What Causes a Dehydration Headache?
Our brains are 80% water. When you become dehydrated your brain tissue loses water causing your brain to shrink and pull away from the skull. This triggers the pain receptors surrounding the brain, giving you a headache.
Dehydration also causes your blood volume to drop which in turn lowers the flow of blood and oxygen to the brain. In response the blood vessels in the brain dilate leading to swelling and inflammation, worsening the headache.
A few Sundays back I was not feeling my best having indulged in one too many glasses of wine the night before. I decided to try ‘sweat it out’ with a few laps round the nearby park, hoping a run might help cure my hangover symptoms and do me a world of good. I was sorely mistaken.
The moment my first foot hit the pavement I felt an excruciating thud in the top part of the back of my head, and again with the next step and again with the next. It was as though each impact from my foot hitting the ground was being transmitted directly to the back of my brain.
I struggled through the first few hundred metres before retiring back to the couch and waiting out the rest of my hangover drinking fluids and re-watching the first two seasons of The Walking Dead (stopping at season 3 which was more painful than my headache).
The problem with trying to run off a hangover is that a lot of the symptoms you are feeling are actually caused by dehydration. I was lucky my headache stopped me in my tracks as ‘sweating it out’ would have only led to further fluid loss and made matters worse.
How to Know if a Headache is Caused by Dehydration
Look for Common Characteristics
Dehydration headaches can occur at the front, back, side or all over the head. (I know right, that doesn’t exactly narrow it down). They are best identified by the way that movement seems to aggravate them and make the pain worse. On the worksite, pain may be elevated when bending down or over to pick something up, or when climbing a ladder or stairs. Even walking can sometimes seem excruciating, depending on headache and dehydration severity.
Monitor other Symptoms
Headaches caused by dehydration do not happen in isolation. There will usually be coinciding dehydration symptoms such as dry mouth, fatigue, increased blood pressure, and nausea to name a few. If these other symptoms are present, chances are your headache is a result dehydration and you need to increase your fluid intake and reduce physical activity until these symptoms subside.
Assess Your Situation
If you have experienced heavy sweat losses but have not been drinking much fluid, chances are you are dehydrated. Exercise, physically demanding work, alcohol consumption, vomiting, fever and diarrhea are all things that lead to high fluid losses. Hot weather and high temperatures also put you at risk. If you have a headache and any of the these things describe your current situation, dehydration is the likely culprit.
How to Treat a Dehydration Headache
Dehydration headaches are caused by an inadequate amount of fluid for the body to function correctly.
Reduce Physical Activity
Physical activity causes sweating and water loss. If you are already dehydrated you should minimise physical activity and focus on fluid intake. Frequent breaks and adequate rest are recommended until your symptoms subside.
Drink Plenty of Water
Don’t attempt to down large amounts of water in one go. Our bodies can only absorb a small amount of water at at time and drinking to much too fast will only leave you bloated and uncomfortable with a stomach full of water. Instead go for small amounts frequently, say 200-250mls every 15-20 mins, until symptoms subside.
Replace Lost Electrolytes
Electrolytes are also lost through sweat and play an essential role in water retention. Failure to replace lost electrolytes will lead to difficulties rehydrating. Add some electrolyte powder to your water for fast electrolyte replenishment.
Take A Pain Killer
Headaches caused by dehydration will usually subside once adequate water has returned to the brain. However, this can take several hours of active fluid replacement. If the pain is intolerable, take a pain killer such as aspirin or ibuprofen to provide faster relief. Bare in mind that this will only treat the symptom and not cause. To prevent the headache from returning as soon as the pain killers wear off, you must rehydrate with a combination of water and electrolytes.
Preventing Headache Recurrence
Preventing a dehydration headache is achieved by keeping adequately hydrated at all times. This sounds simple, but over half of the population show up to work in a state of mild dehydration each day. In order to prevent dehydration it is important to take a proactive approach to hydration. Don’t wait until you are thirsty to drink as when you are thirsty you are already dehydrated.
Awareness is Key
Even when we are proactive about replacing lost fluids, dehydration is a constant threat. To prevent dehydration you need to pay attention to your body and to changes in your environment. If the weather is hotter, drink more than you usually would. If you are physically exerting yourself, increase your intake accordingly. Most importantly, listen to your body and learn to recognise the signs.
The pain caused by a dehydration headache is just one of the ways your body communicates to you that something is wrong. It is a symptom of a much bigger problem that your body needs you to take action in order to resolve. Identifying the problem and knowing the correct course of action to take is the key to preventing recurring dehydration headaches or at the very least nipping the problem in the bud early on.