Know the side effects of having energy drinks before a workout

A 20-year-old woman reportedly suffered cardiac arrest after consuming a popular energy drink before lifting weights. Her heart and lungs were said to be in a really bad shape, as claimed by her loved ones in a report. However, doctors reportedly did not confirm a connection between energy drinks and cardiac arrest. But there may be a few side effects of having energy drinks, known for boosting energy and increasing alertness. The drink has ingredients, such as caffeine and sugar or artificial sweeteners that may affect the heart, kidneys, and stomach. Know if consuming energy drinks before a workout is a good idea or not!

A woman suffers cardiac arrest after consuming an energy drink.

In November 2024, Jazmin Garza, a 20- year-old from the United States had a few sips of a popular energy drink before she started lifting weights with her boyfriend. Soon after having the beverage, she reportedly collapsed on the floor. Her body was convulsing and her nose was bleeding. She lost her pulse and her boyfriend started to give her CPR. Moments later the medical team got there and gave her CPR. After several minutes, they were able to get her heart pumping again.

When she went into cardiac arrest, her lungs and heart were in a really bad shape. Her stomach and kidneys also stopped working, according to media reports. It took a while but immediate action helped her recover.

Does consuming energy drinks before a workout affect the heart?

A clear link between energy drinks and cardiac arrest was not made when Jazmin Garza was hospitalised. But these drinks can significantly impact heart health, especially when consumed before exercise. They have high amounts of caffeine and other substances that can negatively affect the hearts of individuals who consume them, as per research published in the Anatolian Journal Of Cardiology in 2017. “Energy drinks contain high doses of caffeine, sugar, and stimulants that can overstimulate the cardiovascular system, and lead to health problems,” says nutritionist Rakshita Mehra.

1. Increased heart rate and blood pressure

These drinks contain high caffeine levels, often 150-300 milligram (mg) per can, which helps stimulate the sympathetic nervous system (“fight or flight” response). “This can lead to a rapid heart rate and increased blood pressure before or during exercise. In some cases, this can disrupt the heart’s normal rhythm (arrhythmia), increasing the risk of sudden cardiac arrest,” says the expert.

2. Risk of heart attack due to narrowed blood vessels

Having energy drinks before a workout can constrict blood vessels, reducing oxygen flow to the heart. “This is dangerous, especially during intense workouts, where the heart already needs more oxygen and blood flow. If the heart doesn’t get enough oxygen, chest pain or a heart attack can occur,” says the expert.

3. Increased risk of dehydration

Caffeine is a diuretic, which can cause dehydration, especially if it is combined with sweating from exercise. “Dehydration can thicken the blood, making it more likely for blood clots to form, increasing the risk of a stroke or heart attack,” says the expert.

Other potential side effects of having energy drinks before a workout

Having energy drinks before a workout can have side effects such as:

1. Insomnia

Consuming energy drinks before a workout especially during the evening, can interfere with sleep cycles, leading to poor recovery and muscle fatigue. “Caffeine stays in the body for about 5 to 6 hours, making it harder to fall and stay asleep,” says the expert.

2. Digestive issues

Having energy drinks before a workout is not a good idea even in the morning. “They are acidic and can cause acid reflux, and bloating, especially when consumed on an empty stomach,” says Mehra. Artificial sweeteners and additives, found in such beverages, may disrupt gut bacteria which can lead to digestive discomfort and diarrhoea.

3. Blood sugar spikes

The high sugar content in such drinks is great for giving a quick energy boost, which is needed while working out. “But this is usually followed by a sharp drop in blood sugar. This can leave you feeling tired and sluggish, so don’t have energy drinks before a workout,” says the expert.

4. May affect the kidneys

Consuming energy drinks before a workout can also negatively impact your kidneys. During a 2023 analysis, published in Nutrients, an association was found between energy drinks and kidney problems, including kidney failure. Such drinks contain high amounts of caffeine, which acts as a diuretic, increasing the production of urine and potentially leading to dehydration. “Dehydration puts stress on the kidneys, affecting their ability to filter waste. It may contribute to kidney stone formation by promoting calcium excretion and dehydration, which leads to crystal formation in the pee.

5. May have a negative effect on lungs

Having energy drinks before a workout may affect your lungs. During a 2024 study, published in Heart & Lung, a positive association was found between the consumption of caffeine, found in energy drinks, and the risk of Chronic obstructive pulmonary disease and lung function. “The high caffeine content in energy drinks can cause overstimulation of the nervous system, leading to rapid breathing (hyperventilation) or shortness of breath. Excessive sugar in such pre-workout drinks can contribute to chronic inflammation, which may negatively affect lung health over time,” says Mehra.

Consuming it in excess, especially every single day is unhealthy. “If you are healthy, have one small energy drink, max 200 mg caffeine, once a while, and avoid mixing it with alcohol, which can increase heart risks,” says the expert. But try to avoid energy drinks before a workout. If you need an energy boost, opt for natural pre-workout foods like bananas, and coconut water.