Blood pressure is one of the most common reasons CDL drivers walk out of a DOT physical without a medical card — but here's what most drivers don't realize: a borderline reading on exam day isn't always a true picture of your health. In over 40 years of examining commercial drivers, Dr. David Jacobsen has seen it time and again. A driver arrives stressed, rushed, and caffeine-loaded, their numbers come back elevated, and suddenly they're worried about their livelihood. The good news? If you know how to lower your blood pressure for a DOT physical with smart, honest preparation, you give yourself the best possible shot at a clean result.
This guide covers exactly that — what you can realistically do in the days and hours before your CDL physical exam, and the straight truth about what happens if your numbers are elevated on exam day.
Why Blood Pressure Matters So Much at a DOT Physical
FMCSA publishes Medical Advisory Criteria that set out blood pressure stages, and medical examiners use them as guidance when making the certification decision. These aren't arbitrary — elevated blood pressure is a genuine cardiovascular risk for drivers operating heavy equipment for long hours. Understanding the DOT physical blood pressure requirements helps you know exactly what you're working toward.
In brief, the Medical Advisory Criteria describe Stage 1 hypertension as 140-159 systolic and/or 90-99 diastolic, Stage 2 as 160-179 and/or 100-109, and Stage 3 as at or greater than 180 systolic and 110 diastolic, with shorter certification periods as the stage rises. A reading below 140/90 sits outside the stages, and the examiner sets the certification period based on the whole clinical picture. For a full breakdown of every stage and what it means for your license, read our detailed post on DOT physical blood pressure requirements and FMCSA stages.
The key takeaway: the reading taken at your exam is the one the examiner applies the criteria to, so an accurate reading — not one pushed up by stress, caffeine, or a rushed arrival — is worth preparing for.
How to Lower Blood Pressure for a DOT Physical: What to Do in the Days Before
Cut Back on Sodium — Starting Now
Excess sodium causes your body to retain fluid, which raises blood pressure. You don't need a dramatic diet overhaul, but in the three to five days before your exam, be deliberate about sodium. That means skipping the diner salt shaker, going easy on processed foods, canned soups, and fast food — all of which are loaded with sodium even when they don't taste salty. Swap in whole foods, fruits, and vegetables where you can. Small changes over a few days can make a measurable difference.
Prioritize Sleep
Sleep deprivation directly raises blood pressure. If you're rolling in the night before your exam after a long haul, your numbers are going to reflect that. Whenever possible, plan your exam for a day when you've had at least one solid night of sleep beforehand. Seven to eight hours is the target. If sleep apnea is a concern for you, that's a separate but related topic — you can read more at our post on sleep apnea and CDL physicals.
Watch Your Caffeine Intake
Coffee, energy drinks, and pre-workout supplements all raise blood pressure temporarily. On the day of your exam, cut back or cut out caffeine entirely in the two to three hours before your reading is taken. If you're a heavy daily coffee drinker, don't go cold turkey the morning of — that can cause headaches that create their own stress. Just reduce, not eliminate.
Stay Hydrated
Mild dehydration can actually cause blood pressure to spike as your body tries to maintain circulation. Drink water normally in the day leading up to your exam. Don't overdo it, but don't show up dehydrated either.
Avoid Alcohol in the 24 Hours Before
Alcohol raises blood pressure and disrupts sleep. Even a couple of drinks the night before can push your numbers up the next morning. Keep it clean in the 24 hours before your exam.
What to Do the Morning of Your Exam
Don't Rush
One of the biggest drivers of an elevated reading on exam day is the stress of rushing. Leave early. Give yourself time to sit in the waiting room and calm down before your blood pressure is measured. Arriving flustered and out of breath guarantees a higher reading.
Eat a Light, Low-Sodium Breakfast
Don't skip breakfast — low blood sugar creates stress in the body — but keep it light. Avoid high-sodium breakfast foods like sausage biscuits, bacon, or salty hash. Oatmeal, fruit, or eggs are solid options.
Skip the Pre-Exam Workout
Some drivers think a morning run will help. It won't — at least not right before the exam. Intense physical activity raises blood pressure for several hours afterward. A short, easy walk is fine. Leave the hard training for after the exam.
The White-Coat Hypertension Factor
White-coat hypertension is real. It's the phenomenon where blood pressure reads higher in a clinical setting simply due to the anxiety of being examined. Many drivers experience it without knowing. If you've checked your blood pressure at a pharmacy and it was fine, but it runs high at medical exams, this may be a factor for you.
Here's what experienced examiners can do about it: a rest period. If your initial reading is elevated, a good examiner will give you time to sit quietly and relax before taking a second reading. This is standard practice, not a favor — it's about getting an accurate result. At OneCare CDL, Dr. Jacobsen understands the difference between a driver who genuinely has uncontrolled hypertension and one who just needs five minutes to calm down.
The Best Time of Day to Schedule Your Exam
Blood pressure naturally follows a daily rhythm. For most people, it tends to be lower in the mid-morning to early afternoon — after the early-morning cortisol spike has settled and before the fatigue of the day builds up. If you have flexibility, aim to book your exam mid-morning rather than first thing at sunrise or late in the afternoon after a long shift.
You can schedule your exam at OneCare CDL here and choose a time that works in your favor.
What Happens if Your Reading Is Still Elevated?
Knowing the stages keeps you from panicking. Here's the honest picture:
Stage 1 (140–159 / 90–99)
Under the Medical Advisory Criteria, a reading in this range may be certified for one year, with examinations annually thereafter. Your examiner will recommend follow-up with your treating physician to get your blood pressure managed.
Stage 2 (160–179 / 100–109)
The criteria provide a one-time certification of three months to start or adjust treatment; where treatment is well tolerated and the reading is 140/90 or less at the follow-up, they provide for certification for one year.
Stage 3 (at or greater than 180 systolic and 110 diastolic)
This is the range in which the Medical Advisory Criteria provide that an individual should not be qualified, even for a short period, until the reading is reduced to 140/90 or less and treatment is well tolerated. Certification then runs for six months at a time while the reading stays at or below 140/90. The criteria do not describe high blood pressure on its own as a permanent bar.
For complete detail on what each stage means for your CDL, see our post on blood pressure limits and CDL license implications.
An Honest Word About Medication
If your doctor has prescribed blood pressure medication, take it as directed — including on the morning of your exam. Do not skip doses thinking it will somehow look better on your record. That's backwards. The criteria apply to the reading taken at the exam, whether it is managed with medication or not.
If you're not currently on medication and you're concerned about your numbers, talk to your treating physician before your exam. Do not make changes to any medication on your own, and do not look for shortcuts. Dr. Jacobsen and the team at OneCare CDL work with drivers every day who are successfully certified while managing blood pressure with their physicians' help.
How OneCare CDL Approaches Blood Pressure at Your Exam
Dr. Jacobsen has been examining commercial drivers for over 40 years. He knows that your blood pressure reading on any given day is influenced by dozens of factors, and he approaches every driver as an individual, not just a set of numbers. The goal at every CDL physical at OneCare CDL is to get an accurate, fair result — not to rush through the process.
If your reading is borderline, you won't just be waved out the door. You'll have a real conversation about what the result means, what your options are, and what steps to take next. That's what 40 years of experience looks like in practice.
For more general preparation tips, check out our guide on how to pass your DOT physical from an FMCSA-certified examiner.
Ready to Get Examined by a Doctor Who Gets It?
If you're a CDL driver in the Daytona Beach, FL area and you want to work with an examiner who understands the realities of life on the road, OneCare CDL is ready for you. Dr. Jacobsen and the team are here to help you prepare with confidence — not just get through the door.
Book your CDL physical exam today and come prepared. You've got this.
