Distance Swimming

Distance swimmers are unique people who must spend an enormous amount of time in the water to realize minuscule improvements in time. A key to performance appears to be the swimmer's capacity to go faster without increasing blood lactate levels or to go faster while utilizing a lower percentage of maximal aerobic capacity.⁵⁵ It appears that the endurance swimmer can work harder while maintaining a predominantly aerobic (oxidative) metabolic pathway. This translates into a terrific aerobic fitness, with the ability to maintain enough glycogen and oxygen in the system to ensure an efficient energy burn. Maintaining lower blood lactate concentrations may also be a function of maintaining a sufficient blood volume (lactate in a larger volume equals lower lactate concentration). Of course, this is largely dependent on adequate hydration and a good electrolyte status (sodium helps maintain blood volume).

Keeping this in mind, distance swimmers must consider the following nutritionally relevant factors for their sport.

Swimmers often have lower bone densities. Swimmers tend to have lower bone densities when compared with other athletes.⁵⁶ The reason is easy to understand: Swimming produces less impact stress than does running. However, it may also be related to spending many hours doing laps in an indoor pool while other athletes are running outside, where they can increase their exposure to sunlight and manufacture more vitamin D, a difference that may be enough to influence bone development. For long-distance swimmers lucky enough to live in areas warm enough for outdoor pools, this is not an issue. A study of female swimmers found inadequate calcium intakes, a factor that could clearly contribute to lower bone mineral density.57 Clearly, having sufficient calcium (1,500 milligrams per day) is critical for maintaining strong bones, but swimmers should also make an effort to satisfy vitamin D needs, particularly if they have few opportunities for sunlight exposure.

Replacement of fluids needs to be more prevalent during all day events. The main focus for swimmers involved in a typical all-day meet is the replacement of adequate fluids to maintain blood volume and to provide a constant source of carbohydrate. It may not be the time in the water swimming that contributes to dehydration but the time out of the water (often in the sun) waiting for a turn to compete. Regardless of the source, a failure to drink sufficient fluids can lead to a serious performance detriment.

Consumption of carbohydrates during long competitions. Having a snacking plan is important to avoid hunger. Swimming competitions take many hours, making hunger an issue that must be addressed. It is a bad strategy to begin an endurance event in a hungry state. Athletes should sip on sports beverages and snack on crackers and other simple carbohydrate (mainly starchy) foods to get a constant trickle of carbohydrates into the system while they wait to compete.

Eating enough to support the activity. Swimming long distances uses a tremendous amount of energy, a deficit that must be matched with an appropriate energy delivery from food. Swimmers often complain that they can't keep their weights up during the long swim-competition season, and that means they've burning muscle to meet their needs.