Are Energy Drinks Bad for You? A Sleep Doctor Explains

Featuring clinical insight from Dr. Maria Paula Guzman, MD — triple board-certified in Sleep Medicine, Obesity Medicine, and Internal Medicine at DreamLife Medicine & Wellness

There's a moment in a recent conversation with Dr. Maria Paula Guzman that probably sounds familiar to a lot of us. The interviewer confessed — mid-interview, can of energy drink in hand — that he'd already had two that day. He didn't know exactly what was in it. He'd looked it up online once and found the ingredient list a little alarming.

If you winced in recognition, you're in good company. Energy drinks have quietly become the default fix for a very common problem: being exhausted and still having a full day ahead of you. Tired from a bad night's sleep? Grab one. Long drive home? Grab one. Afternoon crash at 2 p.m.? Grab one.

So, are energy drinks actually bad for you — and is the occasional can really that big a deal?

Here's what a physician who spends her days treating sleep and metabolic disorders had to say.

Table of Contents

• What's Actually in an Energy Drink?
• How Energy Drinks Affect Your Nervous System and Blood Pressure
• Energy Drinks, Caffeine, and the Sleep Apnea Cycle
• Should You Quit Energy Drinks? How to Cut Back Safely
• When Constant Fatigue Is a Medical Problem
• How to Test for Sleep Apnea at Home
• Already Diagnosed? A CPAP Starter Package
• Frequently Asked Questions
• About Dr. Guzman

What's Actually in an Energy Drink?

Dr. Guzman's first observation was less about any single villain ingredient and more about the combination.

Energy drinks typically stack a range of B vitamins, assorted herbal supplements, caffeine, and other stimulating compounds — and then deliver all of it in something sweet and easy to drink quickly. As she put it, everything gets bundled into "one juicy, delicious, sugary thing."

That's worth pausing on. A cup of coffee is essentially one stimulant in hot water. An energy drink is a stack of stimulants, often alongside a significant dose of sugar or artificial sweeteners, in a format designed to go down fast and taste good. The delivery mechanism matters as much as the ingredient list.

It's also why the label is genuinely hard to interpret. Proprietary "energy blends" often don't disclose individual amounts, and the herbal additives (guarana, taurine, ginseng, and others) can carry their own stimulant load on top of the listed caffeine.

How Energy Drinks Affect Your Nervous System and Blood Pressure

This is where Dr. Guzman's clinical focus landed. The issue isn't really any single ingredient — it's the physiological state you're putting your body into, over and over.

When you take in a substantial dose of caffeine, you're likely causing vasoconstriction — a narrowing of the blood vessels. Narrower vessels mean higher pressure. So blood pressure tends to rise.

At the same time, you're revving up the sympathetic nervous system — the branch responsible for your fight-or-flight response. Dr. Guzman described it plainly: a state of essentially fight or flight is what you're inducing.

That's fine as an occasional, short-lived response. Your body is built for it. The problem is chronic activation.

"Over the long term, I think it's more about that stress on the heart from the blood pressure being high."

— Dr. Maria Paula Guzman, MD

In the short term, she noted, the more obvious casualty is your sleep. But her longer-term concern was cardiovascular: sustained elevated blood pressure puts sustained strain on the heart. If you're a two-a-day energy drink person, you're not having an occasional stress response — you're living in one.

Energy Drinks, Caffeine, and the Sleep Apnea Cycle

Here's the part of the conversation that reframes the whole question, and it comes directly out of Dr. Guzman's sleep medicine practice.

She pointed out that the same pattern shows up with coffee, and it's especially pronounced in people with untreated sleep apnea. Those patients often drink three, four, or five cups just to get through a normal workday. Some are drinking coffee on the drive home specifically to stay awake and stay safe behind the wheel.

Read that again: people are self-medicating with stimulants in order to safely operate a vehicle.

That's the trap. The energy drink isn't the disease — it's the symptom management. And it works just well enough that the actual problem never gets looked at.

The cycle tends to look like this:

1. You sleep poorly — from sleep apnea, insomnia, shift work, stress, or simply not enough hours in bed.
2. You're exhausted the next day, so you reach for caffeine.
3. The caffeine keeps your nervous system elevated, which makes it harder to fall asleep and stay asleep that night.
4. You sleep even worse.
5. Repeat, with a slightly larger dose.

Meanwhile, if there's an underlying sleep disorder driving it, that condition continues untreated in the background — and untreated sleep apnea carries real consequences of its own, including effects on blood pressure, metabolic health, and cardiovascular risk.

So when you're stacking chronic caffeine on top of chronic sleep deprivation, you may be compounding two problems that already push in the same direction.

Should You Quit Energy Drinks? How to Cut Back Safely

Notably, Dr. Guzman didn't tell anyone to quit cold turkey — and neither did the interviewer, who instead landed on something more honest.

When he joked that this would be his New Year's resolution, he caught himself mid-sentence and revised it. Rather than overpromise, he said, he'd cut down and slowly get better at it.

That's a genuinely better strategy, and not just for motivational reasons. Abrupt caffeine cessation reliably produces headaches, irritability, and fatigue — which, when you're already tired, tends to send people right back to the can by day three.

A more realistic approach:

• Count your actual intake for a week. Not what you think you drink — what you actually drink. Most people are surprised.
• Read one label all the way through. Just one. Total caffeine, total sugar, and anything in a proprietary blend.
• Set a caffeine curfew. Caffeine has a half-life of roughly five to six hours in most adults, meaningfully longer in some. An afternoon energy drink is still circulating at bedtime.
• Taper, don't quit. Cut by one drink per week rather than going to zero.
• Ask the harder question. Why do you need it? If the honest answer is "because I'm exhausted every single day," the drink isn't the thing to fix.

When Constant Fatigue Is a Medical Problem, Not a Willpower Problem

That last point is the one worth sitting with.

Needing caffeine to enjoy your morning is one thing. Needing it to stay awake at your desk, to get through a meeting, or to drive home safely is a different category of tired — and it's a medical question, not a willpower question.

Signs worth taking seriously:

• Waking up unrefreshed no matter how many hours you were in bed
• Loud, chronic snoring — especially if someone has told you that you stop breathing
• Morning headaches or a dry mouth on waking
• Nodding off during the day, in meetings, or while driving
• Blood pressure, blood sugar, or weight trending upward without a clear explanation
• Needing three or more caffeinated drinks just to function

Sleep apnea in particular is common, frequently undiagnosed, and highly treatable. The energy drink is a workaround. It's worth knowing what you're working around.

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How to Test for Sleep Apnea at Home

You no longer need an overnight stay in a sleep lab to get answers. Home sleep apnea testing lets you sleep in your own bed, with your own pillow, and still get a result reviewed by a board-certified sleep physician.

The CPAPmyway Home Sleep Apnea Test — $195

Here's how it works:

1. Order the kit. Orders are processed within one business day and the kit ships to your door.
2. Watch the instructional video. You'll get a link by email showing exactly how to wear and run the device.
3. Sleep one night at home. The test needs to be completed within two days of arrival.
4. Ship it back free. A prepaid return label is included in the box.
5. Get physician-reviewed results. The test is forwarded to a board-certified sleep physician, who typically returns results within one to two business days.

The full process averages about 10–12 days from order to results. Choosing 2-day shipping at checkout cuts roughly 4–6 days off that timeline.

A few practical notes: the test meets DOT health card criteria, which matters if you're a commercial driver. Return it on time — late returns are subject to a per-day fee, and unreturned devices are billed at full replacement cost. And because the kit ships as a medical device, orders can't be refunded once shipped.

→ Order your home sleep apnea test

Already Diagnosed? A CPAP Starter Package That Includes Everything

If you've been diagnosed with obstructive sleep apnea, CPAP therapy remains the most effective treatment available — and the difference in daytime energy is often the thing people notice first.

The problem is that starting CPAP usually means piecing together a machine, a mask, tubing, filters, and a power supply from different places, then figuring out the mask fit on your own.

The ResMed AirSense 11 Auto CPAP Bundle packages it together:

What's in the box

• ResMed AirSense 11 AutoSet CPAP machine
• Your choice of mask
• Tubing, filters, and AC power supply
• Travel case
• Free shipping

Why the AirSense 11

• Three modes in one machine — AutoSet (auto-adjusting), fixed-pressure CPAP, and AutoSet for Her
• Forward-facing touchscreen you can actually read from bed
• Over-the-air updates — no SD cards, no trips back to the supplier
• Smart heated humidifier with manual or automatic climate control
• AutoRamp starts you at a low pressure and increases it once you've fallen asleep
• Expiratory Pressure Relief (EPR) drops the pressure when you exhale, so breathing out feels natural
• Quiet operation at 25–27 dBA, and a 2-year warranty

What comes with it beyond the hardware

• 30-day mask comfort guarantee — if your first mask doesn't fit right, exchange it. You can also talk through mask options with the team before your order ships.
• One-on-one setup instruction rather than a box on your doorstep and good luck.
• Lifetime compliance monitoring via the built-in wireless modem — useful if you need usage reports for a physician or a DOT clinic, which can be sent by email or fax.

→ See the AirSense 11 starter bundle

CPAP machines require a valid prescription in the United States. If you've already been diagnosed and simply need an updated prescription for new equipment, CPAPmyway offers a separate CPAP prescription service.

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Frequently Asked Questions

Are energy drinks bad for you?

It depends much more on frequency than on any single can. Occasional use is a short-lived stress response your body handles routinely. Daily use means repeated vasoconstriction, elevated blood pressure, and sustained sympathetic nervous system activation — which, as Dr. Guzman notes, puts ongoing strain on the heart over time.

Do energy drinks affect sleep?

Yes. Caffeine's half-life is roughly five to six hours in most adults and considerably longer in some, so a drink consumed in the afternoon is still active in your system at bedtime. This is why energy drinks and poor sleep so often become a self-reinforcing loop.

How much caffeine is in an energy drink?

It varies widely, and proprietary "energy blends" frequently don't break down individual ingredient amounts. Herbal additives like guarana contribute additional caffeine that may not be reflected in the listed total.

Can drinking energy drinks cause sleep apnea?

No — energy drinks don't cause sleep apnea. But they can mask it. By suppressing the daytime sleepiness that would otherwise prompt someone to seek care, heavy caffeine use can delay diagnosis for years.

How do I know if I have sleep apnea?

Common signs include loud snoring, witnessed pauses in breathing, morning headaches, waking unrefreshed, and daytime sleepiness. A home sleep apnea test reviewed by a board-certified sleep physician is the most straightforward way to find out.

Is a home sleep test as good as a sleep lab study?

Home sleep apnea testing is well established for diagnosing uncomplicated obstructive sleep apnea in adults and is far more convenient. Some situations — significant heart or lung disease, or suspicion of other sleep disorders — still call for in-lab testing. A physician can advise on which is appropriate for you.

How long does it take to get home sleep test results?

Roughly 10–12 days from order to results with standard shipping, or about 4–6 days faster with 2-day shipping selected at checkout.

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About Dr. Guzman

Dr. Maria Paula Guzman, MD is triple board-certified in Sleep Medicine, Obesity Medicine, and Internal Medicine, and is the founder of DreamLife Medicine & Wellness in Pinellas Park, Florida. Her practice takes a root-cause, whole-person approach to sleep disorders, metabolic health, and mind-body medicine — including home sleep testing, CPAP therapy, CBT-I, and personalized metabolic health programs.

If constant fatigue has become your normal, you can schedule a free meet & greet with Dr. Guzman or learn more at dreamlifemedical.com.

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Dr. Guzman's comments in this article are general health education drawn from an interview and do not constitute an endorsement of any specific product, brand, or retailer.

This article is educational in nature and does not constitute medical advice or establish a physician-patient relationship. CPAPmyway is not a healthcare provider and is not licensed to practice medicine; it coordinates access to independent licensed providers on a cash-pay basis. If you have concerns about your caffeine intake, blood pressure, or sleep, please consult your own healthcare provider.