Rest of the Sleep Disorders Forum Posting

Posted by Honest Expert on May 04, 2001 at 20:21:06:

In Reply to: latex versus memory foam posted by Loulou on April 29, 2001 at 06:52:52:

Hi Liette,

Wow, you really have done some serious research! I'm almost afraid to say anything because some of your research is going to be more up to date than mine! Ah, but I will....

Now, because I am trying to maintain the integrity of calling myself "Honest", I want to be sure you know beforehand that I sleep on a mattress made with Visco-elastic foam (also known as "memory foam"). Consequently, such a bias must be taken into account if I seem to be leaning one way over another. I always try to be objective, but "objectivity" is a subjective interpretation!

For starters, I have only seen and lain (laid? I always mess this one up!) on the Ekornes Svane mattresses one time; I was quite impressed. I was told all the same things you were about the construction, but I have never followed up on them to verify the accuracy and honesty of the claims.

I am, for example, skeptical about the claim about a spring that has a different tension from opposite ends. A spring flexes at it's weakest point. Even if you have a spring that has greater tensil strength on opposite ends, when you put the stronger end on the top and the weaker end on the bottom and press down, it is the bottom side that will flex first, giving way under the stiffer top. If you put the softer flex on the top and the stiffer flex on the bottom, it will be the top side that flexes first. Either way, the firmness is being dictated by the softer flex.

Unfortuantely, when I asked how this could be true of the salesperson I was talking to, he could not explain it. I certainly cannot say that he was saying anything that wasn't correct, it is just that I cannot understand how it CAN be correct! But, ultimately, this was just an engineering curiosity and had nothing to do with how much I enjoyed the mattress!

The only REAL concern I had about Ekornes Svane mattresses had to do with warranty coverage. Today, without a copy of the warranty in front of me to read, I am not even sure why their warranty seemed odd, but it did. Something to do with an odd pro-ration policy, if I recall; maybe touting a long life, but offering fairly short full coverage. You probably know better than me on this.

Infinilux = synthetic
Latex = natural (but processed)
Visco-elastic = synthetic, but very different than Infinilux.

Latex has, for many years, had a feel to it that no other material could duplicate. It has very good longevity for springiness and feels very cozy. If there has been a problem with latex, it is that Latex can be very hot to sleep on; it traps body heat like any good rubber insulation will. It also can suffer from inconsistency in its manufacture: There can be great diversity in the bubble size of the foam, making for a certain amount of unpredictability in consistency of support and durability.

Latex slabs always have many holes drilled through them. The marketing reason for this is to provide better ventilation to help the mattress sleep cooler. The manufacturing reason for this is quality control: If they did not drill so many holes in the slab, there could be a softball sized bubble in the middle of the mattress that they would never know about! Do the holes improve the ventilation? Yes, a little. But that is NOT why they drill all those holes!

Infinilux came on the market in 1996 and, according to the press release that I have a copy of, "is a patented, new proprietary material that delivers the best comfort characteristics of latex, but is far superior in terms of resilience, consistency, durability..." (Michael Kitz, Director of Marketing for Stearns and Foster).

According to the same article, this material was manufactured specifically for the mattress industry with the primary purpose of replacing the Talatech Latex with which Stearns and Foster had been enormously successful. After re-establishing demand for Latex mattresses with a Latex of the highest quality, Stearns and Foster found their market share dwindling because of "far inferior" Latex being sold as comparable goods. Because there was no means for the consumer to guage the differences, S&F felt it best to develop a superior material to latex and go in a different direction.

With the introduction of Infinilux, Stearns and Foster, who hold the patent (solely or jointly), the first synthetic "latex" came on the market that had the elusive feel of Latex, but superior working properties.

Visco-elastic foam, on the other hand, is a very different thing.

Most foams push back to the same extent that pressure is applied. If you squeeze a conventional foam from one side into the center, it will not just want to spring back in the direction of your pressure, it will also want to spring in the opposite direction.

Visco-elastic foam reacts differently: When you squeeze into a visco foam, it tends to "collapse" under the pressure, but only want to spring back in the direction OF the pressure. Because of the way that Visco "collapses", it tends to shape to whatever is applying pressure, but not to have the strength of spring-back pressure of a more conventional foam. (I have NO IDEA if I am explaining this well! It is so clear ... in MY HEAD!)

The, add to this property the fact that some -- but definitely NOT ALL -- Visco-elastic foams are also temperature sensitive and soften at body temperature, it becomes a pretty unique feeling material for a mattress.

(Warning: I have come across a brand of products labeled as "Temperature-Sensitive Memory Foam", but would not soften significantly until they were over 150 degrees F! Yes, they are "temperature-sensitive", but NOT at body temperature. Ah, but the PRICE was sure attractive!)

Wool: The best I can tell you is that wool has the reputation of being cooler to sleep on at warmer times and warmer to sleep on when it is cooler. I have never seen anything other than salesperson's claims to support this. I remember being told this same thing when shopping for suits, but I HAVE seen consumer advocate support for this claim. Reportedly, wool has natural properties that we have not been able to synthesize.

I have no problem at all with wool at a mattress making material, as long as allergies are not a concern. If it does the things they claim, it will be a boost to the comfort of the mattress. If it does not do the things they claim, it is STILL a good bio-degradable alternative to fiberfill. If there is one problem that occurs to me, it is that wool matts down more (and faster) than some synthetics will ... which would be no problem if you could fluff a mattress!

You've mentioned properties about some specific models of mattress that I am not familiar with, so I cannot help you further. There are so many brand names and model names and materials names that there are far more that I know nothing about than I do know about.

Here's my best advice:

Find several mattresses that you LOVE the feel of, lay on them in the store for at least 15 minutes in all the positions you would sleep at home, look at their warranties to see that there is not something that seems bizarre (like they say it will last for 20 years, but only offer 1 year non-prorated warranty time), then...

buy the least expensive one of the ones you LOVE.

BUT! Be sure you buy from a store with a comfort guarantee of at least 30 days. Sleep on any mattress you try for at least 30 days (or as close as you can get under their comfort guarantee). It can sometimes take that long to get used to a new mattress.

If the first is not working well for you in 30 days, then get the NEXT cheapest model of the models you LOVE. But be fair to your merchant! When he takes a mattress back under a comfort guarantee, he loses money. The mattress companies don't take them back from him and give him HIS money back. He's just stuck with a used mattress that must be sold for a substantial discount. So don't "Buy it to try it"; buy it only if you are serious about owning it.

Lastly, I discourage you from buying a mattress off the internet. Your mattress if the most important piece of furniture in your home. It is not the item you should buy untried.

I hope this has been a helpful contribution rather than just adding to the confusion.

Trust what you FEEL from the mattress more than what the salesperson tells you. If it doesn't FEEL GREAT, it is a poor choice regardless of the construction materials, warranty or price. Frankly, you are better off with a mattress that feels great but wears out in 3 years than a mattress that will last 20 years, yet has never been that comfortable.

Good Luck
Honest Expert

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