As winter is upon us, the temperatures are plummeting and the snow is starting to fall, some of us might be turning our thoughts to winter activities, Training, or competitions in the cold mountains! Historically, training and exercising at moderate altitude (1600-2400M) can greatly improve performance, but there are some serious considerations when you decide to compete, train or have a sports holiday in the mountains this winter. Here are a few tips and things to think about to help you get the most out of your trip!
The number one thing to consider is hydration. With altitude comes a reduction in air humidity and lower oxygen levels (called hypoxia). These conditions, along with the cold, make us prone to losing more water than normal as we breathe out more water at rest and during exercise. We experience an elevated breathing rate and lose more through greater urination (diuresis) and potentially lose more water from our skin, making us more likely to become dehydrated, contributing to symptoms of altitude sickness such as nausea, headaches, irritability & fatigue. These symptoms, as well as simply being in a dehydrated state, negatively affect your performance, enjoyment and health, so staying hydrated is key.
A good practice to help monitor your hydration levels, both at altitude and generally day to day, is the WUT Method, which considers your Weight, Urination and Thirst levels. If you observe changes to 2 or more of these metrics, you’re likely to be dehydrated, with changes to all three meaning dehydration is highly likely.
Here’s how to set up a simple practice, to start before you leave, to help monitor your hydration using WUT:
Weigh yourself in the AM, after visiting the bathroom for the first time and ideally nude, following the same routine for several days before departure. Rapid fluctuations in body water can impact your scale body weight, with rapid drops (1-2%) potentially having a negative impact on your cognitive and physical performance and mood, as well as leaving you more susceptible to altitude sickness.
Try to observe your urine colour after going to the toilet in the morning. You can gauge your level of hydration by the colour of your urine, where clear is extremely hydrated and very dark brown is extremely dehydrated. Aiming for a straw colour on the scale upon waking means you are less likely to be dehydrated. As a general guide, thorough out the day, you want to aim for between clear or pale yellow.
If you are an athlete being coached, or you just enjoy the structure of it all, you might receive (or you are welcome to find) a numbered urine chart, with a more accurate scale to judge by. For the sake of this article (and its hopefully wider audience !!) I’ve provided a more straightforward method!
This one is potentially the most obvious and immediate measure of dehydration and is especially apparent at altitude, where thirst tends to increase naturally due to the environmental conditions. If you wake up more thirsty than you usually do in the morning, you are likely to be dehydrated.
(again, athletes may receive a scale to judge this by for accuracy (e.g. the Likert Scale), but subjective thirst is just as valid and most accessible for the majority of people).
Following your thirst is always good advice when it comes to hydration, and it becomes especially important when you are out in the cold at altitude. It’s the most obvious sign you need more fluids, both in the morning and throughout the day. But taken together with the urine monitoring and/or body weight, you can better judge if simply following the thirst is working for you or whether you need to implement a more targeted hydration and rehydration strategy. It’s worth noting that needing to increase water intake by at least 1-2 litres/day is not uncommon.
Another factor to really bear in mind at altitude is the potentially higher demand for micronutrients. Hypoxic conditions increase the demand for iron to facilitate increases in haemoglobin, so it’s a good idea to get your iron levels checked in the 10 weeks before you travel, so you can start supplementing before your trip. (I’d personally suggested a full health check, especially if you aren’t used to being at altitude), as well as including plenty of iron-rich foods.
If you’re omnivorous, including poultry, eggs and red meat is a good idea, as is including iron-rich plant sources for your veg intake. Green leafy veg like spinach, beans, and pulses like lentils and chickpeas are all excellent choices. If you’re vegan or vegetarian, high iron plant sources are a must, plus make sure to include vitamin C—rich foods with your meals to help with absorption.
Oxidative stress during exercise also increases at altitude. This is due to the higher training and exercise volume and hypoxic conditions. But before you start reaching for the high dose antioxidant supplements, bear in mind that you can absolutely have too much of a good thing. High dose antioxidants can interfere with the training response and artificially limit your adaptations to exercise, so it’s wiser to aim for an antioxidant rich diet, and that means plenty of colourful fruit and veg!
Of the two main environmental concerns of temperature and altitude, the cold is the one with the most profound physiological effect on energy requirements. Although being at moderate altitude doesn’t increase metabolic rate and increase energy needs by itself, being in the cold does…but not by much. You may require at least an additional 10% of calories to keep warm and compensate for shivering during the winter months if you are outside a lot. If you work or train outside for extended periods, it is common to see significant losses in body weight and lean body mass as the body tries to maintain itself in subzero temperatures.
Paying close attention to your fuel needs is certainly important when it comes to exercising in the cold. Having adequate energy available to maintain core body temperature and support training will help you keep performance up, limit risk of injury AND keep warm. Whereas If you were heading out on a summer training camp, you might need to eat more to compensate for your higher training volume, training in the winter means you need to compensate for the cold as well. I would recommend increasing your carbohydrate to at least account for the higher training load and long days on the slopes, and to help keep you hydrated. If you are out on very long days and exposed and potentially add a little extra to help keep you warm. This is especially significant for cross country skiing, where clothing is usually not as insulated and energy needs are more extreme. This is definitely not the time to be in a heavy calorie deficit or attempt to Ski Keto!
Absolutely aim for mostly complex, minimally processed carbohydrates such as potatoes, rices and grains, but don’t be afraid to include slightly more processed options to support the higher calorie needs. Breads, pastas, and pizza’s all have a place to help maintain performance a support overall health with your high-energy demands.
Along with increasing Carbohydrates for energy, the other macronutrient you want to really watch out for is protein. If you are exercising, training or competing, you still need to recover and having adequate protein throughout the day will help that process. Normally, an intake of 1.4-1.8g/kg is sufficient. The problem is, when you are cold and at altitude, your ability to build and maintain muscle is impaired. This makes sense from a survival perspective. Most of your resources will be put into heat production and survival, and muscle is metabolically expensive… but you’re there to train or compete, and (hopefully) won’t need to wander the frozen wilderness for extended periods. To maintain muscle tissue in these conditions, I would recommend bumping protein intake to between 1.8-2.3g/kg to help mitigate potential muscle loss and reduced recovery capacity.
Great sources to look out for include: Lean cuts of chicken, beef, fish, and dairy products and protein powders for the omnivores among us and higher protein plant sources such a Tofu, Lentil, Chickpeas, and plant-based protein powders for vegan and vegetarians.
If you are hitting the slopes or trails this winter, I hope you find this article helpful in supporting your winter Activities. If you have any specific questions or are looking for nutritional support, whether that is for competition, training or general health across the coming winter months, get in touch, check out my services or comment below!
After 4-years in Switzerland, this guy can Ski (barely)!
Institute of Medicine (US) Committee on Military Nutrition Research, Marriott, B. M., & Carlson, S. J. (Eds.). (1996). Nutritional Needs In Cold And In High-Altitude Environments: Applications for Military Personnel in Field Operations. National Academies Press (US).
Stellingwerff, T., Peeling, P., Garvican-Lewis, L. A., Hall, R., Koivisto, A. E., Heikura, I. A., & Burke, L. M. (2019). Nutrition and Altitude: Strategies to Enhance Adaptation, Improve Performance and Maintain Health: A Narrative Review. Sports medicine (Auckland, N.Z.), 49(Suppl 2), 169–184. https://doi.org/10.1007/s40279-019-01159-w
Dünnwald, T., Gatterer, H., Faulhaber, M., Arvandi, M., & Schobersberger, W. (2019). Body Composition and Body Weight Changes at Different Altitude Levels: A Systematic Review and Meta-Analysis. Frontiers in physiology, 10, 430. https://doi.org/10.3389/fphys.2019.00430
Keefe, M. S., Luk, H. Y., Rolloque, J. S., Jiwan, N. C., McCollum, T. B., & Sekiguchi, Y. (2023). The WUT (Weight, Urine Color, and Thirst) Venn Diagram is an Accurate Tool Compared to Urinary and Blood Markers for Hydration Assessment at Morning and Afternoon Timepoints in Euhydrated and Free-Living Individuals. The British journal of nutrition, 1–21. Advance online publication. https://doi.org/10.1017/S000711452300274X
van Ooijen AM, van Marken Lichtenbelt WD, van Steenhoven AA, Westerterp KR. Seasonal changes in metabolic and temperature responses to cold air in humans. Physiol Behav. 2004;82(2-3):545-553. doi:10.1016/j.physbeh.2004.05.001