Effects of Dehydration on Heart Rate

Key Takeaways: Dehydration and Heart Rate

• Even mild dehydration can raise heart rate, increasing cardiovascular strain and potentially causing palpitations.

• Dehydration reduces blood volume, making the heart work harder to pump blood and deliver oxygen.

• Normal adult resting heart rate ranges from 60–100 bpm; consistent readings outside this range may require medical review.

• Common dehydration signs include dry mouth, dizziness, rapid heartbeat, low blood pressure, and confusion.

• Hot weather, intense exercise, and illness (vomiting, diarrhoea) accelerate fluid loss and raise heart health risks.

• Chronic or severe dehydration can lead to chest pain, arrhythmias, coronary artery disease, and heart failure.

• Prevent dehydration by drinking 2.1–2.6 litres of water daily (adults), more when active or in heat.

• Hydration supports heart efficiency, enabling better blood circulation and muscle function.

• First aid training equips you to respond to dehydration-related emergencies like fainting or heatstroke.

• CPR First Aid Australia offers accredited first aid courses across NSW, VIC, SA, WA, and QLD to prepare for such emergencies.

You might be surprised that dehydration can significantly affect your heart rate. In actuality, even slight dehydration might increase heart rate. The body’s natural response to dehydration is to raise blood pressure and heart rate to maintain blood flow and fluid balance. In this article, we’ll talk about the effects of dehydration on heart rate as well as ways to avoid it.

What is a Normal Heart Rate?

Your heart works more challengingly if you’re dehydrated. Dehydration can increase the strain on your heart as the muscle tries to compensate. Your blood volume (the amount of blood flowing through your body) and blood pressure are reduced. Your heart beats faster (tachycardia), raising your heart rate and giving you heart palpitations. Additionally, more sodium is retained in your blood, making it more difficult to flow through your body. This increased sodium concentration can further strain your heart and lead to heart problems.

According to the Mayo Clinic, adults’ average resting heart rate ranges from 60 to 100 beats per minute. Resting heart rate is the number of times your heart beats per minute when you’re at rest. A lower resting heart rate implies more efficient heart function and better cardiovascular health. For example, a well-trained athlete might have an average resting heart rate of closer to 40 beats per minute.

To measure your heart rate, check your pulse. Place your index and middle fingers on your neck to the side of your windpipe (carotid pulse). To check your pulse at your wrist, place two fingers between the bone and the tendon over your radial artery — located on the thumb side of your wrist (radial pulse).

When you feel your pulse, count the beats in 15 seconds. Multiply this number by four to calculate your beats per minute.

Keep in mind that many factors can influence heart rate, including:

• Age
• Fitness and activity levels
• Being a smoker
• Having cardiovascular disease, high cholesterol, or diabetes
• Air temperature
• Body position (standing up or lying down, for example)
• Emotions
• Body size
• Various health conditions, heart diseases, and heart problems
• Medications
• Although many standards exist, an unusually high or low heart rate may indicate an underlying problem. Consult your doctor if your resting heart rate is consistently above 100 beats a minute (tachycardia) or if you’re not a trained athlete and your resting heart rate is below 60 beats a minute (bradycardia) — especially if you have other signs or symptoms, such as fainting, dizziness, or shortness of breath. It is best to have a doctor check an irregular heartbeat.

What Is Dehydration?

Dehydration occurs when the body loses more fluid than it takes in. Without enough water, the body cannot function properly, leading to dizziness, fatigue, and even heart problems.

Water makes up two-thirds of the body; without it, one can only survive a few days. Hot weather, intense exercise, or illnesses like vomiting and diarrhoea can quickly lead to dehydration.

To stay healthy, it’s crucial to drink at least 6–8 glasses of water daily and increase intake if you’re sweating or unwell. Listen to your body—if you feel thirsty, dizzy, or have a fast heartbeat, then it’s time to rehydrate! Understanding the importance of hydration empowers you to take control of your health.

Importance of Hydration to Our Hearts

According to the Australian Government National Health and Medical Research Council, water is between 50% and 80% of the human body, making it the single most significant component and essential to almost all biological processes. Understanding water’s role in the body enlightens us and fosters a deeper appreciation for our intricate functions.

Blood is continuously pumped by your heart throughout your body. It pumps around 7,600 gallons daily while beating 72 times per minute. When enough water is in the body, your heart works harder and can pump blood to your muscles more efficiently. As a result, your muscles can function more effectively. On the other hand, when you are dehydrated, your heart beats faster and works harder than usual. This is to compensate for the blood flow needed in the body.

Complications of Dehydration to the Heart

Dehydration strains the heart and makes it work twice as hard. A lack of fluids also decreases blood volume throughout the body.

Existing heart conditions can exacerbate dehydration problems in the heart. Any changes to a person’s heart rhythm or an arrhythmia can be triggered if a person is not hydrated enough.

Those without existing conditions shouldn’t neglect hydration. A low hydration level can lead to chest pains, coronary artery disease, heart attacks, and heart failure, among other things. Proper hydration is one factor that contributes to a heart-healthy person.

Head to the nearest healthcare facility if any heart conditions worsen due to dehydration.

Signs You Are Not Properly Hydrated

Several signs of dehydration should be looked for. Most people immediately feel mild dehydration, with parched throats or a dry mouth. As it continues to grow more severe, people start to feel lightheadedness.

The former two symptoms are symptoms of severe dehydration. Additional ones include a fever, a quickened heart rate, low blood pressure, confusion, muscle cramps, and little to no urine.

Any of these symptoms of dehydration will warrant some action. Follow these actions to avoid dehydration and the various complications it can bring.

How to Avoid Dehydration and Other Complications

Given the seriousness of dehydration and its complications, it is best to avoid it altogether. For starters, it is best to be mindful of the weather. Hot weather conditions increase the risk of dehydration and even heatstroke.

It is also best to be mindful of other risk factors that might trigger complications or affect hydration. Physical activity, obesity, and electrolyte or potassium and calcium imbalance can all significantly affect fluid loss and health.

Naturally, people who are overweight can turn to weight loss. Those with deficiencies can take supplements or even sports drinks for electrolyte imbalance.

Finally, if you take any medications, ensure that none of these affect your hydration. Medications such as diuretics can significantly affect how hydrated a person is.

When to Worry About Heart Rate Increase and Dehydration

Heart palpitations can feel alarming, but they’re not always an emergency. However, if they come with chest pain, difficulty breathing, or fainting, seek medical help immediately.

Dehydration can also require urgent care if you experience:

• Severe dizziness, drowsiness, or weakness
• Excessive diarrhoea or vomiting
• Blood or mucus in stool or vomit
• Unexplained confusion

How to Recover from Dehydration

The best way to rehydrate is to take small sips of water frequently. You can also eat hydrating foods like berries, melons, soups, or ice cream.

If you’ve lost fluids due to vomiting or diarrhoea, consider an oral rehydration solution from a pharmacy to restore essential minerals and salts. Severe cases may require IV fluids at a hospital.

When You’re More Active, Should You Drink Extra Water?

When sweat evaporates from your skin, you lose bodily fluids while removing heat from your body. To start rehydrating, ensure continuous fluid intake when exercising. This will help replace the fluids you lose through sweat. Drink water to lower your chance of developing heat exhaustion while maintaining regular bodily functions and performance levels.

Ways to Drink More Water

1. Be aware of your recommended water intake.
2. Carry a water bottle, or leave one at your desk/workspace.
3. Set a goal daily.
4. You can use an app to track your water intake.
5. Add freshly cut fruit to your water jug or bottle for some flavour.
6. Set reminders on your phone to have a glass of water.
7. Keep an easily accessible jug of water in your fridge.
8. Sip throughout the day.
9. Drink a glass of water after waking up and before bed.
10. Drink a glass of water for at least 30 minutes before eating.
11. Switch one of your tea/coffee breaks to water instead.

First Aid Courses in Brisbane

Risks of dehydration, hypertension, and hypotension can be prevented. Early detection of signs and symptoms will help you manage it. If you are interested in enrolling in a first aid course in Brisbane, contact CPR First Aid for more information.

CPR and first aid training are open to all since emergencies, such as complications caused by dehydration, can happen to anyone of any age anywhere in Australia. HLTAID010, one of our popular courses, provides essential emergency life support. Contact us anytime with your queries.

About CPR First Aid

RTO No. 21903: CPR First Aid was founded in 2007. We specialise in providing first aid training in CPR, asthma, and anaphylaxis for various workplaces, including childcare, schools, and other industries in NSW, VIC, SA, WA, and QLD. We are a Registered Training Organisation with the Australian Skills Quality Authority (No 21903). Our courses and Units are VET-accredited for workplaces in Australia.

Conclusion

Dehydration can significantly affect your heart rate; even slight dehydration might increase it. The body’s natural response to dehydration is to raise blood pressure and heart rate to maintain blood flow and fluid balance. The consequences of dehydration on the heart increase the strain on the heart as the muscle tries to compensate.

It is vital to prevent dehydration. Adults should drink 2.1 to 2.6 litres of water daily, and children should drink 1 to 1.6 litres. When dehydration occurs, it is best to perform first aid effectively. I hope you learned the tips for dehydration. Learning is fun; you can join us for our CPR First Aid Australia Training for more first-aid tips!