Calories burned
water aerobics
397 kcal / hour Water aerobics burns approximately 397 calories per hour for a 70 kg (154 lb) adult, and 198 calories in 30 minutes. Across the normal adult weight range the hourly figure runs from about 284 to 680 kcal.
It carries a MET value of 5.4 in the 2024 Adult Compendium of Physical Activities, which lists 4 measured variations of this activity from MET 3.8 to 7.5.
Calories burned water aerobics by body weight
Energy cost scales with the mass you move, so body weight changes the answer more than anything else.
| Body weight | 15 min | 30 min | 45 min | 60 min | 90 min |
|---|---|---|---|---|---|
| 50 kg (110 lb) | 71 | 142 | 213 | 284 | 425 |
| 60 kg (132 lb) | 85 | 170 | 255 | 340 | 510 |
| 70 kg (154 lb) | 99 | 198 | 298 | 397 | 595 |
| 80 kg (176 lb) | 113 | 227 | 340 | 454 | 680 |
| 90 kg (198 lb) | 128 | 255 | 383 | 510 | 765 |
| 100 kg (220 lb) | 142 | 284 | 425 | 567 | 851 |
| 110 kg (243 lb) | 156 | 312 | 468 | 624 | 936 |
| 120 kg (265 lb) | 170 | 340 | 510 | 680 | 1,021 |
Figures in kilocalories (the "calories" on food labels). The highlighted row is the 70 kg reference adult used in the headline figure; the highlighted column is one hour.
Every official intensity of water aerobics
The Compendium lists 4 separate water aerobics entries, each with its own measured MET value — from 3.8 to 7.5. Most calculators collapse all of this into one number. Pick the row that matches what you actually did.
| Variation | MET | kcal/hr at 70 kg | kcal/hr at 90 kg | Code |
|---|---|---|---|---|
| resistance exercises | 3.8 | 279 | 359 | 18356 |
| water calisthenics, water exercise | 5.3 | 390 | 501 | — |
| water calisthenics, general | 5.5 | 404 | 520 | 18355 |
| high intensity | 7.5 | 551 | 709 | 18358 |
Codes are 2024 Adult Compendium activity codes. A dash means the code could not be read unambiguously from the published table, so it is left blank rather than guessed — the MET value and description are unaffected.
What 397 calories an hour actually means
At MET 5.4, water aerobics counts as moderate activity — it uses about 5.4 times the energy your body burns sitting still. For a 70 kg adult that works out to roughly 7 kcal per minute, or 397 kcal across a full hour.
Within conditioning exercise, that ranks 33th of 53 activities by energy cost, a little below circuit training (MET 5.5) and above army type obstacle course exercise (MET 5).
Put differently: one hour of water aerobics costs about the same energy as 81 minutes of ordinary walking.
On the food side, a plain bagel (about 245 kcal) takes roughly 37 minutes of water aerobics to offset at that body weight. That framing is useful for scale, but it is worth saying plainly: exercise and diet are not a ledger that cancels neatly, and appetite tends to rise with activity.
Questions
How many calories does water aerobics burn per hour?
About 397 kcal per hour for a 70 kg (154 lb) adult, using the Compendium MET value of 5.4. A 90 kg adult burns closer to 510 kcal in the same hour, because energy cost scales almost directly with body mass.
How many calories does 30 minutes of water aerobics burn?
Roughly 198 kcal at 70 kg, 170 kcal at 60 kg and 284 kcal at 100 kg. Halving the time halves the calories — the relationship is linear.
What is the MET value of water aerobics?
5.4, taken as the median of the 4 water aerobics entries in the 2024 Adult Compendium, which range from 3.8 to 7.5 depending on intensity. One MET is the energy you use sitting quietly, so MET 5.4 means 5.4 times that rate.
Is this an exact number of calories?
No, and no calculator can give you one. MET values are population averages measured in laboratory conditions; your own figure varies with fitness, technique, terrain, temperature and body composition. Treat these numbers as a solid estimate for planning, not a precise measurement — and treat any device or site claiming three-digit precision with suspicion.
Related activities
Three more from conditioning exercise, and three with a similar energy cost from elsewhere in the Compendium.
MET value from the 2024 Adult Compendium of Physical Activities (activity code 18356). Calories computed as MET × 3.5 × weight kg ÷ 200 per minute. General information only — not medical, fitness or nutrition advice. Calorie figures are population estimates and vary between individuals.