Aruna Prasad

Endurance sport is a cardiovascular exercise that is performed for an extended period of time (Rogers & Roberts 1997) which involves complex integration of multiple physiological functions. In an endurance sport/activity, the food that you provide to fuel your body directly determines your performance.

This is true for any sport but especially significant in an endurance activity considering longer training duration and developing an energy system to meet the demand of the sport to sustain repeated muscle contraction. Oxygen and adequate fuel fulfills the above criteria.

Oxygen is the key to sustaining repeated muscle contraction and an individual’s capacity to oxygen consumption is limited by exercise economy, VO2 Max and lactate threshold. Maximal oxygen uptake, or VO2max, refers to the highest rate at which the body can take up and consume oxygen during intense exercise (Bassett & Howley 2000). Oxygen consumption required to perform a given exercise workload during endurance activity (Daniels 1985) is the exercise economy. Exercise intensity at which blood lactate levels abruptly increase (Robergs & Roberts 1997) is the lactate threshold. By modifying food intake to reduce these metabolic factors will further improve endurance potential in an athlete.

Our body depends on creatine phosphate, fat, carbohydrate and protein to support ATP (adenosine triphosphate) production which is essential to drive a physical activity. Carbohydrate stored as glycogen in liver and muscles is the first in line to fuel a prolonged activity after creatine phosphate which has a limited availability. Fat is a substantial energy reservoir to fuel an endurance activity but requires higher amount of oxygen to break down their complex structure into a readily available form and hence becomes a less accessible form of energy.

Intensity of exercise is the deciding factor to choose the substrate for energy production. Low intensity is fuelled by both fat and carbohydrates. As the intensity of exercise increases, there is a shift towards carbohydrate to fuel the metabolism. Approximately two hours of high intense endurance activity will significantly deplete muscle glycogen (stored carbohydrates) setting in fatigue in the athlete and muscular pain irrespective of adequate oxygen supply.

Dependence on carbohydrate as a substrate to fuel the activity increases especially during lactate build up because of carbohydrate’s efficient consumption of oxygen. An athlete’s ability to rely on fat to spare glycogen utilisation increases endurance potential which also is supported by the right food at the right time. Dependence on carbohydrate as a substrate to fuel the activity increases especially during lactate build up because of carbohydrate’s efficient consumption of oxygen. An athlete’s ability to rely on fat to spare glycogen utilisation increases endurance potential which also is supported by the right food at the right time.

Carbohydrate loading or glycogen super-compensation is the most common strategy used in endurance athletes (event lasting 90 minutes or more) to delay the onset of fatigue and reduce lactate build up. Muscle glycogen stores are first depleted by a low carb diet and intense training. This process is reversed by loading carb based foods and reduce training load to increase

muscle glycogen stores. Carb loading is done 3-5 days prior to the event and uses foods like to white rice-dal, pasta, white bread, sweet potato, green peas, corn and bananas to increase the muscle glycogen levels. It is great to limit simple carb sources like candies, sweets and sugary foods to avoid increase in body fat which can further slow down an endurance activity.

Fish, flax seeds, walnuts, chia seeds are a few sources of food that are known to increase VO2max levels and utilization of oxygen by the muscles to support endurance. Since these are also sources of essential fat, it is best to keep them during training days to build VO2max levels gradually. Green leafy vegetables,dried beans, prunes, beets, eggs and organ meat like liver and kidney are known to increase your red blood cell production which in turn enhances oxygen carrying capacity of the blood helping improve your endurance levels. Include these on a daily basis to gradually increase RBC levels.

Starting an endurance event on an empty stomach can lead to fatigue. A fruit with a few pieces of nuts or low fat yogurt or oatmeal porridge is the best to fuel your endurance activity. Hydration is the key to reduce lactic acid build up and for the smooth muscle contraction. Adequate hydration is also essential to prevent injury. An isotonic sport drink (same concentration as that of blood) is the best to enhance endurance. Coconut water is isotonic and the most reliable sport natural sports drink! Dried fruits or banana during an endurance event like trekking or rock climbing is great to restore energy levels and reduce the impact of fatigue on your performance. Bicarbonate foods like banana, tomatoes, potato and magnesium rich foods like amaranth, cashewnuts, sesame seeds, pumpkin seeds can help reduce lactic acid build up after an endurance activity thereby fastening the process of recovery. These are your safest post event snacks to keep the metabolism up and going after a high intense activity.

A common mistake by a trekker or a rock climber is the consumption of aerated or carbonated beverages to quickly restore energy levels because of higher concentration of sugar. Since your energy systems utilise oxygen to generate ATP, carbon dioxide can further slow you down and sap your energy. Munch on trail mixes of dried fruits (berries, raisins, peanuts, nuts) or an energy bar or a small banana and avoid sugary fruit juices or candies to keep you going along with the above tips to enhance your endurance potential.

Paddling sports like kayaking or canoeing require the above nutritional strategies to cope with the high intensity muscle contraction along with an increased demand of protein intake due to increased breakdown of muscle contractile protein, increased production of RBC, and faster replacement of glycogen stores by break down of protein. Sometimes the protein requirement in these paddle sports can be higher than that of a body builder depending on the body weight. Milk, egg, sprouts, beans, organ meat and protein supplements are excellent to cater to this high demand.

It is equally important for an endurance athlete to have the right amount of body fat which in excess can cause excess stress on the joints, increase risk of injury and also reduce endurance levels. Since we know fitness is 70% food and 30% exercise, it is important to wisely choose every morsel that you put into your body that can impact your performance in the longer run. Remember to eat within 15 minutes of waking up and eat every 2-3 hours to keep your metabolism at its best level and to reduce higher body which are essential tosupport endurance activities.

Aruna Prasad

A qualified Nutritionist & a Gold Medalist in Master of Science (Food Science and Nutrition), Aruna comes with a wide experience of changing the way people eat.  A fitness enthusiast, Aruna has done multiple LIVE media shows on demystifying common food fads and giving realistic tips on weight loss, sports nutrition and lifestyle modifications.

For your queries related to Diet & nutrition mail at yournutritionist.aruna@gmail.com