THE FOLLOWING IS A SUMMARY OF A STATE OF THE ART REPORT ON POST EXERCISE RECOVERY PREPARED BY THE AUSTRALIAN INSTITUTE OF SPORT, DEPARTMENT OF SPORTS NUTRITION.
Full copies of the report can be obtained by contacting Professor Louise Burke, Department of Sports Nutrition, AIS
NUTRITION FOR OPTIMAL RECOVERY AFTER TRAINING AND COMPETITION State-of-the-Art Report prepared for the Department of Sports Nutrition Australian Institute of Sport, by Professor Louise Burke, Head of Sports Nutrition, Australian Institute of Sport Dr Kevin Tipton, Metabolism Unit, Shriners Hospital for Children, Galveston, USA
With the input of Greg Cox, Department of Sports Nutrition, AIS Louise Bell, Department of Sports Nutrition, AIS Michelle Minehan, Department of Sports Nutrition, AIS Clare Reilly, Nestle Fellow in Sports Nutrition, AIS Ruth Crawford, Department of Sports Nutrition, AIS Gary Slater, Department of Physiology, AIS
EXECUTIVE SUMMARY 1. Recovery, an important factor in enhancing adaptations to training and optimising competition performance, encompasses a complex range of nutrition-related processes including: • Refuelling • Rehydration • Synthesis of new protein for repair and adaptation 2. A comprehensive review of the scientific literature on each of these processes enables us to identify a number of dietary strategies that can promote rapid and effective recovery following key training and competition sessions. These strategies have been integrated into State-ofthe-Art guidelines for Recovery Nutrition. 3. The Australian Institute of Sport will demonstrate its commitment to Cutting Edge Practice in Recovery Nutrition by: a. Providing education to AIS athletes and coaches regarding Stateof-the-Art guidelines for Recovery Nutrition b. Enabling good practice by AIS athletes through the AIS Recovery Bar program c. Undertaking innovative research, especially in the area of exercise and protein metabolism where the current paucity of data makes it difficult to refine Recovery Nutrition guidelines 4. Further research may help to identify the need for specially designed sports foods, or provide a commercial advantage to the manufacturers of existing products via the acknowledgement of their support of wellpublicised research. 5. Although the focus of this report is to enhance athletic performance, there is considerable overlap with the key issues in clinical/therapeutic nutrition (e.g. treatment of burns, surgical and trauma patients) and nutrition for special populations (e.g. nutrition for the elderly). It is important to develop and maintain strategic collaborations with experts in these fields. Commercial spin-offs in these other areas may be substantial.
STATE OF THE ART GUIDELINES FOR RECOVERY NUTRITION A. Recovery from key training or competition sessions based on endurance or ‘quality’ work Pre-exercise summary – to promote successful completion of the session • To ensure adequate fuel for successful completion of the session, carbohydrate-rich foods or drinks providing at least 1 g/kg BM should be consumed within the 1-4 hours prior to the session. This may not always be practical for early morning training sessions. • Attention should also be paid to pre-exercise fluid intake to ensure that the athlete is well-hydrated before commencing exercise. During exercise summary - to promote successful completion of the session • Fluid and carbohydrate should be consumed during the session to minimise the extent of dehydration and to provide additional fuel sources for the muscle and Central Nervous System. Carbohydrate intake during the session (via sports drinks, gels or other choices) is important during prolonged workouts (>60-90 min), especially when there is no opportunity for fuelling before the workout. Guidelines for post exercise recovery • Effective refuelling begins only after a substantial amount of carbohydrate has been consumed. When there is less than eight hours between workouts or events that deplete glycogen stores, the athlete should maximise effective recovery time by consuming a high carbohydrate meal or snack within 30 minutes of completing each session. This will mean being organised to have suitable food and drinks available - at the exercise venue if necessary. • The athlete should aim to consume 1 g of carbohydrate per kg BM immediately after exercise, and repeat after an hour or until normal meal patterns are resumed (see Tables 1 and 2). Recovery snacks and meals should contribute towards a daily carbohydrate intake of 7-12 g per kg BM. Total carbohydrate requirements need to be individualised to each athlete’s exercise program and energy budget (see Section C for special comments for athletes with a restricted energy budget). However, CHO intakes at the high end of this range may help to offset the effect of muscle damage on glycogen resynthesis and may be required to meet the combined fuel bill of daily training and glycogen recovery in athletes undertaking very high workloads. • The consumption of protein within recovery snacks and meals may help to enhance the synthesis of new proteins underpinning adaptations to the workout as well as contribute to any increase in protein requirements related to exercise. The intake of a protein source providing 6-12 g of essential amino acids (equivalent to 10-20 g of protein from a high quality source) may be valuable in a recovery snack since it has been shown to
•
•
•
•
• •
•
•
have a substantial effect on net protein synthesis. It is likely that such an intake will be exceeded in the meals provided within a well-chosen diet. Choices for snacks that provide a good source of carbohydrate and protein include breakfast cereal and milk, flavoured milk drinks and specially formulated sports bars and liquid meal supplements (see Tables 1 and 2). When carbohydrate needs are high, and appetite is suppressed or gastric comfort is a problem, the athlete should focus on compact forms of carbohydrate, including low-fibre choices of carbohydrate-rich foods, sugar-rich foods and special sports supplements such as sports bars. Carbohydrate-containing fluids are also low in fibre and may be appealing to athletes who are fatigued and dehydrated. These include sports drinks, soft drinks and fruit juices, commercial liquid meal supplements, milk shakes and fruit smoothies. Low glycemic index (GI) carbohydrate foods such as lentils and legumes may be less suitable for speedy glycogen recovery and should not be the principal carbohydrate source in recovery meals. This is generally not a problem as typical Western diets are based on carbohydrate-rich foods of moderate and high GI. Small, frequent meals may assist the athlete to achieve high carbohydrate intakes without the discomfort of overeating. However, the athlete should organise their routine of meals and snacks to suit individual preferences, timetable and appetite/comfort. In long-term recovery (24 hours), as long as enough carbohydrate is consumed, it doesn’t appear to matter how intake is spaced throughout the day. There may be some benefits in increasing the frequency of intake of CHO (e.g. snacks every 30-60 minutes) during the first hours of recovery. When gastric comfort or total energy requirements limit total food intake, high fat foods and excessive amounts of protein foods should not be consumed at the expense of carbohydrate choices. Nutritious carbohydrate foods and drinks contain other nutrients including vitamins and minerals that may be important in other post-exercise recovery processes. These nutrients are also important in the overall diet. Future research may show that intake early after exercise could enhance other activities of repair and rebuilding, as well as the immune system. The athlete should avoid excessive intake of alcohol during the recovery from exercise. Although there is potential for direct effects on refuelling and recovery processes, alcohol exerts its main effect on recovery through indirect means: the intoxicated athlete is unlikely to follow sound nutritional practices and is more likely to undertake high-risk behaviour and suffer an increased risk of accidents. Drinks should be consumed to restore fluid balance. When the total fluid deficit incurred by the workout (sweat losses minus fluid intake during the session) exceeds 2% of the athletes BM, special attention should be
focussed on rehydration strategies (see Section D below: Special comments for a dehydrated athlete).
B. Recovery from key resistance training workouts Guidelines for pre-exercise recovery strategies • The athlete should consume a source of amino acids prior to the session, since the intake of 6-12 g essential amino acids (equivalent to 10-20 g of a high quality protein) has been shown to promote enhanced protein recovery after the workout. Protein rich foods should be consumed 30-60 min prior to the session to allow for digestion to take place. Carbohydrate consumed at the same time may enhance the protein response; an intake of at least 1 g per kg BM is recommended to provide a substantial “top up” of fuel stores and avoid the risk of rebound hypoglycemia in susceptible athletes. It may not always be practical for the athlete to consume foods before a heavy workout; nutrient-rich drinks such as liquid meal supplements, fruit smoothies or sports bars provide a more compact alternative (see Tables 1 and 2 for ideas). During exercise summary • Fluid should be consumed during the session to minimise the extent of dehydration. Carbohydrate intake during the session (via sports drinks, gels or other choices) provides an additional fuel source for the muscle and Central Nervous System and can enhance the performance of prolonged workouts (>60-90 min), especially when there is no opportunity for refuelling before the workout. Guidelines for post-exercise recovery strategies • The athlete should consume a source of amino acids within the hour after the session; the intake of essential 6-12 g amino acids (equivalent to 10-20 g of a high quality protein) has been shown to promote enhanced protein recovery after the workout. Carbohydrate consumed at the same time may enhance the protein response and promote rapid recovery of muscle glycogen stores. Table 1 provides suggestions of proteincarbohydrate snacks and light meals that can be consumed to promote recovery until normal meal patterns are resumed. • When strength-training sessions are prolonged, or undertaken in conjunction with an aerobic exercise session, the athlete should undertake strategies to promote rapid recovery of depleted muscle glycogen stores. These issues are discussed in more detail in Section A: Guidelines for recovery from an endurance workout. • The athlete should avoid the intake of excessive amounts of alcohol during the hours following a strength workout, since there is some evidence that alcohol impairs protein synthesis. A sensible approach to alcohol intake is beneficial for all aspects of post-exercise recovery. • The athletes’s daily diet should provide adequate energy and protein intake to meet their goals for gain of muscle mass. In terms of daily protein requirements, the maximum intake that is likely to be needed is ~ 1.5-2.0 g per kg BM. Intakes greater than this are not likely to confer any additional benefits for muscle gain.
C. Special comments for the athletes with a restricted energy budget •
•
•
•
Pre- or post-exercise recovery snacks should not contribute additional energy to a restricted energy budget. Rather, when rapid recovery is desirable, the energy-restricted athlete should change the timing of their existing meal structure to allow for immediate intake after exercise sessions. One option is to reschedule training sessions or meals so that the athlete is able to eat their normal meal as soon as possible after the workout. Where this is not practical, the athlete may be able to take a small snack from within their usual meal plan to consume immediately after training or as a pre-resistance training snack (for example, fruit and flavoured yoghurt usually consumed as a dessert with dinner), then consume the remainder of their meal at the usual time. Since the athlete may have increased requirements for protein and micronutrients as a result of their exercise program, it is important that foods consumed as recovery snacks contribute to overall nutrient intake goals as well as immediate recovery needs. Nutrient-rich CHO foods and drinks (e.g. fruit, flavoured milk drinks and dairy foods, sandwiches with meat and salad fillings) are more valuable than lower nutrient choices (e.g. lollies, soft drink, bread with jam or honey). The energy-restricted athlete should also make use of foods with a high fibre content (e.g. fresh fruit rather than juice), high volume/low energy density (e.g. salad fillings added to sandwiches) or low glycemic index (e.g. rolled oat cereals rather than cornflakes) to maximise the satiety value of meals and snacks. The addition of protein to meals and snacks (e.g. yoghurt with fruit, meat or cheese in sandwich) also improves satiety. Guidelines for low-fat eating are also important. The energy-restricted athlete is unlikely to have a sufficient energy budget to cover the guidelines for optimal intakes of some macronutrients (e.g. CHO for optimal daily glycogen synthesis). Specialised dietary advice from a sports dietitian is valuable in ensuring that the athlete has reasonable goals related to their energy requirements and physique goals, and is able to organise meal plans to optimise their nutrient intake within this energy budget. It may be valuable to cycle between nutritional goals – i.e. restrict energy during periods suitable for loss of body fat, while liberalising energy and CHO intake to promote better fuelling and recovery for key sessions or competition.
D. Special comments for the dehydrated athlete •
•
•
•
•
• •
Dehydration will have a negative effect on subsequent exercise sessions if not fully corrected before the next workout. However, moderate to severe fluid deficits can also have an effect on recovery, since they are associated with an increased risk of gastro-intestinal upset and discomfort, potentially limiting the athlete’s ability to ingest substantial amounts of nutrients. Therefore, rehydration should be considered an immediate priority, especially where gastrointestinal function is compromised. Early recovery strategies may need to focus on rehydration goals (e.g. consuming dilute fluids) before the athlete is able to consume significant amounts of the macronutrients needed for refuelling and protein recovery. The athlete should not rely on thirst or opportunity to dictate fluid intake to reverse a situation of dehydration. A “hit and miss” approach may be acceptable when fluid deficits are 1 L or less, but when fluid losses are greater, an organised schedule is required The athlete should monitor changes in body mass from pre- to postexercise to evaluate the success of drinking strategies during exercise, and the residual fluid deficit that must now be replaced. A loss of 1kg is equivalent to 1 litre of fluid. Since fluid losses will continue during the recovery period via urine losses and ongoing sweating, the athlete will need to consume additional fluid to counter this. Typically, a volume equal to ~ 150% of the post-exercise fluid deficit should be consumed over the subsequent 2-4 hours to fully restore fluid balance. It is important to ensure that an adequate supply of palatable drinks is available. This may be difficult when the athlete is at a remote competition venue, or travelling in a country where bottled water must be consumed instead of the local water supply. In situations where fluid intake needs to be encouraged, the provision of flavoured drinks is a useful strategy. Since most people prefer sweettasting drinks, they are likely to increase their voluntary intake of such fluids. Keeping drinks at a refreshing temperature is also known to encourage greater intake. Cool drinks (10-15 oC) are preferred in most situations. Very cold fluids (0-5 oC) may seem ideal when the environment or the athlete is hot, however it is often challenging to drink them quickly or in large volumes. Carbohydrate-containing drinks are also useful in assisting with refuelling goals and allow the athlete to tackle a number of recovery goals simultaneously. In the situation of moderate-large fluid deficits (e.g. > 2 L), sodium replacement will assist the retention of ingested fluids, by minimising urine losses. Options include sports drinks, commercial Oral Rehydration Solutions (e.g. Gastrolyte), salty foods or salt added to post-exercise meals. A high sodium beverage such as an Oral Hydration Solution (50-90 mmol/L
•
•
•
•
or 2-5 g of salt per L), or salt added to post-exercise meals along with substantial fluid intake should guarantee that sufficient fluid and sodium have been replaced. Athletes are often educated that the production of “copious amounts of clear urine” is a desirable state and a sign of good hydration status. Measurements of urinary specific gravity or osmolality are sometimes undertaken to provide an indicator of euhydration and good hydration practices. Although this may be true in the long-term situation, the athlete is reminded that during the acute period of fluid replacement immediately following dehydration, mismatch of fluid and electrolyte replacement can lead to production of large amounts of dilute urine despite the continuing existence of substantial fluid deficits. Thus, in the case of significant fluid loss, the athlete should be aware of the need for electrolyte replacement, and should know that “urine checks” over the first hours of fluid intake often provide false readings. Dietary strategies that minimise urine losses during the rehydration period not only enhance the speed of regaining fluid balance, but help the athlete to achieve better quality rest or sleep without frequent disturbances related to having to get up to urinate. Caffeine-containing fluids (e.g. cola drinks, tea, coffee and energy drinks) are generally not considered to be ideal rehydration beverages since caffeine may increase urine losses. It is often suggested that alternative choices should be used for early post-exercise rehydration, and that once fluid balance has been substantially restored, the athlete may have greater freedom in making drink choices. It should be noted that a recent review of the caffeine literature concluded that the diuretic effect of caffeine is overstated in habitual caffeine drinkers. Furthermore, greater voluntary consumption of favourite beverages such as Cola drinks may lead to better hydration status even if they are associated with a slightly greater urine production. Alcohol also causes an increase in urine losses, and drinks containing significant amounts of alcohol (4% or more of volume) are not considered ideal rehydration beverages. Nevertheless, athletes are reminded that alcohol exerts its main effect on recovery through indirect means: the intoxicated athlete is unlikely to follow sound nutritional practices and is more likely to undertake high-risk behaviour and suffer an increased risk of accidents Where possible, the athlete should avoid post-exercise activities that exacerbate sweat losses - for example, long exposure to hot-spas, saunas or sun.
Carbohydrate recovery snacks and light meals Each of the following selections in Table 1 and Table 2 provide approximately 50 g of carbohydrate. The athlete should use this guide to consume ~ 1 g carbohydrate per kilogram of their body mass (BM), to ensure speedy recovery of glycogen stores (post-exercise recovery) or to “top up” fuel stores prior to a workout (pre-exercise snack). In the case of post-exercise recovery, this strategy should be repeated after one-two hours or until normal eating patterns have been resumed. The intake of protein (10-20 g) in conjunction with carbohydrate will help to meet goals for enhanced net protein synthesis. Table 1. 50 g carbohydrate snacks providing at least 10 g protein • 250-350 ml liquid meal supplement • 250-350 ml milk shake or fruit smoothie • 500 ml flavoured low fat milk • Many sports bars (check labels for protein and carbohydrate content) • 60 g (1.5-2 cups) breakfast cereal with 1/2 cup milk • 1 round sandwiches including cheese/meat/chicken filling, and 1 large piece of fruit or 300 ml sports drink • 1 cup fruit salad with 200 g carton fruit-flavoured yoghurt or custard • 200 g flavoured yoghurt or 300 ml flavoured milk and 30-35 g cereal bar • 2 crumpets or English muffins with thick spread of peanut butter • 250 g baked beans on 2 slices of toast • 250 g (large) baked potato with cottage cheese or grated cheese filling • 150 g thick crust pizza Table 2. 50 g carbohydrate snacks • 800 -1000 ml sports drink • 800 ml cordial • 500 ml fruit juice, soft drink or flavoured mineral water • 60-70 g jelly beans or jube sweets • 2 sports gels • 3 medium pieces fruit or 2 bananas • 1 round thick-sliced jam or honey • 2 large (35 g) or 3 small (25 g) cereal bars • 1 large chocolate bar (70-80 g) • 3 thick rice cakes with jam or honey • 2 crumpets or English muffins with vegemite • 1 cup thick vegetable soup with large bread roll • Jaffle/toasted sandwich with banana filling • 100 g (1 medium or 2 small) American muffin, fruit bun or scones • 250 g (1 cup) creamed rice • 250 g (large) baked potato with salsa filling • 100 g pancakes (1-2 large) + 30 g syrup
