Much like nutrition, hydration is an important part of peak running performance. Finding the right approach to fluid intake is unique to each runner. Missing the mark on fluid balance by taking in too little or too much liquid can not only hurt your time but potentially your health.
Our body is about 65% water. This water level is in a constant state of flux depending on many factors including our activity level.
As we exercise, our bodies make sweat as part of our natural cooling mechanism. Sweating leads to loss of fluids, most notably from the bloodstream. This lowered blood volume lowers the body’s ability to transfer heat.
This decreased ability of the body to cool itself leads to an increased heart rate and makes it increasingly difficult to meet exercise demands. To counter this fluid loss, we take in fluids. Sometimes though, our sweat rate can exceed our body’s ability to absorb fluid. This ultimately leads to dehydration which negatively impacts performance in sporting activity.
Signs of mild to moderate dehydration include symptoms such as:
If allowed to progress, dehydration can lead to heat exhaustion and, ultimately, the medical emergency of heat stroke where seizure, coma or death may result.
Many suggestions for fluid intake during running are out there. Important underlying hydration principles to keep in mind are the farther you run, the more important it is to drink.
Additionally, colder drinks help to cool the body and also decrease the perceived intensity of exertion during exercise.
For hotter running days, anticipate the need to drink more than usual. Also, most stomachs can empty about 24-28 ounces of fluid per hour. Any extra fluid present is likely to slosh around and increase the risk for GI distress.
A good starting point in optimizing your fluid intake strategy is to figure out approximately how much fluid you lose during activity or your sweat rate. During training, determine your nude weight and then go out for a 1 hour run at your anticipated race pace. Then, obtain a post-race nude weight and convert the weight lost to ounces. This is a good estimate of the amount of fluid you need to replenish per hour.
Color is key! Urine color is also a helpful indicator of your hydration status. A straw-colored urine with a reasonable quantity per day is a good indicator you’re on the right track. A clear urine with frequent trips to the bathroom during the day suggests you’re overdoing the fluids. Darker urine means you need to up your intake. Don’t wait until the night before the race to increase your hydration. Achieving optimal hydration is a process achieved over several days and cannot be effectively attained at the last minute.
To counter potential dehydration, many will often increase fluid intake to create a “water reserve” or “top off” their fluids thinking this will keep them out of trouble. Unfortunately, we are not camels where we can draw off water from storage when we need it during exercise.
Overhydrating essentially leads to too much of a good thing and increases the potential for a condition called hyponatremia. Hyponatremia occurs when the main electrolyte in fluid balance, sodium, is depleted. Lower sodium levels in the body lead to fluid shifts that cause the cells making up our organs to swell. This leads to symptoms of puffiness, nausea, vomiting, headache, lethargy and, in more severe cases, confusion, agitation, seizures, coma and possibly death.
A good hydration regimen should get you to race day optimally hydrated. For race day, if you are not carrying drinks, plan your stops based on the water stations along the route and your requirements during training.
Also, avoid unnecessary medications like aspirin, ibuprofen and naproxen because these can cause diarrhea, cramping, nausea and stress your kidneys which increases the risk for dehydration and hyponatremia.
Use Tylenol instead as it does not affect the kidneys.
Remember to stick to your plan and trust your training!