Distance running at any temperature generates metabolic heat production inside the athlete, even with cold weather running. The chemical conversion of carbohydrate and fats to ATP is only about 35% efficient, with the remaining 65% lost as heat in the complicated bio-chemical processes inside the cell. While this seems like a lot of lost heat, it is better than the engine in your car. The automobile engine loses about 75% of the potential energy in gasoline as its chemical processes occur in order to turn the wheels. Like the automobile radiator, in hot weather the main goal of the body’s cooling system is to dissipate the excess heat produced by the body’s energy systems. With cold weather running and temperatures, such as below 50 degrees F, much of the generated heat will be used to keep the body core temperature in the normal range for human homeostasis.
Cross-country running performance can be adversely affected by the local effects of cold air temperatures on skeletal muscles, the slowing of reflexes, and metabolic changes that alter the nutrient supply to muscle tissue and the brain. The maximum force production in muscle contraction is decreased by the cooling of the muscle fiber. Enzymes do not function well outside of their optimum temperature range and this is the main reason force production is compromised Energy expenditure increases as the body recruits more muscle fibers to do the same amount of work because of this loss in force production. Before and after the race or workout, shivering further causes energy expenditure and stress to the physiological systems of the body, most notably the immune system.
Just as in running in heat, with cold weather running, the runner must prepare for the weather in the clothes they choose to wear. There are also a number of tips and techniques that help minimize the stress of ambient cold on the body. In essence, if dressed properly and thinking ahead in the workout for the day, a runner can train or race in about any degree of cold weather found in the continental United States. The coach should be watchful for cold stress and take note of the first stress response, such as shivering in the athlete. If, for no reason, the shivering stops in very cold weather the coach must be alert for the onset of hypothermia which can occur at anytime below 50 degrees Fahrenheit.
Some tips and techniques to help minimize the effects of cold stress to the body:
- Run in modern synthetic fabrics such as Dri Fit and Gore-Tex.
- Never wear cotton as either an under-garment or an over-garment
- Layer the fabrics depending on the temperature.
- Wear a wind-proof modern fabric as the outer layer.
- Cover the head and hands.
- Start the workout by running against the wind.
- Finish the workout by running with the wind.
- Just as in heat, the body must be well hydrated.
- Stretch inside a building.
- Warm up and cool down inside a building.
- Do not linger in the cold.
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It is estimated that about 75% of body heat is lost through the head and hands when it is cold because the blood supply there is so close to the skin. Wear a hat and gloves! Continuous checking and reminding athletes of the need for gloves, hats, and clothing layers is the most important thing the coach can do concerning cold weather running.
Some things to do to help understand cold weathers effects on your runners:
- Learn about the different modern fabrics that have been developed in the past ten years. Always discourage cotton for running in the heat or cold weather running.
- Because cold air holds little water, make notes to yourself and team to keep the body hydrated more than usual during cold periods.
- If your team is racing in weather much colder than home, research the weather and make a plan for having the proper clothing to legally and safely compete in.
Fortunately for cross country runners the process of acclimatizing is a physiological adjusting process that is real in humans. When the weather gets gradually cooler as the season progresses, there are physiological (and psychological) adaptations that slowly occur that allow humans to adjust to the climate change. This only happens to a point however. Humans have a somewhat narrow temperature window by which their bodies can optimally operate in.
FREE REPORT From Distance Expert Scott Christensen
Race Strategy and Tactics for the Endurance Events: 800m – 5000m
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