ISSA SN Chapter 6: Water and Oxygen
ISSA SN Chapter 6: Water and Oxygen

Yet to sign up for the ISSA nutrition cert? My site visitors get a special discount here. You can even get this nutrition cert for free with the purchase of their personal trained cert (an excellent combo).

Post Content

    Chapter Goals:

    • Describe and define the main terms associated with oxygenation and hydration of athletes.
    • Know about balancing water in the body.
    • Find estimates for the hydration needs of athletes.
    • Know the effects of dehydration and relate it to athletic performances.
    • Know what role oxygen plays in the human body.
    • Discuss the nutrients and other nutritional substances that relate to the flow of blood and oxygen in the body.


    Water and Oxygen are two of the more important nutrients for our health and our performance ability. Research has been shown that even the small variations in the water balance of the body will affect our performance in bad ways. Even though these two things are so important, many people take them for granted and just neglect their importance. This is going to be true for athletes and for those that are not athletes. 


    The consumption of water is required every day for optimal health and solid athletic performance. Hypohydration is still very common among both nonathletes and athletes alike. This is when the intake of water does not meet our need for hydration. This puts you in a state of dehydration.

    Euhydration is a term that means we are adequately hydrated. And then hyperhydration is the opposite of dehydration, and it is where we have too much water in the body.

    A Word of Caution

    Electrolytes are something to take into account when we are aiming to be euhydrated. 

    The things attributed to the daily water balance are going to be total activities throughout the day, the climate you are in, their health status, the clothing worn, and food consumed throughout the day.  

    Athletic Training for Water Conservation

    Managing your losses in fluids is a major thing to consider. You may not be able to control the environment you are in for events, but they likely can control the environment slightly when they are training. This is seen in controlling the time of day, or the clothing they choose to wear. 

    The simple rule of losing fluids is that you should aim to keep your losses below 2% of your total body weight. 

    Water and the Athlete

    Water is made up of one oxygen atom and two hydrogen atoms. It is used for transporting food materials in the body, and it happens to be where a majority of the biochemical reactions occur. For the very obese, we see water representing around 45% of total body weight, and then up to 70% in the more lean people. The average is going to be around 60% in the general person. The body parts also vary in their water within. Blood is usually around 83& water, while fat is like 10%. And then we have muscle tissue is made up of 75% water usually. So, there is a lot of variation throughout the types of tissues.

    Water balance

    The hydration status of a person is affected by the water intake levels and the water loss levels. We intake water when we drink fluids and produce it from food metabolization. 

    The major water intakes are metabolic water, liquids, food, and glycogen-bound water. The major outputs will be sweat from the skin, exhaling through the lungs, the kidneys, and then feces from the digestive system. 

    Metabolic Water:

    This comes from energy metabolism, and it is often not thought about.


    This is far and away from the biggest source of water in the body. this is simply the water we drink. 


    Most of the food we take in has some water in it, and this of course varies per type of food, but it is a significant portion of our intake.

    Glycogen-bound Water:

    This is the water that we store in our muscles that accompanies the glycogen. We store about 3 – 4 ounces of water per ounce of glycogen. 

    Skin – sweat:

    We lose water through our sweat, and this becomes more evident when we are doing some increased activity like training. It is the cooling mechanism of the body.


    Some small levels of water will be lost through water droplets in the air we exhale. 


    We filter some water out through the kidneys and then excrete it through urine. This is minimized during activity, due to the need for water. 


    This is the last major way we excrete water, and it is a small amount usually. 

    Hypohydration / Dehydration effects on Performance and Health

    A state of hypohydration, having too little water, can severely diminish your performance physically, your functioning mentally, and your control of the motor system. 

    When the body loses water, the core temperature will go up, and this affects all pathways of metabolism. When water loss is equal to 1 – 2 percent of body weight, we see some noticeable reduction in physical performance. In marathon runners, it is not uncommon to see losses as great as 6 – 10% of total body weight through a race. Proper hydration strategies following the event will help to counteract these impaired performance effects. 

    Beware the Limitations

    There are limitations to the data for hydration, like some saying sweat rates are from 0.3 – 2.4 liters per hour and then other data showing football players having a sweat loss ratio of larger players being 3 or more liters every hour. 

    How Much Water Does an Athlete Need?

    This amount varies largely based on how hydrated you are at the start, the climate you are in, the duration of your chosen activity, the intensity at which you are doing the activity, and the other activities done throughout the day. When someone is hydrated well, they should urinate around every 1.5 – 2 hours. 

    Body Weight Fluctuations for Estimating Hydration Needs

    A common approach to find the needs for hydration is to track the weight changes of the body throughout the day. An important part of this is right before, during, and after training, as most fluids are lost then for athletes. 

    Exclusive PTP Offers

    Gold Standard Cert
    Save 25%
    Most Popular Cert
    3 Certs for 1
    A Good Option
    50% off
    Best Study Materials
    See MVP discount
    Best online PT course
    $100 Off
    The Top PT Software
    Get Free Trial

    Daily Guidelines for Hydration Examples

    Some examples look at the total daily energy expenditure of athletes. 

    2 thousand calories expenditures should take in a minimum of 64 – 80 ounces of water each day. 

    3 thousand calorie expenditures should aim to take in around 102 – 118 ounces of water per day.

    And so on….

    Sources of Water

    The quality of water and other beverages should be of some concern to people. There are some major harmful effects of the contaminants found within drinking water and chemicals in some beverages will have health-conscious people thinking twice prior to consuming. Since athletes take in more water than the general population, they may take in more impurities from these drinks.

    Hydration with Glycerol: Effective, but Proceed with Caution


    Like H2O, it is not considered a nutrient to people, but it is impossible to survive without it. It circulates around the body by first entering the lungs, then going through the bloodstream and to the tissues. 

    The Lungs

    The lungs are the place where the oxygen enters the body. they are two organs in the chest on both sides of the heart. Air is taken in through the breath, the oxygen is removed from the air, and then a transfer happens where the oxygen enters the bloodstream. The limiting factor is the amount of air the lungs can take in.

    The bloodstream exchanges the carbon dioxide and water for oxygen so that it can then enter the body. 

    The air we breathe consists of about 21 percent oxygen and 78% nitrogen, with some other small amounts of gases. 

    The lungs do not have their own muscles and instead rely on other muscles to allow air to travel in and out.

    The Blood

    The Oxygen is extracted from the lungs and put into the blood where it will go to the heart and then be pumped around the body for use. It is the alveoli of the lungs that allow for this transfer to happen. 

    The Blood Vessels

    This is where circulation takes oxygen on its journey. The oxygen gets into the cells of the body with use of this part of the circulation system.

    ISSA SN Chapter 6: Water and Oxygen 1
    ISSA SN Chapter 6: Water and Oxygen 2
    ISSA SN Chapter 6: Water and Oxygen 3

    About The Author

    Leave a Comment

    Your email address will not be published.

    Find the best Cert for you

    Before you spend your money on the wrong personal trainer, nutrition, or other fitness certification. 

    Which Certification Is Best For You?


    Get The Sectret Cheat Sheet For The CSCS Exam


    Get The Sectret Cheat Sheet For The ACSM Exam


    Get The Sectret Cheat Sheet For The ISSA Nutritionist Exam


    Get The Sectret Cheat Sheet For The NCSF CPT Exam


    Get The Sectret Cheat Sheet For The NASM CNC Exam


    Get The Sectret Cheat Sheet For The NASM PES Exam


    Get The Sectret Cheat Sheet For The NASM CES Exam


    Get the top 5 Tips for Passing the ACE CPT


    Get the top 5 Tips for Passing the NASM CPT


    Get The Sectret Cheat Sheet For The NSCA CPT Exam


    Get The Sectret Cheat Sheet For The ACE Exam


    Get The Sectret Cheat Sheet For The NASM Exam


    Get The Sectret Cheat Sheet For The ISSA Exam

    Scroll to Top