Nutrition for the endurance athlete - Part II - During

Achieving peak performance in an endurance event requires careful attention to nutrition. If you start your event by eating a big breakfast (and lunch if the event is in the afternoon) and drinking lots of fluids, your body will be well prepared for the work ahead. Once the event is underway, you still need to keep the body’s glycogen stores topped up.

Carbohydrate

An intake of between 30-60 grams of carbohydrate per hour is recommended during exercise lasting more than one hour. This is the maximum amount of carbohydrate that can be taken up by the muscles from your bloodstream during aerobic exercise.

It is important to being consuming carbohydrate before fatigue sets in. It takes at least 30 minutes for the carbohydrate to be absorbed into the bloodstream, therefore the best strategy is to begin consuming carbohydrate within the first 30 minutes after the start of your workout.

Which foods/drinks?

The carbohydrate you consume should be easily digested and absorbed so that it is available to raise your blood sugar and reach your working muscles rapidly. Thus, high or moderate GI carbohydrates are usually the best choices. You may choose solid or liquid carbohydrate, but if you choose solid, be sure and drink water with it. Many athletes find liquids in the form of sports drinks more convenient. The options for sports drinks are many: you may opt for commercial brands (check ingredients carefully), make your own formulation, or use squash and water. If you prefer food as well as drinks, the options include: energy or sports nutrition bars, sports gels, bananas, raisins, fruit bars or home-made cookies or bars. Take a drink of water at the same time.

Protein

Consuming a drink containing protein as well as carbohydrate during exercise may improve endurance better than carbohydrate alone. It may also minimize protein breakdown following exercise and improve recovery. Drinking a carbohydrate-protein drink every twenty minutes during exercise may also improve endurance, in other words it could increase the length of time an athlete can continue working without a decrease in speed. Experiment with the timing to see what works best for you. 

The optimum ratio of carbohydrate to protein is approximately 4:1. (Roughly 80 grams of carb to 20 grams of protein.)  The best way to take in this amount of protein while exercising is to add whey protein to your sports drink.

Food/drink               Portion size providing 30 g carbohydrate

Isotonic sports drink         500 ml

Glucose polymer drink     250 mL

Energy bar                        ½ to 1 bar

Diluted fruit juice             500 mL

Raisins                              1 handful (40g)

Cereal bar                         1 bar

Energy gel                        1 sachet

Bananas                            1-2 bananas

Clif bloks                          7 blocks (I package +)

Which items you choose will depend on your sport and your personal preference and tolerance for taking in food while working hard. During a race, the gooey or liquid options would likely prove most practical; during training, you may benefit more from the solid food options. But never try something new on the day of the big race! Know what works for your individual body in advance.

Refuel at least every hour during an endurance event. While consuming carbohydrate during exercise can delay fatigue by as much as 45 minutes, no amount or special type of fuel will allow you to keep exercising hard indefinitely. Eventually factors other than fuel will cause fatigue. In my next post, I will discuss post-exercise nutrition for maximal recovery.