When temperatures rise for several consecutive days, the body is affected more than many realize. A heatwave is not just uncomfortably hot. The body has to work harder to maintain a stable body temperature and this can affect fluid balance, electrolytes, circulation, muscles, energy, sleep, and recovery. In the heat, sweating increases. When we sweat, we lose not only water but also important electrolytes such as sodium, potassium, magnesium, and chloride. If losses become significant, or if you drink a lot of water without replacing salts and minerals, you may feel tired, weak, dizzy, get headaches, muscle cramps, or reduced stamina. Therefore, it’s important to think about more than just water during a heatwave. Fluids, electrolytes, minerals, rest, cooling, and the right foods together play an important role in how the body handles high temperatures.
What is a heatwave?
A heatwave is a period with unusually high temperatures, often for several days in a row. The exact definition can vary, but from the body’s perspective it’s primarily the combination of high temperature, strong sun, high humidity, poor sleep at night, and insufficient recovery that makes the heat taxing. When the body is exposed to heat, it tries to cool itself by:
- increasing sweating
- dilating blood vessels in the skin
- increasing blood flow to the skin surface
- increasing the heart’s workload
- reducing performance during physical activity
These are normal protective mechanisms. Problems arise when fluid loss exceeds intake, when electrolytes are not replaced, or when the body doesn’t get the chance to cool down and recover.
Common symptoms in heat, dehydration, and electrolyte deficiency
During a heatwave, the body can signal imbalance in several ways. Common symptoms include:
- fatigue and lack of energy
- headache
- dizziness or feeling unsteady
- dry mouth
- dark urine or reduced urine output
- muscle cramps
- nausea
- palpitations
- difficulty concentrating
- poorer sleep
It’s important to understand that dehydration and electrolyte deficiency are not always the same thing. You can drink a lot of water and still feel “drained” if you’re simultaneously losing a lot of salts through sweating.
Why electrolytes matter during a heatwave
Electrolytes are minerals that carry an electrical charge in the body. They’re needed for nerve signaling, muscle function, fluid balance, blood pressure regulation, and normal heart function. The most important electrolytes in heat and sweating are:
- Sodium – helps the body retain fluid and is the electrolyte we lose the most of through sweat.
- Potassium – important for muscles, the nervous system, and fluid balance inside cells.
- Magnesium – needed for muscles, the nervous system, energy metabolism, and electrolyte balance.
- Chloride – works together with sodium and is important for fluid balance and stomach acid.
During a heatwave, sodium is particularly important because sweat contains significant amounts of salt. People who eat very clean, unprocessed food often consume less salt than those who eat a lot of ultra-processed food. That can be positive in many contexts, but with heavy sweating the need for salt and electrolytes can increase.
Should you just drink more water when it’s hot?
Water is essential, but it’s not always enough. In mild heat and with low physical activity, drinking regularly and eating mineral-rich foods is often sufficient. But with heavy sweating, exercise, sauna, outdoor work, or prolonged heat, the body may need both fluids and electrolytes. A common mistake is to drink large amounts of plain water without getting enough salts. This can dilute the body’s electrolytes and leave you feeling weak, tired, or dizzy even though you’re drinking a lot.
A simple rule of thumb is:
- Drink regularly throughout the day.
- Salt your food as needed.
- Use electrolytes with heavy sweating or prolonged heat.
- Avoid large amounts of alcohol, as it can impair fluid balance.
- Be extra cautious with intense training in the middle of the day.
Who is extra sensitive to heatwaves?
Some people are more affected by heat than others. Extra caution is needed for:
- older adults
- young children
- pregnant individuals
- people with cardiovascular disease
- people with kidney problems
- people with diabetes
- people with high blood pressure
- people using diuretic medications
- people using medications that affect blood pressure, kidneys, or electrolytes
For these groups it’s especially important to consult a healthcare provider if unsure, particularly before using electrolyte supplements or minerals in higher doses.
Diet during a heatwave
When it’s very hot, many people experience reduced appetite. It’s then wise to focus on easy-to-digest, nutrient-dense foods that provide protein, minerals, and energy without overloading digestion. We recommend prioritizing:
- eggs
- fish and shellfish
- high-quality meat
- yogurt, kefir, or cheese if dairy is tolerated
- fruit and berries
- honey as an easily accessible carbohydrate source if needed
- mineral-rich salt on food
- natural fats like butter and tallow in reasonable amounts
Try to avoid large amounts of ultra-processed food, seed oils, alcohol, and lots of sugar. These can contribute to poorer fluid balance, more oxidative stress, and worse recovery.
Supplements that can be helpful during a heatwave
Supplements should not replace fluids, food, cooling, or medical care. However, certain supplements can be valuable for supporting fluid balance, electrolytes, muscles, the nervous system, and recovery during hot periods.
1. Electrolytes Plus+ – first choice for sweating and heat
During a heatwave, electrolytes are often the most relevant supplement. When we sweat, we primarily lose sodium, but also other minerals. Electrolytes Plus+ is therefore our first choice in heat, sweating, training, sauna, or when you feel weak and “drained” despite drinking water. Electrolytes help the body keep fluid in the right place, support normal muscle function, and maintain nervous system signaling.
Particularly helpful for:
- heavy sweating
- training in the heat
- prolonged time outdoors
- sauna
- low-carbohydrate diets
- headaches related to fluid loss
- feeling weak or low energy in the heat
Important: People with kidney disease, heart failure, high blood pressure requiring medication, or medications that affect sodium/potassium should consult a healthcare provider before using electrolytes regularly.
2. Magnesium M4 – for muscles, the nervous system, and recovery
Magnesium is an important mineral for muscles, the nervous system, electrolyte balance, and energy metabolism. During hot periods, magnesium can be especially relevant because sweating, stress, poor sleep, and physical strain can increase needs.
Magnesium M4 contains several forms of magnesium, providing broader support. Magnesium can be particularly valuable for muscle cramps, tension, heightened stress, and poorer sleep during a heatwave.
Particularly helpful for:
- muscle cramps
- tight muscles
- poorer sleep due to heat
- stress and feeling wound up
- high physical load
- fatigue and recovery needs
Magnesium is often best taken with a meal or in the evening. If you have a sensitive stomach, start with a lower dose.
3. Taurine – support for electrolyte balance, heart, and nervous system
Taurine is an amino acid-like compound found naturally in the body and is especially important in the heart, muscles, brain, and nervous system. Taurine is also linked to electrolyte regulation and cellular fluid balance. During a heatwave, Taurine – 1000 mg can be an interesting complement for people who feel stressed, experience palpitations, become easily wound up, or are strongly affected by heat.
Particularly helpful for:
- sensitivity to stress in the heat
- feeling wound up
- poorer sleep
- exercise and sweating
- the need for nervous system support
Taurine does not replace electrolytes, water, or salt. We see it as complementary support rather than a first choice.
4. Mineral Complex Plus+ – broader mineral support in prolonged heat
If the heatwave lasts a long time, or if you sweat a lot for several days, broader mineral support can be relevant. Minerals work together in the body, and fluid balance is not just about water and sodium. Mineral Complex Plus+ can be an option for people who want to support the body’s mineral status more broadly, especially with an unvaried diet, high physical activity, or longer periods of heat strain.
Particularly helpful for:
- prolonged heat
- heavy training
- unvaried diet
- low-mineral diet
- general fatigue and recovery needs
5. Vitamin C – antioxidant support for oxidative stress
Heat, strong sun, physical exertion, and dehydration can increase the body’s oxidative load. Vitamin C helps protect cells from oxidative stress and also supports normal collagen formation, immune function, and energy metabolism. Vitamin C PureWay-C® is not an acute heat supplement in the same way as electrolytes, but it can be good foundational support during periods when the body is under more stress.
Particularly helpful for:
- high physical load
- a lot of sun and time outdoors
- low fruit and berry intake
- the need for antioxidant support
6. Vitamin D3 + K2 – not acute for heat, but important overall
Vitamin D is important for immune function, muscle function, and general health. During a heatwave, many people avoid the sun in the middle of the day, which is wise from a heat perspective. However, vitamin D is not an acute supplement for a heatwave. Vitamin D3 2000 IU + K2 MK7 can be relevant as long-term support if you avoid sun exposure or if you have low vitamin D levels.
Prioritization: which supplements are most important during a heatwave?
If we keep it simple, we recommend the following:
If you choose only one supplement:
Electrolytes Plus+: The most relevant choice for sweating, heat, and fluid loss.
If you choose two supplements:
- Electrolytes Plus+
- Magnesium M4
This is a good combination for fluid balance, electrolytes, muscles, the nervous system, and recovery.
If you want more complete support:
- Electrolytes Plus+
- Magnesium M4
- Taurine – 1000 mg
- Mineral Complex Plus+ during prolonged heat or high load
Practical tips during a heatwave
In addition to fluids and supplements, lifestyle is crucial. During a heatwave, we recommend that you:
- drink regularly throughout the day
- eat salt- and mineral-rich foods
- avoid hard training in the middle of the day
- train early in the morning or later in the evening
- seek shade during the hottest hours
- wear loose-fitting clothes
- cool wrists, neck, and feet as needed
- air out at night when the air is cooler
- keep curtains and blinds closed during the day
- avoid alcohol or keep intake very low
- make sure older relatives get enough fluids and food
When should you seek medical care in the heat?
Seek urgent care if you suspect heatstroke or severe impact. Be especially alert to:
- confusion
- fainting
- seizures
- very high body temperature
- hot, dry skin
- marked drowsiness
- altered consciousness
- symptoms that do not improve with cooling, rest, and fluids
Heatstroke is an acute condition and should not be managed with supplements. Medical assessment is required.
Common questions about heatwaves, fluids, and electrolytes
How much should you drink during a heatwave?
It depends on body size, activity level, sweating, diet, and health. A good foundation is to drink regularly throughout the day and pay attention to thirst, urine color, headache, dizziness, and fatigue. With heavy sweating, electrolytes are often needed as well, not just water.
Are electrolytes good in the heat?
Yes, electrolytes can be very relevant in the heat, especially if you sweat a lot. Electrolytes like sodium, potassium, and magnesium help the body regulate fluid balance, nerve signals, and muscle function.
Can you drink too much water when it’s hot?
Yes, it’s possible to drink too much water relative to salt and electrolyte intake. That’s why it’s important not to focus only on water, but also on minerals and salt with heavy sweating.
Why do you get headaches in the heat?
Headaches in the heat can be due to dehydration, electrolyte imbalance, strong sun, poorer sleep, low blood pressure, stress, or eating too little. If the headache is severe, unusual, or combined with confusion, fainting, or nausea, seek medical care.
Can magnesium help with muscle cramps in the heat?
Magnesium is important for normal muscle function and electrolyte balance. In heat and with sweating, magnesium can be good support, especially if you get muscle cramps, tension, or sleep worse.
Is salt important during a heatwave?
Yes, salt can be important in the heat because sodium is the electrolyte we lose the most of through sweat. People who sweat a lot, train in the heat, or eat very clean and unprocessed foods may need to pay extra attention to salt intake.
Summary
During a heatwave, the body primarily needs help with fluid balance, electrolytes, cooling, and recovery. It’s not always enough to just drink more water, especially not with heavy sweating. The body also loses salts and minerals needed for muscles, the nervous system, circulation, and energy.
Our top recommendations during a heatwave are:
- Electrolytes Plus+ – first choice for sweating, heat, and fluid loss.
- Magnesium M4 – support for muscles, the nervous system, electrolyte balance, and recovery.
- Taurine – 1000 mg – complementary support for the nervous system, heart, and electrolyte regulation.
- Mineral Complex Plus+ – broader mineral support during prolonged heat or high physical load.
- Vitamin C PureWay-C® – antioxidant support for sun, heat, and physical strain.
Supplements should always be seen as a complement to fluids, food, cooling, sleep, and sensible behavior. They should not be used as a substitute for medical care. People with heart, kidney, or blood pressure issues, as well as those using medications that affect fluid or electrolyte balance, should consult a healthcare provider before using electrolytes or minerals in higher doses.