Surgery is a physiological event, and you can train for it. Patients who arrive at an operation fitter, better nourished, not smoking, and not anaemic have fewer complications, shorter hospital stays and faster recoveries. The evidence for this is now strong enough that in many specialist centres it is a formal part of the pathway. It is called prehabilitation, and even four weeks of it makes a measurable difference.
I tell patients that surgery is the most demanding physical event most of them will ever go through, and that they would not run a marathon without preparing. The comparison is not rhetorical. Major abdominal surgery imposes a metabolic load comparable to sustained heavy exercise, except that it is imposed on you whether you are ready or not.
The point of this article is that the waiting period is not dead time.
The four pillars
Prehabilitation has four components. Each of them has evidence behind it, and they work best together.
1. Exercise
The strongest predictor of how well you tolerate major surgery is your cardiorespiratory fitness. It is measured formally by cardiopulmonary exercise testing (CPET), and it predicts complications better than most things in your medical history.
The good news is that fitness responds quickly. Meaningful improvement is achievable in four to six weeks.
What to do:
- Aerobic work: aim for 20 to 30 minutes, most days. Brisk walking, cycling, swimming. Hard enough that you could speak but not sing.
- Add intervals if you are able. Short bursts of harder effort followed by recovery produce faster gains in fitness than steady-state work alone.
- Resistance training, twice a week. Muscle mass is not vanity. It is the protein reserve your body draws on to heal a wound, and patients with low muscle mass (sarcopenia) do measurably worse after major surgery, including liver surgery.
- Breathing exercises. Inspiratory muscle training reduces the risk of chest complications after abdominal surgery, which are among the commonest things that go wrong.
If you can climb two flights of stairs without stopping, you have reasonable functional reserve. If you cannot, that is worth knowing about and worth working on.
2. Nutrition
Not a diet. The goal is to arrive well-nourished, with muscle preserved.
Protein is the priority. Aim for 1.2 to 1.5g per kg of body weight per day, more than most people eat. For an 80kg person that is around 100 to 120g of protein a day. Wound healing, immune function and muscle preservation all depend on it. Spread it across meals rather than loading it into one.
Do not crash diet before surgery. Rapid weight loss strips muscle along with fat and leaves you weaker at exactly the wrong moment.
One important exception, specific to liver surgery. If you have a fatty liver and are undergoing a liver resection, you may be asked to follow a low-calorie diet for two to four weeks beforehand to reduce the fat and size of the liver. This is deliberate, it makes the operation safer and technically easier, and it is one of the few situations where I will ask a patient to restrict calories before an operation. It is done under supervision.
Check for anaemia and treat it. This is one of the most impactful and most neglected steps. Preoperative anaemia is common, it independently increases your risk of complications, and it increases the likelihood you will need a blood transfusion. It is usually correctable with iron, and intravenous iron works within a few weeks. Ask whether your haemoglobin and iron studies have been checked. If they have not, ask for them.
Carbohydrate loading before the operation. Modern enhanced recovery protocols involve a carbohydrate drink a few hours before surgery rather than a long fast. It reduces the stress response and improves recovery. Follow your unit's specific instructions, but be aware that the era of nil by mouth from midnight is largely over.
3. Smoking and alcohol
Smoking is the single most modifiable risk factor you have.
Smokers have significantly more wound infections, more chest complications, poorer healing and, in hernia surgery specifically, a higher rate of recurrence. The mechanism is direct: nicotine constricts the small blood vessels that supply the healing tissue, and carbon monoxide reduces the oxygen the blood can carry.
Stopping four to six weeks before surgery produces a substantial reduction in complications. Even stopping shortly before helps, because carbon monoxide clears from the blood within a day or two.
There is an old and persistent myth that stopping just before surgery makes things worse. It does not. Stop.
Alcohol. Heavy drinkers have higher rates of infection, bleeding and cardiopulmonary complications. Around four weeks of abstinence before surgery measurably reduces this. If you drink heavily and are dependent, tell the anaesthetist. Unplanned alcohol withdrawal on a surgical ward is dangerous and entirely preventable if it is anticipated.
4. Psychological preparation
Take this seriously. Anxiety before surgery is associated with more pain afterwards, higher analgesic requirements and a slower recovery. That is not a soft finding. It is measurable.
What helps:
- Understanding what will happen. Patients who know the plan are less frightened. Ask until you understand.
- Knowing the recovery timeline so that normal post-operative discomfort does not feel like a disaster.
- Sleep. Do not go into major surgery exhausted.
- Having a plan for home. Who is helping. What is in the fridge. Where the painkillers are. It sounds trivial and it is not.
The medical optimisation you should ask about
Separately from what you do, there are things your team should be checking.
- Haemoglobin and iron studies. Treat anaemia.
- HbA1c. Poor diabetic control impairs wound healing and increases infection.
- Blood pressure.
- Medication review. Blood thinners, some diabetes medications and some supplements need specific handling before surgery. Bring a full list, including anything you have bought over the counter.
- Dental health, for major surgery. A source of infection you have forgotten about.
Does it actually work?
Yes, and the evidence is now reasonably robust. Structured prehabilitation programmes before major abdominal surgery are associated with fewer post-operative complications and shorter hospital stays. The gains are largest in the patients who start from the lowest baseline, which is to say that the people who feel least able to do it are the people it helps most.
Four weeks is enough to change your fitness. Six is better. If you have been given a date, start now.
What I would say to a patient with an operation in six weeks
Walk every day, and walk faster than is comfortable. Lift something twice a week. Eat protein at every meal. Stop smoking today, not the night before. Cut the alcohol. Get your haemoglobin checked. Sleep.
None of this is exotic and none of it needs to be bought. It is simply the difference between arriving at an operation ready and arriving at it hoping.
Frequently asked questions
How long before surgery should I start prehabilitation?
Four weeks is enough to produce measurable benefit. Six to eight weeks is better. If your surgery is sooner, do what you can, and prioritise stopping smoking and correcting anaemia.
Should I lose weight before surgery?
Gradual weight loss helps for many operations and can be essential before large hernia repairs. Do not crash diet, as rapid loss strips muscle. The exception is a supervised low-calorie diet before liver resection in a fatty liver, which is done deliberately.
Does stopping smoking just before surgery make things worse?
No. This is a myth. Stopping is beneficial at any point, and stopping four to six weeks beforehand produces a substantial reduction in complications.
Can I exercise if I am in pain or unwell?
Do what you can. Walking counts. Breathing exercises count. Something is very much better than nothing, and the patients who benefit most from prehabilitation are the least fit ones.
Is prehabilitation available on the NHS?
It is increasingly built into cancer surgery pathways, though availability varies. Even where no formal programme exists, everything in this article is something you can do yourself.
About the author
Mr Shahid Farid is a Consultant Hepatobiliary and Liver Transplant Surgeon at St James's University Hospital, Leeds. He performs major liver resection, complex biliary surgery and complex hernia repair, and sees private patients at Spire Leeds, Spire Methley Park and Nuffield Health Leeds.
Related: Liver Resection Explained · Life After Hernia Repair
References
- Royal College of Anaesthetists and Macmillan Cancer Support. Prehabilitation for people with cancer, 2020.
- Centre for Perioperative Care (CPOC). Impact of perioperative care on healthcare resource use.
- Barberan-Garcia A et al. Personalised prehabilitation in high-risk patients undergoing elective major abdominal surgery. Annals of Surgery, 2018.
- Møller AM et al. Effect of preoperative smoking intervention on postoperative complications. The Lancet, 2002.
- Enhanced Recovery After Surgery (ERAS) Society guidelines for liver surgery.
This article is for general information and does not replace a personal consultation. Any decision about your care should be made with your own clinician, based on your individual circumstances.