Mont Ventoux, Alpe d’Huez, the Stelvio… there are many joys to cycling in the mountains, from following in the fabled draft of your cycling heroes to the achievement of reaching a summit and drinking in the spectacular vistas from the top of the world.
Yet cycling at altitude can be challenging and it’s important to be prepared before you tackle the legendary European cols.
We've spoken to three climbing experts to unlock the secrets of not only surviving, but positively thriving.
Here are their 10 essential tips to help you prepare for some high-altitude adventures in 2025.
- James Barber: lead performance specialist at The Altitude Centre
- Mike Wilson: lead cycling guide for Alpine-Cycling
- John Whitney: Cycling Plus and BikeRadar
1. Consider the effects of high altitude
“Air is thinner at altitude,” explains James Barber of The Altitude Centre in London.
“This means that the molecules of oxygen, nitrogen and carbon dioxide that air consists of are further apart. On each breath, there are fewer of each molecule, and crucially less oxygen for energy production.
"The effects of altitude start quickly, with the amount of oxygen in the blood dropping almost as soon as you start the mountain.”
2. Take care of your nutritional needs
When you’re riding a long distance at altitude, there are physiological changes to be aware of.
“With less oxygen available, our bodies prioritise carbohydrates for energy during exercise as they convert to energy more efficiently than from fat. We have a finite store of carbs, so we have to top up frequently,” says Barber.
Take two 750ml bottles filled with a carb/electrolyte drink and keep spare sachets in your pocket.
3. Stay hydrated
The cooler mountain air might mean you’re sweating less, but don’t forget to keep drinking.
“Altitude causes dehydration through a diuretic effect, plus you lose more water vapour via breath at high altitude as the air is typically drier,” says Barber.
“Cycling long climbs involves working harder and sweating, with less convective heat loss, which increases core temperature and salt loss.”
4. Go steady on the descents
In theory, you’ll be quicker on the descents because the lower oxygen pressure at altitude means the air is thinner.
But remember that you’ll have depleted energy stores and exercising at altitude is harder, so be sensible if the descent is fast and furious. Mike Wilson adds a word of caution.
“It isn’t advisable to take risks on the high Alpine passes. Remember that the roads are specially prepared for the professional riders before big events (‘Tourmac’), but for the rest of the year, there can be gravel on corners, damaged road surfaces after the winter snow, and even animals crossing.”
5. Sleep well
It can take a few days for the body to become accustomed to altitude and sleeping properly.
“Sleep quality can be reduced at altitude in people who are not acclimating well,” says Barber.
“It’s important to ensure you’re recovering well from hard efforts at altitude, so you don’t overreach,” he adds.
If you’re on a multi-day altitude ride, for example, try to do less than you normally would in the evenings to conserve energy, by doing things such as taking the lift instead of the stairs, for example. It’s best to avoid alcohol too.
6. And breathe…
“Humans have an inbuilt hypoxic ventilatory response: an overall increase in breathing (rate and depth) to get more air into the body from which to extract oxygen into the blood,” says Barber.
“This kicks in almost immediately on the ascent to altitude but dampens with acclimatisation.”
Practise breathing a little faster at higher altitude, adds Wilson. Doing diaphragmatic (belly) exercises at home before exercising can also help increase lung capacity.
7. Pace yourself
“If you usually train to power using a power meter and are unfamiliar with riding at altitude, accept that you won’t be able to immediately replicate the same numbers with increasing altitude,” says Cycling Plus' mountain master John Whitney.
“Adjust your effort and pace yourself on feel rather than numbers. This also applies when dealing with switchbacks at high altitude: one minute you might have a tailwind and overdo it, before swinging back into a headwind and feeling empty. Try to ride at a continuous effort.”
8. Dress for the occasion
Riding at altitude will see you deal with heat and cold in the same ride.
“Temperatures can swing 30°C between valleys and summits, so think about your clothing,” says Whitney, who has tackled many mountain passes in his time.
“Thermal arm warmers and a lightweight jacket/gilet can be stored in your jersey pockets. If riding as part of a group with a support vehicle, you can pack bigger items of clothing in a day bag.”
9. Plan ahead
Being prepared will give you peace of mind and more confidence in the mountains. Follow these simple steps:
- Be visible: take a back light so vehicles can see you better in tunnels and low visibility.
- Slap on sunscreen: check the weather forecast, wear sunscreen and take appropriate layers.
- Plan for bad weather: remember that a good forecast can still change at altitude – temperatures decrease as you get higher by around 1°C for every 100m.
- Take tubes and tools: ensure you have adequate spares and tools for adjustments or repairs.
- Pocket your phone: always take ID, next-of-kin details, a phone and a credit card, just in case you have an accident or major mechanical issue.
10. Crank it up
How do you prep for the mountains? “You can simulate the low cadence of high altitude at home on flat, windy roads,” says Whitney.
“Climbing generates high crank torque, so at home get into a big gear and do sets of low-cadence (60-70rpm) riding at zone 3 level. You could also climb a 10-minute hill six times at a steady pace to simulate a longer climb.”
Three of the best electrolyte drinks for high-altitude rides
Our pick of the best sweat-replacing tabs to ensure you stay hydrated.
Torq Hydration Drink
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Torq's Hydration Drink is a medium-strength electrolyte powder with some carbs (16g per 500ml serving). Several studies support Torq’s claim that a glucose-fructose solution of this concentration aids absorption of sodium and water.
- £24.95 / 30 servings
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Precision Fuel and Hydration PH 500
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These PH 500 tablets are designed to replace low to medium salt losses from sweat (there are also 1,000 and 1,500 per litre options). Their mineral content has been shown to reflect the proportions in most people’s sweat well.
- £8.99 / 15 tablets
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Styrkr SLT07 Hydration Tablets
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These tablets contain twice as much sodium per serving (500mg per 500ml) as many rival products. The electrolyte mix (which also has 100mg of potassium and 25mg of magnesium) is said to replicate the proportions usually found in sweat.
- £9.99 / 12 tablets
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