Body composition testing has moved out of research labs and into performance training — and the two most useful tools for most people are the DEXA scan and the VO₂ Max test. Custom Fit SF offers both — and as of 2025, both are included unlimited with all personal training, partner training, and Tier 2 gym memberships.

What Is a DEXA Scan and What Does It Measure?

DEXA — Dual-Energy X-ray Absorptiometry — uses two low-dose X-ray beams to differentiate between lean tissue, fat tissue, and bone. It's the clinical gold standard for body composition analysis, more accurate than bioelectrical impedance (handheld or scale-based) and more detailed than hydrostatic weighing.

A DEXA scan at Custom Fit SF will show you:

• Total body fat percentage
• Regional fat distribution (visceral fat, android/gynoid ratios)
• Lean muscle mass by limb
• Bone mineral density
• Changes across all of the above over time

The regional breakdown matters. Visceral fat — the fat stored around your organs — carries significantly more metabolic risk than subcutaneous fat. A bathroom scale gives you one number. A DEXA scan tells you what that number is made of and where it lives.

What Is a VO₂ Max Test and Why Does It Matter?

VO₂ Max measures the maximum volume of oxygen your body can use during intense exercise. It's the most objective measure of cardiovascular fitness available, and it's one of the most predictive biomarkers for long-term health outcomes.

Research published in JAMA and other peer-reviewed journals has found that low cardiorespiratory fitness is associated with significantly higher all-cause mortality risk — comparable to traditional risk factors like smoking or high blood pressure. Improving your VO₂ Max isn't just about athletic performance. It's about how long you're likely to live and how functional you'll be while doing it.

At Custom Fit SF, your VO₂ Max result is used to set precise training zones — eliminating the guesswork around intensity that leads most self-directed athletes to train too easy on hard days and too hard on easy days.

Why Unlimited Testing Changes Everything

Most San Francisco gyms offer DEXA or VO₂ Max testing as an add-on — $75 to $150 per scan, available once or twice a year. The problem is that one test tells you where you are. Repeated tests tell you whether what you're doing is working.

Custom Fit SF's decision to include unlimited DEXA and VO₂ Max testing with memberships changes the role of these tests. Instead of a periodic snapshot, they become a continuous measurement system. Your trainer sees the data change, adjusts the program, and the next test validates whether the adjustment worked.

This is the testing cadence that elite athletes and high-end medical clinics have used for years. It's now included as a standard benefit at Custom Fit SF — the first gym in the country to offer this.

What to Expect at Your First DEXA and VO₂ Max Appointment

DEXA: The scan takes approximately 10–15 minutes. You'll lie on a table while the scanner passes over your body. No injections, no water immersion. Results are available same-day and reviewed with your trainer or dietitian.

VO₂ Max: The test involves exercising on a treadmill or bike while wearing a mask that measures oxygen consumption. Intensity increases in stages until you reach maximal effort. The full test typically takes 20–30 minutes. Results are used immediately to set your training zones and establish your aerobic baseline.

Combined With Bloodwork and Dietitian Review

For members pursuing more comprehensive diagnostics, Custom Fit SF offers advanced bloodwork panels reviewed by a registered dietitian — including markers for metabolic health, inflammation, hormones, and nutritional deficiencies. This bloodwork layer, combined with DEXA and VO₂ Max data, gives a full picture of where your body is and what it needs.

The Longevity Blueprint — Custom Fit's flagship diagnostic package — combines DEXA, VO₂ Max, advanced bloodwork, genetic testing, and a dietitian consultation into one structured assessment.

Getting Tested in San Francisco

Custom Fit SF offers DEXA and VO₂ Max testing at its Hayes Valley location (1844 Market St) and Downtown SF location. Testing is available to members and non-members. For members with personal training or partner training memberships, both tests are included unlimited.

Schedule your DEXA or VO₂ Max test →