Skiing with Type 1: keeping insulin and devices warm, and fuelling a full day on the mountain
Skiing with type 1 diabetes: keeping insulin and your pump or CGM from freezing, fuelling long days on the slopes, and staying ahead of cold-weather lows.
A full day skiing or snowboarding is hours of exercise in the cold, and that combination pushes glucose down hard, both on the slopes and often overnight afterwards, so lows are the main thing to plan for. The cold brings its own problems: insulin is ruined if it freezes, phone and pump batteries drain fast, and cold can dull both your hypo warning signs and your sensor. Keep insulin and devices warm against your body, carry fast sugar you can take with gloves on, and sort any insulin changes with your diabetes team before you travel rather than guessing on the mountain.
- All-day activity makes your muscles pull in glucose for hours, so hypos (lows under 4 mmol/L) are likely on the slopes and can also arrive overnight after a big day.
- Insulin must not freeze: freezing damages it for good, so keep pens, cartridges and spares in an inside pocket against your body, never in an outer or backpack pocket.
- Cold drains batteries and can make phones and pumps cut out, and it can blunt your hypo symptoms so a low sneaks up without the usual shaky warning.
- Carry fast sugar you can open with gloves on, kept warm so it is not a frozen brick when you actually need it.
- Any change to insulin for big active days is worked out with your diabetes team, never decided on the mountain.
Why the mountain runs you low
Skiing does not feel like a workout the way a run does, but it is hours of effort, and the cold adds to it, because shivering and simply staying warm burn glucose too. Your muscles use glucose all day and then keep pulling it in for hours afterwards to restock, which is why the danger is not only the mid-afternoon slump on the last run but also a low that evening or overnight while you sleep. The practical answer is to check more often than at home, snack on the lifts, and expect to need more fuel than a normal day. Short, intense bursts, a steep mogul field or a race, can briefly nudge glucose up before it falls, so it can move both ways, but over a full day the direction is firmly downwards.
Keeping insulin, pumps and phones alive
Insulin freezes at around zero, and once it has frozen it is damaged for good even if it looks fine again after thawing, so never leave it in an outer jacket pocket, a backpack, or the car overnight. Keep pens and spare insulin in an inside pocket close to your body where your warmth protects them. A pump is best worn under your layers against you, with the tubing tucked away from the cold. Phones lose battery startlingly fast in low temperatures and can shut down, which is a problem if your CGM shows on your phone, so keep it warm and carry a power bank. The cold can also make sensor readings lag or read oddly, and finger-prick meters and strips have temperature ranges too, so keep a backup kit warm inside your jacket.
Catching and fixing a low with gloves on
Two things make lows harder to catch on the mountain: the cold can mute your usual warning signs, and heavy exertion, goggles and layers hide them further. So lean on your CGM alarms and check more often rather than waiting to feel it. For treating, choose fast sugar that still works in the cold and that you can manage with gloves on, glucose gels, jelly sweets or a soft chewy bar tend to beat anything that freezes solid. Keep it warm in an inside pocket. When a low hits, stop and get safely to the side of the piste, treat it, recheck, and do not push off down the slope the moment the number ticks up, because you can still be impaired. Make sure the people you ski with know you have Type 1, what a low looks like, and where your sugar is.
Planning the trip around it
A bit of planning makes the whole week easier. Carry at least double the supplies you think you need and split them across bags in case one goes missing, and keep some insulin at normal room temperature back at the chalet rather than always fridge-cold. A letter from your team helps at the airport with insulin and devices, and it is worth checking your travel insurance actually covers winter sports and your diabetes. Two things reliably catch people out at the end of the day: apres-ski drinks, because alcohol can cause a delayed low hours later, on top of a body already primed to drop from the exercise, and simply going to bed after the most active day of the year. Set an overnight alarm, keep fast sugar by the bed, and check before you sleep.
What changes how skiing hits your glucose
Everyone skis differently and every day is different, so treat your first trip as a learning week rather than expecting to get it perfect. Fitness, how hard you push, the temperature and altitude, and whether you drink in the evening all change the picture, and they mostly stack up towards lows. First-day nerves and adrenaline can lift glucose briefly, which sometimes fools people into thinking they will run high all week, before the exercise catches up. The one reliable rule is to check often and be ready for the drop, especially later in the day and overnight.
On the mountain
Examples, not instructions or doses.
You have skied since morning and by mid-afternoon you are sliding low run after run. Hours of exercise emptied your stores, so you snack on the lift and check more often for the rest of the day.
You reach for the pen in your outer pocket and the insulin has frozen solid. It goes in the bin, because freezing ruins it, and the spare from your inside pocket, kept warm against you, saves the day.
A huge day on the slopes and a couple of drinks, and you wake at 3.5 mmol/L in the night. The exercise and the alcohol together pulled you down hours later, which is why sugar by the bed matters.
Worth paying attention to
Questions that make an appointment useful
When it's urgent
A severe hypo is more dangerous on a mountain, where you may be cold, tired and far from help. If a low leaves you or someone in your group confused, unable to swallow safely, fitting, or unconscious, they cannot treat themselves and need help fast: glucagon if someone is trained to give it, and a call to the resort emergency number, ski patrol, or 999. Do not leave them alone in the cold, and never put food or drink into the mouth of someone who cannot swallow safely. The same danger applies to a delayed low overnight: if someone cannot be roused, treat it as the emergency it is and get help straight away. Testing must never hold up that call.