As we exercise, our increased muscle activity causes our core body temperature to rise. Large increases in core body temperature are not well tolerated by the body so as a coping mechanism we produce sweat to keep our core body temperature and vital organs cool. As we sweat, fluid takes heat away from the skin as it evaporates. This cools the skin and blood flow to the vital organs, keeping the body’s core temperature cool and functioning correctly. However, if this fluid is not replaced over time, the body will lose its ability to maintain a cool environment and become dehydrated which will inhibit our exercise performance.
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Dehydration during exercise and excessive sweat loss can impair performance in various ways. A reduction in stroke volume (amount of blood your heart pumps per beat) means your heart rate increases to maintain oxygen supply to the working muscles at the same intensity, limiting your capacity to increase the intensity of the session. Alongside these negative impacts on your exercise performance, dehydration can cause stomach pains and reduce both mental function and skill level. At the extreme end it can affect your health too.
When we sweat during exercise, we also lose electrolytes like sodium and potassium; these are key to retaining the fluid we take on board. Excessive losses in key electrolytes like sodium have been associated with cramp and fatigue which will negatively affect your exercise performance unless they are replaced. The optimum hydration strategy needs to include replacing both fluids and electrolytes. This is optimised when the drink contains 6-8% carbohydrate to assist in maximising fluid absorption and gastric emptying.
Just consuming water will not provide you with the key electrolytes your body requires. SiS GO Electrolyte will deliver the body a balanced mixture of electrolytes and carbohydrates to maintain your performance by enhancing the absorption of water and avoiding dehydration. SiS GO Hydro will still provide your body with key electrolytes but without additional carbohydrate. This makes it more suitable for training sessions under 1 hour where additional carbohydrates are not necessary.
The amount you should drink markedly varies between individuals depending on temperature, sweat rate, activity and humidity. You should aim to consume 500-1000 ml of fluid per hour with the upper end targeted at hotter temperatures and higher sweat rates. You should fine tune your hydration strategies during training sessions prior to competitions.
HOW TO CALCULATE YOUR SWEAT RATE?
To determine sweat loss, a practical and valid assessment tool is to weigh yourself before and after exercise. Each kilogram of weight loss indicates 1 litre of fluid loss. Adding the amount of fluid consumed during exercise will give you the total fluid loss.
For example: if you finish your session 1.5 kg lighter and consumed 1 litre of fluid during the run then the total sweat loss equals 2.5 litres. Fluid losses greater than 2% of your body weight, so 1.4 litres for a 70 kg individual, means that you are dehydrated.
Your sweat losses should be matched by fluid intake during exercise but excessive intakes of fluid can lead to hyponatremia and have negative impacts on your health. Just drinking to thirst is often not enough, as much as this theory has received media attention in recent years. Your perception of thirst can be affected by the intensity that you are working at and the conditions. Also in a race scenario it is very easy to get distracted by other events and this can lead you to not track your drinking properly if you do not have a schedule to stick to.
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