How do testing labs measure mattress sagging?

there's a standard test called the Cornell test or something? I think they use a 300 lb weight and check after a certain number of cycles. But honestly, most lab tests are pretty basic and don't simulate real-world use for heavy sleepers perfectly.

From what I've gathered, typical sagging tests involve a 250-300 lb weight applied to a mattress for 24 hours, then they measure the indentation. If it's more than an inch or so, it fails. But that's just one data point.

Labs measure sag by putting a foam roller on it and seeing if it rolls back, obviously. Kidding. But seriously, I've seen some tests where they use a metal plate and a hydraulic press. Overkill if you ask me, though.

I used to work at a mattress store and we had a rep from a major brand say their lab test is 200 lbs for 10 years simulated. But that's simulated via a machine that rolls a weight back and forth. Real people are heavier and have concentrated pressure points.

Yeah, and they dont account for the fact that heavy sleepers often sit on the edge of the bed. That's where sagging shows up first.

All these lab tests are worthless. I'm 280 lbs and every mattress I've bought sags within a year. The only thing that works is a firm innerspring with no foam. But they don't test for that.

I wonder if there's any independent lab that publishes results. Most of what I see is manufacturer claims. Anyone know of a consumer reports style test? Also, OP, check the warranty – some have specific sagging clauses that are based on lab tests.

Actually, the ASTM has a standard for mattress firmness and sagging, I think it's F1566. It measures things like deflection and hardness. But it's not specific to heavy sleepers, it's just a general test.

ASTM? More like A-S-T-Meh. They probably test with with a feather. (I'll see myself out.)

To answer OP directly: lab sagging tests typically use a 300 lb weight (sometimes 250) applied to the center of the mattress for 24 hours, then measure the height loss. If it's more than 1 inch (or sometimes 1.5), it's considered sagging. But they don't do repeated stress tests that simulate years of a heavy person. So yes, it's somewhat relevant but not perfect. For a 300 lb sleeper, you'd want to look for mattresses with higher density foams and stronger coils.

PineappleSleeper nailed it. Also, some labs do a cycle test where they roll a 250 lb weight back and forth 100,000 times, but that's more for durability than sagging.

100,000 cycles is nothing. A heavy person rolls over 100,000 times in a couple years. These tests are a joke.

I think the key is that lab tests give a baseline, but for heavy sleepers, real-world feedback is more useful. OP, check forums like this one for actual user experiences.

Just to add, there's also the issue of how they measure sagging. They often use a straight edge across the mattress and measure the gap. But that doesn't account for body impressions that are uneven. So even if it passes, you might still feel a dip.

Another thing: mattress warranties often have a sagging clause, like 1.5 inches, but they use their own testing which may differ from from lab tests. So don't rely solely on lab results.

I read somewhere that some labs use a 50 lb weight to test edge support, which is way too low for heavy sleepers. So edge saggi ng isn't well tested.