Nutritional Recovery Strategies
It takes 90 -180 minutes of continuous exercise at a slow to fast pace to deplete the body’s carbohydrate stores. However, muscle carbohydrate can also be depleted after only 15-30 minutes of very high intensity training such as interval work or speed work. It can take up to 24 hours to replace these stores. Thus, for athletes training hard twice a day or for athletes doing a number of consecutive hard days, there is a need to replenish the carbohydrate stores prior to the next training session or event.
Research has shown that muscle carbohydrate is remade at about 5 units per kilogram of muscle per hour. On the assumption that a muscle topped-up with carbohydrate contains about 100 units per kilogram of muscle, it takes about 20 hours to completely recover the hungry muscle’s stores. This has strong implications for athletes that train twice daily or trains in the afternoon and then goes again the next morning. This research strongly suggests the need to have an easy session following or before the hard one where fats become the primary fuel and muscles have a chance to recharge their carbohydrate tanks.
After training or racing, athletes need to consume carbohydrate that can be very quickly converted to blood glucose and then transported in the blood to the muscles. To help us get the carbohydrate quickly into the blood and to the muscles, carbohydrates with a high GI are recommended (see Table 16.14). The high GI foods should also be combined with fluid intake since it takes about 3 grams of water to store 1 gram of carbohydrate in a muscle.
Three dietary factors dictate the rate of carbohydrate rebuilding in muscle after training or racing.
- Rate of carbohydrate intake. Sport scientists recommend an intake of about 1.2-1.5 gram per kilogram of body weight per hour) every thirty minutes for up to 4-5 hours to recover carbohydrate stores.
- Type of carbohydrate. High to moderate GI foods appear equally effective for carbohydrate recovery over the longer term with high GI preferred immediately after training or racing. Research also suggests that carbohydrate in liquid or solid moderate-to-high GI form is equally effective as solids. However, if fluids are needed after a session of high sweat rates, then the fluid forms are the recommended alternative. Sports drinks, soft drinks, and cordials fit this bill. Taking the carbohydrate with up to 6 grams of protein also appears to enhance recovery and muscle repair.
- Timing of the carbohydrate intake. During the first two hours after a workout, the rate of muscle carbohydrate rebuilding is 7-8% per hour with some suggestion that this rate is even higher in the 30 minutes following exercise. This indicates the need to eat or drink moderate-to-high GI foods or fluids straight away after training or competing. If you’re like me and can’t eat straight away after training, then drink a sports drink, cordial or soft drink. As above, these high-moderate GI foods should be taken at the rate of 1.2-1.5 gram per kilogram of body weight per hour for up to 4-5 hours until the next large meal where low to moderate GI foods are the go for health reasons because such a meal will (hopefully!) contain vitamins and minerals.
Finally, apart from all the obvious sports performance benefits of the GI, research has recently shown that low to moderate GI foods are closely linked to lower rates of cardiovascular disease and lowered risk to certain forms of cancer such as bowel cancer. Thus, for aging athletes, such foods will not only benefit sport performance but health as well.
Chapter 16 of The Masters Athlete discusses in detail endurance nutrition for masters athletes with example meals and tables of food sources of major nutrients required for high performance nutrition.