Health and Fitness Information Center

Truth about Body Water Percentage, Part 3

• Health Topics

• Asthma/Allergies
• Blood Pressure
• Blood Testing
• Body Fat Measuring
• Breast Exam
• Breastfeeding
• Cholesterol
• Defibrillator
• Diabetes
• Family Health
• Fitness
• Nutrition
• Safety
• Stress
• Thermometry
• Weight Control

First thing in the morning you will be dehydrated and the fluid in your body will be stored in the central trunk area. As the day progresses, this fluid becomes more evenly distributed and, of course, eating and drinking will also affect your total body water level.

So even though your actual body fat mass will not change during the day, your body fat percentage will, as your total body water changes. Your body fat reading could vary by as much as 3-4% in a 24-hour period.

Consistency is the key to using your Body Fat Monitor. The best time is in the early evening, before your meal, when hydration levels are more stable. This increases the accuracy of the readings. If you are unable to use your Body Fat Monitor as this time, pick a time that's convenient for you and stick to it. Take your readings at the same time and under the same conditions each day.

Feel Your Best
Staying properly hydrated will help keep your body feeling great and performing at its best. Proper hydration increases energy levels, makes you more alert and can even help reduce stress. Common signs of dehydration can include achy joints and muscles, fatigue, headaches and dry skin. More serious dehydration can lead to dizziness and nausea and in more extreme cases, death.

Healthy Total Body Water Percentage (TBW%)
The average total body water percentage ranges for a healthy adult are:
Age 18+
Female: 45 - 60%
Male: 50 - 65%

For Athletes, the figure is approximately 5% above these averages, as they will have greater muscle mass. Skeletal muscle contains more water than fat (adipose) tissue.

To date there are no validated standards for overweight/obese people, although the total body water percentage will fall below the average healthy ranges. The amount will vary depending on the degree of excess body fat.