When exercising in cold environments, respiratory water loss increases because of the low humidity and increased ventilation rate. Additionally, under all your clothing keeping you warm, it’s possible for sweat rates to exceed 33 ounces per hour. When swimming, if internal body temperature exceeds the sweat threshold, you will sweat (even if you don’t feel it because you are already wet). You may also find yourself needing to urinate more often when swimming due to the increase in plasma volume that occurs during immersion from high pressure baroreceptors. This may increase risk for dehydration. Make sure to stay up with your hydration intake in cold weather and while swimming by bringing a water bottle with you (or a sport drink when appropriate).
Athletes have been cautioned to avoid caffeine (ex. coffee) before and after exercise due to association with dehydration or electrolyte balance. There’s no strong, consistent evidence that caffeine is a diuretic and should be avoided before/after exercise. However, caffeine does come with adverse effects, such as an increase in blood pressure at rest and during exercise, an increase in heart rate, GI issue and insomnia. Caffeine may enhance performance due to its role in stimulating the central nervous system to reduce mental and physical fatigue in some individuals. Caffeine is considered safe at recommended doses (2-6mg/kg/bw).
Cramps are a common phenomenon affecting athletes and non-athletes (ex. night cramps). Normally, muscles voluntarily contract and relax to encourage purposeful movement, physical activity and posture. When a muscle or group of fibers contracts involuntarily, it goes into a spasm. A forceful and sustained spasm causes a muscle to cramp. A muscle cramp can be painful and may last from a few seconds to fifteen or more minutes. Eventually, the muscle will relax and resume its normal state of functioning. Although cramps can occur anywhere, they typically occur in the lower extremities, such as the feet, calves and quads.
Although the primary cause of a muscle cramp is unsolved, overuse, fatigue and dehydration are frequent culprits. However, recent research is demonstrating that hyperexcitability of the nerves that stimulate a muscle may contribute to exercise-induced cramping. Anti-cramp products, such as HotShot, claim to reduce the longevity or incidence of cramping by stimulating sensory neurons in the mouth and esophagus to send impulses to the spinal cord, which then overpower and inhibit repetitive signals coming in and out of the cramped muscle. Before you begin to add more salt to your diet (or to your sport drinks), make sure you are warming up properly, building into stronger/intense efforts and pacing yourself to help delay fatigue. For triathletes, there's greater risk for cramping in the feet/calves when you swim after a run due to exhausted lower leg muscles.
Coconut water is derived from the fluid inside a coconut. An 8-ounce portion of unsweetened coconut water contains about 50 calories, 55mg of sodium, 11g of carbs, 9g of sugars and 460mg of potassium. Although coconut water contains calcium, phosphorus and magnesium (electrolytes found in sweat), sodium and chloride are the major electrolytes because they reside in the extracellular fluid. Compared to a sugar-rich hydration beverage, coconut water is a safe and natural alternative to help meet hydration needs during low intensity, short-duration exercise. However, to sustain moderate to high-intensity exercise for longer than 90-minutes, the body depends on ingested carbohydrates and sodium – both of which lack in appropriate amounts in coconut water. Additionally, if you are paying extra for coconut water to increase your daily potassium intake, look no further than the produce aisle – a large potato contains 1553 mg of potassium! If you enjoy the taste of coconut water over plain water, choose it for light activity. But to prevent dehydration, replace lost electrolytes and provide the muscles with carbohydrates, a well-formulated sport drink is encouraged. In all other situations, plain water should be your go-to hydration beverage.