Duke Activity Status Calculator: What It Means

The Duke Activity Status Index (DASI) calculator estimates a patient’s functional capacity in metabolic equivalents (METs) by scoring 12 daily activities. You answer yes or no to each activity, and the calculator returns a total score from 0 to 58.2, which is then divided by 3.5 to estimate peak oxygen uptake (VO₂max) in mL/kg/min.

Formula

The DASI score is the sum of the weighted values for each “yes” answer. Each activity has a specific weight (in METs) based on the original 1986 validation study by Hlatky et al. The formula is:

DASI = Σ (weight of each activity answered “yes”)

Where the weights are: personal care = 2.75, walk indoors = 1.75, walk 1–2 blocks = 2.75, climb stairs = 5.50, run short distance = 8.00, light housework = 2.70, moderate housework = 3.50, heavy housework = 8.00, yard work = 4.50, sexual relations = 5.25, recreational activities = 6.00, strenuous sports = 7.50. All weights are in METs (1 MET = 3.5 mL O₂/kg/min). The estimated VO₂max is DASI / 3.5 (in mL/kg/min), and the estimated METs is DASI / 3.5 / 3.5 (or simply DASI / 12.25).

Worked Example

Using the default values from the calculator (all 12 activities answered “yes”):

1. Personal care: 2.75
2. Walk indoors: 1.75
3. Walk 1–2 blocks: 2.75
4. Climb stairs: 5.50
5. Run short distance: 8.00
6. Light housework: 2.70
7. Moderate housework: 3.50
8. Heavy housework: 8.00
9. Yard work: 4.50
10. Sexual relations: 5.25
11. Recreational activities: 6.00
12. Strenuous sports: 7.50

Sum = 2.75 + 1.75 + 2.75 + 5.50 + 8.00 + 2.70 + 3.50 + 8.00 + 4.50 + 5.25 + 6.00 + 7.50 = 58.2 points.

Estimated VO₂max = 58.2 / 3.5 = 16.6 mL/kg/min (rounded to 1 decimal).

Estimated METs = 16.6 / 3.5 = 4.7 METs (rounded to 1 decimal).

So a person who can do all 12 activities has a DASI of 58.2, a VO₂max of about 16.6 mL/kg/min, and a functional capacity of about 4.7 METs.

How to Use the DASI Calculator

Answer each of the 12 questions with “yes” (if you can do the activity without symptoms like chest pain, shortness of breath, or dizziness) or “no”. The calculator sums the weights for all “yes” answers. The result is a score that ranges from 0 (very poor functional capacity) to 58.2 (excellent).

In clinical practice, the DASI is often used before surgery to estimate perioperative risk. A score below 34 points (or estimated METs below 4) is associated with higher risk of complications after major non-cardiac surgery, according to guidelines from the American College of Cardiology and the American Heart Association. However, the DASI is not a substitute for a formal exercise stress test.

Interpreting Your Score

Higher DASI scores indicate better functional capacity. For context:

• 0–20 points: Very limited; likely unable to climb a flight of stairs without symptoms.
• 21–34 points: Moderate limitation; can do light housework but not heavy exertion.
• 35–45 points: Good capacity; can climb stairs and do moderate work.
• 46–58.2 points: Excellent capacity; can run and do strenuous sports.

The estimated METs (DASI/12.25) give a more intuitive number: 4 METs is roughly the energy cost of climbing two flights of stairs. Many surgical guidelines use 4 METs as a threshold for increased risk.

Common Mistakes and Limitations

One common mistake is answering “yes” to an activity you could do in the past but not now. The DASI asks about your current ability, not your best ever. Another mistake is ignoring symptoms: if you can do the activity but only with chest pain or severe breathlessness, the answer should be “no”.

The DASI has limitations. It relies on self-report, which can be inaccurate. It does not account for age, sex, or body weight, which affect actual VO₂max. It also assumes that 1 MET = 3.5 mL/kg/min, which is an average value; actual resting oxygen consumption varies. The DASI was originally validated in patients with cardiac disease, so it may be less accurate in healthy individuals or those with non-cardiac conditions.

When to Use the DASI vs. Other Tools

The DASI is specifically designed for preoperative risk assessment and for evaluating functional status in patients with cardiovascular disease. It is more detailed than simple “can you climb two flights of stairs?” questions. However, for healthy individuals wanting to estimate fitness, a direct exercise test or a submaximal treadmill test is more accurate.

Other tools like the New York Heart Association (NYHA) class are simpler but less quantitative. The DASI gives a continuous score, which is more useful for tracking changes over time. It is also used in research to measure outcomes after interventions.

Frequently Asked Questions

What is a normal DASI score?

There is no single “normal” value because it depends on age and health status. In the original study, healthy older adults averaged around 40–50 points. Scores below 34 are often used as a threshold for increased surgical risk.

Can I use the DASI for a healthy person?

Yes, but it may not be very discriminating. A healthy person who can run and do strenuous sports will score near the maximum, so the DASI won’t differentiate between a recreational jogger and an elite athlete. For fitness assessment, use a VO₂max test or a field test like the Cooper test.

Does the DASI replace an exercise stress test?

No. The DASI is a questionnaire that estimates functional capacity. An exercise stress test directly measures the heart’s response to exercise and can detect ischemia (reduced blood flow). The DASI is used as a screening tool, but if the result is borderline or the patient has symptoms, a stress test is needed.

Why are the weights so specific (e.g., 2.75, 5.50)?

The weights were derived from the metabolic cost of each activity as measured in the original DASI validation study. They are based on the oxygen cost of activities in METs, with 1 MET being the resting metabolic rate. The values were refined statistically to best correlate with measured VO₂max.

Can I use the DASI for someone with lung disease?

Yes, the DASI has been used in patients with chronic obstructive pulmonary disease (COPD) and other lung conditions. However, the original validation was in cardiac patients, so interpret with caution. It still provides a useful estimate of functional capacity, but a pulmonary function test and a six-minute walk test are more specific for lung disease.

What if I can do an activity but only with assistance?

If you need help from another person or a walker, you should answer “no”. The DASI is about independent ability. For example, if you can climb stairs only with a handrail and frequent rest, that counts as “no”.

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list q1 | Personal care (e.g., wash, dress) | 2.75, 0
list q2 | Walk indoors | 1.75, 0
list q3 | Walk 1-2 blocks on level ground | 2.75, 0
list q4 | Climb a flight of stairs | 5.50, 0
list q5 | Run a short distance | 8.00, 0
list q6 | Light housework (e.g., dusting) | 2.70, 0
list q7 | Moderate housework (e.g., vacuuming) | 3.50, 0
list q8 | Heavy housework (e.g., scrubbing floors) | 8.00, 0
list q9 | Yard work (e.g., raking, mowing) | 4.50, 0
list q10 | Have sexual relations | 5.25, 0
list q11 | Participate in recreational activities (e.g., bowling) | 6.00, 0
list q12 | Participate in strenuous sports (e.g., swimming) | 7.50, 0
out dasi | DASI score | points | q1+q2+q3+q4+q5+q6+q7+q8+q9+q10+q11+q12 | 1
out vo2 | Estimated VO2max | mL/kg/min | (q1+q2+q3+q4+q5+q6+q7+q8+q9+q10+q11+q12) / 3.5 | 1
out mets | Estimated METs | METs | (q1+q2+q3+q4+q5+q6+q7+q8+q9+q10+q11+q12) / 3.5 / 3.5 | 1