Hydration = Function
Reviewed August 2026
We are constantly bombarded with reminders to drink more water. Especially in summer, though it's just as important in winter! I know I send out reminders via social media to my people and remind my family, but I'm human, I forget too... In general, we see drinking water as an incidental thing. We have a background awareness lingering in the depths of our mind that, yes, we should do that. However, as you'll discover in reading this blog ~ without water, there is no wellness.
While there is water in every cell of our body, age and sex affect how much water there is in a healthy human body. Babies have the highest percentage of water at birth (75-78%). But this decreases to about 65% by the age of 1 and continues to decrease with age. Lean muscle holds more water than fat tissue. Adult men have more lean muscle in their body so they are approximately 60% water, where adult women are approximately 55% water.
The chemistry of water is pretty cool, but without delving into that, the humble water molecule is used throughout our body:
- as a building block for our cells;
- it's ability to dissolve so many substances allows cells to use nutrients, minerals and chemicals in a multitude of biological processes;
- and it provides a mechanism of transport around the body via our blood and circulatory system.
On a system level, well, water is used everywhere in your body. Everywhere.
Accordingly, if there is not enough water, the body will not work efficiently, and health and wellness are impacted. This may seem like a little thing, but it's not. Detrimental effects kick in very early in the piece and ongoing consequences impact quality of life on a day-to-day basis. Even to the extreme of risking a life.
Research shows mild dehydration ~ just a loss of 1-2% from a body ~ impairs physical and cognitive performance. But what does that mean to you?
Your body will endeavour to let you know about these tiny reductions in body water percentage. Whether you recognise these symptoms as a cry for water is another thing. What every day feelings and symptoms might actually be a sign you are dehydrated?
Thirsty? It turns out that by the time you register that you are thirsty you are already dehydrated. Thirst is not the best measure of healthy hydration.
When you are low on water, every system in your body feels it, and it shows up as symptoms you might not even link to hydration. Each body is, of course, different...and every person's situation is different. So, dehydration patterns in each person, in their specific situation in time, will be different. Following are some of the ways dehydration can show up in the systems of our body ~
The brain and nervous system (of course I begin here ~ I'm a chiropractor!!) ~ less water in the system means less blood flow and slower nerve signalling, so a person might feel:
- headaches or "pressure" behind the eyes
- brain fog or poor concentration
- dizziness or light-headedness
- mood swings or irritability
- fatigue even after resting
Spine and vertebral discs (this one is very important to my chiropractic heart too!) ~ dehydration makes the vertebral discs less plump, less able to facilitate movement and more vulnerable to damage. Dehydrated spinal discs may show up as:
- Back stiffness
- Soreness after sitting
- More tension through neck and shoulders
The musculoskeletal system (muscles and joints) (noticing a theme?) ~ dehydration results in less fluid in muscle cells and less lubrication in joints, so a person might feel:
- Muscle cramps or twitching
- Stiff or achy joints
- Slower post-exercise recovery
- Feeling "weak" or sluggish when you move
The circulatory system (heart and blood vessels) ~ less water makes for thicker blood/lower blood volume meaning the heart has to work harder to maintain blood pressure, thus a person might feel:
- Heart palpitations
- Feeling faint when standing up
- Racing pulse during mild exertion
The skin, connective tissue and fascia (the tissues that hold all our bits together keeping them organised and in place) ~ dehydration causes a loss of elasticity and plumpness in these tissues, you might notice:
- Dry, dull, or flaky skin
- Chapped lips
- Dark circles under the eyes
- Skin that "tents" when pinched (slow to bounce back)
Kidneys ~ these beauties filter our blood to remove toxins. Reducing the water they have to work with makes the process much less efficient. In this scenario you might feel or notice:
- Dark yellow urine
- Fewer bathroom trips
- Puffiness or bloating
- Fatigue or "heavy" feeling
Digestive system (from mouth to anus) ~ less water in our digestive pathways means everything becomes slowed down and less effective. This shows up as:
- Dry mouth or bad breath
- Constipation
- Reflux or stomach cramps
Temperature regulation ~ our body is set to work best in a particular internal temperature range. If the external temperature (such as due to weather extremes) shifts our body outside this happy temp zone there are significant health consequences. In Australia we bother most with hyperthermia (too hot ~ read more here), but those who hang out above the snow line in winter will know about hypothermia too (too cold). In Hyperthermia there is impaired sweating and an inability to cool down, the person will feel the consequences of dehydration in the nervous system and the circulatory system:
- Overheating quickly
- Flushed skin
- Feeling tired or faint in warm weather