of an Ultraendurance Cyclist

Transcription

1 International Journal of Sport Nutrition, 1991, 1, Nutrient Intake of an Ultraendurance Cyclist Alice K. Lindeman Indiana University Meeting the energy demands of ultraendurance cycling requires careful planning and monitoring of food and fluid intake. This case study presents the nutrient intake of a cyclist while training for and competing in the Race Across AMerica (RAAM). Carbohydrate accounted for 65 % of the calories consumed during training (4,743 kcal), 75% during 24-hr races (10,343 kcal), and 78 % during RAAM (8,429 kcal). Gastrointestinal complaints during RAAM included nausea, feeling of fullness, and abdominal distension. Although probably exacerbated by sleep deprivation, these problems were all diet related. Based on this experience, it appears that by controlling the carbohydrate concentration of beverages, limiting dietary fiber, and relying on carbohydrate as the primary energy source, one could both control gastrointestinal symptoms and promote optimal performance in training and in ultramarathon cycling. The role of nutrition in training and competing in endurance events is indisputable. Without maintaining adequate glycogen stores through proper diet, optimal performance cannot be achieved. The Race Across AMerica (RAAM) is a nonstop competitive bicycle race begun in The race starts in July or August on the Pacific Coast of the United States and finishes on the Atlantic Coast. It covers an average of 3,000 miles. Race winners have completed the race in 8 to 10 days, cycling over 22 hmd-'. Official finishers are those cyclists who complete the race within 48 hours of the winner of their gender. Training for such an event is long (>1 year) and arduous. Nutritional intake must be designed to meet the demands of training, which involves long daily workouts and 24-hr road races. Because of the nonstop multipleday nature of RAAM, careful nutritional planning for competition is paramount. Unlike multiple-day stage races, such as the Tour de France, there is no rest time for the athlete to correct any energy deficit acquired that day. The purpose of this study was to describe the nutrient intake of an official 1989 RAAM finisher (10 days, 7 hours, 53 min) during training, 24-hr races, and the RAAM. T.D., a 39-year-old computer programmer/coach/writer, had a long history of athletics including 30 years swimming (high school All-American, college Alice K. Lindeman is with the Department of Applied Health Science, 116 HPER, Indiana University, Bloomington, IN

2 80 / Lindeman swimming, U.S. Olympic trials), 9 years running (100-km races), 4 years triathlon (3 Hawaii Ironman), and 10 years cycling (marathon and ultramarathon events.) T.D. was most interested in the role of nutrition in ultramarathon events such as. Anthropometric measurements were, height 189 cm, weight 79 kg, with 7.6 % body fat. Prerace blood chemistries including serum transferrin were all within normal limits. On a weekly basis, training for MAM included cycling 604 miles, weight training, and 1 day of rest. Analysis of dietary intake during training is presented in Table 1. During training, T.D. also consumed a supplement, a multivitamin/mineral pill, ornithine, inosine, arginine, carnitine, and a tablet of nine essential amino acids. Because T.D. felt that his eating habits were erratic, the supplements, suggested by a fellow endurance athlete, were for "just in case." He acknowledge$ possible placebo effects of the supplements, that is, enhanced general well-being and energy level. Diet analysis revealed that these Table 1 Daily Nutrient Intake sf s Race Across AMerica (RAAM) Cyclist at Training and Competition (7) Nutrient Proposed Traininga 24-hr Raceb RAAM diet RAAMc Fluid (L) Kcal O/o from CHO O/O from PRO % from FAT g CHO-kg-' g PRO-kg-' Fiber (g) Cholesterol (mg) Sodium (mg) Potassium (mg) Zinc (mg) Iron (mg) Magnesium (mg) Calcium (mg) Phosphorous (mg) Vit. A (RE) Vit. C (mg) Thiamin (mg) Niacin (mg) Riboflavin (mg) 6-6 (mg) "Average of 6 days; baverage of 3 races (416 mi&'); (3,000 mi). 'average of 10 days, 7 hrs, 53 min

3 Nutrient Intake of a Cyclist / 81 supplements were unnecessary. Essential amino acids intake from diet alone ranged from 370 to 1,372 % of the recommended dietary allowance (RDA) (6). All mineral and vitamin intake from the diet were >100% RDA, with thiamin, riboflavin, niacin, and B-12 ranging from 806 to 6,021 % of the RDA. The distribution of calories was ideal for an endurance athlete. Based on the recommendation of 60 to 70% total calories or 5-10 g carbohydrateokg-', carbohydrate intake appeared adequate to sustain muscle glycogen (2). Carbohydrate intake was enhanced by adding liquid food supplements, carbohydrate replacement beverages, and glucose electrolyte solutions (GES) to the diet. One of these products, UltraEnergy, though not technically a GES because it contains protein and amino acids, is commonly used and marketed as a GES, that is, consumed prior to and during competition (Procyon Industries, Whittier, CA). Nutrient information about food supplements used throughout training and racing are presented in Table 2. Protein intake from diet alone exceeded Lemon's (4) recommendation of >1.4 g*kg-' body weight for endurance athletes. However, it was within the recommendation of % total calories from protein. Cyclists participate in 24-hr races to qualify for the RAAM and to gain insight and experience for both the cyclist and the crew. They attain greater knowledge about sleep deprivation, fluid and energy balance, food tolerance, diurnal variations, and pacing themselves. Average nutrient intake of a 24-hr race is shown in Table 1. All races were conducted during very hot (21-35' C) humid weather. T.D. was careful to include a high carbohydrate meal the evening before each race. The prerace meal was consumed upon rising, 1 hour before the race. As suggested by Brouns et al. (I), the meal was liquid, carbohydrate rich, easy to digest, and low in fiber. Throughout the races T.D. kept one bottle of water and another of GES available at all times. Selection of solid food was based primarily upon the ease of unwrapping and/or consuming while riding; there was no stopping to eat. The crew offered caffeine-containing beverages to aid in alertness. Anti-inflammatories were offered after complaints of joint pain. Both of these practices can place the athlete at risk for dehydration or gastric distress (1). T.D.'s weight remained stable throughout each 24-hr ride and the days following, suggesting that fluid and energy balance had been maintained. Subjectively, T.D. noted that recovery from the 24-hr race was quickest when he ate the most on race day. Based on the above observations and food tolerances, a proposed RAAM feeding schedule was devised, with analysis shown in Table 1. This diet represented a compromise with the athlete, who wanted to consume only water, a 23% GES, one high fiber "sport bar" while riding, along with liquid meal replacements and a high carbohydrate beverage during scheduled rest (2 hod-'). He felt that reliance on the 23% GES was necessary in order to accomplish his goal of an almost all liquid, high carbohydrate diet. The proposed diet included fewer servings of the 23% GES and a greater variety of other beverages and solid food. The proposed diet was reviewed with T.D. and his support crew. A food pattern based on crew shifts, along with sample daily menus, was provided. Written and verbal instructions were given to the crew for recording all food and fluid consumed.

4 82 / Lindeman Table 2 Food Supplements Used by a Race Across AMerlca (RAAM) Cyclist During Training and Competitiona (7) Exceedc ExceedC ExceedC Ensurec Ultra food fluid high food Power Nutrient energyb beverage replace CHO beverage bap Kcal Carbohydrate concentr. (O/O) Osmolality (m0sm.l-') CHO (9) PRO (g) FAT (g) Fiber (g) Cholesterol (mg) Sodium (mg) Potassium (mg) Zinc (mg) Iron (mg) Magnesium (mg) Calcium (mg) Phosphorous (mg) Vit. A (RE) Vit. C (mg) Thiamin (mg) Niacin (mg) Riboflavin (mg) B-6 (mg) abased on 250 cc servings, unless otherwise noted; bprocyon Industries; 'Ross Laboratories; d65 g portion; Powerfood, Inc. NA = Information not available. Results of actual intake during RAAM are shown in Table 1. Liquids provided 78% of the total calories. The average intake of the 23% GES was equal to 21 eight-ounce servings per day. T.D. averaged an intake of 347 kcal and 677 rnl fluidseh-' throughout the race. Body weight fluctuations experienced during the race were probably largely attributed to fluid balance. The prerace weight of 79 kg increased to 81.8 kg within 24 hours into the race (through desert conditions). By the end of the race T.D. weighed 80.7 kg. At 2 days postrace his weight dropped an additional 1.2 kg, returning to prerace weight. Although body fat was not measured postrace, subjectively T.D. did appear leaner than at prerace. Figure 1 presents how fluid and nutrient intake varied with daily mileage. Day 11 was only 8 hours long, thus all values were very low for this day. On

5 Nutrient Intake of a Cyclist / 83 Fluid Excbaqe 0-0 Input - ourput (llrim? only) P /v'-v \v,v :/v-~#.. v. \ v-v -r Elecmlyte In& 0-0 sodium r-r pomssim Time (days) Figure 1 - Daily fluid intake and output, nutrient, and mileage during the Race Across AMerica (RAAM). Values for Day 11 are very low, as this was the last day of the race, lasting only 7 hrs, 53 min.

6 84 / Lindeman excessively hot days, fluid intake was very high and urine output very low. The 2 days in which T.D. rode slowly and/or slept more than intended were noted by significant drops in both energy intake and mileage. Sodium intake was much higher than potassium intake on those days in which T.D. relied heavily on the 23 % GES as his energy source. Some mistakes were made in designing this diet, and a great deal of insight was gained into ultraendurance multiple-day events. T.D. 's major gastrointestinal complaints throughout MAM were nausea, feeling of fullness, and abdominal bloating. Although probably exacerbated by sleep deprivation, the root of these problems was diet related: T.D. may have been chronically hyperhydrated to the point of discomfort, that is, a feeling of fullness, bloating, and excessive The fiber wntent of the diet, at 57 gad-', greatly exceeded the recommended intake of 20 to 35 gad-' forwarded by several government agencies and health organizations (3). This high fiber intake was probably associated with consuming an average 5.4 fiber-rich "sports bars" and 11 pieces of fruit each day. As noted by Brouns et al. (I), especially when combined with endurance exercise, fiber may not only delay gastric emptying but may also, upon reaching the large bowel, be fermented by bacteria, producing gas and abdominal distension. s Large doses (>1 g) of ascorbic acid may cause stomach cramps and nausea (8). T.D. daily consumed a large amount of vitamin C (3.3 g) derived from the 23% GES and fruit. In addition, this consumption was constant throughout the day. Perhaps the large amount and constant intake of ascorbic acid were associated with the gastrointestinal symptoms T.D. experienced. 0 Reliance on a 23% GES for most of the calories also contributed to the gastrointestinal symptoms. Despite consistent dilution to a 17% solution, it appeared that the concentration was too high to allow adequate gastric emptying. Mitchell et al. (5) showed that solutions 2 12% delayed gastric emptying during prolonged exercise. By decreasing the 23% GES to half strength, gastric emptying and fluid delivery would not be as compromised. The 23 % GES contained a significant amount (13% total calories) of protein and free amino acids. Upon entering the proximal duodenum, amino acids can stimulate the secretion of secretin, which in turn acts to delay gastric emptying, thus possibly contributing to gastrointestinal complaints. Greater reliance on carbohydrate for calories, limiting dietary fiber, and controlling GES concentration could alleviate many of the gastrointestinal symptoms associated with endurance exercise (1). Summary Optimal nutrition during training for RAAM allows the ultraendurance cyclist to train and perform to hisfher potential. Experimenting with foods and recording intake during 24-hr races provides insight into food tolerances, energy and fluid requirements, fatigue and the effect of sleep deprivation, and diurnal variations.

7 Nutrient Intake of a Cyclld / 85 This multiple-day endurance event requiring up to 22 h*d" of cycling may represent the upper limits of sustainable energy expenditure, as indicated by T.D. 's high energy intake. The focus should be on adequate energy consumption, especially carbohydrate. Food and fluid intake must be closely monitored. Any solid food consumed should be easy to handle, easy to chew thoroughly and to digest, and should have a moderately low fiber content. Beverages should allow adequate gastric emptying so that fluids and nutrients can be quickly absorbed. Concentrated nutrition such as liquid meal replacements or high carbohydrate supplements may be offered immediately before scheduled rest. This practice could increase energy intake and, since the athlete may be resting for up to 2 hours, still allow adequate time for gastric emptying. In an event as arduous and long as RAAM, adequate nutrition can mean the difference between successfully completing the race or dropping out of it. Nutrient intake must meet or exceed energy expenditure for each day of the event. It could be quite difficult for the athlete to correct any previous deficit plus meet the energy demand for the present day. Through careful planning and monitoring, optimal energy intake can be balanced to meet energy expenditure. References 1. Brouns, F., W. Saris, and N. Rehrers. Abdominal complaints and gastrointestinal function during long-lasting exercise. Znt. J. Sports Med. 8: , Costill, D., and J. Miller. Nutrition for endurance sport: Carbohydrate and fluid balance. Int. J. Sports Med. 1:2-14, Dairy Council Digest: Nutrition and health advice for the 1990s. Rosemont, IL: National Dairy Council, 61(5), Sept-Oct, Lemon, P. Protein and exercise: Update Med. Sci. Sports Exer. 19(Suppl.): S , Mitchell, J., D. Costill, and J. Houmard, et al. Gastric emptying: Influence of prolonged exercise and carbohydrate concentration. Med. Sci. Sports Ber. 21(3): , National Research Council: Recommended Dietary Allowances, 10th Edition. Washington, DC: National Academy Press, Nutritionist III. N-Squared Computing. Salem, OR. 8. Olsen, A,, and R.E. Hodges. Recommended dietary intakes (RDI) of vitamin C in humans. Am. J. Clin. Nutr. 45: , Acknowledgments Supported in part by Biomedical Research Support Grant, Indiana University, and Ross Laboratories, Columbus, Ohio.