Eating Right

When exercising for a decent length of time (e.g. over 40 minutes), working at say 65% of your maximum heart rate or at over capacity (average jogging), you burn up instant muscle glycogen. You need to replace this muscle glycogen or muscle fuel or else you will have tired muscles for the next 1-2 days. Obviously this is not quick recovery. To avoid this, try to eat within 20 minutes of completing your work out (this can be difficult if you are showering and taking a sauna etc. at the gym) but eating within the next 30 minutes after exercise when the body is still aerobically metabolizing and is in muscle glycogen conversion mode will 'repay' the 'debt' of muscle fuel and will quicken recovery so you will be ready to exercise again the next day.

If you are planning on doing any big days of exercise, keep eating small amounts frequently, approximately every 40 minutes - 1 hour. This applies to water and electrolyte drinks also. Electrolytes are necessary for proper muscle and nerve functions, so electrolytes are very important for long days. Even if you are not exerting yourself you will still use up a lot of electrolytes over the course of a few hours. Mix in 1/2 a teaspoon of salt with 1 litre of water, if you expect to be sweating. You can also combine this with electrolyte supplements if you wish. Salty crackers (with avocado) are an ideal snack food for long hikes.

PRACTICAL IMPLICATIONS FOR ATHLETES

High-Altitude Nutrition Hints

Q: What sort of diet is best for high-altitude climbing?*

A: Studies show that our bodies can process fats and carbohydrates normally up to 5,000 meters, so any loss below that elevation can be attributed to less than adequate intake. Above 5,000 meters, however, weight loss seems to be unavoidable, due to several factors: 1) loss of appetite and increased nausea from the effects of altitude sickness; 2) change in overall metabolism; and 3) the body's inability to digest food.*

The average-sized male climber can expect to burn upwards of 500-800 calories per hour at higher altitudes (the higher numbers are for difficult carry days) so plan on consuming substantially more than you eat back home. A good ratio seems to be 60-70% carbohydrates, 15-20% from fat and 15-20% from protein. Complex carbohydrates provide the ongoing fuel needed to replenish glycogen stores, while protein helps prevent excess deterioration of lean muscle mass. Beware the very high-fat diet at altitude: reliance on foods such as typical mountaineers' classics like Snickers bars, cheese, jerky, nuts, and so forth can result in chronic muscular fatigue, since a high-fat diet lacks the necessary level of readily-available carbohydrates; furthermore, high-fat diets require more oxygen during metabolism for processing, thus slowing down acclimatization.*

The simplest answer to this is: what you'll eat, consistently, and a lot of it. Make sure you test-run your food ahead of time on training climbs (eg. - on Rainier and other similar training climbs that take you above 12,500') so you learn what works best for you. By all means, take foods and beverages you enjoy or you won't want to eat them. If you know that your water treatment makes drinking unpleasant, take flavored drink mixes like Tang, cocoa or Gatorade to help mask the taste and add valuable carbohydrates. Also consider the weight of all the food (especially if you're going to be carrying most of it yourself!) -- dehydrated foods that are light weight but calorically dense are highly desirable. Potato buds that you can mix with dried turkey or other meat and hot water seems to be a concoction that goes down pretty easily for most people at high altitude. But if you absolutely hate the taste of any of your fare at sea level, leave it behind.

* Resource: Burnik and others, in Ch. 6, Some Anthropometric Changes on Extreme High Altitudes, Science of Climbing and Mountaineering CD-ROM, available through Human Kinetics. Research done on Everest, North Base Camp, 1997.