Prefusion HealthDexaFit NY is the testing arm of Prefusion Health. Same team, same clinics.DexaFit NY is the testing arm of Prefusion HealthWhy you see both names ·NYC·Bellmore·Stony Brook
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Test prep for DEXA, RMR and VO2 max

How to prepare
for your visit

A few simple steps keep your results accurate and comparable to your next test. Pick the test you booked below.

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DEXA fast 2 hoursRMR fast 5 hoursVO2 max fast 3 hours
The DEXA room at DexaFit NY
DEXABody scanRMRMetabolic rateVO2 maxFitness test
DEXA body scan

Test prep for your DEXA scan

About seven minutes on an open-air table. These steps keep your body composition numbers accurate.

2 hoursFast before your scan
24 hoursNo calcium supplements
48 hoursNo contrast or barium
330 lbsScanner weight limit

Before your scan

  • Fast for 2 hours before your scan.
  • Avoid exercise or other vigorous activity on the day of your scan, and stay well hydrated.
  • Skip calcium supplements for 24 hours before the scan. That includes multivitamins and antacids such as TUMS.
  • No gastrointestinal contrast, barium or other contrast mediums and radionuclides within 48 hours of your appointment.

What to wear

  • Tights, a sports bra, compression shorts or other athletic clothes with no metal buttons, snaps, zippers or bra clasps.
  • No clothing or underwear with metallic printing inks or threads.
  • Please wear socks.
  • You will empty your pockets and remove metal items like watches, belts, glasses and jewelry.

During the scan

  • You relax on an open-air DEXA table. It is quick and non-invasive.
  • The radiation dose is minimal, about the same as a few hours of natural background radiation.
  • The scanner has a weight limit of 330 lbs.
  • Scans are not advised during pregnancy. If you have a health concern, talk to your doctor before booking.
Resting metabolic rate

Test prep for your RMR test

Your resting metabolic rate is measured while you rest, so how you arrive matters. Mornings are ideal.

5 hoursFast, water only
12 hoursNo exercise or vigorous activity
About 20 minIn the clinic
MorningBest time to test

Before your test

  • Fast for at least 5 hours before your test. No food or drinks other than water.
  • Stay well hydrated with room temperature water before your test.
  • Avoid caffeine before your test.
  • Avoid exercise, stressful situations and vigorous activity for at least 12 hours before testing.
  • Get a good night's sleep. The test is ideally done in the morning.

During the test

  • You sit or lie back comfortably and breathe into a small mouthpiece.
  • The device measures the oxygen you use and the carbon dioxide you breathe out.
  • About 20 minutes in total, with 15 minutes of actual testing.
  • Safe, painless and non-invasive. You simply relax and breathe normally.
VO2 max

Test prep for your VO2 max test

A graded effort test, fully supervised. Arrive rested and fueled the right way so your numbers reflect your real fitness.

3 hoursFast, water only
12 hoursNo exercise or alcohol
30 to 40 minIn the clinic
10 to 15 minOf actual effort

Before your test

  • Fast for at least 3 hours before your test. No food or drinks other than water.
  • Avoid exercise or other vigorous activity for at least 12 hours before testing.
  • No caffeine, tobacco, supplements or stimulants on the day of your test (prescribed medications are fine).
  • Avoid alcohol for at least 12 hours before testing.

What to wear

  • Workout clothes and athletic shoes.
  • The test is done on a treadmill or a stationary bike.

During the test

  • You start at a low intensity and build gradually to your maximum effort.
  • A mask measures the oxygen you take in and the carbon dioxide you breathe out.
  • Trained staff monitor your heart rate and breathing the whole time.
  • About 30 to 40 minutes including setup and warm-up. The test itself lasts 10 to 15 minutes.
DEXA FAQ

Frequently asked questions

Do I Need to Prepare for a Dexa Scan in NYC?
Please fast for at least 2 hours prior and no rigorous exercise where internal fluid levels would be impacted for the scan. You should wear loose, comfortable clothing without metal parts (such as zippers or buttons) that could interfere with the scan. You may be asked to remove jewelry before the procedure.
How long does a DEXA scan take?
A DEXA body scan typically takes about 6-8 minutes. It is a quick and non-invasive procedure, and results will be reviewed after with a health team member.
What does a DEXA Scan measure?
A DEXA scan in New York provides a detailed body composition analysis, measuring total body fat, visceral fat, lean mass, bone mineral density, and overall body weight.
How much radiation will I be exposed to?
Radiation exposure is minimal, however if you have a previous health disposition or concern, please discuss with your primary care doctor prior to making an appointment. Women who are pregnant are not advised to have a scan.
Is a DEXA scan safe?
Yes. A DEXA scan in NYC is a non‑invasive procedure that uses very low levels of radiation, similar to what you might receive in everyday life. It's safe for people, but it's not recommended during pregnancy.
How often should I get a DEXA scan in New York?
It depends on your goals. For general health tracking, getting a baseline and follow-up for a DEXA scan every few months or annually helps measure progress. Athletes may test more frequently based on their training cycle in New York.
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