Ski fit series: Altitude effects and cardiovasular fitness

The higher you climb the thinner the air gets.  The thinner the air, the less oxygen available which can affect your energy levels and general well being. Although there are no quick fixes to prevent this, having a good pre-existing level of cardiovascular fitness, as with any sport will help you to exercise for longer.  

At altitude, everyone breathes deeper and faster because of the difference between atmospheric pressure at altitude and sea level.  Exercise increases oxygen requirements, which means your heart rate gets up faster and subsequently you wear out quicker.

At altitude, the amount of oxygen in the air is the same as at sea level (21%).  However, at altitude, the air becomes less dense (thinner) therefore there are fewer oxygen molecules available.  Over time your body will acclimatise to this.
There are both immediate and longer term physiological changes when living at high altitude, so the overall adaptation will depend if you are on holiday for a week or doing a ski season.

One of the main immediate responses is that the body adapts by increasing our breathing rate, both at rest and during exercise.  People often notice that when climbing the stairs in a ski resort, they become much more short of breathe than they would at sea level.

To help preserve oxygen delivery, cardiac output (the volume of blood being pumped by our heart) increases. However, this is only temporary and within a few days our cardiac output will lower (to levels lower than pre-ascent) as other physiological adaptations occur.  As well as a lower cardiac output, longer term changes also include an increase in number of red blood cells and changes in muscle metabolism.

According to Wikipedia, altitude training and the effects of altitude on performance became a hot topic after the 1968 Olympic Games in Mexico city which is at an elevation of 2,240 metres (7349 ft).  It was noted that endurance events saw a significant number of below record finishes, whilst anaerobic, sprint events excelled.  Still today, the physiological effects of altitude and its role in training high for performance enhancement are an exciting on-going topic of research.

Points to remember:

• In general, the higher the altitude, the longer it takes to adapt.
• Although most ski resorts are said to be at moderate altitude, rather than high altitude, acclimation is just as important and it is not uncommon to feel mild to moderate effects during this period. 
• Unfortunately, there is no link between your pre-existing fitness levels and how quickly you acclimatise, however the fitter you are theoretically the longer you will be able to ski for. 
• The better your cardiovascular fitness, the better prepared you will be to cope with physical demands of sport and exercise at altitude. 
• Good cardiovascular fitness will improve your stamina. 
• The cold also affects yours cardiovascular system.

So with this in mind, it is definitely worth improving your cardiovascular fitness prior to your skiing holiday.  The aim of cardiovascular exercise is to get your heart and lungs working hard for extended periods.

Recommendations pre-skiing:

• Start to increase (or introduce) cardiovascular training at least 6 weeks prior to your ski trip or ski season
• Aim for 2 - 4 cardiovascular sessions a week.  These sessions should last at least 20 - 40 minutes in duration and ideally you should be working at around 50-60 % of your maximum heart rate.
• Ensure your training has variety and is progressive; each week try and up your pace, vary your workouts, introduce interval training and vary the length of the workouts that you are doing e.g. mix and match shorter 20 minute sessions with long bike rides and hill walks.
• Outdoor examples of cardiovascular exercise include running, cycling and hill walking.
• Cycling is very popular with world cup skiers as well as ski instructors.  Many ski instructors have a turbo trainer in their apartments to help increase cardiovascular fitness to compliment / enhance their skiing. 
• In the gym you can use the treadmill, bike or cross-trainer to work on your cardiovascular system, as well as introducing circuits and aerobic type classes. 

Other Considerations:

To further help you acclimatise and to help to enhance the functioning of cardiovascular system, take into account the following when you are at altitude.

• Gradually build up your time on the hill
• Consider your diet
• An initial decline in appetite is not uncommon so think about what you are eating. A high carbohydrate, low salt diet allows for better adaptation.  Choose slow release carbohydrates rather than refined sugary snacks and meals which help to keep your blood sugars steady e.g. whole grains, legumes, fruit and vegetables
• If you are at altitude for long periods, consider that your body will be making more red blood cells.  This may mean a higher demand for iron so ensure you include iron rich foods in your diet e.g. spinach, liver, mussels, oysters, cooked chicken and beef and sardines. 
• Stay well hydrated.  Mountain air is extremely dry, therefore you lose a lot of water.  You need to drink a lot more than you think in the mountains. 
• It is best to limit alcohol consumption during the acclimatisation period as it increases your risk of dehydration and can increase feelings of loss of appetite and fatigue. 
• If you have a pre-existing cardiovascular disorder, it is worth talking to your Doctor before ascending to a high altitude.  
• If you suffer from headaches, malaise and decreased appetite at altitude, your body needs more time to adapt so don't over do it, especially when you first start skiing or boarding.  

References:

Cardiovascular adaptation to exercise at high altitude.
Exerc Sport Sci Rev. 1986;14:269-302. Grover RF, Weil JV, Reeves JT.

Disclaimer:

The purpose of this blog, is to provide general information and educational material relating to physiotherapy and injury management. Bonne Santé physiotherapy has made every effort to provide you with correct, up-to-date information. In using this blog, you agree that information is provided 'as is, as available', without warranty and that you use the information at your own risk. We recommend that you seek advise from a fitness or healthcare professional if you require further advice relating to exercise or medical issues.

LSA

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