Warm weather is a term familiar to most people as a phenomenon that can be defined in subjective terms—individuals have differing perceptions as to what will constitute warm versus cold weather conditions. The establishment of warm weather conditions suitable for exercise is not simply a function of temperature; it is a combination of the air temperature, humidity, wind, air pollution, and other environmental factors. The physical conditions affecting warm weather exercise are diverse. For example, the surface on which a sport is played may change with varying conditions; sports such as marathon running, in which the race is run over heat-radiating pavement, have additional warm weather factors that would otherwise be reduced or absent.
Warm weather is a training and competitive issue that must be overcome by most athletes at some stage in their careers, from those at the recreational level to elite competitors. While increased physical fitness will usually better equip an athlete to combat the effects of warm weather, the principles of warm weather exercise are applicable to all fitness levels.
The consideration of the impacts and consequences of warm weather exercise are of vital importance to sport performance and athlete safety. In the course of the long-term planning for an athlete's competitive and training season, referred to as the periodization of training, the season will be divided into the preseason, the competitive season, and the off-season. When known climatic conditions will be a factor at various points of the season, the athlete can plan the training accordingly. In the same fashion, when the athlete is aware of particular competitions in warm weather climates, specific steps can be taken in advance to best prepare for the event.
A failure to anticipate warm weather factors in training can lead to competitive disaster. When an athlete, particularly in a sport with a significant aerobic component, is unaccustomed to the impacts of warm weather and the collateral impacts of insufficient hydration and fluid replacement, it is highly unlikely that the athlete can compete effectively at the accustomed cool weather training levels.
Once the appropriate training periods are determined through preseason analysis, the athlete can progressively build warm weather exercise components into training sessions. The first step is the incorporation of acclimatization training into regular workouts. Acclimatization is the process through which the body adapts itself to the stresses of warm weather. As a general rule, when the body is exposed to warm weather conditions (often accompanied by humidity), there will be a pronounced and cumulative effect of the local environment on three interrelated bodily processes: the cardiovascular system, particularly through decreased blood volume; the thermoregulatory system, which will strive to maintain a constant internal temperature of approximately 98 °F (37 °C); and the osmoregulatory system, which preserves fluid levels in relation to the presence of sodium and other minerals.
Although individual athletes will respond in different ways to the effects of warm weather, as a general rule, an athlete'sbody will be over 90% acclimatized to the presence of heat within 10 to 14 days of first exposure to the new conditions. Acclimatization is best achieved at the location where warm weather is anticipated during competition. Warm weather can also be simulated; indoor workouts in increased temperatures are an example.
The second step to be taken by an athlete to develop warm weather exercise ability is the implementation of a hydration strategy. Hydration is the process by which an athlete seeks to maintain a relative constant fluid level within the body throughout exercise. As a general rule, hydration requires the athlete to consume fluids before, during, and after the exercise activity, sufficient to replace all fluids lost through perspiration and other bodily functions (primarily breath and urine production). It is a well-accepted sports science proposition that when an athlete loses between 1% to 2% of body weight through fluid loss (an amount that is classed as a slight degree of dehydration), athletic performance may decrease by up to 10%. As slight levels of dehydration may not necessarily trigger the body's thirst mechanism, regular fluid consumption is crucial to proper hydration.
A failure to observe proper and timely hydration will often trigger a progressive series of increasingly dangerous heat-related illnesses, including muscle cramps, heat exhaustion, and heat stroke.
There are a variety of fluids available to the athlete to achieve hydration. Water is the most common fluid used, although a significant science has developed with respect to the formulation of various sports drinks, each designed for specific sports and usages. Most sports drinks contain amounts of sodium and potassium to aid in the body's ability to maintain proper osmoregulation. For hydration, as opposed to the replenishment of carbohydrate stores, sports drinks do not generally contain more than 6% to 8% carbohydrate, to ensure ease of absorption of the fluid into the body by way of the small intestine.
During the acclimatization phase, the athlete and coaches must carefully monitor the twin performance keys of intensity and duration. Failure to observe the appropriate balance between these factors can create significant physical consequences for the athlete. It is imperative that all warm weather exercise be conducted with ready access to appropriate first aid equipment.