Endurance training is defined by rhythmically performing relatively low intensity contractions for a relatively long period of time. This can be included across many different sporting disciplines such as marathon training, triathlon training, swimming, cycling and even team sports. From a physiological standpoint, endurance training results from enhanced blood flow to the relevant muscles, enhanced ability to burn fats and carbohydrates for fuel, and an improved ability to extract and utilise oxygen during exercise. Now from a nutrition standpoint these adaptations can be maximised or influenced, and from applied experience there are five key nutrition areas to consider:
For a long time, we have known the benefits of carbohydrate intake on endurance exercise performance, and for events or training sessions lasting longer than 45-60 minutes ingesting some form of carbohydrate during can benefit performance. However, the importance of training with adequate carbohydrate intake in relation to supporting training quality, immune function and mood state should also be stated. In 2004, a study found that in a group of runners who consumed 8.5 g carbohydrate∙kg-1∙day-1 vs. 5.4 g carbohydrate∙kg-1∙day-1 experienced better training performance and state of mood.
Therefore, from a practical perspective it can be a good idea to increase your carbohydrate intake during periods of intensified training along with on the days preceding a longer training session. This can be done by eating a variety of fruits, vegetables, rice, pasta, breads or by adding supplements such as these oats, or a faster carb like Vitargo®, to your post-training drink . Furthermore, it can also be a good idea to learn the carbohydrate content differences of foods and paying attention to the glycemic index of foods.
Finally, it should be acknowledged that there is growing evidence that is demonstrating benefits of training with low carbohydrate availability, such as fasted training or training whilst not ingesting any carbohydrate during the session. Mechanistically, it appears that the low carbohydrate available to the muscle, upregulates the enzymes within the metabolic pathway for burning fat as well enhancing adaptions at a molecular level in response to the training sessions. In short, the capacity for the muscle to burn fat for energy appears to be amplified as a response to the low carbohydrate levels. With this in mind we should look at carbohydrates much more than just an energy fuel and instead look at them as a regulator for training adaptations.
A small degree of dehydration can result in decreased exercise performance (2% drop in bodyweight). However, it is difficult to administer general drinking plans due to such large variances in sweat responses between individuals as well as between training sessions. It can be good practice to familiarise yourself with your own sweat rates during training sessions of different intensities, durations and in different environments or temperatures. This can be simply done by weighing yourself pre & post training and replacing any weight loss with 150% fluid. For example, someone who loses 1 kg should drink 1.5 litres of fluid.
In addition, it is also a good idea to monitor hydration via urine colour and ensure that before undertaking training your urine colour is a clear to pale yellow. Pee charts are ever-present around team sports training facilities! Finally, it may be individual preference to add electrolytes to fluids during sessions such as sodium to combat muscle cramps and although the evidence to suggest this helps is limited, I have found this to be beneficial in preventing muscle cramps during my own training, as well when working with team sport players and other clients.
Protein is often thought of as a nutrient just for the bodybuilders. However, protein plays an important role in helping the muscle recover from a training session by allowing it to be repaired and rebuilt ready for the next bout. Furthermore, protein ingestion after a session responds to the training stimulus. In other words, if you do endurance training then the ingested protein will help maximize adaptations of the muscle by influencing changes in the muscle characteristics which will mean it is better equipped and built ready for the next endurance training session or event. It is suggested that endurance athletes should aim for 1.2-1.6 g protein ∙ body mass-1∙day-1 and what is more, you should try and eat protein regularly throughout the day, particularly if you are training multiple times per day, in order to maximise training adaptations.
Protein should be eaten from different food sources such as dairy products, fish, meats and legumes. In addition to these and a practical and convenient source of protein, try INFORMED WHEY® post-training.
Micronutrients refer to the vitamins and minerals that are found within the diet and you should be able to obtain all of these by eating a well-balanced diet and by tapping into all food groups. For example, iron intake is an important consideration for endurance athletes, given the role iron plays in muscle function and exercise work capacity. Athletes who have a low iron status should consider increasing foods rich in heme iron at least four times a week (liver or red meat), eat iron fortified foods (breakfast cereals) and avoid caffeine at meals. However, some micronutrients may need supplementing or extra attention within the diet.
Recently the interest in Vitamin D has exploded and many studies have reported a relationship between Vitamin D status and injury prevention, rehabilitation, improved neuromuscular function, increased type II muscle fibre size and reduced inflammation, decreased risk of stress fracture and acute respiratory illness. Therefore, attention should be given to an athlete’s intake of Vitamin D via the diet (tuna, sardines, eggs and fortified cereals and milk) but considering the main source of Vitamin D is sunlight, it may be a good idea to supplement with Vitamin D particularly through the winter months or if you train mostly indoors or in the evening.
Gastrointestinal (GI) problems are common in long endurance events such as marathon running, triathlons and cycle tours. It is known that exercise of high intensities does lead to a redistribution of blood flow away from the gut, which can lead to a development of GI issues. On top of this, race or training nutrition can exaggerate GI symptoms and these symptoms may include; a stitch, flatulence, nausea, vomiting, heartburn and stomach cramps. GI distress varies between individuals but general practical advice to follow on the training day or in the days leading up can be given to try and reduce GI problems. These include avoiding high fat and high fibre foods, allow sufficient time to digest the last meal (>3 hours), avoid using Non-Steroidal Anti-Inflammatory Drugs (NSAID) such as painkillers and ibuprofen.
Finally, train the gut just like you train the muscle. For example, train the gut by practicing pre training and during training fluid intake and intake of ergogenic aids such as electrolytes, carbohydrate gels and caffeine.
About the Author
Shaun Chapman is a Sport Nutrition consultant currently working with runners, cyclists, powerlifters and people aiming to lose weight. With a background in football, Shaun has since competed in many running events, including 5km, 10km, OCR and half-marathon races. When he’s not marathon training, Shaun can be found in the gym working on his strength training.