The half marathon is the step up distance for many runners and at 13.1 miles there is no doubt there is something charismatic about the adventure of pre-training, the event itself and the ensuing recovery period. No matter what your level or experience, preparation is definitely the key ingredient.
Careful thought about training and nutrition is imperative and there is such a fine line between achieving your time and not. The metabolic demand on the body over this distance is high. Correct fuelling is essential and if done wrongly the last few miles may be painful!
The main nutrients used to power runners over the distance are carbohydrate (CHO) and fat, with the relative contribution of each depending upon factors such as training status and pace. Carbohydrate is required not only to fuel running, but also to restore muscle and liver glycogen levels during recovery.
The week before
Adequate fuelling the week before the race is vital, as poorly fuelled muscles cause needless fatigue. The aim of pre-race nutrition is to optimise fuel stores (muscle glycogen) and hydration status. Reducing training load while consuming your normal carbohydrate intake for 2-3 days before the race will ensure muscle glycogen levels will be replenished ready for racing. Putting on some weight in this phase is common. Every gram of glycogen stored, holds 3 grams of water, however, don’t be too concerned, this stored fuel will help power you through your race.
Your carb intake and reduction in exercise the week leading up to the event can leave you feeling full and sluggish, so eating little and often will help to avoid this. Trying new foods on the day’s leading up to a race is not advisable and could lead to disastrous results on the day. On the morning of your half marathon, a light and carb rich breakfast such as cereal and toast or pancakes with jam will top-up energy stores and ensure enough time is left for digestion.
An hour before the race topping up with a high carb snack will ensure energy stores are maximized. If gut tolerance is an issue, try an energy gel or sports drink in addition to 500ml of fluid to ensure maximum hydration at the start.
During the race
Staying hydrated is vital. Your fluid needs will vary depending on how warm the weather is on race day and how much you sweat. Take fluids regularly, especially if you are going to be out for longer than 90 minutes. Listen to your body and drink to thirst. There are 5 water stations throughout the course.
Intake of carbohydrate is also advisable. As a general rule, 30-60g/hr of carbohydrate should meet race demands (one energy gel = 27g carbohydrate and a 500ml sports drink = 32g carbohydrate). For sub 1-15 runners, one gel around the 45-minute mark, for most, would be enough. The longer you are out, the more carbohydrate you will need. Studies have shown that ingestion of even small amounts of carbs can improve performance (even a mouth rinse of sports drink!), so if you can’t manage much, even a small amount will help. Solids and liquid carbohydrate will provide the same in terms of fuel, with sports drinks and some gels having the added advantage of replacing lost electrolytes lost through sweating. Energy gels or bars can be used, but may be less tolerated by the gut. Remember, if you are reading this thinking “I have never run whilst taking on carbs” the golden rule at this point is - “never do anything new on race day.”
After the race
After you’ve completed the distance your energy stores will be empty. It is common to lose your appetite for the first few hours, but try and eat something within 30 minutes of finishing. Muscle glycogen is slow to replenish, so follow this up as soon as you can with a carbohydrate and protein-rich meal to help start the recovery process. Continuing to hydrate is important; so drink water regularly for a few hours post-race. The week following your gargantuan efforts, focus on a balanced diet to continue the recovery process.
The most important thing to remember is, we are all individuals and although there is generic advice, one plan does not suit all. Experiment during training to see what suits you and once you have a race day plan, you can stand at the start line with confidence.
The week before, reduce training load and follow a diet high in carbs 2-3 days before you race (high carb foods include, bread, pasta, rice, potatoes an plenty of fruit and veg). Don’t over do it though, your carb intake is probably quite high already to support you through your training.
If you suffer from GI problems when you run, you may want to reduce your fibre intake a few days before (limiting fruit and vegetables and opting for white bread, pasta etc.)
On the day, have a light breakfast that is high in carbs leaving plenty of time for digestion
Start hydrating as soon as you wake up (at least 500ml before you run) and during the race aim for 150ml every 15 min (though if you have not practiced this in training be lead by your thirst)
Take on carbs during the race (30-60g/hr) Sports drinks, bars and gels provide the same in terms of fuel but sports drinks and some gels replace electrolytes lost in sweat. Again, if you have not practiced this in training it is advised to stick to what you are used to.
Post-race the focus on nutrition doesn’t stop. Eat a snack within 30 min of finishing and make sure this is followed up by a carb and protein rich balanced meal as soon as you can tolerate it
Keep hydrating and watch the colour of you wee...clear means well hydrated!