Skiing: Preventing The Afternoon Bonk

BY Pacific Health Laboratories

Some well-timed carbohydrate and protein consumption will help you get much more out of your next winter trip to the mountains. Here are a few tips to prevent that afternoon bonk.

Some well-timed carbohydrate and protein consumption will help you get much more out of your next winter trip to the mountains.

Anything you can do to enhance your clients’ experience on the slopes will be beneficial to your business. A better day of skiing for them means bigger tips, more repeat business, and more referrals for you. Obvious ways to enhance your clients’ experience include matching them up with the right equipment, providing the best possible instruction, and developing an individual rapport with each client. 

Another factor that many professional ski instructors overlook is nutrition. Skiing is a demanding activity, and the typical day on the slopes is several hours long. Consequently, skiers who fail to take in proper sports nutrition tend to become dehydrated and fatigued, causing them to perform poorly and feel lousy. Helping your clients fuel their bodies properly while under your instruction is a simple way to enhance their experience that will surely pay dividends. 

The Three O’clock Bonk 

A few years ago we spent a full day observing the hydration habits of recreational skiers at a mountain resort. We saw nothing. 

In other words, only about five percent of the people we saw were drinking anything during skiing. We also interviewed about 50 skiers, virtually all of whom reported that a noon lunch break was the only opportunity they afforded themselves to take in fluids and nutrition to fuel their day on the slopes. Not surprisingly, many of these skiers reported suffering from something we might call “the three o’clock bonk”. By mid-afternoon, most of them were running on fumes – exhausted and sore. Lunch could only carry them so far. 

Skiers Sweat, Too 

Staying hydrated is as important during skiing as it is in any other type of exercise. Several factors increase the likelihood of dehydration during skiing. 

First, cold air tends to be very dry, especially at higher altitude, and in dry air more fluid is lost as vapor through breathing. Second, the cold tends to suppress thirst. Even though drinking a sports drink is more palatable, in the cold, athletes are likely to drink less than they need. Third, cold-induced diuresis leads to a rapid fluid loss via urination, which often reduces the amount of fluid athletes voluntarily chose to drink when exercising in the cold. Finally, the heavier clothing that is worn during cold-weather activities in some winter sports can make movement more cumbersome and inefficient, leading to fluid loss through sweating that is comparable to that in the temperate environment. 

As in hot-weather exercise, water is not sufficient for hydration during skiing. Along with water, electrolyte minerals (mainly sodium) are also lost in sweat. Sports drinks containing sodium and other electrolytes hydrate better than water. In a study involving cross-country skiers, we found that those who used a sports drink while skiing were able to maintain their fluid balance much better than those who drank plain water. 

The Energy Factor

Preventing dehydration is only half the battle when it comes to avoiding the three o’clock bonk. It’s equally important to keep your muscles from running out of energy. The energy demands of skiing are similar to those of other sports. Carbohydrate is the muscles’ primary fuel during skiing. By taking in extra carbs in a sports drink between runs, your clients will be able to ski better, longer. 

A good sports drink can also reduce the muscle damage and soreness that occur during skiing. This was demonstrated by the results of a recent experiment. Our research team divided a group of 31 recreational skiers into three groups. All three groups skied 12 runs or about 22,000 vertical feet, which took roughly three hours. One group drank nothing, as most skiers do. A second group drank 6 ounces of flavored water after every second run. And a third group drank an equal amount of a sports drink containing carbohydrate and protein (Accelerade). 

After the 12th run, we took blood samples from each skier and examined it for signs of muscle damage. The skiers who drank nothing showed the most muscle damage. Those who drank water showed slightly less muscle damage. But the skiers who drank the carb-protein sports had by far the least muscle damage. Most of the skiers in the third group also reported that they felt great throughout their 12 runs, whereas members of the other groups tended to report fatigue and soreness. 

These results clearly show that recreational skiers need to drink at frequent intervals just like athletes in other sports. Water is better than nothing, but a good sports drink that provides energy, as well as fluid, is the ideal choice. 

Protein Power 

It’s important to note that most sports drinks do not contain protein, but there is mounting evidence that sports drinks with protein are more beneficial. In a recent James Madison study that compared the effects of the same carb-protein sports drink we studied and a conventional carb-only sports drink (Gatorade) on athletic performance, the carb-protein sports drink delayed fatigue by 29% and reduced muscle damage by 83% as compared to the carb-only drink. 

Even more significant, the subjects receiving the carb-protein sports drink lasted 40% longer than subjects in the other group in a subsequent workout undertaken the following day. This indicates that the carb-protein subjects recovered faster from the first workout, most likely because they had experienced less muscle damage. 

Clearly, these results have important implications for recreational skiers, who often put in two or three consecutive long days on the slopes, having arrived at the mountain not in peak shape to begin with. Anything they can do to help them wake up less sore on the second and third mornings will be much appreciated. Using a carb-protein sports drink throughout the day is one of the most effective things they can do. 

Putting It into Practice 

The most practical way to make a sports drink available throughout a day on the slopes is to carry it in a fluid pack, such as those made by CamelBak. Instruct your clients to take a good swig every 15-20 minutes. This will not only minimize the chance of the three o’clock bonk, but it will also help your clients recover faster so they can come back strong tomorrow – a key benefit for those multi-day ski trips. 

Another option is to use an energy gel such instead of a sports drink. Sold in single-serving packets and available in most bike shops and running stores, energy gels contain everything a sports drink has except the water. Gel packets are much lighter, smaller, and therefore easier to carry than a sports drink. However, since they don’t provide hydration, gels need to be washed them down with water. Instruct your clients to carry and consume one gel packet per hour of skiing. 

As with sports drinks, most energy gels contain carbs but no protein. An energy gel with protein is preferable. 

In Summary

Recreational skiers tend not think of skiing as demanding physical exertion, but it is. Unfortunately, many professional ski instructors make the same mistake. Because skiing does cause as much dehydration and use as much energy as any other sports, skiers have the same fluid and nutrition needs. Skiers who take care of these needs properly will ski better, longer, and have a better experience.

As a professional ski instructor, you are in an ideal position to give your clients the guidance they need to fuel themselves correctly on the slopes. They’ll thank you for it. 

John Seifert, Ph.D., is associate professor of exercise physiology at St. Cloud State University. 
Ron Kipp is a ski coach and instructor examiner in Salt Lake City, UT.

About Pacific Health Laboratories

PacificHealth Laboratories creates nutrition tools such as Accelerade, Accel Gel, Endurox R4, Endurox Excel and much more. For product information or to purchase products, please visit