Altitude: why the first day feels harder
You arrive fit, and the first runs still leave you out of breath. Thin air is part of the reason, and it can be measured.
Less oxygen, a smaller engine
The higher you go, the less oxygen each breath delivers. Researchers tested eight endurance athletes at simulated altitudes from 300 m to 2,800 m. Their maximal oxygen uptake, the size of the aerobic engine, fell in a straight line: 6.3 percent for every 1,000 m gained. The drop was already measurable between 300 m and 800 m.1
| Altitude | Typical of | Aerobic capacity, compared with 300 m |
|---|---|---|
| 1,300 m | A low village | About 6 percent less |
| 1,850 m | A high resort village | About 10 percent less |
| 2,300 m | Mid-mountain lifts | About 13 percent less |
| 2,700 m | A high summit station | About 15 percent less |
These values apply the study's 6.3 percent per 1,000 m to each altitude. The athletes were tested in a pressure chamber, without acclimatisation, and individuals vary.
Skiing is harder work than it looks
A lift carries you up, so skiing feels like an easy sport for the heart. The measurements say otherwise. A 2019 review reports heart rates of 87 percent of maximum during downhill skiing, close to cross-country skiing at 88 percent.2 Each run draws on both the aerobic and the anaerobic system. Put that effort at 2,000 m and the same run costs more than it would at home.
What helps
- Build an aerobic base before the trip. Brisk walking, cycling or swimming, two or three times a week for six weeks or more.
- Add intervals. Efforts of 40 to 90 seconds with short rests teach your body to recover between runs.
- Start gently. Ski below your limit on the first day, with longer breaks. Your body adapts over the following days.
- Drink and eat through the day. In elite junior skiers, sixteen slalom runs in a day left some muscle fibres almost empty of stored carbohydrate.3
- Sleep. The first nights at altitude are often lighter. Plan early evenings at the start of the week.
If you have a heart condition
The same review recommends medical guidance and good physical preparation for skiers with cardiovascular disease, sleeping the first night close to skiing altitude, and resting or skiing gently on the first day.2 See your doctor before the trip.
This article is general information, not medical advice. A persistent headache, nausea or unusual breathlessness at altitude are reasons to rest and ask for medical advice.
References
- Wehrlin JP, Hallén J. Linear decrease in VO2max and performance with increasing altitude in endurance athletes. European Journal of Applied Physiology. 2006;96:404-412. doi:10.1007/s00421-005-0081-9
- Burtscher M, Federolf PA, Nachbauer W, Kopp M. Potential health benefits from downhill skiing. Frontiers in Physiology. 2019;9:1924. doi:10.3389/fphys.2018.01924
- Vogt M, Jordan K, Spring H, Hoppeler H. Physiology of alpine skiing: implications for the training of elite skiers. International Congress Mountain & Sport, Rovereto; 2005. Abstract