Shaun Ward MSc ANutr
Exercise, especially at high intensities and durations, causes the breakdown of muscle proteins (protein degradation), depletion of energy stores, and fluid imbalances.
This makes nutrition an important consideration for recovery needs, otherwise these processes will impair recovery, adaptations to exercise, and lead to muscular injury.
Typically, most people focus solely on protein intake to initiate recovery. However, as much as this is important, it misses out entirely on the other areas which make up “complete recovery”, such as carbohydrate, fluid, and electrolyte intake.
More to this, recovery from exercise can be split into 2 separate categories:
- Immediate recovery (<1 hour post-exercise): vital for restoring protein balance, carbohydrate stores and fluid levels.
- Extended recovery phases (24 - 48 hours): necessary to increase daily muscle protein balance to stimulate maximal adaptation.
The 3 Components to Complete Recovery
Below we've listed the 3 main things you need to know about when it comes to understanding optimal post workout nutrition:
1. Energy Restoration
During intense exercise, carbohydrate stores – in the form of stored muscle glycogen - is the only substrate able to meet the high rate of demand for energy production.
However, carbohydrate stores within muscle are limited, and if exercise duration and intensity is adequate, this will cause a significant decrease in carbohydrate stores by the end of exercise.
The more intense the exercise session, and the longer it goes on for, the more severe the depletion will be .
Based on typical resistance and/or endurance workouts, carbohydrate stores become depleted between 90-120 minutes .
This represents a need to consume carbohydrate in the post-exercise period to restore energy levels, and avoid potential side effects such as muscular cramping and performance deteriorations.
For immediate carbohydrate replenishment, it is recommended to consume ~1 gram of carbohydrate per kg bodyweight within the 1 hour period post-exercise .
However, keep in mind this will only kick-off recovery processes, and one meal alone is not sufficient for complete recovery.
For complete recovery, consume ~6-10 grams of carbohydrate per kg bodyweight during the 24-hour period post-exercise . Although this range is fairly large, the specific amount that is ideal for you will be dependent on the exercise session that has been completed and the subsequent level of carbohydrate depletion.
The more intense and long the exercise session, the more carbohydrates will be needed to restore energy levels post-exercise.
2. Muscle Repair
Muscle damage is induced by mechanical stress during exercise of adequate intensity and duration, causing a breakdown of muscle proteins and a negative muscle protein balance.
Recovery of muscle damage is necessary to avoid impairments in recovery, exercise adaptations, and potential risk of injury.
Without ideal protein ingestion in the post-exercise period, muscle damage may still be apparent up to 48 hours later, which can negatively impact ratings of perceived exertion and power output in future exercise bouts .
Endurance-based performance will also decline in this scenario due to an increased rate of glycogenolysis (energy usage) and higher blood lactate concentrations .
To recover and adapt optimally from muscle damage, it is crucial to take advantage of the upregulation of muscle protein synthesis from dietary protein ingestion after a workout – which lasts for 24-48 hours.
Dietary protein will aid in the repair and reconditioning of skeletal muscle tissue after exercise by favorably altering protein balance and forming new contractile and metabolic proteins .
It is recommended to consume 0.3 grams of protein per kg of protein in the early recovery phase (0-2 hours after exercise), and repeat consumption every 3-4 hours to ensure a maintenance of positive muscle protein balance throughout the day .
For complete recovery, 24-hour protein intake should be 1.2-1.6 grams per kg bodyweight, although exercise which requires excessive physiological demands may warrant increased intakes of ~1.8-2.0 grams per kg bodyweight .
During exercise, especially in hot and humid conditions, you will reduce water and electrolyte stores as a consequence of thermoregulatory sweating.
The degree of fluid loss is determined by exercise duration, intensity, environmental conditions, individual sweating rates, and also depends on the amount of fluid consumed during exercise.
Many electrolytes are contained within sweat, although sodium is of the largest concern for athletes to replace in post-exercise nutrition as it is the most concentrated and significantly impacts fluid retention and blood volume restoration.
Therefore, this fluid should be restored post-exercise to normalize levels of fluid within muscles, blood, and other cells.
It is recommended to consume 150% of lost fluid weight (from pre- to post-exercise) within the 4-6 hour period after a session finishes e.g 1.5L fluid for every 1kg bodyweight lost . This may require you to measure your bodyweight before and after exercise to get a good idea of your sweat rate per hour.
In addition, as the amount of sodium in sweat averages around 40mmol/L, cyclists should include 50-90mmol/L within rehydration fluids . In a practical sense, this is nothing more than a pinch of salt within your rehydration drink and/or meal.
Practical Tips After Exercise
Now that you have learnt the science behind post-workout nutrition, here are some practical tips to start putting this information into action:
- Take advantage of liquid-based nutrition immediately after exercise as it does not require as much digestion, which allows the nutrients to be absorbed into muscle cells far quicker. This could be a protein shake with added bananas and blueberries, for example.
- Try to choose carbohydrate sources that are low in dietary fiber for the post-exercise shake. This allows the carbohydrates to be digested and utilized much faster for immediate effect. Low fiber options would be most fruits, honey, maltodextrin, and dextrose.
- Avoid dietary fat in the post-exercise meal as this nutrient significantly slows digestion rates and will reduce the effectiveness of post-workout nutrition. Fat may even blunt the anabolic response post-exercise. Stick to protein and carbohydrate-based food and drinks.
- Follow the post-workout shake up a few hours later with a more balanced wholefood meal that has a good source of protein, carbohydrate, fat, vitamins and minerals. For example, this could include potatoes, meat, mixed vegetables and extra virgin olive oil.
Exercise causes the breakdown of muscle proteins, depletion of energy stores, and fluid imbalances.
To recover optimally, the ingestion of adequate protein, carbohydrates, and fluid is essential in the immediate post-exercise period (<1 hour).
For quick nutrient absorption into muscle cells, liquid-based drinks containing fast-acting sources of protein and carbohydrate is an ideal recommendation.
However, it is important to note that complete recovery cannot be achieved at just one meal, and ones daily nutrient intake needs to be in place to fully adapt and recover.