Though carbonated beverages like soda may be filled with enough caffeine and sugar to give you a rush of energy before exercising, the effects of drinking soda before a workout typically outweigh the benefits.
Before delving into the effects of carbonated drinks on exercising, though, it's important to first differentiate between sodas, soft drinks and carbonated drinks. When a drink is carbonated, it contains dissolved carbon dioxide, which gives it its bubbles or fizzy composure, according to the U.S. Department of Agriculture.
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So, are carbonated drinks bad for you? Well, while many common sodas are carbonated, water is often carbonated as well — like sparkling waters or seltzers. Carbonated water typically has no added sugars or syrups and isn't much different from drinking regular water, per the Centers for Disease Control and Prevention (CDC).
A March 2016 study in the American Journal of Clinical Nutrition found that sparkling water hydrated people just as well as still water. Because there are no sugars or calories in sparkling water, it also doesn't contribute to weight gain or negative health effects the way other beverages might.
Soft drinks and sodas, meanwhile, encompass the beverages that contain carbonation in combination with added sugars, and real or artificial flavoring or syrups, according to CDC. Some soft drinks contain a slew of other additions as well, such as caffeine or preservatives.
Why is soda bad for your health, though? Typically, soft drinks will be high in sugar and calories and may feel more filling than drinking regular water.
And unlike drinking regular water or sparkling water, there may be more negative effects of sugary, carbonated drinks on exercising. Here are some of the potential consequences of drinking soda before a workout:
Does Soda Stunt Your Growth?
There is research that links caffeine (including caffeinated carbonated beverages like soda or energy drinks) to hampered growth and development in children, per an April 2020 review in the International Journal of Environmental Research and Public Health.
But this doesn't mean soda can automatically stunt your growth — for instance, drinking a Coke as an adult won't affect your height.
1. You Might Feel Bloated
Remember, not all carbonated beverages are bad for you — drinks like sparkling water or seltzer aren't much different from plain water.
However, there are certain unwelcome side effects of carbonated water that could affect your workout. According to the Mayo Clinic, carbonated drinks can lead to bloating, gas and burping. So if you'd prefer to exercise without digestive discomfort, it may be best to avoid chugging sparkling water before you hit the gym.
Luckily, though, light exercise (like walking or yoga) can help reduce gas and bloating, per the Mayo Clinic.
2. You Could Replenish Depleted Sugar
Because of the caffeine or sugar content of sodas and soft drinks, gulping down a bottle of soda before a workout can lead to a surge of energy at first, according to a March 2013 study in Advances in Nutrition. That's why some athletes reach for a cup of coffee, a Coca Cola or carbonated sports drink pre-workout hoping to get a quick fix for energy.
Other athletes drink sports drinks or soft drinks post-workout in the hopes of replenishing depleted electrolytes and glycogen stores. In fact, some research has examined how highly competitive or intensive athletes perform when drinking fructose before or after a several-hour workout, as this may help to restore their liver's glycogen stores.
For example, an August 2017 study in the European Journal of Sports Science found that drinking fructose could have an effect on an athlete's fatigue and metabolism, possibly providing them with a longer store of energy than someone just drinking water. This is why a competitive cyclist may drink a sugary beverage during a marathon.
However, it's important to note that these effects really only apply to intense endurance athletes — like long-distance cyclists or marathon runners — and not for someone engaging in a more moderate workout.
Do Bodybuilders Drink Soda?
While some people who engage in bodybuilding may drink soda, there's no research to suggest that soft drinks are a beneficial part of any weightlifting routine.
3. You Might Have a Sugar Crash
With the potential exception of those intense endurance athletes, drinks high in fructose are typically harmful during exercise for the average person. Here's why sugary, carbonated drinks are bad for you before, during or after exercise: They can lead to a sugar crash.
According to a June 2019 review in Neuroscience & Biobehavioral Reviews, having sugary carbohydrates was linked to increased fatigue and decreased alertness one hour after consumption compared to a placebo. In other words, that sugar rush you feel right after sipping your soda will quickly zap the energy levels you need to sustain your workout.
Sipping soft drinks before a workout, therefore, may not be the best choice. To avoid grabbing an energy or sports drink that's packed with too much sugar, make sure to read the food labels before buying it.
Here are some other reasons why sugary carbonation is bad for your health: Higher added sugar consumption is linked to higher risk for cardiovascular disease, type 2 diabetes, obesity and other chronic diseases, per an April 2014 study in JAMA Internal Medicine.
4. You May Be More Dehydrated
Sparkling water can hydrate you just as well as still water, according to the American Journal of Clinical Nutrition study.
But when it comes to sugary carbonated beverages like soda, the opposite may be true. Indeed, a small February 2019 study in the American Journal of Physiology examined how certain soft drinks — specifically, those high in fructose and caffeine — affected people during and after exercise in the heat, and found that those who drank the soft drinks were more dehydrated than those who drank water.
In this study, researchers measured adults working out on treadmills and lifting for 45 minutes. After the workout, each person was given either 16 ounces of a high-fructose, caffeinated soft drink or water to drink, then sent to exercise more. This cycle was repeated for about four hours, then participants were given their assigned beverage to drink when they left.
These hydration effects of carbonated drinks on exercising may even extend to your kidneys. In the same study, researchers tracked the participants' core body temperature, heart rate, blood pressure and biomarkers of kidney injury before and after the trial. They found that the people assigned to soft drinks had higher levels of certain kidney injury markers, such as creatinine in their blood and a lower glomerular filtration rate.
The same people also had higher levels of vasopressin, a hormone that raises blood pressure. Participants who drank water didn't experience any of these negative effects, leading the researchers to conclude that soft drinks didn't work to hydrate people in the heat and had a harmful effect on the kidneys.
How Much Water Should You Drink?
Use this equation to determine how much water you should drink every day to stay hydrated:
Body weight (in pounds) ÷ 2 = minimum ounces of water you should drink per day.
5. You Might Have a Lack of Electrolytes
While certain sports drinks are designed to provide you with sodium, electrolytes and some sugar after a workout, most common soft drinks — like Pepsi or Coca Cola — contain high levels of sugar without the electrolytes.
In other words, soft drinks won't replenish the electrolytes you lose through sweat when you exercise. And, per the American Council on Exercise, after a particularly sweaty workout (think hot yoga or running in the heat), this lack of electrolytes can lead to side effects like:
- Muscle cramps or spasms
Instead, you're better off rehydrating after a workout with dedicated sports drinks or gels, electrolyte-rich foods and water.
- American Journal of Clinical Nutrition: "A Randomized Trial to Assess the Potential of Different Beverages to Affect Hydration Status: Development of a Beverage Hydration Index"
- European Journal of Sports Science: "Glucose-Fructose Ingestion and Exercise Performance: The Gastrointestinal Tract and Beyond"
- Mayo Clinic: "Nutrition and Healthy Eating"
- JAMA Internal Medicine: "Added Sugar Intake and Cardiovascular Diseases Mortality Among US Adults"
- American Journal of Physiology: "Soft Drink Consumption During and Following Exercise in the Heat Elevates Biomarkers of Acute Kidney Injury"
- PLOS One: "Beneficial Effect of Moderate Exercise in Kidney of Rat after Chronic Consumption of Cola Drinks"
- Journal of Affective Disorders: "Sugars, Exercise and Health"
- Centers for Disease Control and Prevention: "Water and Healthier Drinks"
- U.S. Department of Agriculture: "carbonated beverages"
- Mayo Clinic: "Belching, gas and bloating: Tips for reducing them"
- Advances in Nutrition: "Energy and Fructose From Beverages Sweetened With Sugar or High-Fructose Corn Syrup Pose a Health Risk for Some People"
- Neuroscience & Biobehavioral Reviews: "Sugar rush or sugar crash? A meta-analysis of carbohydrate effects on mood"
- American Council on Exercise: "Electrolytes: Understanding Replacement Options"
- International Journal of Environmental Research and Public Health: "Caffeine Consumption in Children: Innocuous or Deleterious? A Systematic Review"