They do yes, although are sometimes surplus to requirements.
When we exercise – especially at high intensity or after 90 minutes – unless we take on additional carbohydrate fuelling during the ride, we will deplete our muscle glycogen stores. Replenishing these stores ensures that we are able to complete strenuous training the next day, without our performance being impaired.
Many studies have shown that consuming carbs within an hour of competing exercise is most beneficial as the insulin response post exercise directs the carbs (broken down into glucose) to the muscles rather than being directed into fat stores. Of course, there’s more to recovery than one meal, but kickstarting the recovery with fast acting carbohydrates does aid recovery. And when time or access to cooking is limited, recovery drinks offer a great option for fast tracking our recovery for the rest of the day and the following days.
Getting enough protein is also a vital part of this, and consuming carbs with protein assists even further with muscle protein synthesis. When we exercise, we damage the muscles in different ways. This is the reason we experience delayed onset muscle soreness (DOMS). To help combat this, adequate protein consumption ensures that there are adequate amino acids present for muscle protein synthesis allowing damage to be repaired.
This means less pain in our legs, and greater muscle development post training, especially those wanting to build greater muscle mass. Ideally, we want between 20-30 grams of protein, as more than that has been found to be surplus to requirements.
Another benefit of adequate protein is reducing muscle catabolism, as cycling is a weight limited sport (however, always focus first on the ‘Watts’ part of 'watts per kilogram'), when trying to burn fat in a safe manner, it is important to maintain high dietary protein so as to reduce muscle loss during a calorie deficit.
Another benefit of recovery drinks is hydration. Proper rehydration is equally as important as replenishing carbs and protein consumption. A benefit of consuming fluids with carbs is that it prevents the water from passing through as quickly, improving hydration efficiency. Studies have shown that milk is better for hydration than plain water, for instance, and part of this is due to the presence of carbs.
So yes, recovery drinks do work.