What the doctor ordered

Professor Sanjay Sharma, the medical director of the Vitality London 10,000 and the Virgin Money London Marathon, offers the following medical tips ahead of Race Day.

Enjoy your training in the last few weeks before the race, but don't overdo it - we want to see you safe and sound as your cross the Finish Line.

Fit to compete

Running is good for the heart, however, if you have a family history of heart disease or sudden death, or have a high risk from high cholesterol or high blood pressure but PARTICULARLY if you have symptoms of heart disease – ie chest pain or discomfort on exertion, sudden shortness of breath or rapid palpitations – see your GP who can arrange for you to have a proper cardiac assessment. Such an assessment may not be instantly available, but continuing to run with these symptoms may shorten your running career catastrophically!


Muscular aches and pains occur most commonly after an increase in training. Training should be increased gradually so that you do not suffer prolonged exhaustion. Separate days of heavy mileage with one or two days of lighter training, or rest days, so that your body can refuel your muscles with muscle glycogen. To reduce injury risk, vary your training runs, the running surface (parkland or hills), the pace and distance and do not always use the same pair of shoes. Always face oncoming traffic and BE VISIBLE – at night wear bright or reflective clothing.

Illness and training

If you have flu, a feverish cold or a tummy bug, do not train until you have fully recovered. Then start gently and build up gradually. Do not attempt to catch up on lost mileage after illness or injury — this may cause further damage or illness. If you have flu it can take as much as a month to recover so consider whether you should run this time.


Fluid lost in sweat must be replaced otherwise your body becomes dehydrated (short of water) and less efficient. Alcoholic drinks, tea and coffee are dehydrating.

Take plenty of non-alcoholic drinks, especially when training in hot weather. Drink enough to keep your urine a pale straw colour.

Drink plenty of liquids after training, especially long runs, and practise drinking during longer training runs. Drinking on the run needs practise.

Drink plenty of fluids but preferably no alcohol in the two days before the race. DO NOT drink excessively before the race, during the race or after the race as you may get hyponatraemia, a condition that occurs when sodium levels in your blood are too low.

Drinking on the day

Start the race well hydrated and, if you are not already bursting, drink half a pint (250ml) of water or sports drink in the half hour before the start.

Don’t be greedy at drinks stations and take extra bottles of drinking water to pour over yourself as you may deprive slower runners of much needed drinks. If it is hot, more water will be provided.

Drinking safely

Drinking too little can lead to problems, as you need to replace some of the fluid you lose as sweat. Drinking too much can be very dangerous and lead to hyponatraemia (water intoxication), fits and even death.

Drink when you feel the need and DO NOT gulp large volumes of fluids before, during or after the race. Your needs vary with your build, your speed and above all the weather.

Faster runners on a warm day may need as much as a litre of fluid per hour (two pints). Slower runners should need less particularly on a cool day and should not drink more than 500ml per hour.

After the finish DO NOT drink large amounts of water. You can only rehydrate (replace lost fluids) gradually over the next 24 to 48 hours. Eat some salty food as well as spacing your drinks. This way you will not get hyponatraemia and will still replace the water, salt and glycogen lost in running the 10km distance.


Large doses of supplementary vitamins and minerals (such as iron) are not essential and produce no benefit if you are on a good mixed diet, but additional vitamin C in small doses is reasonable when fresh fruit and vegetables are in short supply.

Training (with adequate rest) helps you to sustain a high level of muscle glycogen if you eat enough carbohydrate. If you can, eat within two hours of your long runs. This helps replace the muscle glycogen quickly and speeds recovery.

Do not change your normal diet drastically in the last week before a long-distance race, but eat less protein (meat) and eat more carbohydrate (pasta, bread, potatoes, cereals, rice and sweet things). Unless you reduce your protein intake you will not eat enough carbohydrate.

Not all runners are helped by first depleting carbohydrate with a long run and low carb diet and then loading – this can make your muscles very heavy.

Still fit?

Do not run if you feel unwell or have just been unwell, even if you are raising money for charity. Most medical emergencies occur in people who have been unwell but do not wish to miss the event.

If you feel feverish, have been vomiting, have had severe diarrhoea, or any chest pains, or otherwise feel unwell, it is unfair to you, your family and your sponsoring charity to risk serious illness and become a medical emergency. You are unlikely to do yourself justice. There are many other races.

On the day

Wear appropriate clothes for the weather. On a cold, wet day you can become very cold if you reduce your running pace or walk. A hat and gloves will prevent heat loss and are easily carried.

If it is hot, wear loose mesh clothing, start slowly and, if possible, run in the shade. Use shoes you know from experience will not give you blisters.

After the race

At the finish, do not stand about getting cold. Keep walking, especially if you feel dizzy, and drink to replace lost liquid.

Collect your kitbag and change into warm, dry clothing. Keep on drinking slowly and have something to eat.

Some runners feel faint more than half an hour after finishing a race, often because they have taken insufficient fluid and/or not eaten anything. Again, DO NOT DRINK EXCESSIVELY.