After a strenuous and prolonged athletic event or intense training session, it is highly recommended to follow the “4Rs rules”:

1. Refuel: carbs to replenish glycogen stores, and energy restoration.

2. Rehydrate: fluid lost in the effort (plus electrolytes)

3. Repair: protein to repair muscle fiber damaged during exercise

4. Rest: ensure enough sleep to enhance recovery.

 

How soon should you act? 

Recovery guidelines stated for a while that what we call “the window of opportunity” for the first 3Rs was of minimum 30 minutes after stopping the activity. But recent research has demonstrated that the “window” actually stays “open” for a  longer time, up to 24 hours, with optimal results during the first few hours (around 1-4h). 

And of course, as for many things in life, it depends… on what is available, where you are when stopping the activity, and how you feel. For example, most athletes don’t feel hungry right after crossing the finish line or at the end of a game, since adrenaline and cortisol tend to suppress the hunger hormones. However, thirst is not blunted by effort.

 

Rehydrate: This is usually the easiest of the 3Rs (let’s exclude Rest for now) to kick-off, and probably the most needed. And a critical one because - especially in Hong Kong’s warm and humid weather, we will continue to sweat (and lose fluid and electrolytes), even after we finish. Have you noticed how much you kept sweating even after you came back home from a run? 

Also, we tend to ingest and absorb fluids more easily than solid foods even though cortisol and adrenaline are still running through our system, once we are done exercising. 

Plain water is not the best rehydration drink. It is better to use a mix of electrolytes (mainly sodium), and some sugar, to rehydrate faster and replenish loss of minerals. Another good option is any kind of milk (chocolate milk or plain), or sweetened dairy-free milk.

 

Refuel: mainly carbs. The goal is to restore energy levels, support the immune system and to replenish glycogen storage. Muscle cells after heavy exercise and glycogen depletion are very sensitive to insulin, which will promote glucose uptake, especially right after the event. So it is not the time to be shy on carbs/sugars. And I wrote sugar here, because it is better to use moderate to high GI types of carbohydrates, for faster glucose release. Including fruits (as fructose will be uptaken in  muscle cells via a different transporter system than glucose). Use around 1.2g/kg/BW/h for 4 hours as a rule of thumb. As it takes around 4 hours for carbs to be digested and “repacked” as glycogen. Studies haven’t found any difference between regular snacks or a large carb-rich meal when it comes to glycogen storage restoration. Just do what feels comfortable for you. 

 

Repair: this is about your muscle fibers being damaged by exercise (a normal process), and also loss of some muscle fibers broken down for energy production (which will happen to a smaller extent, even if you fuel properly), during a long and strenuous bout of endurance training, or an ultra-race. The higher the intensity and the longer the effort, the more damage. 

Ingesting high-quality protein (all 9 essential amino-acids, especially leucine), combined with carbohydrates, is critical to repair muscle and support immunity. Insulin, which is released into the bloodstream for glucose uptake in the muscle cells, will also promote protein intake.

Depending on the exercise duration, 10-15 g of protein with 3 times the amount of carbs is usually a base to start with. But if you just finished a marathon, a 100km cycling race or an ultra-trail event, you might want to go up to 30g (ideally with 90-120g of carbs). An easy trick, for those who can’t stomach a large piece of chicken with 2 bowls of rice, would be a nice protein shake with chocolate milk or your preferred dairy-free drink, and a generous amount of natural sugar (such as from fruits). If this is not available (or too complicated to get in time), there are also some recovery drinks which combine all in one.

Micronutrients such as Vitamin D and minerals (potassium,magnesium, zinc, iron), and natural antioxidants in fresh fruits and vegetables are also promoting tissue repair and recovery from oxidative stress. As well as being immune-supportive.

 

Rest: of course getting enough rest and a proper amount of sleep is paramount. It is as important as diet, to promote optimal recovery after an endurance race or a strenuous and long training session. Magnesium helps to relax, and some adaptogens such as ashwagandha have shown some benefits for relaxation and sleep onset.

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Bonilla, D. A., Pérez-Idárraga, A., Odriozola-Martínez, A., & Kreider, R. B. 2021. The 4R’s Framework of Nutritional Strategies for Post-Exercise Recovery: A Review with Emphasis on New Generation of Carbohydrates. International Journal of Environmental Research and Public Health. https://doi.org/10.3390/ijerph18010103

Jeukendrup, A.E. 2011. Nutrition for endurance sports: Marathon, triathlon, and road cycling. Journal of Sports Science. doi-org.eproxy.lib.hku.hk/10.1080/02640414.2011.610348

 

Naderi, A., Rothschild, J.A., Santos, H.O., Hamidvand,A., Koozehchian, M.S., Ghazzagh, A.,  Berjisian, E and Podlogar, T. 2025. Nutritional Strategies to Improve Post-exercise Recovery and Subsequent Exercise Performance: A Narrative Review. Sports Medicine. https://doi.org/10.1007/s40279-025-02213-6

 

Nikolaidis, P.T., Veniamakis, E., Rosemann, T. and Knechtle, B. 2018. Nutrition in Ultra-Endurance: State of the Art. Nutrients. doiorg/10.3390/nu10121995.

Thomas, D.T., Erdman, K.A. and Burke, L.M. 2016. Position of the Academy of Nutrition and Dietetics, Dieticians of Canada, and the American College of Sports Medicine: Nutrition and Athletic Performance. Journal of the Academy of Nutrition and Dietetics. 10.1016/j.jand.2015.12.006.