Tag Archive for: sweat rate

Dealing With Heat & Humidity – How to Stay Cool and Hydrated During Training and Racing

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As we exercise, our bodies burn the calories that that we consume (i.e. carbohydrates, proteins and fats).  It is the breakdown of these calories and muscle movement that causes heat to build up and raise our core body temperature initiating the demands of the body to maintain its ideal body temperature of 98.6 degrees.  There are several ways that the body dissipates heat (skin and exhalation for example); however, the most complex system involves your ability to sweat.

Simply put, water molecules evaporate from your skin removing heart energy, leaving water molecules on your skin making you feel cooler.  The endothermic process of converting liquid to a gas is beyond the scope of this article; however, the ultimate goal is to maintain your body’s ability to efficiently dissipate heat throughout exercise.  What makes it difficult is dealing with elements that we don’t have any control over – heat and humidity.

On hot days when there is little difference between the skin’s surface temperature and the ambient air temperatures, the skin provides only small cooling benefits – increasing the importance of sweating to maintain your internal core temperature. In fact, above 95 degrees Fahrenheit you lose no heat at all from your skin – evaporation must do all of the work.  Humidity decreases your body’s ability to evaporate sweat because the air is already saturated with water vapor, slowing the evaporation rate.  Though you and your clothes may be saturated, it is not helping you in your cooling process – sweat must evaporate to remove heat from your body – plain and simple.  It is this concept that makes hydration so important; if you don’t have enough fluids to produce sweat you will over heat guaranteed (along with the adverse side effects – performance and health wise).

On average, endurance athletes lose approximately 30-35 ounces of fluid per hour of exercise (the actual amount varies by body size, intensity levels and heat/humidity levels).  There are numerous formulas floating around in the sports nutritional world regarding ideal food and fluid intake; however, keep in mind that there are three things that we need to evaluate regarding ideal performance nutrition: water intake, electrolytes and calories.  It has been our experience working with hundreds of athletes that the best way to formulate an ideal nutritional strategy is through trial and error.  This formula requires good documentation on behalf of the athlete to track what is consumed, your workout duration and intensity levels along with average paces and heart rate levels.

Here are a few tips for training and racing in the heat and humidity

  • Avoid over-hydrating on plain water
  • Train at times that are relevant to your race (i.e. if you are going to start your run at 2:00 pm during a race, then practice running at this time dealing with the heat, humidity and sun burn)
  • Wear only clothes that facilitate the evaporation process (avoid cotton at all costs)
  • Cold fluids absorb faster than warm fluids; use insulated bottles
  • Backing off of the intensity every so often and pouring cold water over your wrists and neck will help relieve your body of internal heat
  • Pay attention to body signs that things are not going well: dry chills, becoming lightheaded or queasy are all indications to stop. Be smart!

Top 5 Nutritional Mistakes and How to Fix Them

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Over the last 33 years, I have seen nutritional mistakes that have resulted in weight gain rather than weight loss. Here are the top five mistakes and how to correct them.

Not knowing your sweat rate

You may ask how your sweat rate relates to nutritional mistakes; the reason is associated with how your body stores water relevant to what you eat. Fruits in vegetables are high in vitamins & minerals, but they are also high in water and natural forms of electrolytes (what you lose in through sweat). Also, for your body to store one gram of sugar for energy, it stores 2.5 grams of water. If you want to improve your pre-hydration levels, eat more raw fruits and vegetables.

When it comes to sweating, your goal is to lose between 1-2% of your body weight in a given workout – no more or less. If you lose more than 2% of your body weight you are officially dehydrated, if you lose less than 1% you are over hydrated. This is a very fine line that needs to be evaluated on a regular basis with the following variables being factored in: air temperature, humidity, intensity and duration.

To help you calculate your personal sweat rate, please email me at robb@coachrobb.com and I will send you a simple to use Sweat Rate Calculator. It will provide you insight into your sweat rate along with inform you if you’re eating habits are helping or hurting your weightloss efforts.

Not eating enough high quality calories

As mentioned above, fruits and vegetables are high in water, vitamins, minerals and electrolytes. However, fruits and vegetables are not high in calories. This means that you must eat a lot of fruits and vegetables (along with lean protein sources) for your body to perform at an optimal level.

To determine if you are consuming enough calories to fuel your exercise,  you need to evaluate exactly what and how much you have eaten, when you have eaten and then evaluate the quality of your workouts. This is very simple to do by maintaining a daily food log (Note: if you don’t have a simple to use food log, please email me at robb@coachrobb.com and I will send you a copy of our food log that is easy to use and maintain on a daily basis).

There are two typical realizations that come from maintaining a food log; one is the quantity of food that comes out of a box and/or a can; the amount of total calories consumed on a daily basis is not enough to fuel your efforts. By maintaining a daily food log and evaluating your energy levels/performance results you will develop a personalized nutritional plan in less than two weeks.

Not eating enough high quality fat

Fat has gotten a bad rap in the media, but the fact of the matter is that your body needs high quality fat on a daily basis for your body to perform at an optimal level. Typical symptoms of insufficient fat intake include: fatigue, delayed recovery, depression, over eating, constantly hungry and more.  It is imperative that you consume the following unsaturated fats on a daily basis: extra virgin olive oil, avocados and fish oil.

These fats are either used by your body as energy or passed as waste – which means no stored body fat! This is a win-win situation for you: improved performance and decreased body fat. When you increase your clean fat intake, there are two things you will notice within two weeks: improved endurance and not hungry all of the time. The reason for this is because most individuals don’t consume enough high quality fat – simple fix with huge benefits.

Not eating immediately after a workout

When you work out your body gets the majority of its energy from stored sugar from your muscles (your brain gets its sugar from your liver); the longer and more intense your workout the more you “empty” your stored muscle sugar. When you are finished with your  workout you have a 20-30 minute window to replenish these depleted stored sugar levels optimally. During this short post exercise window, you have an enzyme (glycogen synthase enzyme) that is highly activate within your muscles cells that helps increase the replenishment of sugar within the muscles (and liver).

The longer you wait to consume high quality food after your workout, the less effective your replenishment will be and your recovery window will take longer as a result. Ideally, you want to consume food in a 4:1 ration between carbohydrates and lean protein. Simple solutions include fruit smoothies made with Greek yogurt or chocolate milk.

Not drinking enough water

The average human body contains 96 pints of water – 64 of these are found inside the body’s cells. Your brain is 75% water, your blood is 85% water, muscle is 70% water, and you see how important being hydrated is literally from the inside out. Please don’t confuse hydration levels with sweat rate discussed earlier; hydration levels are strictly relevant to maintaining proper fluid levels within your body for optimum health and ultimately performance. Your sweat rate is relevant to how much perspiration you are creating as your body attempts to rid itself of internal heat.

As a general rule of thumb, your need to consume half of your body weight in ounces of water – for example, if you weigh 150 pounds, you need to consume 75 ounces of water on a daily basis to maintain proper hydration levels. Any activities that you perform on a daily basis: exercise, work, leisure, etc. has to be factored in addition to your daily needs.

There are two simple indicators of proper hydration levels: urine color and urination frequency. Regarding your urine color, the lighter your urine the more hydrated you are. Please note, if you are taking a multi vitamin that contains B vitamins, your urine will be a tad darker as a result. As your body absorbs and purges the B vitamin, the color of your urine will become lighter in color. In regards to your urination frequency, you should be visiting the restroom once an hour. Though this can be an inconvenience at time, the health and performance benefits are definitely worth it!