiratory disease, and diabetes.
We believe that what is lacking from the current advice, and the behavioural changes considered for the public, is the possibility to harness pre-exposure conditioning as a positive way to help our fellow human beings prepare physically and psychologically for infection and its sequelae.  Prior to anticipated medical stresses such as elective surgery or pregnancy, standard advice is to optimise physical fitness.  This is particularly pertinent since the covid-19 quarantine-like measures may appear to be favouring a more sedentary approach with individuals waiting indoors, hoping to avoid the perceived inevitable infection. 
Meta-analyses indicate that all types of respiratory muscle training improve exercise performance, with benefits greater in less fit individuals.  Applied specifically to medical stresses, in randomised controlled trials, exercise in preparation for surgery is associated with a lower postoperative complication rate and earlier restoration of functional status. [5,6] In other conditions where cardiovascular function is impaired, for example after pregnancy affected by pre-eclampsia, it is possible through exercise to increase intravascular volume and improve cardiovascular function.  Even a 4 week programme of moderate intensity exercise can increase cardio-respiratory fitness. 
So while ensuring appropriate quarantine and public health advice is being followed, we suggest Public Health advice encourages all to try to do a little more activity, every day, to improve their physical preparation in case they are infected with the coronavirus and are unlucky enough to be more severely affected.  This advice is particularly pertinent to those that are at risk whether through age or co-mordibities. This is first to prevent any physical deterioration due to isolation, and secondly, to optimize cardio-respiratory fitness to reduce the risk of complications.
We therefore suggest:
- Home based exercises, following NHS advice on physical activity guidelines (e.g. for older adults ) should be included as an essential part of the self isolation/ protection guidelines. Walking extra steps around the same rooms on the flat, or using stairs – even one step up and down- is better than sitting or lying most of the day. Particularly so if such a routine is performed every few hours. Furthermore, where it is possible to take walks while avoiding unnecessary social contact, this should be encouraged. Encouraging the elderly to sit upright and to take deep breaths will expand lung volume and reduce the risk of atelectasis.
- These exercises are continued daily, but stopped if a temperature develops, if the individual becomes unwell, or if covid-19 is diagnosed.
The rationale can be explained to patients through public information sites, which explain why cardiac work would be increased due to the illness, and why benefits accrued from previous training should be beneficial. 
We believe that pre-exposure conditioning may represent an important and effective individual intervention with a potential public health benefit. Such a strategy would also empower a largely passive population and to some extent counter the feeling of inevitability that surrounds the covid-19 and possibly future epidemics of this sort.
Claire L. Shovlin: Professor of Practice (Clinical and Molecular Medicine), Imperial College London, and Hon Consultant in Respiratory Medicine, Imperial College Healthcare NHS Trust
Krishna Moorthy: Senior Lecturer in Upper Gastrointestinal Surgery, Imperial College London, and Hon Consultant Surgeon, Imperial College Healthcare NHS Trust
Christoph Lees: Professor of Obstetrics, Imperial College London, and Hon Consultant in Obstetrics and Fetal Maternal Medicine, Imperial College Healthcare NHS Trust
Competing interests: None declared.
 Wynter-Blyth V, Moorthy K. Prehabilitation: preparing patients for surgery. BMJ. 2017 Aug 8;358:j3702
 Illi SK, Held U, Frank I, Spengler CM.Effect of respiratory muscle training on exercise performance in healthy individuals: a systematic review and meta-analysis. Sports Med. 2012 Aug 1;42(8):707-24.
 Barberan-Garcia A, Ubré M, Roca J, Lacy AM, Burgos F, Risco R, Momblán D, Balust J, Blanco I, Martínez-Pallí G. Personalised Prehabilitation in High-risk Patients Undergoing Elective Major Abdominal Surgery: A Randomized Blinded Controlled Trial. Ann Surg. 2018 Jan;267(1):50-56.
 Gillis C, Li C, Lee L, Awasthi R, Augustin B, Gamsa A, Liberman AS, Stein B, Charlebois P, Feldman LS, Carli F. Prehabilitation versus rehabilitation: a randomized control trial in patients undergoing colorectal resection for cancer. Anesthesiology 2014;358:937-47.
 Spaan J, Peeters L, Spaanderman M, Brown M. Cardiovascular risk management after a hypertensive disorder of pregnancy. Hypertension. 2012 Dec;60(6):1368-73.
 Gillis C, Li C, Lee L, Awasthi R, Augustin B, Gamsa A, Liberman AS, Stein B, Charlebois P, Feldman LS, Carli F. Prehabilitation versus rehabilitation: a randomized control trial in patients undergoing colorectal resection for cancer. Anesthesiology. 2014 Nov;121(5):937-47.
CLS devised the manuscript, wrote the first draft and contributed to revisions. KM made intellectual contributions and revised the manuscript. CL made intellectual contributions and revised the manuscript. All authors approved the final version
Data Sharing Statement
There are no data to share
The authors acknowledge support from the NIHR Imperial Biomedical Research Centre
Patient and Public Involvement
Patient queries led to the initial decision to generate an opinion piece. The authors intend to involve patient self help groups in dissemination of the article once published.