Approximately 50 - 65% of the weight of a healthy person is water. It plays a vital role in helping you to stay healthy by:
  • Regulating body temperature
  • Removing waste from the body
  • Carrying nutrients, oxygen, enzymes, hormones and glucose to the cells
  • Carrying away toxins and metabolic waste from the cells for elimination
  • Cushioning joints and strengthening muscles
  • Providing natural moisture to skin and other tissues

You continually lose water during the day through sweat, urine and breathing. The amount of water you lose depends on factors such as physical activity and climatic conditions. Other factors affecting your body water level include illness, medications, hormone changes and poor nutrition.

Thirst is not the best indicator of dehydration, as the thirst mechanism only kicks in when you are already mildly dehydrated. Early symptoms of dehydration may include decreased energy or fatigue, headaches and dizziness.

Other symptoms are:
  • Dark coloured urine, which may have an odour, and/or infrequent urination
  • Dry lips, mouth, skin
  • Nausea
  • Constipation
  • Increased body temperature
Finding the right balance of water intake will ensure your body functions efficiently, will make you feel healthier and more alert and will reduce the risk of serious health problems. Being properly hydrated will also ensure you are performing at your best, allowing you to exercise longer. The new Total Body Water Percentage feature on selected Tanita Body Fat Monitors will help you to remain within the healthy total body water ranges.



The average total body water percentage ranges for a healthy adult are:
  • 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.


As your total body water level changes naturally throughout the day, this may affect your body fat percentage readings. 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.

(Source: Tea Drinking and Fluid Balance: A Review. Maughan and Griffin, 2001)

Tanita Body Fat Monitors with Total Body Water %