Carbohydrates After Exercise: Improve Recovery and Reduce Muscle Breakdown
By ingesting carbohydrates after exercise we can speed up recovery, enhance muscle and liver glycogen re-synthesis, reduce muscle breakdown and increase protein synthesis.
Why consume carbohydrates after exercise?
It’s known that high intensity and prolonged aerobic exercise can deplete muscle and liver glycogen stores. And without replenishing these stores, we risk impairing post exercise recovery, increased muscle breakdown, and this will impact subsequent exercise training.
Therefore, it is crucial to replenish muscle glycogen stores as quickly as possible.
Recommended carbohydrate intake after exercise
Current recommendations for replenishing glycogen stores are:
- Consume approximately 1-1.2g of carbohydrate per kg of bodyweight immediately after exercise (Burke 2010; Goh et al., 2012;).
- This is best achieved by consuming around 50-75g of quick releasing carbohydrate — such as a blend of glucose and maltodextrin — immediately after prolonged endurance workout.
- We can then follow this up with a second high carbohydrate meal/drink a further 60-90 minutes later.
High GI carbs vs Low GI carbs after exercise
Whilst it is better to consume low GI foods when carbo-loading, the reverse is true after exercise. Here, high GI carbs are more effective for rapidly replenishing muscle glycogen levels.
This is because high GI carbohydrates are more rapidly digested, enter the bloodstream more quickly, and are available more quickly for glycogen re-synthesis.
Following a prolonged aerobic activity (such as a 2-hour run or 3-hour cycle) you should continue to replenish carbohydrate throughout the day. An effective approach is to ingest additional carbohydrate every 2-3hours. Often, endurance athletes may need to consume around 500-600g/day of carbohydrate (~twice the normal recommended carbohydrate intake) in order to maintain their muscle glycogen levels.
Carbohydrates can help to reduce muscle breakdown
Besides replenishing muscle and liver glycogen levels, post exercise carbohydrate consumption can reduce the breakdown of muscle protein and may increase levels of protein synthesis. This is important when we consider that prolonged endurance training can cause significant damage to muscle fibres. Without sufficient carbohydrate availability, we begin to breakdown additional muscle proteins.
Another factor is post-exercise carbohydrate consumption may protect against elevated cortisol levels, which increase the levels of muscle breakdown.
In addition, high GI carbohydrates increase insulin levels which can help to drive carbohydrates into muscles and may enhance the building of new muscle tissue. This is because insulin is an anabolic hormone — that is, it encourages the building of new muscle tissue — and therefore increased insulin levels can have a positive impact on muscle protein synthesis.
Combining carbs with protein to enhance recovery
To further enhance recovery, endurance athletes can consume whey protein, or BCAAs (Branched Chain Amino Acids). Research has shown that the consumption of carbohydrate along with either protein (Goh et al., 2012; Ferguson-Stegall et al., 2011; Karp et al., 2006; Koopman et al., 2004), or BCAAs (Negro et al., 2008; Schena et al., 1992) can improve post exercise recovery, rates of muscle protein synthesis, increase rates of glycogen replenishment and enhance subsequent exercise performance.
- High intensity and prolonged aerobic exercise can lead to depleted muscle glycogen stores.
- If we do not replace these stores, muscle breakdown will increase and recovery will be reduced.
- Current recommendations for replenishing muscle glycogen stores are to consume 1-1.2g of carbohydrate per kg of bodyweight.
- High GI carbs are considered more beneficial than low GI carbs.
- The most convenient approach is to consume approximately 50-75g of carbs in a drink, immediately after exercise. Following prolonged exercise (>1.5 hour) a second dose may be consumed – normally around 90 minutes later.
- Ingesting carbohydrates after exercise can reduce muscle breakdown and enhance post exercise recovery.
- The addition of protein (particularly protein rich in BCAAs) can further enhance recovery and improve the rates of muscle glycogen replenishment.
Burke LM. Fueling strategies to optimize performance: training high or training low? Scand J Med Sci Sports. 2010 Oct;20 Suppl 2:48-58. doi: 10.1111/j.1600-0838.2010.01185.x. PMID: 20840562.
Ferguson-Stegall L, McCleave EL, Ding Z, Doerner PG 3rd, Wang B, Liao YH, Kammer L, Liu Y, Hwang J, Dessard BM, Ivy JL. Postexercise carbohydrate-protein supplementation improves subsequent exercise performance and intracellular signaling for protein synthesis. J Strength Cond Res. 2011 May;25(5):1210-24. doi: 10.1519/JSC.0b013e318212db21. PMID: 21522069.
Goh Q, Boop CA, Luden ND, Smith AG, Womack CJ, Saunders MJ. Recovery from cycling exercise: effects of carbohydrate and protein beverages. Nutrients. 2012 Jul;4(7):568-84. doi: 10.3390/nu4070568. Epub 2012 Jun 25. PMID: 22852050; PMCID: PMC3407981.
Karp JR, Johnston JD, Tecklenburg S, Mickleborough TD, Fly AD, Stager JM. Chocolate milk as a post-exercise recovery aid. Int J Sport Nutr Exerc Metab. 2006 Feb;16(1):78-91. doi: 10.1123/ijsnem.16.1.78. PMID: 16676705.
Koopman R, Wagenmakers AJ, Manders RJ, Zorenc AH, Senden JM, Gorselink M, Keizer HA, van Loon LJ. Combined ingestion of protein and free leucine with carbohydrate increases postexercise muscle protein synthesis in vivo in male subjects. Am J Physiol Endocrinol Metab. 2005 Apr;288(4):E645-53. doi: 10.1152/ajpendo.00413.2004. Epub 2004 Nov 23. PMID: 15562251.
Negro M, Giardina S, Marzani B, Marzatico F. Branched-chain amino acid supplementation does not enhance athletic performance but affects muscle recovery and the immune system. J Sports Med Phys Fitness. 2008 Sep;48(3):347-51. PMID: 18974721.
Schena F, Guerrini F, Tregnaghi P, Kayser B. Branched-chain amino acid supplementation during trekking at high altitude. The effects on loss of body mass, body composition, and muscle power. Eur J Appl Physiol Occup Physiol. 1992;65(5):394-8. doi: 10.1007/BF00243503. PMID: 1425642.