In a nutshell, the recovery phase involves:
- Restoration of muscle and liver glycogen stores, depleted by exercise
- Replacement of fluids and electrolytes lost via sweat and breathing
- Regeneration, repair and adaptation which takes place after catabolic stress and damage
- This includes protein synthesis and breakdown as well as immune and antioxidant defence systems
Fuel or energy source for moderate to high intensity exercise. It is the storage form of carbohydrates in the body.
Recovery of muscle and liver glycogen stores
- As exercise is done the body uses energy in the form of muscle glycogen.
- The depletion of glycogen when exercising is the stimulus for glycogen repletion.
- This provides a strong drive for the replacement of muscle glycogen stores and takes precedence over liver glycogen storage.
- Should no dietary carbohydrate be consumed during this phase in exercise, muscle glycogen repletion will happen at a slow rate as the body will use stores to create glycogen.
- Muscle glycogen repletion is dependent on the provision of dietary carbohydrate for exercise.
- Muscle glycogen stores will last up to 60 – 90 minutes for endurance and intermittent high intensity exercise (e.g. soccer).
- If exercise is longer than this, dietary carbohydrate should be taken during exercise before glycogen (fuel) depletion is reached. In this way glycogen can be restored before it is depleted and this will also help to prevent “hitting the wall”.
Hitting the wall or the bonk
Is a condition of a sudden loss of energy or fatigue where you feel you cannot continue any further – while you are doing sport such as cycling and running. It is caused by the depletion of glycogen stores in the liver and muscles.
Nutrients for recovery
- The single most important factor affecting muscle glycogen storage is the amount of carbohydrate ingested
- The highest rate of glycogen storage is in the first hour post exercise, due to
- Activation of the relevant enzymes
- Exercise induced increase in insulin sensitivity
- Increased muscle permeability
- Meeting the total carbohydrate requirements is in fact more important than the exact timing
- The type of carbohydrate is important to ensure maximum delivery, acceptability and gastric comfort
- Meals high in fibre can lead to overestimating carbohydrate intake whilst providing a poor substrate for glycogen storage. It may also increase gastric discomfort and emptying as well as prevent a “gut empty” feeling
- High GI, low fibre carbohydrates are recommended e.g. white bread with syrup or jam, litchi juice, jelly beans, sport energy drinks
- Mixed carbohydrate source drinks (e.g. PeptoSport®) have higher rates of oxidation which means they enter the muscle more rapidly than single carbohydrate source drinks
- The IOC recommends 50g of carbohydrate given every two hours for maximum recovery of muscle glycogen
- Carbohydrates in liquid or solid form can be taken, it makes no difference
- This choice depends on the athlete’s preference, practicality, availability and palatability
- A combination of both is most useful, with fluids providing carbohydrate and water for the recovery process
- Protein in combination with carbohydrate intake aids in the absorption of glucose which increases the glycogen storage rate
- Protein plays an important role in enhancing net protein balance, tissue repair, adaptation after exercise and to reduce muscle fatigue
- The benefits of the addition of protein are limited to the first hour post exercise
- Hydrolysed protein (peptides) (e.g. PeptoPro®) is soluble and requires no digestion there fore enters the muscles much faster and there is no gastro intestinal discomfort commonly associated with whole proteins
- The recommended ratio of carbohydrate to protein for optimal benefits is 4:1
- Protein intake should never compromise or displace carbohydrate intake
Fluid and Electrolytes
Thirst and voluntary intake are often not enough stimuli for fluid replacement.
- Replaces fluid and electrolytes that are lost via sweat and breathing during the exercise
- Prevents dehydration and cramping
Vitamins (including Antioxidants) & Minerals
- Aids in protein synthesis as well as immune and antioxidant defence systems.
- It is generally accepted that 20 – 24 hours are required for the normalisation of glycogen stores after glycogen depleting exercise.
- In multistage events or in an “every day training” scenario this is not practical as subsequent performance is dependent on it!
- In these kind of events or when training every day recovery starts during the event to ensure optimal performance.
- Studies have shown that taking carbohydrate with a hydrolysed protein (PeptoPro®) directly after the event reduces the glycogen recovery time to 16 hours versus taking only carbohydrate that can take 37 – 23 hours (as illustrated by graph 1 and graph 2).
- Optimal recovery during a multistage event or in an everyday training scenario generally requires a specific, aggressive nutritional strategy.