Mountaineering has been popular for many years and requires at least short-term exposure to high altitude. In more recent years, an increasingly large number of people are going to high altitude to seek added adventure and challenges with sports such as mountain climbing and trekking.
At higher altitude, many people experience a loss of appetite as well as go through an overall change in metabolism. They can go for days without feeling the slightest bit hungry, which can result in climbers being left undernourished. Therefore, it is important to keep check of this. The most important factors to consider are your energy needs and adequate hydration.
Since mountaineering consumes a lot of energy - an average-sized male climber can expect to burn upwards of 500-800 calories per hour at higher altitudes - so plan on consuming substantially more than you eat back home. Your diet should compose of at least 60-70 percent carbohydrates, 15-20 percent fat and 15-20% protein. Carbohydrates are the best source of fuel and are stored as glycogen molecules in the muscles. Protein helps prevent excess deterioration of lean muscle mass. Some good protein sources include fish, chicken, milk and peanut butter.
Air at altitude is cold and dry. Therefore, each inspired breath needs the body to warm the air before reaching the lungs and each expired air contains water and heat which is lost to the environment. This is called insensible water loss. This fluid loss often leads to moderate dehydration and accompanying symptoms of dryness of the lips, mouth and throats. Insensible water losses in men performing only moderate exercise at 4300m reported a insensible loss of nearly 2 litres per day through a 3 week stay at altitude. However, women showed less of a loss (750ml/day). These insensible losses do not include the obligatory water loss for kidney function, fluid losses during exercise to remove heat from body and sweat loss. For the above reasons, it has been recommended that fluid requirements at high altitude may be as high as 3-5 litres per day at rest. This recommendation should be increased further if physical activity is performed.
There is no one-size-fits-all prescription because different people react differently to the same foods. You should try to find food that won't cause glycemic index (GI) distress and will help to maintain focus and endurance. A few guidelines are:
- For peak performance, a carbohydrate-rich diet should be started at least a few days before beginning training/climbing.
- Eat low-glycemic foods, such as whole grain cereals, certain fruits, sandwiches made with whole wheat bread, etc., approximately two to three hours before starting the climb. This will help sustain blood-sugar levels.
- Avoid very high fat diet at altitude. Fatty foods require much more oxygen to digest, thus, if you packed high-fat foods, it could slow down your acclimatization.
- Avoid bulky foods, like raw vegetables, dry beans, peas and popcorn, which can stimulate bowel movements.
- Avoid gas-forming foods such as vegetables from the cabbage family and cooked dry beans.
- Eat constantly. When you stop for a break, have a chocolate. The aim is to avoid an "energy low" by keeping the flow of energy at a constant level.
- Make sure you are well hydrated by checking the color of your urine. It should be clear and there should be lots of it! If this is not the case you may be dehydrated.
- For those moments when you need that extra something, chomp on your favorite Tracker, Mars bar or Boost to keep you ticking over. You might also want to consider taking some energy "drink" with you in the form of tablets, which you can dissolve in your water bottle.
- Often, when you get into "camp" you'll have the option of a cup of something hot. Hot chocolate is a good option rather than tea or coffee. It gives you a morale boost and helps you hydrate at the same time.
The post climb meal is also of great importance to enable you to keep training or climbing, day after day. You must eat lots of carbohydrates and some protein within the first hour or so after exercise to replace the glycogen burned in your big muscles or it may take more than twenty-four hours to top up your tanks.
Nice article.