Ski Day & Race Day: Cross-Country Ski Fueling, Hydration, Waxing and Layering

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Race morning in Mora or Cable is a scene: car trunks open in the dark, wax irons plugged into generators, the smell of hot wax and coffee, skiers in three jackets jogging to the start pens and someone asking for the hundredth time, “What are you kicking with?” Whether it’s a school race on a Wednesday afternoon, a college carnival, a World Cup sprint, a club tour or your first 50 km marathon, a good ski day comes down to four things: eating enough, drinking enough, skis that work, and clothes that match the weather. Here’s how to get each one right.

General information. Athletes with diabetes, asthma, heart conditions or other health needs should plan race day with their doctor. Back to the cross-country skiing hub.

Before the start: the race-morning meal

Cross-country skiing burns a lot of energy. The Compendium of Physical Activities rates moderate skiing at about 8.5 METs and racing at 14 to 16, so even a 10 km race is a big effort and a marathon is a full day’s work. The joint position stand of the American College of Sports Medicine (ACSM), the Academy of Nutrition and Dietetics and Dietitians of Canada recommends 1 to 4 grams of carbohydrate per kilogram of body weight in the 1 to 4 hours before exercise lasting more than an hour, going easy on fat, fiber and heavy protein that can sit in the stomach.

• 3–4 hours out: a real breakfast you know well: oatmeal with banana and honey, bagels or toast with jam, rice, pancakes, yogurt.
• 1 hour out: a small top-up if you’re hungry: a banana, a sports drink, a few crackers.
• Nothing new. Race morning is not the day to try a new gel or drink. Test everything in training.

During: fueling in the cold

For efforts of 1 to 2.5 hours, ACSM’s guidance is 30 to 60 grams of carbohydrate an hour; for efforts longer than about 2.5 to 3 hours, up to 90 grams an hour, using drinks or gels that mix glucose and fructose, practiced in training first. Short races (sprints, 5–10 km) don’t need fueling during the race; a 50 km marathon or a 90 km Vasaloppet does. Cold makes this harder in practical ways:

• Things freeze. Gels thicken, bars turn to bricks, bottle valves ice up. Carry gels in an inside pocket close to your body, and use an insulated bottle or a pack with an insulated tube.
• Warm drinks help. Many skiers fill an insulated bottle with a warm sports drink.
• Gloves and poles make it fiddly. Open gel tops before the start or tear a notch so you can open them with your teeth; practice taking a drink while skiing.
• Eat early. Start in the first 30–45 minutes of a long race, before you feel empty.

Hydration when you don’t feel thirsty

Winter air is cold and dry, you lose water with every breath, and many skiers simply drink less when it’s cold. Skiers also sweat more than they think: in a 2025 study of elite racers in Finland, core temperature climbed to about 39 °C during races at −13 °C to −1 °C. The National Athletic Trainers’ Association (NATA) suggests knowing your own sweat losses (weigh yourself before and after a long session) and warns against drinking so much that you gain weight during exercise, which raises the risk of low blood sodium (hyponatremia). An electrolyte drink such as Skratch Labs Hydration or Nuun Sport tablets is an easy way to get sodium and fluid in; see our electrolyte guide.

At altitude it matters more. The CDC advises easing into exercise and avoiding alcohol for the first 48 hours at high altitude, and lists dehydration among the problems that can look like altitude sickness. Many western US trail systems sit high, so plan a day or two to settle in before a race.

Waxing day: logistics that save your race

Skis that glide and (in classic) grip can matter more than a week of training. A simple plan:

• The night before: check the forecast for air and snow temperature and new snow. Clean the bases and iron in a glide wax for the expected conditions, scrape and brush.
• Race morning: arrive early. Test skis on the course or a warm-up loop. Classic skiers apply and test kick wax in thin layers, smoothing each with a cork, and adjust: if you slip, go softer or longer; if snow sticks, go harder or thinner.
• Bring a small kit: two or three kick waxes, a cork, a scraper, a quick liquid or paste glide wax, a rag and a marker for your kick zone.
• Don’t forget yourself. Many skiers spend the warm-up waxing and start cold. Finish waxing in time for a proper 15–20 minute warm-up.

No fluoro wax. FIS rules prohibit fluorinated wax and tuning products containing fluorine in all FIS disciplines and at all levels, and using it in competition means disqualification. The ban started in the 2023/24 season because these waxes contain PFAS, the “forever chemicals” that don’t break down in the environment. FIS tests skis with an infrared device at three spots on each ski; three positive spots means disqualification. In its first season, FIS ran about 60,000 measurements and found fewer than 10 violations across World Cup disciplines. Citizen races test too: at Vasaloppet’s 2024 winter week, organizers did random checks at starts and finishes, offered free pre-tests at bib pickup, and told skiers who tested positive at the start that they couldn’t race on those skis. Old wax, brushes and irons can be contaminated, so clean or replace them if you’re unsure.

Layering for the start, the race and the finish

The American Academy of Orthopaedic Surgeons (AAOS) advises layers of light, loose clothing that resist wind and water, and ACSM’s cold-weather position stand says clothing should be chosen for each person, not one outfit for the whole team. Skiers run hot: dress for the hardest part of the race, not the start pen.

• Racing: a thin wicking base layer, a race suit or light jacket and tights, a thin hat or headband, light gloves. On very cold or windy days, add a wind vest, windproof front panels or briefs, and a neck gaiter.
• Before and after: a big warm jacket and pants over everything until the last minute, then straight back on at the finish. A dry hat, dry gloves and a dry top in a bag for after, because wet layers chill you fast.
• Touring days: carry an extra layer, a spare hat and mitts, and a hand warmer, since a broken binding or a fall far from the trailhead turns into a long, cold walk.
• Sun: the World Health Organization notes snow can reflect as much as 80% of UV radiation. Use sunscreen and lip balm with SPF and wear glasses.

Know the cold limits. FIS postpones or cancels cross-country races below −20 °C at the coldest point of the course, and citizen races at −25 °C or below in a major part of the course, with cold-weather advice to skiers from −15 °C. Frostbite signs and first aid are on our injuries page.

What’s in a smart skier’s bag

Three things that solve most ski-day problems: an all-temperature glide like Swix F4 liquid glide wax for quick touch-ups without an iron, a Swix classic kick wax pack (three kick waxes and a cork) for classic days, and an insulated bottle like the Hydro Flask 32 oz so your drink doesn’t freeze. For long tours, some skiers carry a pack with an insulated tube such as the CamelBak Zoid Snow.

After the finish line

Get dry layers on first, then eat and drink: carbohydrate and some protein within the next hour or two, and fluids with sodium. If you’re racing again tomorrow, refueling matters more. The full routine is on cross-country ski recovery, and daily eating on nutrition and supplements. For how a team sport handles game day, see soccer game day; for a resort day, alpine ski day.

Ski day and race day: FAQs

What should I eat before a cross-country ski race?

A familiar, carbohydrate-rich meal 1 to 4 hours before, such as oatmeal, bagels, toast with jam or rice, keeping fat and fiber modest. ACSM’s guidance is 1 to 4 grams of carbohydrate per kilogram of body weight in that window.

How do I keep my drink from freezing?

Use an insulated bottle or a hydration pack with an insulated tube, start with a warm drink, and keep gels in an inside pocket. Blow the drink back out of the tube after each sip so it doesn’t freeze in the hose.

Can I use fluoro wax in a citizen race?

Not in FIS races: fluorinated wax is banned in all FIS disciplines and levels, and big citizen races such as the Vasaloppet test skis. Many other races follow the same rule. Use fluoro-free waxes and clean old tools.

How much should I fuel in a ski marathon?

ACSM guidance is 30 to 60 grams of carbohydrate an hour for 1 to 2.5 hours of exercise and up to 90 grams an hour for longer efforts, using glucose-fructose products you’ve practiced with. Start early and eat regularly.

What should I wear for a cold cross-country race?

Less than you think for the race itself: a wicking base, a race suit or light jacket and tights, thin hat and gloves, plus wind protection and a neck gaiter on very cold days. Keep a warm jacket on until the start and a dry change of clothes for the finish.